question

How may vertebrae are there?

answer

33

question

What are the high points of the spinal canal?

answer

C3 & L3

question

What are the low points of the spinal canal?

answer

T6 & S2

question

Where does the SC extend from?

answer

The foramen magnum to lumbar level 1 in adults & 3 in the newborn

question

The SC terminates at the _____ _____ & the _____ ____ extends down & anchors in the lower sacral region.

answer

conus medullaris filum terminale

question

There are ____ pairs of spinal nerves.

answer

31

question

What is the nerve group in the lower dural sac?

answer

The cauda equina (horses tail)

question

What ligament runs from the sacrum to C7?

answer

The supraspinous ligament

question

What ligament runs the full length of the spinal column?

answer

The interspinous ligament

question

Which ligament occurs in short segment between spinous processes?

answer

The ligamentum flavum

question

The _____ _____ is the space that surrounds the spinal meninges.

answer

epidural space

question

The epidural space extends from the ____ ____ to the _____ _____.

answer

foramen magnum to the sacral hiatus

question

Which ligament binds the epidural space posteriorly?

answer

The ligamentum flavum

question

At what level is the epidural space the widest?

answer

L2

question

At what level is the epidural space the narrowest?

answer

C5

question

Where does the dura mater extend from?

answer

The foramen magnum to S2-3 vertebrae

question

Where does the arachnoid end?

answer

S2

question

What space lies between the arachnoid & pia mater?

answer

The subarachnoid space

question

The epidural space is a potential space that is bound by the ____ & _____ ____.

answer

dura ligamentum flavum

question

Where is the blood supply to the SC & nerve roots derived from?

answer

A single anterior spinal artery & paired posterior spinal arteries

question

Where is the principle site of action for neuraxial blockade?

answer

The nerve root

question

Most important factors in determining distribution of LAs for spinal anesthesia

answer

Density Dosage & volume injected Position of the patient during & immediately after injection..other factors are height, spine, needle angle, site of injection, dose, vol, baracity density, sg

question

Uptake of LA is greatest where the concentration of the LA is the ______.

answer

greatest

question

What determines the level of a block?

answer

Position

question

How do all subarachnoid blocks work?

answer

By diffusion down a concentration gradient

question

What does the rate of elimination determine?

answer

The duration of spinal anesthesia

question

How are LAs eliminated?

answer

By vascular absorption via subarachnoid & epidural blood vessels

question

The more the LA is bound to lipids, the less chance there is for ____ ____.

answer

vascular absorption

question

What will decrease the rate of elimination of LAs?

answer

Decreases in SC blood flow Vasoconstriction

question

What is the predominant action of sympathetic blockade due to?

answer

Venodilation

question

What does venodilation result in?

answer

Reduced venous return, SV, CO, & BP

question

What can occur is sympathetic outflow from T1-T4 is blocked by a LA?

answer

Unopposed vagal stimulation will produce bradycardia (Bainbridge reflex)

question

What is bradycardia associated w/?

answer

Blockade of the cardioaccelerator fibers & decreased venous return

question

What occurs w/ the decrease in venous return & corresponding reduction in right atrial filling?

answer

The frequency of action potentials from stretch receptors to the RA & great veins is diminished -> a reflex decrease in HR

question

What is the best means for treating hypotension during spinal analgesia?

answer

Give IV fluids if not normovolemic Give ephedrine if normovolemic

question

Why should glucose solutions be avoided in the treatment of hypovolemia?

answer

Glucose acts as a diuretic & can worsen the situation (hypotension)

question

What is the best drug of choice for symptomatic bradycardia & why?

answer

A mixed alpha & beta agonist (ephedrine) It increases the HR & peripheral vascular resistance

question

What occurs w/ a high block (C2-C3)?

answer

Phrenic nerve paralysis & loss of accessory muscle of ventilation -> hypoxia

question

What ventilatory changes occur w/ a high spinal?

answer

Decreased FRC d/t paralysis of abdominal muscles Apnea (d/t hypoperfusion of the respiratory centers in the medulla 2˚ to severe hypotension)

question

At what level of blockade do patients start to feel dyspneic?

answer

T2-T4

question

What is the advantage of spinal over epidural anesthesia?

answer

The ability to control the spread of the anesthetic by controlling the specific gravity of the solution & the position of the patient.

question

How can trauma to the dura be minimized in the sitting position?

answer

Using a pencil point needle (separates the dura) If using a cut-bevel, needle will need to face either left/right to separate (rather than tear) the dura

question

How can trauma to the dura be minimized in the lateral position?

answer

Using a pencil point needle (separates the dura) If using a cut-bevel needle, the needle must face up or down

question

How long should ticlodipine (ticlid) be stopped prior to neuraxial anesthesia?

answer

14 days

question

How long should clopidogrel (Plavix) be stopped prior to neuraxial anesthesia?

answer

7 days

question

How long should LMWH (enoxaparin [lovenox]) be delayed postop to decrease the risk of a spinal hematoma?

answer

24 hrs

question

If postop LMWH will be used, epidural catheters should be removed _____ ____ prior to the 1st dose.

answer

2 hrs.

question

T7 dermatome

answer

Inferior border of scapula (lower tip)

question

L4 dermatome

answer

Iliac crest (superior)

question

L1 dermatome

answer

Inguinal ligament

question

Absolute contraindications to spinal anesthesia

answer

Infection at injection site Shock/severe hypovolemia Increased ICP Gross abnormality of blood clotting mechanism Patient refusal Severe AS/MS

question

Relative contraindications to spinal anesthesia

answer

Major surgical procedure above umbilicus Deformity of the spinal column Chronic HA/backache Sepsis Mobitz I or II 3˚ heart block w/o pacer

question

Describe the spread of LAs

answer

Spreads to the nerves of the cauda equina & laterally to the nerve rootlets & nerve roots Can also diffuse into the SC

question

List the structures penetrated by the needle for a subarachnoid block (midline)

answer

Skin SC tissue Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural space Dura mater Arachnoid mater

question

What structures are bypassed with a lateral approach to a subarachnoid block?

answer

The supraspinous & interspinous ligaments

question

What symptoms should be identified as signs of central hypoxia until proven otherwise?

answer

N/V

question

What is the most common complication of neuraxial anesthesia?

answer

Backache

question

What is the 2nd most common complication of neuraxial anesthesia?

answer

Postdural puncture HA (PDPH) - except in OB (#1)

question

Describe the PDPH

answer

Bifrontal & occipital (involves head, neck & shoulders) Aggravated by upright position, coughing, or straining

question

S/S of PDPH

answer

Nausea, loss of appetite, photophobia, ∆s in auditory acuity, tinnitus, depression, bed-ridden

question

What causes a PDPH?

answer

A decrease in the amount of CSF in the subarachnoid space causing the medulla & brainstem to drop into the foramen magnum.

question

What is an additional complication to a decrease in CSF caused by PDPH?

answer

Cranial nerve palsy->decreased blood supply to the nerves

question

How is a PDPH treated?

answer

With a blood patch: 10-30 cc injected into the epidural space until patient can feel pressure in their back

question

Elbow

answer

Extend: Radial Flex: Musculocutaneous

question

Forearm

answer

Supinate: Radial Pronate: Medial

question

Wrist

answer

Extend: Radial Flex: Medial and ulnar

question

Fingers

answer

Extend: Radial Adduct: Ulnar Abduct: Medial Flex lateral 3: medial Flex and oppose to thumb: ulnar

question

What are the preganglionic and postganglionic neurotransmitters for the somatic nervous system, the PNS, and SNS?

answer

Somatic: preganglionic-Ach PNS: preganglionic & postganglionic-Ach SNS: preganglionic-Ach, postganglionic-NE

question

In regards to the SNS, where do preganglionic B fibers originate?

answer

In the intermediolateral cell column segments T1-L2 or L3

question

In regards to the SNS, where do preganglionic B fibers exit the spinal cord?

answer

With the ventral ramus.

question

In regards to the SNS, once the preganglionic B fibers exit the spinal cord with the ventral ramus they synapse. Where do they synapse?

answer

Synapse in the lateral chain ganglia along the ventrolateral surface of the vertebral bodies or pass thru to synapse in other (collateral) sympathetic ganglia.

question

What type of neuron leave the ganglia and travel to segmental nerves & target organs?

answer

Postgagnlionic neurons (unmyelinated C fibers).

question

Describe the lateral chain ganglia?

answer

Paravertebral ganglia T1-L2 on the anterolateral surface of the vertebral bodies.

question

What are the collateral ganglia?

answer

Cardiac, celiac, superior % inferior mesenteric ganglia.

question

What do the collateral ganglia accommodate?

answer

Preganglionic fibers which do not synapse in lateral chain, but continue in visceral ramus->splanchnic nerves which end in collateral ganglia.

question

What are the superior cervical ganglion?

answer

C1-C4

question

What are the middle cervical ganglion?

answer

C5-C6

question

What are the inferior cervical ganglion?

answer

C7 & C8

question

What are the target organs of the superior cervical ganglions (C1-C4)?

answer

Iris & ciliary body Lacrimal & salivary glands Parotid gland Heart

question

What are the target organs of the middle cervical ganglions (C5-C6) & the stellate ganglions?

answer

Heart All preganglionic fibers arise below the stellate, blockade at this level affects all sympathetics above this level.

question

Describe the lumbo-sacral lateral chain

answer

Receives all presynaptic input enters from L1 & L2. These ganglia are not fused but the coccygeal ganglia meet at the midline

question

What forms the stellate ganglion?

answer

Inferior cervical ganglion fuses w/ T1.

question

What are the target organs for the celiac ganglion?

answer

Stomach, small bowel, adrenal medulla

question

Where does the cardiac plexus receive its sympathetic input from?

answer

T1-T4

question

What are the target organs of the superior mesenteric ganglion?

answer

Large & small bowel

question

What are the target organs of the inferior mesenteric ganglion?

answer

Lower colon & rectum

question

What are the target organs of the hypogastric ganglion?

answer

Urogenital organs

question

What ganglions are supplied by the greater, lesser, & least splanchnic nerves?

answer

Greater & lesser: celiac plexus Least: inferior mesenteric & hypogastric ganglia

question

Blocking what ganglion will knock out all the sympathetics, why, and what can it result in?

answer

Stellate ganglion. All preganglionic fibers arise below the stellate ganglion. Could result in Horner's syndrome

question

Blocking what plexus is indicated in treatment of intraabdominal malignancies & chronic pancreatitis; diagnostic (local or therapeutic (neurolytic block)?

answer

Celiac plexus

question

Blocking what ganglion is indicated in painful conditions of the lower extremities and pelvic viscera and vascular insufficiency in the legs?

answer

Lumbar sympathetic ganglion.

question

Blocking what plexus and ganglion is indicated in tx of painful conditions of the pelvis and perineum?

answer

Superior hypogastric plexus & ganglion impar

question

Describe the cervical lateral chain.

answer

Located in the neck. All presynaptic input enters from T1 w/ minor contributions from T2 & T3. Cervical lateral chain ganglia are fused.

question

Where do all sympathetics to the head & neck come from?

answer

T1 or below

question

Where is the cervical sympathetic chain located?

answer

Lies on the anterolateral surface of the vertebral bodies.

question

Where does the cervical sympathetic chain receive its input from?

answer

T1 or below

question

Blocking what ganglion is indicated in treatment & diagnosis of pain syndromes, vascular insufficiency, hyperhidrosis, and dysrhythmias?

answer

Stellate

question

What are the S/S of Horner's syndrome?

answer

Ptosis (drooping of eyelid), flushing, miosis (pupillary constriction), anhidrosis (lack of sweating).

question

Describe the cardiac plexus

answer

Superficial & deep divisions. Both organized around the aortic arch.

question

Where do the celiac ganglion (collateral ganglion) receive its input?

answer

From the greater & lesser splanchnic nerves.

question

What does sympathetically mediated pain involve (CRPS)?

answer

An initiating event-crush, stretch, axotomy, ischemia, etc... to a peripheral nerve.

question

What does CRPS stand for?

answer

Complex regional pain syndrome.

question

What occurs with sympathetically mediated pain?

answer

There is a sensitization of peripheral (C-fibers) & central (dorsal horn laminae 1& 2).

question

What does the sensitization of peripheral (C-fibers) & central (dorsal horn laminae 1& 2) involve?

answer

↑ spontaneous neuronal activity d/t ectopic pacemakers (probably dysfunctional Na channels) ↑ response to stimuli ↓ stimulus threshold (less stimulation required to cause nerves to fire).

question

What does C fiber sensitization lead to?

answer

↑ adrenergic receptors ↑ sensitivity to stimuli (↑ action potential per stimulus) ↑ "cross talk"

question

What is "cross talk"?

