All Formulas for Final – Flashcards
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10mg/mL |
1:1000 |
1 mg/mL |
C |
5/9(F-32) |
F |
(9/5C)+32 |
K |
C +273 |
BMI |
Kg/M2 |
BSA |
(Height (cm) x Weight (kg))/3600 then take square root |
Partial Pressure |
Percent Concentration x 760 mmHg |
Percentage of a Gas |
(Partial Pressure/760 mmHg) x 100 |
MAP |
(Systolic + 2Diastolic)/3 |
Systemic Perfusion Pressure |
MAP-CVP |
Cerebral Perfusion Pressure |
MAP-ICP |
Coronary Perfusion Pressure |
Diastolic Pressure- LVEDP |
SVR |
(((MAP-CVP)/CO) x 80 |
pH |
-log(hydrogen concentration) |
Hydrogen Concentration |
10-pH |
4-2-1
Maintanence Fluids |
4 ml x first 10 kg
2 ml x 10 kg
1 ml x remainder of weight |
MABL |
Weight(kg) x Blood Volume x (Hcto-Hctl)/Hcta |
ETT Size |
(Age + 16)/4 |
ETT Depth |
(Age/2)+12 |
Size |
(kg/5)0.5 |
Estimation of Weight in Pediatric Patients |
kg= (Age x 3) +7 |
Average Atomic Weight |
Percentage of your isotope added together |
Osmolarity |
Moles/L of solution |
Osmolality |
Moles/kg of solvent |
Pressure |
Force/Area |
Pascal (Pa) |
1 N m2
|
100 kPa |
1 bar (0.987 atm) |
1 atm |
1.013 bar |
Boyle |
PV=P1V2 |
Charles Law |
V=V1 T=T1
|
Gay-Lussac |
P=P1 T=T1
|
Combined Gas Laws |
PV T
|
Fick Law |
Rate of gas diffusion is proportional to the gradient |
Graham's Law |
States that the rate of diffusion is inversely proportional to the square root of the molecular size |
Henry Law |
States that the partial pressure of gas in a liquid is equal to its partial pressure in the gas phase |
Dalton Law |
States that total pressure of gases in a liquid is equal to the sum of the partial pressures of the gas overlying the liquid |
Ohm's Law |
E=IR
or
P=QR |
Hagan-Poiseuille |
R=8Ln/?r4
Laminar flow
Turbulent |
LaPlace |
T=Pr/2 |
Inward Force |
2?r x Tension |
Outward Force |
?r2 |
Percent by weight to Volume |
g per 100 mL |
Percent by weight to weight |
g per 100 g of solution |
Parts per million |
g of solute/g of solution x 1 million |
Solubility
(Henry's Law) |
S= KH x Pgas |
Raoults Law |
Change in vapor pressure from the introduction of a solute |
Solubility Product |
Ksp= [M+]x[A-]y |
LeChatelier's Principle |
Systems always strive to establish equilibrium |
K
(Equilibirium Constant) |
[D]d[C]c [A]a[B]b
aA+bB=cC+dD
|
pKa |
-log(Ka) |
pH |
pKa + log[A-]/[HA] |
Ohm's Law in Electricity |
E=IR
Voltage= Amperage x Resistance |
Impedence |
Frequency x Inductance
or
1/(Frequency x Capacitance) |
Circuit Breakers |
15-20 A |
Macroshock |
Current flow in excess of 5 mA |
1 mA |
threshold of perception |
10-20 mA |
Let go current |
50 mA |
Pain |
100-300 mA |
V-fib |
6000 mA |
extensive tissue damage |
Line Isolation Monitors |
2-5 mA |
GFCI
Ground Fault Circuit Interrupter |
;5mA shuts everything off |
Upper Limit of Leakage Current |
10 microamps |
Unipolar electrosurgical devices |
Should not be used within 15 cm of a pacemaker |
Alkanes |
CnH2n+2 |
Alkenes |
CnH2n |
Alkynes |
CnH2n-2 |
Alcohols |
R-OH |
Ethers |
R-O-R' |
Amines |
R3N |
Aldehydes |
Hydrogen bonded to the carbonyl group |
Ketones |
Two Alkyl groups bonded to a carbonyl group |
Carboxylic acid |
carbonyl group bonded with a hydoxyl group |
Ester |
Product between carboxylic acids and alcohols |
Amides |
Carboxylic acids and amines |
Carbohydrates |
Cx(H2O)y |
Glucose's energy |
4 kcal/gram |
Glycerides |
Esters composed of glycerol and fatty acid |
Phospholipid |
Phosphate ester group and two fatty acids |
Amino Acids |
Carboxylic Acid (negative) and an Amine group (positive) |
Zwitterion |
Have positive and negative charges within the same molecule |
Nucleic Acids |
Phosphate sugar and a nucleoSide base |
Nucleotides |
Phosphate Ester and a nucleoSide |
Oxygen E Cylinder |
2000 psi
660 L |
Critical Temperature of N2O |
36.5 C
