Ruminant Anesthesia – Flashcards
Unlock all answers in this set
Unlock answersquestion
List the anesthetic agents (that she thinks are important) that have an MRL and therefore and be used in food animals (6)
answer
xylazine Detomidine Azaperone Procaine Isoflurane Various NSAIDs
question
What is bloat/regurgitation of ruminants during anesthesia primarily due to?
answer
positioning >> won't occur unless the animal is *recumbent*
question
Which sedative can make regurgitation happen more often in ruminants? Rarely?
answer
rarely = xylazine Often = acepromazine IF ALSO RECUMBENT
question
What is the pathogenesis of bloat/regurigitation in ruminants during anesthesia?
answer
esophageal spincter is covered with fluid (below the fluid line) so gas is kept in
question
Why is a standing cow not susceptible to bloat (in comparison to a recumbent one)
answer
ruminal fluid line below the esophageal sphincter
question
In cattle, many procedures are performed with what level of anesthesia?
answer
under local anesthesia +/- sedation
question
In sheep and goat, many procedures are performed with what level of anesthesia?
answer
general anesthesia
question
If a cow dies with NSAIDs in its body, why is it such a big problem? How can you kinda skirt around it?
answer
NSAIDs kill birds that will eat the carcass Meloxicam however is not too toxic to vultures
question
Can you use opioids in ruminants?
answer
yes, but it's off label
question
Why is it bad to OD ruminants on opioids?
answer
they tend to get excited
question
Which sedative agents are commonly used in adult cattle (3)? Which ones are licensed?
answer
xylazine = licensed Detomidine = licensed Acepromazine = NOT LICENSED
question
What is the big benefit to using an a2 adrenoceptor agonist to sedate something?
answer
they can be reversed if necessary (eg using atipamezole)
question
TQ: What sedative are cattle ESPECIALLY sensitive to and its very effective in?
answer
xylazine Especially in comparison to horses and dogs
question
How much xylazine should you use in a cow as compared to a horse?
answer
1/10th of the dose *lower dose IV and epidural*
question
What route is not licensed to give xylazine in cattle?
answer
IV
question
When is the use of xylazine contraindicated in cattle? Why?
answer
*last trimester* of pregnancy Increases uterine contractions and vascular resistance and is abortogenic
question
Xylazine has breed sensitivity issues for what spp?
answer
cattle, sheep, goats
question
Major side effect of xylazine in cattle
answer
*hypoxia* >> basically it causes pulmonary edema in the lungs
question
How much detomidine should you give to a cow as compared to a horse?
answer
same amount Doesn't have the dose sensitivity species difference that you see in xylazine
question
Why is detomidine useful for standing surgery
answer
less hyponotic than xylazine therefore the cow is less likely to go down
question
What anesthetic is better when you have a pregnant cow: xylazine or detomidine?
answer
detomidine - less uterine effects
question
Why do you get hypoxia when using a2 in ruminants? (3)
answer
pulmonary cellular infiltration Pulmonary edema Positional (the least important factor)
question
What sedative choice would you use in a pregnant ruminant?
answer
acepromazine/morphine
question
What sedative choice would you use to enhance sedation in ruminants?
answer
acepromazine/morphine
question
What major problem comes when anesthetizing ruminants after giving acepromazine/morphine?
answer
likely to then regurgitate
question
Can you use chloral hydrate in ruminants?
answer
yes BUT not licensed
question
What dilution and volumes of chloral hydrate do you use in ruminants?
answer
use as dilute as possible And infuse a large volume
question
What route of administration must you give chloral hydrate?
answer
IV Very irritating if given outside of a vein
question
What are the potential complications of using general anesthesia in a cow? (5)
answer
regurgitation Bloat Salivation Respiratory depression Hypoxemia
question
Why is salivation a problem in the generally anesthesized cow?
answer
they naturally produce a lot of saliva but this time they aren't swallowing
question
What level of anesthesia can cows do active regurgitation? When?
answer
under light anesthesia Maybe under intubation
question
What are the major reasons a cow will passively regurgitate (4)
answer
deep anesthesia *positioning* Drug specific Disease specific = HIGH RISK IN A DA
question
How long should you deprive a cow of food and water before surgery in order to *prevent regurgitation*?
answer
starve = 12-24 hours Withhold water = 12 hours
question
What should you do if a cow regurgigates while under
answer
keep the head elevated (if you can) and intubate ASAP
question
How can you prevent bloat in a cow during anesthesia? (3)
answer
withhold highly fermentable food 24 hours prior *Minimize anesthetic time* Continue monitoring post operatively
question
Why are cows so prone to bloat during anesthesia?