answer

Phenomenon where neurons carrying normal sensory info cross over & are interpreted as high intensity pain & accounts for allodynia

question

Describe the dorsal horn changes that occur w/ sympathetically mediated pain.

answer

A-beta fibers form abnormal connections in shallow laminae (1 & 2)->normal sensory input interpreted as high intensity noxious stimuli. ↑ gene expression for receptors for pain related neurotransmitters (substance P). ↓ opioid binding sites.

question

Describe the wind-up theory.

answer

Involves repetitive noxious stimuli (c-fibers)->prolonged discharge of dorsal horn cells-> progressive ↑ in APs per stimulus->long term potentiation (LTP).

question

What occurs with LTP?

answer

↑ in receptive field of nociceptive neurons d/t formation of more dendrite connections in the dorsal horn. Dropout of inhibitory neurons.

question

What are NMDA receptors important for?

answer

In triggering wide dynamic range (WDR) neurons that are responsible for generalization of specific nociceptive info.

question

What are the NMDA agonists and what releases them?

answer

Aspartate, glutamate, etc-released by c-fiber stimulation.

question

What are the NMDA antagonists, what are they useful for?

answer

Ketamine, dextromethorphan, methadone, PCP Useful in chronic pain syndrome

question

In regards to the lumbo-sacral lateral chain, where do most sympathetic fibers to the lower ext pass thru, and what would blockade at this level cause?

answer

Pass thru L2/L3. Causes near complete sympathectomy of the lower ext.

question

In regards to the cardiac plexus, where does sympathetic input arise from?

answer

Cervical ganglia.

question

In regards to the cardiac plexus, where does parasympathetic input arise from?

answer

Vagus & recurrent laryngeal nerves.

question

Describe "cross talk".

answer

Abnormal connections by demyelinated (loss of myelin d/t some sort of neurologic phenomenon) neurons called ephapses.

question

How does the body send signals over long distances?

answer

Chemical messengers, electrical or a combination of the two. Peripheral nerves are constructed for electrical transmission that leads to a chemical messenger activation.

question

Describe the cell body (soma).

answer

Contains the nucleus, located mainly in the CNS.

question

Where are the cell bodies of sensory neurons located?

answer

In the dorsal root ganglia (DRG).

question

Where are the cell bodies of motor neurons located

answer

In the ventral horn.

question

What are dendrites, where are they located, and what are their functions?

answer

Multiple branches close to cell body allow local cell to cell communication.

question

Where is the axon located and what are their functions?

answer

Extends from the cell body, impulse transmission over long distance, defines receptive field.

question

Describe Schwann cells

answer

Envelopes every axon, produces myelin. May produce myelin sheaths around larger axons (>1 micron)

question

Describe the myelin sheath

answer

Supporting cells wrap layers of their own PM around the axon forming an insulating layer. Each supporting cell surrounds about 1 mm of axon-many cells required to cover whole axon.

question

How does myelination affect capacitance?

answer

Decreases capacitance (decreases the loss of electrical signal).

question

Describe the nodes of Ranvier

answer

Interruptions in the myelin sheath.

question

What are the functions of the nodes of Ranvier?

answer

Allows axolemma to be exposed to the extracellular matrix-specifically the Na channel (the axonal membrane is uninsulated & therefore capable of generating electrical activity). Allows for more rapid electrical conduction. Largery axons transmit impulses at a faster rate (less Na channels to open).

question

Describe how nerve impulses travel along unmyelinated axons.

answer

Travel as a uniform wave of depolarization d/t conformational changes in ion channels.

question

Describe how nerve impulses travel along myelinated axons.

answer

The Na channels act like booster stations for the propagation of a passively conducted electrical current. This is a more rapid and efficient system.

question

Describe peripheral nerves

answer

Mixed type w/ afferent & efferent fibers, a single nerve is both myelinated & unmyelinated.

question

Describe the anatomy of a nerve.

answer

Three layers: Endoneurium Perineurium Epineurium

question

Describe the endoneurium

answer

Surrounds each individual axon, non-neuronal glial cell.

question

Describe the perineurium

answer

Contains the nerve fibers in fascicles, semipermeable, acts as a major barrier to diffusion of LAs (tight junctioned).

question

Describe the epineurium

answer

Sheath covering the entire nerve, contains nutrient blood vessels.

question

Describe A-fibers.

answer

All myelinated. Alpha, beta, gamma, delta.

question

What are the functions of a-fibers (alpha, beta, gamma, delta)?

answer

Motor, tactile, proprioception, muscle tone, touch.

question

What are the functions of small A delta fibers?

answer

Pain and temperature.

question

Describe B fibers

answer

Myelinated, preganglionic autonomic

question

Describe C fibers (sC, dC)

answer

Unmyelinated, postganglionic autonomic

question

What are the functions of C fibers (sC, dC)?

answer

Pain and temperature.

question

Describe the phospholipid bilayer.

answer

Impermeable to ions, electrical capacitance (acts as a capacitor plate)

question

Describe depolarization & action potential of a nerve.

answer

Must hit threshold (point at which the cell will become fully depolarized) Once threshold reached, Na channels open rapidly, the cell becomes positive (depolarized).

question

Describe repolarization & action potential if a nerve.

answer

Na channel closes, K channels open (inside of cell is negative).

question

Describe the resting phase

answer

Na & K channels are closed but K channels leak (100x more leaky than Na channels) Na K ATPase restores ionic gradients.

question

What is the Nernst potential

answer

The electrical potential across a cell membrane that exactly opposes the net diffusion of a particular ion through the membrane following its concentration gradient.

question

Describe the hyperpolarization phase (refractory period)

answer

The membrane potential becomes transiently more negative than the normal resting potential. Refractory period makes the axon unidirectional.

question

Describe membrane threshold

answer

That point in the process of depolarization when continued stimulation leads to complete action potential.

question

Describe impulse firing threshold

answer

Point where the balance of ionic currents reverses from ATP requiring polarization to gradient dependent depolarization.

question

What is normal resting potential of a neuron?

answer

-60 mV

question

What are the 2 means of propagation?

answer

Passive spread & active spread

question

Where does passive propagation occur?

answer

In the dendrites & cell body-different kinds of Na channels depending on nerve cell type.

question

What are the different kinds of Na channels involved in passive propagation?

answer

Ligand gated, gap junctions, temperature gated, mechano gated. Very few voltage gated.

question

What is passive propagation responsible for?

answer

Sensory function, cell-to-cell communication & impulse modulation.

question

Describe active propagation.

answer

Occurs in the axon. Myelinated-node to node (more rapid & efficient). Nonmyelinated- continuous wave.

question

In regards to active propagation, describe what occurs.

answer

Once an action propagation is initiated in 1 region of a neuron, the depolarization "wave" will spread out sequentially to the rest of the neuron.

question

Potential complications of any regional anesthetic technique include: a. Infection b. Bleeding c. block failure d. all of these are correct e. Nerve damage

answer

d. all of these are correct

question

Addition of NaHCO3 to local anesthetics accomplishes all of the following except: a. Speeding the onset of local anesthetic block b. Intensifying local anesthetic block by ion trapping c. Causing more of the local anesthetic to be in its unionized form d. Decreasing the pH of local anesthetic rendering it more water soluble e. Acidifying the axonal cytoplasm

answer

d. Decreasing the pH of local anesthetic rendering it more water soluble

question

Propagation of an impulse wave down an axon occurs due to: a. Activation of the sodium / potassium ATPase pump b. Ionic diffusion c. Two of these are correct d. Electrical conduction e. Closure of voltage gated sodium channels

answer

c. Two of these are correct

question

Which sequence correctly lists injection sites in order from most rapid systemic absorption to least rapid? a. Epidural > subarachnoid > brachial plexus > subcutaneous > intercostal b. Intercostal > subarachnoid > brachial plexus > epidural > subcutaneous c. Intercostal > epidural > brachial plexus > subarachnoid > subcutaneous d. Brachial plexus > subcutaneous > subarachnoid > intercostal > epidural e. Subcutaneous > Intercostal > epidural > brachial plexus > subarachnoid

answer

c. Intercostal > epidural > brachial plexus > subarachnoid > subcutaneous

question

The injection of local anesthetic into which site would provide the highest venous plasma level? a. Subarachnoid b. Caudal c. Subcutaneous d. Brachial plexus e. Lumbar epidural

answer

b. Caudal

question

Which LA results in cardiotoxicity: fast in, slow out leads to reentrant dysrhythmias?

answer

Bupivicaine

question

Which LA results in a poor differential block?

answer

Etidocaine

question

Which LA has prolonged metabolism in the fetus?

answer

Mepivicaine

question

Which LA metabolizes to O-toluidine in the liver, potentially causing methemoglobinemia?

answer

Prilocaine

question

Which LA has a S isomer leads to less cardiotoxicity and is an intrinsic vasoconstrictor?

answer

Ropivicaine

question

Which LA may render bupivacaine and epidural narcotics ineffective?

answer

Chloroprocaine

question

Which LA is used as a topical anesthetic, rapid onset, and medium to long duration?

answer

Tetracaine

question

Which LA is used for IVRA, epidural, peripheral nerve block, topically on mucous membranes, and IV to blunt airway reflexes?

answer

Lidocaine

question

What local anesthetic is an amide? a. Procaine b. Chlorprocaine c. Cocaine d. Bupivacaine e. Teracaine

answer

d. Bupivacaine

question

Addition of epinephrine to local anesthetic solutions has which of the following effects? a. Slows absorption b. Lowers the pH c. All of these are correct d. Causes more profound motor block e. Direct antinociceptive effects at the spinal cord level

answer

c. All of these are correct

question

Describe tonic block.

answer

Closed channel inhibition

question

Describe phasic block

answer

The anesthetic binds when channels are stimulated or open.

question

The maximum recommended dose for plain bupivacaine given in the epidural space is approximately ____ mg/kg. a. 5 b. 1 c. 10 d. 2 e. 7

answer

d. 2

question

Changes in fluid and electrolye disposition in response to surgical stress include: a. Sodium and water loss b. Increased functional extracellular fluid (intravascular volume) c. Potassium excretion d. Diuresis from increased ADH e. Hypoglycemia

answer

c. Potassium excretion

question

In the sympathetic division of the Autonomic Nervous System, the main neurotransmitter for the postganglionic axon is? a. glutamine b. acetylcholcholine c. dopamine d. norepinephrine. e. epinephrine

answer

d. norepinephrine. NE is the main neurotransmitter for the sympathetic division of the ANS. NE is also a catecholamine released from the adrenal medulla effector organ when stimulated to cause vasoconstriction in the periphery.

question

Describe the resting phase

answer

Na & K channels closed, K channels leaking

question

Describe the refractory phase

answer

Slow voltage gated Na channels closed and inactivated.

question

Describe the repolarization phase

answer

Na channels are inactivated K channels open

question

Describe the depolarization phase

answer

Na channels open

question

A more profound depth of conduction blockade may be attained by adding Na+ bicarb to the local anesthetic, for all of the following reasons EXCEPT a. Decrease in intracellular pH occurs from CO2 diffusion across the cell membrane b. Direct depressant effects of CO2 on nerves c. The bicarbonate ion diffuses into the cytoplasm, contributing to ion trapping. d. By raising the pH, you increase the non-ionized form of the local anesthetic outside the axolemma e. CO2 lowers the intracellular pH and traps the ionized form of the local anesthetic in the cytoplasm

answer

c. The bicarbonate ion diffuses into the cytoplasm, contributing to ion trapping.

question

The pKa of a local anesthetic is correlated with which characteristic of local anesthetics? a. Duration of action b. Potency c. color d. pH e. Latency of conduction blockade (onset time)

answer

e. Latency of conduction blockade (onset time)

question

What is the primary result of increased cortisol

answer

Gluconeogenesis, lipolysis, protein catabolism

question

What is the primary result of increased catabolic hormones?

answer

Negative nitrogen balance

question

What is the primary result of increased ADH?

answer

Free H20 retention

question

What is the primary result of Virchow's triad?

answer

Increased DVT risk

question

What is the primary result of severe anxiety?