Therefore N2O exists as a liquid in the tank |
N2O E Cylinder |
90-95% liquid
1590 L of gas evolves
745 psi |
Air E-Cylinder |
Nitrogen- 78%
Oxygen- 21%
Argon- 1%
2000 psi |
Regulators |
Decrease the pressure to 50-60 psi
Converts variable high pressure input to a constant low pressure output |
Gauges |
Bourden Tubes
Should be able to read 33% higher than maximum working pressure |
Flush Valve |
35-70 L/min @ 50 psi |
Oxygen Fail Safe Valve |
shuts off other gas flow if oxygen pressure falls below 20-25 psi
Does NOT prevent a hypoxic mixture |
High Flow Rates in Flowmeters |
Floats acts as a constrictor producing turbulent flow
Gas density is the major flow rate factor |
Low FLow Rates in Flowmeters |
Laminar flow is present
Viscosity becomes a major factor in gas flow |
Helium and Oxygen |
Have simular viscosities and can be changed out at low flows |
Carbon Dioxide and Nitrous Oxide |
Have similar densities and can be changed out at high flows |
Decreased barometric pressures |
Underestimates gas flows in flowmeters |
High barometric pressure |
Overestimates gas flow in flowmeters |
Proportioning System |
Equipped to never give gas flow with less than 25% oxygen
ONLY control oxygen and nitrous |
MAC |
Concentration of anesthetic that produces immobility in 50% of patients
When expressed as a PARTIAL PRESSURE it is indepedent from atmospheric pressure |
Des Saturated Vapor Pressure @ STP |
91% |
Iso Saturated Vapor Pressure @ STP |
31% |
Sevo Saturated Vapor Pressure @ STP |
22% |
Vaporizer Output |
O= I + (VP/ATM x O) |
Agent |
O-I |
Pumping Effect is greatest |
at low flow rates and small amounts of liquid in vaporizer |
Desflurane Vaporizer |
Fixed output vaporizer
Heats agent to 39 C to produce 1500 mmHg of pressure
Passes gas flow through a resistance and measuring back pressure to see how much Des to give |
CO2 Absorber Reaction |
CO2 + Ca(OH)2 --> CaCO3 + H2O
Sodium hydroxide is a catalyst and therefore isnt created or destroyed |
CO2 Absorber Fun Facts |
14 kcal of heat is released with each mole of CO2
Resistance is about 10 cmH2O at 60L/min
Want intergranular space to be greater than tidal volume- Canisters have about 500 cc of airspace so should be changed when 1/2 exhausted
Watch out for channeling
1000 gram canister can absorb 200L of CO2 |
CO2 Absorber and Volatile Agents |
CO2 and Sevo react to form Compound A
Des and Iso react with CO2 to form Carbon Monoxide |
Dead Space |
Areas of bi-directional flow
ETT, mask, Y piece |
Coxial or Bain Circuit |
FGF is placed within the expiratory hose |
Types of HME |
Hydrophobic- pleated surface, effective for bacterial and viral filters
Hygroscopic- more effective in increasing humidity rather than bacterial/viral effects |
CO2 Production |
200 cc/min |
Physiological Dead Space |
33% of tidal volume but increases to 50% in IPPV |
O2 consumption |
250 cc/min |
Critical Ventilatory Parameters |
TV
MV
Inspiratory Flow Rate |
Volume Limted Settings |
Are sensitive to air leaks but can overcome changes in compliance and resistance |
Pressure Limited Settings |
Are sensitive to changes in compliance and resistance but not to leaks |
Minute Volme |
80-100 cc/kg/min |
Tidal Volume |
8-10 cc/kg
Constant throughout life |
Inspiratory Flow in Adults |
10-50 L/min |
Bellows |
Anesthetic gases are contained inside the bellows
O2 is pressurizing outside of bellows
Actual tidal volume is a combination of FGF and what is inside the bellows (fresh gas flow coupling)- Tidal volumes are considerably larger than what is shown displaced by the bellows |
Fresh Gas Flow Decoupling |
Volume monitoring with tidal volume adjustment
Diversion of gas during inspiration by a decoupling valve |
NIOSH Recommendations |
Halogenated agents < 2 ppm
Nitrous Oxide < 25 ppm
Halogenated agents + N2O < 0.5 ppm
10 exchanges per hour of OR air |
N2O pollution |
High pressure leaks is the primary cause of pollution when OR not in use |
Savenging System |
19 mm hose
Rigid to withstand 10kg/cm pressure
Exhaust hose from circuit to ventilator system |
Inspiratory Baseline in Capnography |
Phase I
CO2 concentration should be 0
later part represents exhaled dead space |
Expiratory Upstroke in Capnography |
Phase II aka Transition Phase
Lungs recoil and gas exits through trachea
Slanted if airflow is obstructed |
Expiratory Plateau |
Lung units with lower V/Q ratio empty into the sampling site, thus the slight incline |
PaCO2 vs. PeCO2 |
Usually differ between 3-5 mmHg
Arterial is higher because some dead space is lingering about |
Abnormal Capnographs |
Increased Airway Resistance- flattening of expiratory upstroke
Cardiac Oscillation- indicate a very high cardiac output
Curare Clefts- sharp down-stroke during the expiratory plateau indicates ventilatory attempts by the patient- neuromusclar blockade warn off
Elevated Baseline- indicates rebreathing |
Hypoxia |
PaO2 < 60 mmHg |
Oxygen Galvanic Cell |
Ouput voltage is proportional to O2 partial pressure
Voltage produced by the oxygenation of the lead electrode |
Polargraphic Sensors |
Applies current to reduce O2 in hydroxide anion
Change in current is proportional to O2 in solution |
Paramagentic Analyzer |
Applying a magnetic field to a stream of gas changes the pressure of the stream which can be calculated |
Incorrectly Assembled Circuit |
FGF- never between patient and expiratory valve
APL- never between patient and inspiratory valve
Reservoir bag- never between patient and any valve |
CO2 Absorber Failure |
Bypass Valve open
Channeling
Exhaustion |
Minimum Fresh Gas Flow Requirements |
Mapelson A: 70-100 mL/kg/min for spontaneous ventilation
Mapelson D: 70-100 mL/kg/min for controlled ventilation |
Electrical Failure |
30 min of battery backup
Takes 16 hrs to recharge battery
If power goes out ventilator doesnt have backup- youll have to bag
|
Anesthesia Effect on Temperature |
Causes vasodilation
Reduces shivering threshold 2-4 C
Affect BMR, sympathetic tone, and vascular tone |
Accurate Core Temperatures |
PA cather, distal esophagus, tympanic membrane, nasopharynx |
BP Formula |
BP= CO x SVR |
Gravitational Forces on Invasive BP monitoring |
Reduces mean 7.5 mmHg/ 10 cm of height |
Invasive BP Monitoring |
When pressure are taken more peirpherally systolic increases and diastolic decreases
Vascular disease and vasoconstriction decrease peripheral readings up to 50 mmHg
Mean pressure is the area under the waveform |
Arterial Waveform |
Ring= underdampened- results in increased systolic readings
Flattened, dampened peaks= overdampened
Crisp upstroke = hyperdynamic circulation
Broad Peak= high cardiac output
Fast flush should be 1-3 oscillations
Diacrotic Notch= AORTIC VALVE closure |
EKG Paper |
Paper speed 25 mm/sec
0.04 sec each box
Each bold line is 0.2 seconds
HR can be calculated by dividing 300 by the number of bold vertical lines between the QRSs
Horizontal line represents voltage: 1 cm/1mV |
Manual Blood Pressure |
Riva-Rocci
Systolic pressure is lower and diastolic is higher than with direct monitoring
Oscillometric begins with sytolic and maximum is MAP |
Oxygen Content
(CaO2) |
(1.37 x Hgb x O2%/100) + (0.003 x PaO2)
Normal is 20 cc/100 mL blood |
Oxyhemoglobin Dissociation Curve |
PaO2 40, 50, 60= 70 %, 80%, 90% |
O2 Delivery |
(CaO2 x 10) x CO |
O2 consumption |
[1.37 x (Hgb x O2sat/100 - O2venous/100 x Hgb)] x 10 x CO
250 cc/min |
Pulse Oximetry |
Based on the assumption that arterial blood is only pulsatile
660 oxy 940 deoxy
Beer-Lambert
Does not correlate with peripheral perfusion |
EKG Leads |
I- Right arm to left arm
II- Right arm to left leg