answer

Increased catecholamines, increased overall stress response

question

Hyperglycemia in response to surgical stress may be caused by all of the following except: a. Glycogenolysis from increased epinephrine and glucagon b. Increased secretion of atrial natriuretic peptide c. Gluconeogenesis from increased epinephrine, glucagon, and Cortisol d. All of the choices are correct e. Insulin resistance

answer

b. Increased secretion of atrial natriuretic peptide

question

Factors contributing to the resting membrane potential include: a. 2 of these 3 choices are correct b. All of these choices are correct c. Potassium ion leakage d. Sodium / potassium ATPase pump e. Sodium channels

answer

a. 2 of these 3 choices are correct

question

Which of the following amide local anesthetics has the lowest pKa? a. Bupivacaine b. Lidocaine c. Ropivacaine d. Mepivacaine e. Tetracaine

answer

d. Mepivacaine

question

The Nernst potential is: a. The electrical potential at which enough Na+ channels open to propagate an impulse b. The minimal voltage required to stimulate an axon c. The ionic concentration gradient across a capacitance membrane d. The electrical potential across a cell membrane that exactly opposes the net diffusion of a particular ion through the membrane following its concentration gradient e. All of the choices are correct

answer

d. The electrical potential across a cell membrane that exactly opposes the net diffusion of a particular ion through the membrane following its concentration gradient

question

Which ionic fluctuation is primarily responsible for early depolarization? a. Potassium Efflux b. Sodium Efflux c. Potassium Influx d. Sodium Influx e. Calcium influx

answer

a. Potassium Efflux

question

Which of the following local anesthetics can cause methemoglobinemia? a. Chirocaine b. Benzocaine c. Ropivacaine d. Mepivacaine e. Bupivacaine

answer

b. Benzocaine

question

All of the following cross the plasma membrane easily except a. Carbon dioxide b. Bicarbonate ion c. Local anesthetics at pH > pKa d. Hydrophobic drugs e. Unprotonated local anesthetics

answer

b. Bicarbonate ion

question

What is the MOA of LAs?

answer

Bind to receptors on Na channels, inhibit the flux of Na ions & prevent membrane depolarization. Work by blockade of the excitation conduction process in the nerves.

question

Describe use dependent inhibition (AKA-phasic inhibition).

answer

The channel opens & the LA binds More depolarization leads to more rapid response

question

Describe LAs

answer

All lipid soluble to some degree, weak bases

question

What form does the LA have to be in to penetrate the cell?

answer

Must penetrate the cell in unionized state to bind from the cytoplasmic side of the Na receptor.

question

Describe the structure of the more potent LAs.

answer

Higher lipid solubility Greater hydrophobicity (ionized form less soluble) Covalent dipolar bond linking the aromatic moiety to the tertiary amine group

question

What is the effect of higher lipid solubility?

answer

Allow for more rapid transfer across the membrane. Higher concentration in the bilayer.

question

What is the effect of greater hydrophobicity?

answer

Blocks the resting or closed Na channels

question

Describe the ester & ether bond, linear amide bond, and cyclic amide bond.

answer

Ester & ether bonded are more potent. Linear amide bonded less potent. Cyclic amide bonded least potent.

question

What are the determinants of potency?

answer

Dependent more on the inhibition of Na currents alone. Some LAs also block K current (these are less potent). CO2 potentiates the conduction blockade.

question

What is the effect of the potentiated conduction blockade of CO2?

answer

Raises the threshold for impulse firing. Acidifies the cytoplasm & ↑ the cationic form of the LA

question

What does the onset, depth, and duration of the block depend on?

answer

Amount How rapidly it arrives How rapidly it's removed from the site

question

What agents diffuse more rapidly?

answer

More hydrophobic, neutral & unprotonated (unionized) agents.

question

What greatly enhances the uptake of LAs?

answer

CO2

question

Describe the depot effect of the myelin sheath.

answer

Highly lipophilic agents go to the myelin (acts as a depot, gives prolonged block).

question

What does uptake (speed of onset) depend on?

answer

pKa of the LA: low pKa=more rapid onset (more hydrophobic, less ionized) pH of the various compartments: LAs won't work at sites of infection (more acidic)

question

What does duration depend on?

answer

Protein binding strength, pKa & partition coefficient

question

What would occur if insufficient length of the nerve is blocked?

answer

The impulse conduction will be slowed down, but complete conduction block will not occur.

question

What fibers are most sensitive to blockade?

answer

Pain & temperature fibers-smallest myelinated A & nonmyelinated C fibers. Light touch & hair vibration-larger myelinated A fibers.

question

What fibers are the most difficult to block?

answer

Large A fibers that are responsible for proprioception & motor function.

question

Describe the distal block and proximal block in regards to differential blockade among fibers.

answer

Mantle bundles (proximal) 1st to be anesthetized-early block. Core bundles (distal) last to be anesthetized-delayed block.

question

What are the effects of Mu1 opioid receptors?

answer

Analgesia (supraspinal, spinal); euphoria; low abuse potential; mitosis, bradycardia, hypothermia, urinary retention.

question

What are the effects of Mu2 opioid receptors?

answer

Analgesia (spinal); respiratory depression; physical dependence; marked constipation.

question

What are the effects of kappa opioid receptors?

answer

Analgesia (supraspinal, spinal); dysphoria; sedation; low abuse potential; mitosis; diuresis

question

What are the effects of delta opioid receptors?

answer

Analgesia (supraspinal, spinal); respiratory depression; physical dependence; marked constipation; urinary retention.

question

What are the Mu1 & Mu2 agonists?

answer

Endorphins, morphine, synthetic opioids

question

What are the kappa agonists?

answer

Dynorphins

question

What are the delta agonists?

answer

Enkephalins

question

What are the Mu1, Mu2, kappa, and delta antagonists?

answer

Nalaxone, naltrexone, nalmefene.

question

Where does resting or tonic inhibition occur?

answer

In a closed channel

question

Describe ionization of LAs.

answer

Ionization of a weak base occurs when the pH is pKa

question

Describe how the length of the nerve determines the amount of LA needed to block it.

answer

In smaller nerves, the same diffusion of LA blocks 3 nodes of Ranvier, where on the larger nerve it only blocks one.

question

Critical density is ____ ____ to conduction velocity & nerve size as conduction velocity increases & more LA is required to block conduction.

answer

Directly proportional

question

In regards to phasic inhibition describe charged LAs vs uncharged LAs.

answer

Charged LAs are more effective at inhibiting the Na channels Uncharged LAs penetrate lipid bilayer easier

question

In regards to phasic inhibition describe LAs & inactivated Na channels.

answer

During stimulation Na channels in the inactivated state bind LAs more tightly which stabilizes the channel the inactive state.

question

Describe LAs & open & activated Na channels.

answer

Open & activated channels react most rapidly w/ LAs but bind less tightly.

question

What drug characteristics are more potent in producing a tonic block?

answer

Hydrophobic & neutral drugs.

question

What drug characteristics have a weaker tonic block?

answer

Very polar & charged LAs.

question

What determines how rapidly the LA arrives?

answer

pKa, pH, & hydrophobicity

question

What determines how rapidly the LA is removed from the site?

answer

pKa & protein binding

question

What opioid receptors have low abuse potential?

answer

Mu1 and Kappa

question

Which opioid receptors provide spinal and supraspinal analgesia?

answer

Mu1, kappa & delta

question

Which opioid receptors are associated w/ respiratory depression?

answer

Mu2 and delta

question

Which opioid receptors are associated w/ marked constipation?

answer

Mu2 and delta

question

Which opioid receptors are associated w/ urinary retention?

answer

Mu1 and delta

question

Which opioid receptors are associated w/ mitosis?

answer

Mu1 and Kappa

question

What occurs w/ the anticipatory response (cognitive anticipation of stress or trauma)?

answer

Limbic system influences (via amygdala): Brainstem (locus coeruleus)-> ↑d catecholamines Prefrontal cortex signals the hypothalamus to ↑ secretion of CRH-> ↑ pituitary secretion of ACTH.

question

What factors are involved in the sequential physiology of pain (processes involved in pain).

answer

Induction/transduction Inflammation Granulation & healing Conduction/transmission Modulation Perception

question

Describe induction/transduction in regards to sequential physiology of pain.

answer

Conversion of physical stimulus to nociceptive action potential via peripheral sensory neurons.

question

Describe inflammation in regards to sequential physiology of pain.

answer

Leukocyte adhesion, diapedesis, mediator release Complement, kinin, & coagulation activation Arachidonic acid metabolites

question

Describe conduction/transmission in regards to sequential physiology of pain.

answer

Nociceptive impulses are carried to CNS

question

Describe the nociceptive response to stress.

answer

Arrival (in CNS) of nociceptive signals from PNS: Pain impulses (c-fiber) ascend (via lateral spinothalamic tract) to thalamus triggers: ↑ hypothalamus release of CRH->release of pituitary hormones. Hypothalamic signals to locus coeruleus-> ↑ production & release of NE.

question

Describe the inflammatory response to stress.

answer

Tissue damage incites immediate production & release of inflammatory mediators: Initiation of plasma defense systems: kinin, complement, coagulation Leukocyte adhesion, diapedisis, & release of chemotactic factors & inflammatory mediators Production & release of arachidonic acid metabolites.

question

Describe the endocrine response to stress.

answer

↑ catabolic hormones ∆ in anabolic hormones

question

Describe what occurs w/ carbohydrate metabolism d/t the stress response.

answer

Hyperglycemia, glucose intolerance, insulin resistance d/t ↑d glycogenolysis & gluconeogenesis ↓d insulin secretion & responsiveness

question

Describe what occurs w/ protein metabolism d/t the stress response.

answer

Muscle protein catabolism, ↑d synthesis of acute-phase proteins

question

Describe what occurs w/ fat metabolism d/t the stress response.

answer

↑d lipolysis & oxidation

question

Describe what occurs w/ fluid & e-lyte flux d/t the stress response.

answer

H20 & Na retention, K excretion, ↓d functional ECF

question

Describe when & why hypercoagulability occurs d/t the stress response.

answer

Throughout the peri-operative period-Virchow's Triad

question

How does pain and anxiety affect the surgical stress response?

answer

Compounds it.

question

What are the adverse effects of post-op pain on the pulmonary system?

answer

Atelectasis, V/Q mismatch, arterial hypoxemia, hypercapnia, pneumonia

question

What are the adverse effects of post-op pain on the CV system?

answer

HTN, tachycardia, myocardial ischemia, dysrhythmias

question

What are the adverse effects of post-op pain on the endocrine system?

answer

Hyperglycemia, Na & H20 retention, protein catabolism, K wasting

question

What are the adverse effects of post-op pain on the coagulation system?

answer

↑d platelet adhesiveness, ↓d fibrinolysis, hypercoagulability, DVT

question

What are the adverse effects of post-op pain on the GI/GU system?

answer

Ileus (d/t ↑d sympathetic output), urinary retention

question

How do spinals & epidural affect the response to surgical stress?

answer

Blunts peri-op stress hormones Blunts metabolic response

question

How do spinals & epidural affect the fluid e-lyte shifts d/t surgical stress?

answer

Complex relationship-↓ GFR; blunts stress hormones that cause Na & H20 retention & K excretion

question

How do spinals & epidural affect thermoregulation d/t surgical stress?

answer

Vasodilation predisposes to hypothermia

question

How do spinals & epidural affect platelet aggregation d/t surgical stress?

answer

Platelets-blunts ↑d aggregation (direct effects of LAs-inhibit ADP induced aggregation)

question

How do spinals & epidural affect factor VIII activity d/t surgical stress?

answer

Inhibits increased activity.

question

How do spinals & epidural affect fibrinolytic activity d/t surgical stress?

answer

Inhibits post-op inhibition

question

How do spinals & epidural affect plasminogen activity d/t surgical stress?

answer

Activity increased

question

How do spinals & epidural affect inhibition of leukocyte adhesion d/t surgical stress?

answer

Preservation of endothelial structure ↓ the inflammatory phase.

question

Describe immunocompetence

answer

Degree of post-op immunodepression is correlated w/ the amount of surgical trauma rather than type of anesthetic (exception-thermoregulation) Minimal effects

question

What is the primary stress hormone?

answer

Cortisol

question

What are the inflammatory mediators?

answer

Interleukins (IL) & tumor necrosis factor (TNF)

question

What does the Virchow triad include?

answer

1) Hypercoaguability 2) Endothelial damage 3) Venous stasis

question

What are the catabolic hormones that are released by the endocrine system?

answer

ACTH, cortisol, ADH, GH, catecholamines, renin, angiotensin II, aldosterone, glucagon, IL-1, IL-6

question

What are the anabolic hormone changes caused by the stress response?

answer

insulin ↓s, testosterone ↑s

question

What factors are involved in glyogenolysis?

answer

Epi, glucagon

question

What factors are involved in gluconeogenesis?

answer

Cortisol, glucagon, GH, epi, free fatty acids

question

What causes the ↑d synthesis of acute-phase proteins?

answer

↑d cortisol, epi, glucagon, IL-1, IL-6, TNF.

question

What causes ↑d lipolysis & oxidation?

answer

↑d catecholamines, cortisol, glucagon, GH

question

What causes H20 & Na retention, K excretion, ↓d functional ECF known as 3rd spacing & intracellular shift?

answer

↑d catecholamines, aldosterone, ADH, cortisol, angiotensin II, prostaglandins

question

What is Virchow's Triad and what is involved?

answer

Risk of thromboembolism & DVT Fibrinolysis- ↑d intra-op, ↓d post-op ↑d platelet aggregation

question

What are the stress hormones that are blunted by spinals and epidurals?

answer

Cortisol, RAAS, epi/NE, GH

question

What metabolic responses are blunted by spinals and epidurals?

answer

Hyperglycemia, ketosis

question

What causes shivering?

answer

Not necessarily d/t hypothermia: Protective reaction to cold environment (vasodilated pt) LA S.E.

question

What is the locus coeruleus

answer

A nucleus in the brainstem involved w/ physiologic responses to stree & panic.

question

With the anticipatory response to stress, how doe the prefrontal cortex signal the hypothalamus?

answer

Via the thalamus.

question

What is ↓d functional ECF known as?

answer

3rd spacing & intracellular shift

question

What innervates the kidneys?

answer

T10-L1

question

In regards to perception, where is nociceptive info processed?

answer

In the cerebral cortex prefrontal gyrus/cingulate gyrus.

question

In regards to modulation, where do interneurons modulate ascending impulses?

answer

In the substantial gelatinosa/periaqueductal grey matter.

question

In regards to modulation how does descending modulation occur?

answer

Via the corticospinal tract

question

Describe Amino Esters

answer

No i before the caine (only one i) Cocaine, procaine, chloroprocaine, tetracaine

question

Describe the amino amides

answer

All have i before caine (have two i's) Lidocaine, bupivicaine, mepivicaine, prilocaine, etidocaine, ropivicaine

question

Describe the chemical stability of esters and amides?

answer

Esters=unstable in solution (mix when used) Amides=extremely stable

question

Describe the site of action for esters & amides

answer

Na channels for both

question

Describe biodegradation of esters & amides

answer

Esters=break down in high temps, hydrolyzed by plasma cholinesterase to PABA Amides=enzymatic degradation in the liver

question

Describe the allergic potential of esters and amides

answer

Esters=PABA-para-amino benzoic acid causes allergic reactions Amides=very rare allergic reactions

question

Describe anesthetic potency of LAs

answer

Lipid solubility-varies w/ aromatic groups & pKa & pH of solution. Vasodilation of tissue redistribution The higher the octonal/buffer partition coefficient the more potent the LA

question

Describe latency of conduction blockade of LAs

answer

Correlated to the local pH, pKa & MW of the LA. Uncharged base forms diffuse more rapidly than charged cationic forms. pKa of LAs are higher than the surrounding pH-> ↑ ionized form. B(unionized) + H+ BH +

question

When pH ____pKa ionization is minimized.

answer

When pH > pKa ionization is minimized

question

What pH are most LAs stored at and why?

answer

5 or 6. ↑s the ionized form & improves stability for storage. Addition of epi ↓s the pH to 3 or 4

question

What are the effects of increasing the bathing solutions pH?

answer

Reduces the onset of duration, but risks precipitation of the LA.

question

What is the onset time clinically influenced by?

answer

Dose, concentration (chloroprocaine 3%)

question

What agents have a faster onset and why?

answer

Lido and mepivicaine, have a low pKa

question

What agents have a delayed onset and why?

answer

Procaine, chloroprocaine, tetracaine, have high pKas

question

What does the DOA correlate with?

answer

Degree of protein binding, peripheral vascular effects

question

Describe how the degree of protein binding affects the DOA

answer

The stronger the protein binding to the Na channels & other cytoplasmic or membrane proteins the longer the DOA.

question

Describe how the peripheral vascular effects affect the DOA

answer

The more vasodilation, the shorter the DOA. Prolong the effect by the addition of epi.

question

Epi has a more profound effect on which type of LAs?

answer

More profound if the drug is a vasodilator (tetracaine), & less profound if its a vasoconstrictor (ropivicaine)

question

What factors influence anesthetic activity?

answer

Needle has to be in right place (has to bathe the nerves you are aiming for) Dosage Site of injection/type of block Vasoconstrictors Carbonation (CO2) & pH adjustment (NaHCO#3) Mixtures of LAs Pregnancy

question

What are the effects of increases the dosage of LAs?

answer

More profound depth of block, prolongation of satisfactory anesthesia, ↓ in onset, more SE & risk of complications.

question

How can the dosage of LAs be increased?

answer

Administer a larger volume->more rapid absorption, more S.E. More concentrated solution (risky if BV entered) Mostly vasodilators at clinical dosage

question

What dosage of epi can be added to decrease the rate of vascular absorption?

answer

5 mcg/ml-epi 1:200000=5 mcg/cc

question

What are the effects of adding epi to LAs?

answer

↓ the rate of vascular absorption, more profound motor block, direct antinociceptive properties in the spinal cord, ↓s the pH to 3-4-> to formation of cationic forms of the LAs.

question

What are the effects of adding epi to bupivicaine, prilocain, and etidicaine?

answer

No effect

question

How does the site of injection/type of block influence anesthetic activity?

answer

Duration is dependent on location (intrathecal, SQ, brachial plexus block). Areas where LAs are more rapidly cleared have a shorter DOA. Central blocks have more rapid clearance than peripheral blocks.

question

Describe how pregnancy influences anesthetic activity.

answer

The spread & depth of spinal & epidural anesthesia are enhanced during pregnancy Venous dilation ↓s the capacitance of the epidural & subarachnoid spaces Hormonal factors-progesterone levels elevated

question

What is vascular absorption dependent on?

answer

Injection site, dosage/volume, addition of a vasoconstrictor

question

The degree of addition of a vasoconstrictor is ____ ____ to the intrinsic vasodilatory effects of the LA.

answer

Directly proportional

question

What agent has intrinsic vasoconstrictor effects?

answer

Ropivicaine

question

How does injection site affect absorption?

answer

Highest venous plasma levels to lowest. Intercostal>paracervical>caudal>lumbar epidural>brachial plexus>subarachnoid>subcutaneous

question

Describe the two-three compartment model.

answer

Alpha phase-uptake by rapid equilibration of tissue Beta phase-distribution of slowly equilibrating tissues, biotransformation & excretion

question

Describe biotransformation & excretion of amino esters

answer

Plasma cholinesterases hydrolyze the esters making PABA Excreted by kidney

question

Describe biotransformation & excretion of amino amides

answer

Metabolized mainly by the liver. Rate is inversely r/t protein binding-hepatic extraction ratio. Excreted by the kidney (pH dependent)

question

What patient characteristic could influence the disposition of LAs?

answer

Patient age

question

What is elimination of LAs influenced by?

answer

Individual patients hepatic, renal, & cardiac status.

question

What are the S/S and causes of CNS toxicity in the initial phase?

answer

Tinnitus, lightheadedness, confusion, circumoral numbness. High blood flow areas.

question

What are the S/S and causes of CNS toxicity in the excitation phase?

answer

Shivering, muscular twitching & tremors, tonic-clonic seizures. Inhibition of inhibitory pathways in the cerebral cortex.

question

What are the S/S and causes of CNS toxicity in the depression phase?

answer

Unconsciousness, CNS depression, respiratory arrest. Inhibition of inhibitory and facilitatory pathways.

question

What causes CV toxicity?

answer

Alter electrical acitivity Alter muscular activity

question

How does altered electrical activity cause CV toxicity?

answer

Exacerbated by hypoxia, acidosis, hypercapnia: Bupivicaine (fast in, slow out)-depresses rapid phase of AP->unidirectional blockade->reentrant dysrhythmias

question

How does altered muscular activity cause CV toxicity?

answer

Dose related negative isotropy, exacerbated by hypercapnia, acidosis, & hypoxia, r/t binding Na & Ca channels.

question

What are the S/S of CV toxicity in the initial phase?

answer

HTN, tachycardia during CNS excitation

question

What are the S/S of CV toxicity in the intermediate phase?

answer

Myocardial depression, ↓d CO, mild-moderate hypotension

question

What are the S/S of CV toxicity in the terminal phase?

answer

Peripheral vasodilation, profound hypotension, SB, conduction defects, ventricular dysrhythmias, circulatory collapse.

question

What factors enhance CV toxicity?

answer

Specific agents (bupivicaine CV/CNS toxicity highest), pregnancy (higher toxicity w/ bupivicaine), acidosis, hypoxia.

question

What LA causes local tissue toxicity, what are the S/S of local tissue toxicity & why?

answer

Chloroprocaine, muscle damage, back pain. Due to preservatives: bisulfate, EDTA.

question

Besides prilocaine, what other LAs can produce methemoglobinemia?

answer

Cetacaine, benzocaine, lido

question

What causes the allergic reactions associated w/ LAs?

answer

PABA in esters, methylparaben in multi dose amides

question

What is cocaine and what is it used for?

answer

An ester, used topically for anesthesia & vasoconstriction (awake nasal intubation).

question

Why is procaine rarely used?

answer

Short duration, slow

question

Describe chloroprocaine

answer

Rapid onset low toxicity, used for fast onset epidurals, renders bupivicaine ineffective, muscle spasm w/ high doses.

question

What is tetracaine used for?

answer

Long duration spinals, epi prolongs spinal block

question

Describe lidocaine

answer

Widely used, good for everything, cauda equina syndrome/TNS seen w/ 5 % spinals.

question

Describe mepivicaine

answer

Similar to lidocaine, less toxic (less vasodilation), not effective topically, metabolism very slow in fetus & newborns.

question

Describe prilocaine

answer

Least toxic, useful in IVRA (bier block), methemoglobinemia.

question

Describe bupivicaine

answer

Used for everything but topical and IVRA, differential blockade, cardiac toxicity.

question

Describe etidocaine

answer

Rapid onset long duration, dense muscle block

question

Describe robivicaine

answer

S-isomer, similar to bupivicaine, less CV toxic

question

What is the disadvantage of cocaine?

answer

High toxicity, addictive potential

question

What is the disadvantage of chloroprocaine?

answer

May render bupivicaine & epidural ineffective, toxicity d/t pH, bisulfate, & EDTA

question

What is a disadvantage of tetracaine?

answer

Motor block outlast sensory

question

The spinal canal runs from the ____ _____ to the _____ _____.

answer

Foramen magnum sacral hiatus

question

Where does the spinal cord begin?

answer

At the medulla oblongata

question

Where does the spinal cord end?

answer

L1-2 conus medullaris->cauda equina

question

What is the primary site for neuraxial anesthesia?

answer

The lumbar vertebral column

question

Describe the bony anatomy of the vertebrae

answer

Anterior-vertebral body, disc Posterior-ring containing the spinal cord-body, fascicles, laminae

question

What attaches to laminae superiorly & inferiorly?

answer

Ligamentum flavum

question

What is found in the epidural space?

answer

Epidural fat, blood vessels (epidural veins), nerve roots (spinal nerves)

question

Describe the dura mater

answer

Outer most layer covering the spinal cord

question

What is the dura mater attached to?

answer

Attached superiorly to the foramen magnum

question

Where does the dura mater end?

answer

Inferiorly it ends at the S1-S2 vertebra

question

What covers spinal nerves?

answer

Dura mater

question

Where do the spinal nerves exit?

answer

Via the intervertebral foramina (in pedicles)

question

Where do spinal nerves enter?

answer

The paravertebral space

question

The meninges consist of 3 layers, name them.

answer

Dura mater, arachnoid mater, pia mater

question

The sympathetic are part of the _______ system.

answer

thoracolumbar system

question

Describe the thoracolumbar system

answer

Sympathetic nerve fibers run thru the intermediolateral cell column of T1-L2 & consist of preganglionic beta fibers.

question

What vertebral levels are the cardiac accelerators?

answer

T1-T4 (T5)

question

Efferents at every level contribute to ____ ____->sympathectomy causes _______ in proportion to the ______ of ______ blocked.

answer

vasomotor tone vasodilation # of dermatomes blocked

question

What are the 4 major structural ligaments of the spinal column?

answer

Posterior to anterior Supraspinous ligament Interspinous ligament Ligamentum flavum Posterior longitudinal ligament

question

What does spinal cord consist of?

answer

An outer white matter & middle gray matter

question

What does the gray matter consist of

answer

Shaped like a butterfly Consists of anterior, lateral, & dorsal horns

question

Sympathetics exit via ____ ____ then enter the ____ _____ ____.

answer

spinal nerves lateral sympathetic chain

question

Why nerve fibers are involved in sympathetically mediated pain?

answer

Afferents (sensory)

question

How do the afferent nerves affect the SNS?

answer

Activated by stretching, ischemia, & inflammation

question

What is the only parasympathetic nerve that innervates the heart?

answer

Vagus

question

What parasympathetic nerves are affected by epidural blockade?

answer

Only sacral S2-4

question

What parasympathetic nerves are not affected by epidural blockade?

answer

Cranial nerves (vagus, oculomotor, facial, glossopharyngeal, & accessory)

question

Spinal or epidural above _______ leads to increased risk of trauma to spinal cord.