III- Left arm to left leg
Augmented leads: aVR, aVF, aVL
V4- mid clavicular line 4th-5th intercostal space
V5- anterior axillary 4th-5th intercostal space
V6- Mid Axillary line 4th-5th intercostal space
In precordial system: neutral electrode is formed by standard leads |
Modified Chest Leads |
MCL look at single precordial leads
MCL 5 is most common to detect lateral wall ischemia
MCL 1- MCL 6
Lead II and V5 are the best at detecting ischemia and arrhythmias |
CO |
Amount of injectate/ area of dillution curve
Stewart-Hamilton formula
When exponential decay reaches 30% it extrapolates to minimize artifacts due to recirculation of the indicator
Errors: reduced volume, slow injectate, warm indicator, tricuspid regurge, assumed precision |
Bioreactance |
Measures phase shift in voltage across the thorax
Phase shift results in pulsatile flow
Amplitude is the magnitude of impedance, phase is the direction of impedance
High frequency 75 kHz sine wave generator and 4 dual electrodes
CO is measured from the average the signals from both sides
Peak rate of change is proportional to peak aortic blood flow during each beat |
LASER |
Light amplification with stimulated emmision of radiation
Coherent, columnated, monochromatic |
CO2 Laser |
< 0.5 mm penetration
Most commonly used b/c limits amount of tissue damage during surgery
Damaged to cornea
Can be blocked with any type of glasses |
YAG and Argon |
YAG: dark tissue, 2-6 mm, deepest penetration
Argon: 0.5-2mm hemoglobin and melanin
Damage to the retina |
Consideration when Using Lasers |
Have goggles and signs
FiO2 less than 30%- N2O is flammable
Metallic coated tubes and airway packed with soaked gauze
No NC- if so off 1 min prior
2 syringes available to put out fire |
Primary Response to Airway Fire |
Remove ETT and any flammable/burning material
Discontinue all gas flow
Pour saline into airway
Ventilate with Low FiO2 to prevent smoldering |
X-Rays |
Sudden deceleration of a stream of electrons
Heat 99% and x-ray photons 1%
30-150 kV
Deadman switch must be held throughout exposure
X-ray scatter is what healthcare providers need to be conscious of |
Factors Determining X-Ray Scatter |
Energy of x-ray beam kV
Size of the part being imaged
Duration of the imaging
Stochastic radation is what we are worried about- cancer causing |
Annual Dose Limit of Radiation |
5 rem
(50 mSv)
Highest radiation exposure in the OR is from Fluroscopy
NORA- CT scans |
Cardinal Principles of Radiation Protection |
Time- short
Distance- I1D12=I2D22
Shielding- 0.5 mm thick lead minimum
Dosimetry Bag if 1/10 of yearly exposure |
MRI |
Atoms aligned by strong magnetic field and a pulse radiofrequency alters their orientation and the process of energy released forms an image |
MRI Hazards |
Ferromagnetic Projectiles
Induction of Heat- EKG leads
Noise- 125 dB
Implanted Objects- pacemakers etc
Tattoos and Eye Makeup
Cardiac Pacemakers
ECG Changes- T wave changes from sumperimposed induced voltage |
MRI Zones |
Zone 1- free access
Zone 2- under supervision of personel
Zone 3- ferromagnetic objects can result in injury or death
Zone 4- MRI scanner magnet room |
Ultra Sound |
Wave travels by compressing and rarefracting matter
Measure in frequency: number of cycles per second Hz
2.5-10 MHz diagnostic ultrasound
High frequency (5-10 MHz) great resolution, poor penetration
Low Frequency (2.5-5 MHz) great penetration, poor resolution
Best images when transducer is perpendicular
Can be continuous or pulsed
B Mode is 2-D images and M-Mode is moving targets |
Doppler Imaging |
Uses low frequency ultrasound waves
Reducing depth and size of the color box and reducing scanning sector will compensation for poor resolution
BART: blue away blood flow, red toward blood flow
Perpendicular is black
Turbulent flow is green or white |