answer

L1-L2 Must go below

question

Why is it safer to place a spinal or epidural below L1-2?

answer

Cauda equina nerves freely float in CSF = not easily traumatized

question

Why is the lumbar epidural the most commonly performed block?

answer

Easiest approach d/t near horizontal spinous processes, ligamentum flavum thick in comparison to thoracic, bigger interspaces

question

What disease process causes difficulty in regards to a lumbar epidural?

answer

Osteoarthritis

question

What is the most common injection site in a lumbar epidural and why?

answer

L3-4 Larger interspaces

question

How do spinal nerves that come off the spinal cord innervate the body?

answer

In a dermatomal fashion

question

What do dermatomes correspond with?

answer

The level at which the nerves exit the spinal cord, they don't correspond w/ peripheral nerves

question

In regards to dermatomes blocking what level leads to hand numbness?

answer

C6, 7, 8

question

In regards to dermatomes what level affects below the clavicle?

answer

T1

question

In regards to dermatomes what level affects the nipple line?

answer

T4

question

In regards to dermatomes what level affects the xiphoid process?

answer

T6

question

In regards to dermatomes what level affects the umbilical level?

answer

T10

question

In regards to dermatomes what level affects the ilio-inguinal level?

answer

L1

question

In regards to dermatomes what level affects the pubic rectal area?

answer

S2-4

question

At what level do spinous process meet their maximal angulation?

answer

T7 (60˚ angle)

question

Where is the site of action of epidurals & why is this important?

answer

Peripheral cord Spinal nerve roots, the LA has to cross all 3 layers of meninges = slower onset than spinals

question

What layer of meninges acts as a major barrier to diffusion in epidurals and what is its effects?

answer

Arachnoid-epidurals set up slower than spinals

question

What is the mechanism of epidural blockade?

answer

Spread of local in the epidural space (bidirectional spread) Crosses meninges

question

Describe a differential blockade w/ epidurals.

answer

Lower concentrations block sympathetic & sensory fibers while leaving proprioception & motor intact.

question

What are CV effects dependent on?

answer

Dose & level obtained

question

At what level would adrenal afferents be knocked out and what is the effects?

answer

T6-L1; increased vagal tone->blunts HR response

question

What factors cause a decrease in arterial pressure?

answer

↓ peripheral resistance ↓ CO d/t ↓d venous return & T1-T5 blocked-> ↓d HR & contractility ↓ in central venous pressure d/t venodilation

question

What is the major factor causing a decrease in arterial pressure and why?

answer

↓ CO d/t venodilation causing ↓ venous return Also blocks T1-5

question

How does arterial vasodilation & ↓ BP affect limb blood flow?

answer

Limb BF below the block is improved Limb BF above the block is reduced

question

At what level are CV effects of neuraxial blockade at maximal level?

answer

T1 (after T1 will result in profound bradycardia)

question

Arterial vasodilation but local compensation: Only ____-____% ↓ total vascular resistance. Mean arterial pressure only ↓ ___-____% even w/ high block provided CO maintained.

answer

15-18% 15-18%

question

Venodilation may be maximal May be ____ ____ w/ changes in posture. What do pooling effects lead to?

answer

venous pooling ↓ preload & CO

question

What is CO determined by? May be normal if ______ & _____ ____ _____ ____.

answer

Preload May be normal if normovolemia, & legs above heart level.

question

What happens to the HR w/ a T1-T4 block?

answer

Decreases

question

What happens to HR if RA pressure is decreased?

answer

Decreases (usually ↓ 10-15% unless T1 block or ↓↓ RA pressure)

question

What is the key to preventing a decrease in HR?

answer

Volume loading

question

If a patient c/o nausea what could be the cause and how should it be treated?

answer

↓ BP-ephedrine

question

Describe how neuraxial blockade can effect the respiratory system.

answer

Rare. Can block the phrenic nerve if C3C4 blockade ("high spinal"). Chest wall heaviness common - Intercostal muscles segmentally innervated - Lack of sensation (proprioception).

question

Describe how neuraxial blockade can effect the GI system.

answer

Unopposed vagal tone-> ↑ in GI motility ↓ incidence of colonic anastomotic dehiscence d/t improved BF

question

What are the indications for epidural blockade?

answer

Surgical anesthesia, relief of acute & chronic pain

question

What procedures are associated w/ acute pain and would be relieved w/ epidurals?

answer

OB, post-op pain, fractured ribs, etc...

question

Epidurals block ____ & _____ at the level of the nerve root.

answer

Afferents & efferents

question

How should an epidural be placed in order to minimize SE & maximize therapeutic effects?

answer

Should be placed at the center of the dermatome providing the maximal stimulation. Epidurals provide segmental analgesia->spreads from a central area where they are placed then cephalic & caudal.

question

What are the advantages of epidurals in OB?

answer

Sympathectomy early ↑ing UBF (if BP maintained) Motor blockade can be minimized Continuous dosing Lower body only 2nd stage labor (S2-4) needs deeper block (need larger volume) Easy to convert for c-section Advantage in certain OB complications ↓ the BP on pre-eclamptic pts

question

What are the absolute contraindications for epidurals?

answer

Hypovolemia, ↑d ICP, infection at site, septicemia, hypocoagulation states, patient refusal (assault), critical AS

question

Why is it contraindicated to perform an epidural on a pt w/ critical stenosis?

answer

Restrict the ability of the ♥ to ↑ CO as compensation for hypotension d/t the sympathectomy induced by neuraxial anesthesia. In these circumstances, the hypotension can become refractory to tx.

question

What are the relative contraindications for epidurals?

answer

Severe AS (need a-line) Chiari malformation & cerebral aneurysms (risk occurs w/ wet tap) Degenerative spine ds w/ neurologic findings (sciatica, foot drop, etc) Unstable neurologic ds Spine pathology (prior sx, severe scoliosis)

question

What is the most common approach for epidurals?

answer

Lumbar midline approach-pt in upright or lateral position.

question

____ _____ is at L4 spinous process.

answer

Iliac crest

question

What level is the best place for epidurals?

answer

L3-4

question

What factors need to be considered in regards to lateral positioning in men & women, especially w/ spinals?

answer

Women have larger hips->will cause hyperbaric LA to travel more cephalad Men have broader shoulders->higher chance of inadequate spinal

question

What techniques are used in neuraxial anesthesia?

answer

Paramedian lumbar & thoracic approach Midline thoracic approach Cervical approach Caudal approach

question

Describe the paramedian approach

answer

Bypasses the supraspinous & interspinous ligaments->resistance can be boggy until ligamentum flavum is engaged.

question

What are the 2 risks involved w/ epidurals and how can it be prevented?

answer

Accidental intrathecal or intravascular injections. Test dose

question

What drugs and dosages are used w/ epidural test doses?

answer

1.5% lido w/ epi 1:200,000 3cc = 45mg lido + 15 µg epi Allow enuf time (sensory check)

question

Why should each dose of an epidural be treated as a test dose?

answer

Catheters can migrate intrathecally after a negative test dose->need to aspirate & don't give big doses as a bolus = high spinal

question

What level should be blocked for labor analgesia?

answer

L2-L4

question

What level should be blocked for hip/knee surgery?

answer

L2-L4

question

What level should be blocked for laparotomy under GA?

answer

T8-T10

question

What level should be blocked for a thoracotomy or fractured ribs?

answer

At relevant interspace usually T5-T7

question

What is the MOA of duramorph?

answer

↓ substance P mediated transmission from A-delta & C fibers by ↓ing presynaptic Ca influx & hyperpolarizing the 2nd order ascending nerve by ↑ing K conductance->suppresses expansion of nociceptive field of 2nd order neuron-> ↓s c-fos expression.

question

What is the DOA of duramorph?

answer

Long-24˚

question

What are the disadvantages of duramorph?

answer

Slow onset-1.5-3˚ Can cause delayed respiratory depression up to 12˚

question

What are the differences between duramorph & lipid soluble opioids?

answer

Duramorph spread more = > risk for CNS SE

question

What are the advantages of lipid soluble opioids?

answer

Quick onset, low risk of respiratory depression (less dermatomal spread)

question

What are the disadvantages of lipid soluble opioids?

answer

Short DOA, must be injected near the site of action (d/t less dermatomal spread), rapid systemic absorption

question

What are the S.E. of neuraxial opioids?

answer

Respiratory depression (may be delayed 8-12˚), N&V, pruritis, urinary retention, ↓ GI motility (less than w/ IV)

question

Why does urinary retention occur w/ neuraxial opioids?

answer

Due to inhibition of sacral parasympathetics

question

Describe why pruritis occurs w/ neuraxial opioids and how its treated.

answer

Mu receptor, peripheral histamine release Antihistamines have limited efficacy, narcotic agonist/antagonist best-naloxone

question

How does addition of epi affect neuraxial blockade?

answer

Vasoconstriction-> ↓d uptake of LAs, prolongs block, ↓d spinal cord BF, intensifies motor block, direct α-2 mediated antinociceptive effects on 1˚ afferents & descending pathways.

question

How does addition of phenyephrine affect neuraxial blockade?

answer

Vasoconstrictor->prolonged block, ↓d uptake May ↑ risk of TNS

question

Describe effects of adjuvant clonidine & neuraxial blockade

answer

Inhibit A-delta & C fiber afferents by ↑d K conductance Rapid systemic absorption->peripheral inhibition of norepi release

question

Describe effects of adjuvant neostigmine & neuraxial blockade

answer

Acetylcholinesterase inhibitor-> ↑ Ach, stimulates receptors in substantia gelatinosa

question

What is a disadvantage of neostigmine?

answer

High incidence of nausea

question

Describe effects of adjuvant ketamine & neuraxial blockade?

answer

Non-competitive NMDA atagonist-> ↓s central sensitization "wind up"

question

Describe effects of adjuvant ketorolac & neuraxial blockade?

answer

COX inhibitor (NSAID)->under investigation, may enhance opioid & clonidine analgesia

question

What patients cannot be sedated prior to epidural blockade?

answer

OB pts

question

Between ephedrine & phenylephrine which is a better choice in treatment of hypotension & why?

answer

Ephedrine best (↑ preload & CO) Phenylephrine (↑ afterload)

question

Why is atropine a poor choice in the treatment of hypotension?

answer

↑ HR & MVO2

question

What factors affect the spread of LAs in the epidural space?

answer

Rapidity of dose (>), volume injected (>), placement of catheter, position, unique epidural anatomy (prior sx, spinal stenosis, pregnancy, ht)

question

Describe the difference in subarachnoid block vs epidural block.

answer

Dura & arachnoid intentially punctured, smaller needle gauge, pencil point needles (less risk of PDPH), introducer needles used.

question

Why are introducer needles used w/ subarachnoid blocks?

answer

Due to smaller needle gauge (25-27 ga), prevents skin "coring" & provides rigidity.

question

Where are spinals performed?

answer

Below L2-3->spinals above L2-3 carry the additional risk of direct trauma to the cord (iatrogenic syringomyelia) or the posterior spinal artery.

question

With a subarachnoid block where is the drug deposited?

answer

Into the CSF

question

How are spinals performed?

answer

Single shot

question

With a subarachnoid block what determines the level?

answer

Baricity & positioning

question

Describe onset of the subarachnoid block

answer

Rapid->LA doesn't have to diffuse across dura & arachnoid->rapid sympathectomy

question

What are the advantages of a subarachnoid block?

answer

Lower dose of LA needed, slower absorption of LA Both decrease risk of systemic toxicity

question

Where do subarachnoid blocks work?

answer

Directly on nerve roots & spinal cord (Virchow-Robin spaces)

question

What factors affect the distribution of subarachnoid anesthetics?

answer

Relative baricity of LA, position, volume inj, level where spinal was placed, rapidity of inj

question

How does the rapidity of the injection affect the aubarachnoid block?

answer

Provides good mixing w/ the CSF->causes turbulence

question

____ is duration. ____ determines the level.

answer

Dose is duration Positioning determines the level

question

Compare epidural vs spinal blockade

answer

Covering the nerves-onset Location of action Differential blockad-more difficult w/ spinals Dermatomal spread Density differences

question

What dermatome level is necessary for upper abdominal surgery w/ a spinal?

answer

T4-T5 (nipple)

question

What dermatome level is necessary for intercostal sx (including appy, gynecologic pelvic sx, & ureter & renal pelvic sx) w/ a spinal?

answer

T6-T8 (xiphoid)

question

What dermatome level is necessary for a TURP, obstetric vaginal delivery, & hip sx w/ a spinal?

answer

T10 (umbilical)

question

What dermatome level is necessary for TURP, if no bladder distention; thigh sx; lower limb amputations w/ a spinal?

answer

L1 (inguinal ligament)

question

What dermatome level is necessary for foot surgery w/ a spinal?

answer

L2-L3 (knee & below)

question

What dermatome level is necessary for perineal surgery, hemorrhoidectomy, anal dilation w/ a spinal?

answer

S2-S5 (perineal)

question

When a spinal is done & the pt is laid completely flat where does the LA usually spread & why?

answer

T4, it's a little above the bottom of the thoracic kyphosis (most dependent portion of the thoracic spine)

question

How is the epidural space identified?

answer

With loss of resistance

question

How is a combined spinal-epidural performed?

answer

Epidural space identified, subarachnoid block then performed by inserting a spinal needle thru the Touhy/modified Touhy, epidural catheter is then inserted via the Touhy

question

What are the advantages of a combined spinal-epidural?

answer

Offers the advantages of rapid onset & dense block of a spinal & the flexibility of redosing via an epidural catheter.

question

After the subarachnoid block is performed, the epidural must be threaded & secured expeditiously so the pt may be positioned to allow proper spread of the subarachnoid LA, what would occur if the pt remained seated too long?

answer

A saddle block would result

question

When dosing the epidural after spinal block, the epidural exerts a ____ ___ on the epidural space, this will push the spinal level _____ than expected for simple epidural dosing.

answer

mass effect higher

question

When dosing an epidural after a dural puncture, some local will leak thru the puncture site, what does this result in?

answer

Some degree of subarachnoid block.

question

Describe the complications associated w/ neuraxial anesthesia

answer

Systemic toxicity (less w/ spinals), accidental IV dosing (rare w/ spinals-very placement w/ asp of CSF)

question

What are the S/S of a high spinal?

answer

High level of sensory & motor blockade, C3-5 paralysis (respiratory arrest), hypotension & apnea.

question

How are high spinals treated?

answer

ABCs - epi early

question

Describe the subdural/epiarachnoid space

answer

Potential space between the dura & arachnoid

question

What occurs w/ an accidental subdural/epiarachnoid blockade?

answer

Unusual presentation-patchy block, high level block, hypotension, respiratory depression, unilateral/bilateral

question

How is an accidental subdural/epiarachnoid blockade treated?

answer

Supportive

question

When does high epidural blockade occur?

answer

With large volumes

question

How is a high epidural blockade treated?

answer

Supportive, usually resolves w/in 30 minutes

question

How is a high epidural blockade prevented?

answer

Incremental dosing

question

What are the symptoms of a dural puncture?

answer

HA (positional in nature) can be severe-occiput distribution, CN involvement

question

What can a dural puncture cause?

answer

Subdural hematoma or ICH

question

How is a dural puncture treated?

answer

Conservative-IV fluids, rest, caffeine, epidural blood patch

question

What is the success rate of the epidural blood patch?

answer

90-95% provides immediate relief

question

When should the blood patch be performed?

answer

Sooner the better, no coagulopathy

question

How does the blood patch work?

answer

Mass effect in epidural space-> ↑ in ICP, blood clots cause a temporary seal

question

How is the blood patch performed?

answer

Strict sterile technique, same as epidural, draw 20cc of blood from the pt, inject w/o causing pain (nl pressure)

question

What are the common complaints of pts while receiving blood patches?

answer

Low grade fever, back spasm, radiculopathy, sore back.

question

What are the common discharge orders after a blood patch?

answer

No lifting for 2 wks, no heavy exercise, tylenol/motrin for pain, heating pad & massage to lumbar musculature, notify MD if radiculopathy, high fever or return of pain

question

What are the causes of neurologic damage?

answer

Trauma, anterior spinal artery thrombosis, adhesive arachnoiditis, spinal cord compression, injection of a neurolytic agent (accidental, drug toxicity)

question

What should raise a red flag w/ trauma in regard to neurologic damage?

answer

Parasthesias

question

Describe anterior spinal artery thrombosis.

answer

Rare but catastrophic, rapid, painless permanent paraplegia

question

How is adhesive arachnoiditis caused and what are the S/S?

answer

Injection of wrong drug (preservatives, betadine, other into CSF) Chronic pain Paraplegia possible

question

What causes spinal cord compression, how is it diagnosed & treated?

answer

Epidural hematoma/abscess MRI Immediate decompression laminectomy

question

Organotomes spinal level for stomach and site of referred pain.

answer

T5-9 Epigastric or LEFT hypochondrium

question

Organotomes spinal level for duodenum and site of referred pain.

answer

T5-8 Epigastric or RIGHT hypochondrium

question

Organotomes spinal level for jejunum and site of referred pain.

answer

T6-10 Periumbilical

question

Organotomes spinal level for ileum and site of referred pain.

answer

T7-10 Periumbilical

question

Organotomes spinal level for cecum and site of referred pain.

answer

T10-11 Periumbilical or RLQ

question

Organotomes spinal level for appendix and site of referred pain.

answer

T10-11 Periumbilical, then to right iliac fossa

question

Organotomes spinal level for ascending colon and site of referred pain.

answer

T10-12 Periumbilical or right lumbar

question

Organotomes spinal level for sigmoid colon and site of referred pain.

answer

L1-2 LLQ

question

Organotomes spinal level for spleen and site of referred pain.

answer

T6-8 Left hypochondrium

question

Organotomes spinal level for liver & gallbladder and site of referred pain.

answer

T6-T9 Epigastric-later to right hypochondrium

question

Organotomes spinal level for pancreas and site of referred pain.

answer

T7-9 Inferior epigastrium

question

Organotomes spinal level for kidney and site of referred pain.

answer

T10-L1 Small of back, flank

question

Organotomes spinal level for ureter and site of referred pain.

answer

T11-L1 Loin to groin

question

Concerning the addition of epinephrine to a neuraxial block which statement is INCORRECT: a. increases systemic uptake of local anesthetics b. intensifies motor block c. decreases spinal cord blood flow d. direct alpha-2 antinociceptive effects on primary afferents and decending pathways e. decreases pH of local anesthetic solution

answer

a. increases systemic uptake of local anesthetics

question

The Superior Laryngeal Nerve (SLN) and Recurrent Laryngeal Nerve (RLN) are branches of which cranial nerve? Choose one answer. a. IX-Glossopharyngeal nerve b. VIII-Vestibulocochlear nerve (aka auditory-vestibular nerve) c. X-Vagus nerve d. IV-Trochlear nerve e. phrenic nerve

answer

c. X-Vagus nerve

question

T/F Hyperbaric solutions sink to the dependent portions of the subarachnoid space.

answer

True

question

T/F A paravertebral block is performed at the level of the spinal nerve root.

answer

True

question

Which statement is incorrect in regards to the facial nerve (cranial nerve VII)? a. None of these answers are correct b. Supplies taste and sensation to anterior tongue c. Passes through the sublingual salivary gland d. Supplies motor function to muscles of facial expression e. Exits the skull via the stylomastoid foramen

answer

c. Passes through the sublingual salivary gland

question

T/F The substantia gelantinosa contains a high concentration of opioid receptors.

answer

True

question

For an intercostal nerve block, what needle insertion approach has a greater risk for pneumothorax? a. paravertebral b. lateral c. Inferior-vertebral d. Superior-lateral e. anterior midline

answer

b. lateral

question

Which of the following is NOT a side effect of neuraxial opioids? Choose one answer. a. respiratory depression b. puritis c. nausea and vomiting d. increased GI motility e. urinary retention

answer

d. increased GI motility

question

A combined spinal-epidural is performed in the sitting position. If too much time elapses between injection of the hyperbaric marcaine into the subarachnoid space and positioning the patient supine, the likely result is: Choose one answer. a. astigmatism b. a Saddle Block c. Dural puncture headache d. a Bier Block e. Cauda Equina Syndrome

answer

b. a Saddle Block

question

Why is the presence of a cerebral aneurysm a relative contraindication for placement of an epidural catheter? a. Patients with aneurysms have high ICPs which would contraindicate an epidural b. Patients with aneurysms have coagulopathies c. Aneurysms cause a decrease in afterload and if the epidural accidentally went intrathecal, the patient would receive a high spinal d. This is an unstable neurologic state e. An accidental dural puncture would cause a rapid decrease in ICP thereby increasing the transmural pressure gradient across the aneurysm increasing risk of rupture

answer

e. An accidental dural puncture would cause a rapid decrease in ICP thereby increasing the transmural pressure gradient across the aneurysm increasing risk of rupture

question

Oculocardiac reflex can lead to which of the following: Choose one answer. a. asystole b. dysrhythmias c. All of these are correct d. None of these answers are correct e. bradycardia

answer

c. All of these are correct

question

Which statement about lipid soluble neuraxial opioids is INCORRECT: Choose one answer. a. produce quick onset of action b. have short duration of action c. high risk for respiratory depression d. rapid systemic absorption e. limited dermatomal spread

answer

c. high risk for respiratory depression

question

The spinal cord ends at the following level: Choose one answer. a. L4-S2 b. T10-T11 c. L1-L2 d. S2-S4 e. T10-T12

answer

c. L1-L2

question

T/F Paravertebral and intercostal blocks provide relief from somatic pain.

answer

True

question

Preoperative management of an epidural block includes all of the following EXCEPT: a. Be prepared for any disaster b. Discuss and obtain consent c. Position & sedate if applicable d. Monitor the patients e. All of the above must be considered

answer

e. All of the above must be considered

question

Which of the following is not found in the epidural space? Choose one answer. a. Nerve roots b. Blood vessels c. Fat d. all of these are found in the epidural space e. Cerebrospinal fluid

answer

e. Cerebrospinal fluid

question

The meninges are composed of 3 layers. Which of the following is in the correct order starting with the outermost layer? Choose one answer. a. Arachnoid mater, dura mater, pia mater b. Dura mater, arachnoid mater, pia mater c. Dura mater, pia mater, arachnoid mater d. Pia mater, arachnoid mater, dura mater e. Whatsa mater, aintgonna mater, tow mater

answer

b. Dura mater, arachnoid mater, pia mater

question

T/F The addition of phenylephrine to neuraxial blockade may increase the risk of TNS?

answer

True

question

Which of the following is not a complication or side effect of a Cervical Plexus block? Choose one answer. a. Hoarseness b. Hemidiaphramatic paralysis c. All of the above are potential side effects or complications of cervical plexus block d. Total Spinal e. Seizures

answer

c. All of the above are potential side effects or complications of cervical block

question

T/F The substantia gelatinosa (lamina II) receives input from A-delta and C-fibers?

answer

True

question

Which of the following is an advantage of a periorbital block versus a retrobulbar block. Choose one answer. a. Less failure rate b. Less expensive c. Less complications d. None of these answers are correct e. Less volume of local anesthetic is needed

answer

c. Less complications

question

Which of the following borders the epidural space posteriorly? Choose one answer. a. The posterior longitudinal ligament b. The dura mater c. The supraspinous ligament d. The subarachnoid space e. The ligamentum flavum

answer

e. The ligamentum flavum

question

Which of the following is a major diffusion barrier for epidurals? Choose one answer. a. The pia mater b. The arachnoid mater c. The subdural space d. cerebrospinal fluid e. The dura mater

answer

b. The arachnoid mater

question

Which of the following dermatome levels is improperly matched? Choose one answer. a. T6 : Xyphoid Process b. T4 : Nipple Line c. T1 : Below clavicle d. L1 : Umbilical Level e. L3 anterior knee

answer

d. L1 : Umbilical Level

question

T/F Preganglionic sympathetic nerves enter the lateral chain upon leaving the spinal cord?

answer

True

question

Which landmark would be located for a superior laryngeal nerve block? Choose one answer. a. The hyoid bone b. The mastoid process c. The cricothyroid membrane d. The junction of the sternum and clavicle

answer

a. The hyoid bone

question

Which of the following is not a contraindication for an epidural? Choose one answer. a. The patient has a platelet count of 93,000 b. The patient has road rash over their entire back c. The patient's ICP is 5 mmHg d. The patient refused the epidural e. Last dose of plavix 4 days ago

answer

c. The patient's ICP is 5 mmHg

question

After performing a combined spinal-epidural, extra caution is needed when dosing the epidural catheter because of which factors? Choose one answer. a. The compression of the subarachnoid space by the local anesthetic in the epidural space can raise the neuraxial level quickly. b. A small amount of medication leaking through the dural puncture from the epidural to the subarachnoid space. c. None of these answers are correct d. 2 of these answers are correct e. Mass effect from the volume of local anesthetic in the subarachnoid space causes greater spread of the epidural medication.

answer

a. The compression of the subarachnoid space by the local anesthetic in the epidural space can raise the neuraxial level quickly.

question

The epidural space extends from ____ ____ ____ to _____ ____.

answer

base of skull to sacrococcygeal membrane

question

In adults, ___-____ mL of LA per segment to be blocked.

answer

1-2 mL (i.e. want a T4 sensory level from an L4-5 injection site - 12 segments to reach T4 (12 x 1-2 mL/segment = 12-24 mL)

question

What LAs have a fast onset & short durations?

answer

Chloroprocaine & prilocaine

question

What LAs have an intermediate onset?

answer

Lidocaine & mepivicaine

question

What LAs have a slow onset & long duration?

answer

Bupivicaine & ropivicaine

question

What are the 2 mechanisms of epidurally-produced conduction block?

answer

The LA acts directly at the nerve roots & dorsal ganglia beyond the dura after diffusing thru the intervertebral foramen The LA acts on the dorsal & ventral rootlets & SC after diffusing across the dura & arachnoid The LA also diffuses thru the CSF & into the SC

question

For intrathecal (spinal) or epidural anesthesia, LAs act on ___ ___, ____ ___, & the _____ _____.

answer

nerve roots nerve rootlets spinal cord

question

List in order which nerves are blocked following epidural administration of a LA.

answer

B fibers (preganglionic sympathetic efferents) C & A-delta fibers (pain, tempurature, & touch afferents-postganglionic sympathetic neurons) A-gamma A-beta A-alpha

question

Explain the differential nerve blockade

answer

Small-diameter nerve fibers are found close to the nerve root surface (shortens the diffusion path of LAs) The diffusion path to the large-diameter fibers is longer (situated deep to the nerve bundle)

question

What fibers see the greatest concentration of LAs 1st?

answer

B fibers then C fibers

question

What family of fibers receives a lesser concentration of LAs & what is the importance of this?

answer

A They are VERY sensitive

question

List the nerve fibers in order of sensitivity.

answer

Large myelinated > smaller myelinated > unmyelinated (large myelinated fibers require less LA to be blocked)

question

List in order the structures the needle passes through for an epidural block.

answer

Skin SC tissue Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural space

question

Distance from skin to epidural space in an average adult.

answer

4-6 cm

question

Distance from skin to epidural space in an obese individual.

answer

Up to 8 cm

question

Distance from skin to epidural space in a thin person.

answer

3 cm

question

What is the most sensitive indicator of initial onset of sensory block?

answer

Alcohol swab to assess loss of temperature sensation

question

What is the most ACCURATE assessment of overall sensory block?

answer

The pinprick

question

What factors affect sensory block?

answer

Site of injection & nerve root size

question

What are the most common complications of epidural blockade?

answer

Penetration of a blood vessel Intravascular catheterization

question

Why is a test dose performed after satisfactory placement of the epidural catheter?

answer

It detects subarachnoid & intravascular injection

question

How far is the epidural catheter threaded into the epidural space?

answer

4 cm

question

Advantages of spinal vs. epidural anesthesia

answer

Takes less time to perform Rapid onset Sensory & motor block quality is better Pain during sx is less

question

Advantages of epidural vs. spinal anesthesia

answer

Less risk of PDPH Less hypotension Can prolong block w/ catheter Catheter can be used for postop pain management

question

Anatomy of the caudal epidural block

answer

Sacrum: triangular bone consisting of 5 fused sacral vertebrae

question

What membrane is penetrated during a caudal epidural?

answer

The sacrococcygeal membrane

question

What is the most common postop complaint w/ a caudal epidural?

answer

Pain at the injection site

question

What is the 2nd most common postop complaint w/ a caudal epidural?

answer

Urinary retention

question

Dosages for caudal epidural block in adults

answer

S5-L2 15-20 mL S5-T10 25 mL

question

Dosages for caudal epidural block in children

answer

0.5-1.0 mL/kg of 0.125% to 0.25% bupivicaine Chloroprocaine 1 mL/kg as bolus; o.3 mL/kg until desired level is met (kids calm down & pinch test)

question

Cervical plexus

answer

C1-C5

question

Phrenic nerve

answer

C3-C5 w/ C4 making major contribution

question

Brachial plexus

answer

C5-C8, T1

question

Advantages of the axillary block

answer

Provides anesthesia for sx on forearm & wrist Fewer complications than supraclavicular block Safest & most reliable for the patient

question

Limitations of the Axillary block

answer

Not for shoulder or upper arm sx Musculocutaneous nerve lies outside sheath & must be blocked separately

question

Complications of the axillary block

answer

Intravascular injection Increased risk of hematoma in patients w/ elevated bleeding times

question

Volume of lidocaine, etidocaine, & bupivicaine for an axillary block.

answer

30-40 mL

question

Which nerve is most superior in the brachial bundle?

answer

Median

question

Which nerve is most inferior in the brachial bundle?

answer

Radial

question

Which nerve is most medial in the brachial bundle?

answer

Ulnar

question

Sensory distribution of the ulnar nerve

answer

Both surfaces of the medial 1-1/2 fingers (ring & pinky)

question

Sensory distribution of the radial nerve

answer

Dorsal surface of the lateral 3-1/2 fingers (1st, middle, ring)

question

Sensory distribution of the median nerve

answer

Palmar surface of the later 3-1/2 fingers (1st, middle, ring)

question

What is the femoral nerve & 3-in-1 block provide?

answer

Anesthesia for the anterior thigh, knee, & small part of the medial foot

question

What are you watching for w/ the nerve stimulator when performing a femoral nerve block?

answer

Quadricep twitch or patellar snap

question

How much LA is injected for a femoral nerve block?

answer

30 mL

question

What nerves are blocked w/ the 3-in-1 block?

answer

The femoral, obturator, & lateral femoral cutaneous nerves

question

Complications of a femoral nerve block

answer

Intravascular injection -> LA toxicity

question

Where does the sciatic nerve originate?

answer

From the lumbosacral trunk

question

What is the sciatic nerve composed of?

answer

The nerve roots L4-5 & S1-3

question

What does the sciatic nerve supply?

answer

Sensory fibers to the posterior hip capsule & knee

question

What does the sciatic nerve provide?

answer

Motor activity to the hamstrings & to all the lower extremity muscles distal to the knee.

question

The sciatic nerve provides all sensory innervation to the lower extemity distal to the knee, except for the ______ aspect, which is covered by the _____ nerve.

answer

anteromedial saphenous

question

How much LA is injected for a sciatic nerve block?

answer

20 mL

question

Where does the femoral nerve lie in relation to the femoral artery (pulse)?

answer

Lateral Medial -> lateral (VAN) Vein - Artery - Nerve

question

What response do you look for when performing a sciatic nerve block w/ a nerve stimulator?

answer

A motor response in the distal ankle, foot, or toes

question

What are the most frequent complication of the sciatic nerve block?

answer

Partial block d/t the branching of the sciatic nerve Intraneural injection

question

What are the 2 major nerves supplying the leg?

answer

The femoral and the sciatic nerves

question

Just below (distal to) the knee, the femoral nerve continues as the ____ ____.

answer

saphenous nerve.

question

In the proximity of the knee, the sciatic nerve bifurcates into the ____ ____ ____ & the ____ _____.

answer

common peroneal nerve tibial nerve

question

What does the common peroneal nerve bifurcate into?

answer

The superficial peroneal never & the deep peroneal nerve

question

What does the tibial nerve give rise to?

answer

The sural nerve

question

What does the ankle block consist of ?

answer

Anesthetizing 5 nerves: Posterior tibial (L4-5, S1-3) Sural (branch of the tibial nerve) Saphenous (branch of the femoral nerve) Deep peroneal (L4-5, S1-2) Superficial peroneal (L4-5, S1-2)

question

Which nerve of the ankle is the most difficult to block?

answer

Posterior tibial

question

Which nerve of the ankle is the most superficial (easier to block)?

answer

All the nerves that begin w/ S (saphenous, superficial peroneal, & sural) & the deep peroneal

question

Which nerve of the ankle is the deepest?

answer

Posterior tibial

question

Describe the tibial nerve

answer

Largest division of the sciatic trunk w/ fiber from L4-S3

question

What does the tibial nerve supply?

answer

Sensation to skin of heel & medial side of the sole of the foot

question

What does the superficial peroneal nerve supply?

answer

Sensation to dorsum of foot & adjacent sides of the 1st -5th toes

question

What is the largest sensory branch of the femoral nerve?

answer

The saphenous nerve (L3-L4)

question

What does the saphenous nerve supply?

answer

Skin on the medial side of the legs, ankle, & onto the foot

question

What does the sural nerve supply?

answer

Sensation to posterior lateral aspect of lower calf & lateral side of foot & 5th toe

question

Where does the deep peroneal nerve enter the ankle?

answer

Between the flexor hallicus longus & the extensor digitorium longus tendons

question

What does the deep peroneal nerve innervate?

answer

Toe extensors

question

What does the deep peroneal nerve supply?

answer

Sensation to the medial half of the dorsal foot, 1st & 2nd digits

question

Describe the location of the 5 nerves of the ankle in relation to a clock.

answer

Deep peroneal at 12 o'clock Saphenous at 3 o'clock Posterior tibial at 5 o'clock Sural nerve at 7 o'clock Superficial peroneal at 9 o'clock

question

Complications of the cervical plexus block

answer

Phrenic nerve block (hiccups) Horner's syndrome Hoarseness (RLN block) Accidental subarachnoid/epidural injection

question

Horner's syndrome

answer

Ptosis, miosis, facial & arm flushing, anhydrosis, nasal congestion (on same side of face as the block)

question

How much LA is used at each level of the cervical plexus block?

answer

3-5 mL

question

Advantages of the interscalene block

answer

Appropriate for shoulder sx Risk of pneumo is small Landmarks are easy to identify in obese pts

question

Problems associated w/ the interscalene block

answer

Parasthesias are elicited Ulner nerve frequently blocked

question

Complications associated w/ the interscalene block

answer

Unintentional epidural/spinal anesthesia Vertebral artery puncture Unilateral phrenic nerve block

question

Dosages of lidocaine, mepivicaine, etidocaine, bupivicaine for interscalene block

answer

20-40 mL

question

Advantages of the supraclavicular block

answer

Brachial plexus most compact here (3 trunks) Quick onset

question

Limitations & problems of the supraclavicular block

answer

Need parasthesias Difficult to perform/teach Pneumo is a risk

question

Contraindications to a supraclavicular block

answer

Severe respiratory ds Bilateral upper extremity block (avoid bilateral phrenic nerve block, avoid pneumo)

question

Dosages of mepivicaine, etidocaine, & bupivicaine for a supraclavicular block

answer

40 mL

question

Advantages of the infraclavicular block

answer

Nerves missed w/ axillary approach are blocked Musculocutaneous nerve blocked

question

Limitations of the infraclavicular block

answer

No pulse to assist locating bundle (needle advanced blindly) If injection too far proximal to the clavicle, the musculocutaneous & axillary nerves are missed

question

Motor effects of the radial nerve

answer

Extension at elbow Supination of forearm Extension of wrist & fingers

question

Motor effects of the median nerve

answer

Pronation of the forearm Flexion of wrist Opposition of the middle, forefinger, & thumb Flexion of the lateral 3 fingers

question

Motor effects of the ulnar nerve

answer

Flexion of wrist Adduction of all fingers Flexion & opposition of medial 2 fingers toward thumb

question

Motor effects of the musculocutaneous nerve

answer

Flexion at elbow

question

What is the maximum volume of solution used on each side of the digit?

answer

2 mL on each side total of 4 mL

question

Complications of intercostal nerve blocks

answer

Pneumo, toxicity of LAs, total spinal, nerve injury

question

What should the tourniquet pressure be for a Bier block?

answer

250-300 mmHg (shouldn't feel a pulse)

question

Dose for a Bier block

answer

40-50 mL of 0.5% lidocaine

question

Contraindications to a Bier block

answer

Infection, poor circulation, seizure disorders, heart block

question

Describe the signs of a perineural injection

answer

May produce a brief accentuation of the paresthesia

question

Describe the signs of a intraneural injection

answer

Produces an intense, searing pain that serves as a warning to immediately terminate the injection and reposition the needle.

question

How can surgical anesthesia of the upper extremity & shoulder be obtained?

answer

Following neural blockade of the brachial plexus (C5-T1) or its terminal branches at several sites.

question

What approach is most optimal for procedures on the shoulder, arm, and forearm?

answer

The interscalene approach

question

Injection at the interscalene level tends to produce a block that is most intense at the ___-___ dermatomes and least intense in the ___-___ dermatomes.

answer

C5-C7 C8-T1

question

What is the most optimal approach for procedures from the elbow to the hand?

answer

The axillary approach to the brachial plexus

question

The axillary approach tends to produce the most intense block in the distribution of ____-____ (____-____).

answer

C7-T1 (ulnar nerve)

question

Infraclavicular blocks

answer

Provide good homogeneous anesthesia to the brachial plexus & can be used for procedures involving the hand, forearm, elbow, & upper arm & are quite conducive for placement of an indwelling catheter for postop analgesia.

question

Femoral nerve block

answer

Useful in numerous procedures involving the thigh & knee, such as skin grafting, knee arthroscopy, & patellar surgery, or as an adjunct to procedures distal to the knee that require anesthesia to the medial aspect of the lower leg (saphenous distribution).

question

Sciatic nerve

answer

Useful for many surgical procedures involving the hip, knee, or distal lower extremity

question

Popliteal nerve block

answer

Useful for foot & ankle surgery Can result in complete anesthesia of the limb distal to the knee if a separate saphenous nerve block (terminal nerve of the femoral nerve) is also included.

question

Contraindications to Peripheral Nerve Blocks.

answer

Uncooperative patient Bleeding diathesis Infection Local anesthetic toxicity Peripheral neuropathy

question

What is generally indicative of an intravascular injection?

answer

An abrupt increase in HR >20% over baseline

question

What produces a field block? Give an example of a field block.

answer

A single injection or multiple injections of a relatively large volume of LA in the general location of cutaneous nerves. Superficial cervical plexus block

question

How do intercostal nerves travel?

answer

In a neurovascular bundle on the undersurface of the inferior border of each rib. The nerve maintains an inferior position in the bundle; from superior to inferior the order is vein, artery, & nerve (VAN).

question

Describe the location of the femoral nerve

answer

The femoral nerve is always lateral to the artery; from lateral to medial the order is nerve, artery, vein, empty space, and lymphatics (NAVEL).

question

When a needle makes direct contact with a sensory nerve, a paresthesia is elicited in its area of sensory distribution. With this technique, it is important to ascertain that the needle is making contact with the nerve rather than penetrating it, and that the injection is in ____ to the ____ (_____) rather than within its ____ (_____).

answer

proximity to the nerve (perineural) substance (intraneural).

question

What can the high pressures generated by a direct intraneural injection cause?

answer

Hydrostatic (ischemic) injury to nerve fibers.

question

What is the brachial plexus formed by?

answer

The union of the anterior primary divisions (ventral rami) of the 5th through the 8th cervical nerves & the 1st thoracic nerves

question

The superior trunk of the brachial plexus is predominantly derived from ___-___, the middle trunk from ___, and the inferior trunk from ___-____.

answer

C5-6 C7 C8-T1

question

This interscalene groove lies at the level of the ____ _____.

answer

cricoid cartilage

question

If a nerve stimulator is used, activity of the phrenic nerve suggests the needle is too "_____," whereas stimulation of the trapezius muscle indicates the needle may be too "_____."

answer

anterior posterior

question

What activity should be elicited when performing an interscalene block?

answer

Motor activity of the arm, wrist, or hand, but success has been reported w/ a response noted in the deltoid or pectoralis muscles, w/ subsequent LA injection.

question

What are the potential side effects of an interscalene block?

answer

The phrenic nerve is commonly blocked-> respiratory failure in patients w/ inadequate pulmonary reserve. Horner's syndrome (myosis, ptosis, & anhidrosis), dyspnea, & hoarseness The proximity of the vertebral artery to the injection site increases the risk of an intraarterial injection->seizures

question

Complications of an interscalene block?

answer

Inadvertent epidural, subarachnoid, or subdural injection Pneumothorax

question

Complications of a supraclavicular block

answer

High incidence of pneumothorax (1-6%) Hemothorax Horner's & phrenic nerve block

question

The infraclavicular approach blocks the brachial plexus at the level of the ____.

answer

cords

question

Complications of an infraclavicular block

answer

Pneumothorax, hemothorax, & chylothorax (with a left-sided block) are possible & occur at a higher rate than w/ the supraclavicular approach.

question

In the axilla, the musculocutaneous nerve has already left the sheath and lies within the ____ ____.

answer

coracobrachialis muscle

question

Describe the locations of the median, ulnar, & radial nerves in relations to the axillary artery

answer

The median nerve lies superior to the pulse. The ulnar nerve lies inferior & the radial nerve inferior-posterior to the pulse.

question

What muscles are innervated by the musculocutaneous nerve?

answer

the biceps and brachialis muscles

question

The musculocutaneous nerve supplies sensory input to the lateral aspect of the ___ & ____.

answer

forearm and wrist

question

Indications of an axillary block

answer

Provides an excellent block for procedures distal to the elbow.

question

What muscle does the radial nerve innervate?

answer

The triceps muscle

question

Where do the sensory branches to the lateral side of the thumb lie?

answer

Between the radial artery and the flexor carpi radialis tendon.

question

Complications of radial nerve blockade

answer

Radial artery injection and intraneural injection

question

Describe the location of the median nerve

answer

At the level of the proximal wrist flexion crease, it lies directly behind the palmaris longus tendon in the carpal tunnel.

question

Complications of median nerve blockade

answer

Brachial artery injection or intraneural injection

question

WHere does the ulnar nerve lie in the wrist?

answer

Lateral to the flexor carpi ulnaris tendon & medial to the ulnar artery.

question

Sensory innervation of each finger is provided by ___ small digital nerves that enter each digit at its base in each of the four corners.

answer

four

question

What are the major nerve distributions to the lower extremities?

answer

The lumbar and the lumbosacral plexi

question

The lumbar plexus is derived from the ventral rami of __-__, with some occasional contribution from ____

answer

L1-4 T12

question

The lumbar plexus, primarily from L2 to L4, forms three major nerves that innervate the lower extremity, what are they?

answer

The lateral femoral cutaneous, femoral, and obturator nerves.

question

What do the lateral femoral cutaneous, femoral, & obturator nerves predominantly supply?

answer

Motor & sensory innervation to the anterior portion of the lower extremity & the cutaneous sensory portion of the medial lower leg

question

The lumbosacral plexus is derived from the nerve roots of ___-__ and ___-___ and primarily forms the ____ _____.

answer

L4-5 S1-3 sciatic nerve

question

What does the sciatic nerve supply?

answer

Both motor & sensory innervation to the posterior aspect of the lower extremity & foot

question

What does the sciatic nerve branch into?

answer

The tibial & the common peroneal nerves.

question

What is the easiest and most commonly used lower extremity block, and what is it typically used for?

answer

Ankle block Foot surgery.

question

What are the four major nerves innervate the lower extremities?

answer

The femoral (L2-4), obturator (L2-4), lateral femoral (L1-3), and sciatic nerves (L4-S3).

question

What is the lumbar plexus derived from?

answer

The ventral rami of the lumbar nerve roots.

question

Describe the coarse of the lumbar plexus

answer

The plexus courses via the "psoas compartment" as defined by the fascia of the psoas muscle (which lies anterior to the plexus) & the fascia of the quadratus laborum (which lies posterior to the plexus).

question

Indications of a lumbar plexus (psoas) block

answer

Anesthetizes the lateral femoral cutaneous, femoral, & obturator nerves. Useful for procedures involving the knee, anterior thigh, & hip.

question

Indications of a femoral nerve (3-in-1) block

answer

Provide anesthesia for the anterior thigh, knee, & a small part of the medial foot.

question

What does the lateral femoral cutaneous nerve (L2-3) supply?

answer

The cutaneous sensory innervation of the lateral thigh.

question

Indications of a lateral femoral cutaneous nerve

answer

For a skin or muscle biopsy or a harvest site for a skin graft from the lateral thigh, an isolated block of this nerve may be performed.

question

What does an obturator nerve block provide?

answer

An obturator nerve block provides anesthesia to the medial thigh & muscle relaxation of the adductor muscles of the hip.

question

What does the obturator nerve supply?

answer

Sensation to the medial thigh & the hip joint & motor innervation to the adductor muscles of the thigh.

question

Indications of an obturator nerve block

answer

Commonly performed as a compliment to additional blocks performed for knee surgery (eg, femoral and sciatic nerve blocks)

question

What nerve originates from the lumbosacral trunk and is composed of nerve roots L4-5 and S1-3?

answer

The sciatic nerve

question

What does the sciatic nerve supply?

answer

Sensory fibers to the posterior hip capsule Motor activity to the hamstrings & to all the lower extremity muscles distal to the knee. All the sensory innervation to the lower extremity distal to the knee except along the anteromedial aspect

question

What nerve provides sensory innervation to the anteromedial aspect of the knee?

answer

Saphenous nerve.

question

Indications of the sciatic nerve block

answer

Procedures involving the hip, knee, or distal lower extremity

question

Complications of the sciatic nerve block

answer

Partial block due to an injection distal to the branching of the sciatic nerve & intraneural injection

question

What is the upper popliteal fossa bounded by?

answer

Laterally by the biceps femoris tendon & medially by the semitendinosus & semimembranosus tendons.

question

Describe the location of the popliteal artery and vein.

answer

Cephalad to the flexion crease of the knee, the popliteal artery is immediately lateral to the semitendinosus tendon. The popliteal vein is lateral to the artery

question

Describe the location of the tibial & common peroneal nerves

answer

Just lateral to the vein and medial to the biceps tendon, 4-6 cm deep to the skin.

question

What are the 5 nerves that supply sensation to the foot?

answer

Saphenous, deep peroneal, superficial peroneal, posterior tibial, & sural nerve

question

What does the deep peroneal nerve provide?

answer

Sensation to the medial half of the dorsal foot, particularly the 1st & 2nd digits

question

What does the saphenous nerve supply?

answer

Superficial sensation to the anteromedial foot

question

What does the superficial peroneal nerve provide?

answer

Cutaneous sensation to the dorsum of the foot & 5 toes.

question

What does the sural nerve provide?

answer

Sensation to the lateral foot.

question

How is the deep peroneal nerve blocked?

answer

By identifying the groove formed proximally by the extensor hallicus longus tendon & the extensor digitorum longus tendons.

question

Complications of an ankle block?

answer

Hydrostatic damage to small nerves, such as those w/in closed ligamentous spaces, like the tibial nerve.

question

Indications of the superficial cervical plexus block

answer

Performed for unilateral procedures on the neck, such as CEA. Also done as an adjunct to an interscalene block used for shoulder surgery, particularly w/ very anterior incisions.

question

Describe the anatomy of the cervical plexus block

answer

The cervical plexus is formed from the anterior rami of C1-4, which emerge from the platysma muscle posterior to the sternocleidomastoid muscle.

question

What does the cervical plexus supply?

answer

Sensation to the jaw, neck, the occiput posteriorly, & areas of the chest & shoulder close to the clavicle.

question

Complications of a cervical plexus block

answer

Rapid systemic absorption and intravascular injection of local anesthetic

question

Indications of an intercostal block

answer

Supplements to GA, for postop analgesia following thoracic & upper abdominal surgery, & for relief of pain associated w/ rib fractures, herpes zoster, & cancer.

question

Where do the intercostal nerves arise from?

answer

The dorsal and ventral rami of the thoracic spinal nerves.

question

Complications of intercostal blocks

answer

Can result in the highest blood levels of LA per volume injected of any block in the body Pneumo

question

Where do the ilioinguinal and iliohypogastric nerves arise primarily from?

answer

L1 but may derive fibers from T12.

question

What does the lateral branch of the iliohypogastric nerve supply?

answer

Sensory to the lateral aspect of the buttock and hip.

question

What does the anterior branch of the iliohypogastric nerve innervate?

answer

The lower abdomen.

question

What does the ilioinguinal nerve supply?

answer

Sensation to the scrotum, penis, & medial thigh in the male, or an equivalent area of the labia & mons pubis in the female.

question

The genitofemoral nerve is derived from ___ & ___.

answer

L1 and L2

question

Innervation of the penis is derived from the ___ ____

answer

pudendal nerve

question

What 2 nerves may additionally provide sensation to the base of the penis via subcutaneous branches?

answer

The genitofemoral and ilioinguinal nerves

question

What signs are characteristic of high spinal and inadvertent cervical epidural anesthesia?

answer

Mental obtundation, apnea, hypotension, and bradycardia

question

Which of the following is a terminal branch of the femoral nerve? A)Saphenous B) Obturator C) Tibial D) Sciatic

answer

A)Saphenous

question

Injury to this nerve eventually causes claw hand. A)Median B) Radial C) Ulnar D) Musculocutaneous

answer

C) Ulnar

question

Which nerve of the ankle is most difficult to block? A) Sural B) Deep peroneal C) Saphenous D) Posterior tibial

answer

D) Posterior tibial

question

What substance decreases the release of substance P in the spinal cord? A) Enkephalin B) Acetylcholine C) Norepinephrine D) Serotonin

answer

A) Enkephalin

question

C fibers synapse in what layers of the dorsal horn? A) Lamina I and IV B) Lamina II and III C) Lamina III and IV D) Lamina IV and V

answer

B) Lamina II and III

question

What spinal cord tract modulates pain? A) Cuneatus B) Gracilis C) Dorsolateral D) Lateral spinothalamic

answer

C) Dorsolateral

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