answer
accumulate CO2 and methane in the rumen still But no eructations wile unconscious
question
Cow bloat during anesthesia messes with what?
answer
ventilation >> causes hypoventilation
question
How can you stop bloat during anesthesia in a cow?
answer
stomach tube Trochar in an emergency
question
Salivation by a cow during surgery can contribute to?
answer
respiratory obstruction
question
TQ? DO NOT administer what drug if you see a cow salivating during anesthesia? Why?
answer
*Atropine >> induces ileus and increases viscidity of saliva*
question
How can you avoid a cow inhalaing its saliva during anesthesia?
answer
intubate
question
Ketamine mixed with what drugs can provide a good alternative sedative for cows?
answer
midazolam Guaifenesin
question
Why is thiopental or other hypnotics not given much to sedate cows?
answer
they metaboliza most hypnotic type sedatives very rapidly
question
Which drug is a cow more likely to regurgitate with: ketamine or thiopental?
answer
thiopental
question
What are the 3 ways to ET tube a cow? What things are needed with each way?
answer
manual palpation - 'guard' the cuff or it'll get damaged on teeth Visual = need a large and expensive laryngoscope Blind = VERY deep anesthesia
question
'Triple drop' for cows? Why?
answer
guaifenesin/ketamine/xylazine Anesthetic maintenance
question
Why do we only use 5% guaifenesin in a triple drip in cows?
answer
they're more sensitive to the hemolysis effects of guaifenesin than horses
question
What should you still be doing during anesthetic maintenance that you did in induction?
answer
intubate and give oxygen
question
Because cows have very shallow and fast breathing during anesthetic maintenance, what should you be prepared to do?
answer
change the CO2 absorber because it'll get used up very quickly
question
Why is it preferable to be able to do mechanical ventilation in cows?
answer
spontaneous ventilation and it tends to be rapid and shallow
question
How do you position a cows head during anesthesia and why?
answer
always keep head elevated and mouth below poll so that saliva, regurgitation drains downwards and out
question
Eye position in ruminants when they're very light?
answer
eyes are down
question
Eye position in ruminants when at a good level of anesthesia
answer
eyes are central
question
HR, RR for cows under anesthesia
answer
HR = 45-80 RR = 15-30
question
What is the tidal volume of cows?
answer
small!!! 4-6 ml/kg
question
Where do you tend to measure direct BP in cows?
answer
auricular artery
question
ETCO2 in cows
answer
tends to be very high
question
Anesthetic drugs cause what complication in cows?
answer
central depression
question
Due to recumbency in cows during anesthesia, what happens?
answer
ventilation/perfusion mismatch
question
Why do cows show hypoventilation during anesthesia?
answer
low chest wall and pulmonary compliance Abdominal pressure on the diaphragm (esp if preggo) Expanding rumen
question
Because cows are so prone to hypoventilation and/or hypoxemia during anesthesia you should be prepared to
answer
mechanically ventilate
question
How do you place cows in anesthetic recovery?
answer
sternal recumbency and well supported BEFORE extubation
question
How long should you maintain the ET tube in cows? NB?
answer
maintain ET tube in situ until chewing/swallowing starts May chew off and inhalate tube o_O Some gags can be used to prevent this from happening
question
What should you give to cows while recovering from anesthesia?
answer
supplementary oxygen
question
Goats are particularly sensitive towhat anesthetics?
answer
local aesthetics Or just easily overdosed
question
Sheep are more likely to get pulmonary edema wih what drugs?
answer
xylazine or other a2 agonists
question
What predisposes sheep to have a worse time during anesthesiia than cows?
answer
more likely to have a preexisting respiratory disease
question
What anesthetic advantages to small ruminants have over cattle?
answer
smaller size so can keep sternal and its practicable to use propofol Many practicable IV injection sites
question
IVcatheterization in goats and sheep jugulars
answer
goats = easy to hit BUT DON'T HIT THE CAROTID Sheep = very mobile skinn over the jugular so the catheter may pull out
question
Why do you need good quality catheter for sheep and goats?
answer
all of their veins are very fragile
question
Why are cephalic catheters in small ruminants advantageous
answer
non-mobile skin
question
What are the main a2 agonists using in small ruminants?
answer
xylazine, medetomidne
question
Why does our prof avoid a2 in the small rumis if possible?
answer
risk of pulmonary edema
question
NB of using acepromazine in small rumis
answer
regurgitation if to be recumbent
question
What benzos are used as sedatives in small rumis? Why do they work well?
answer
diazepam and midazaolam Benzos are so good because they almost work hynoptically
question
What opioids are used as sedative agents in small rumis
answer
morphine, buprenorphine
question
What drugs in ruminants can be used as induction agents but not maintenance agents due to their very rapid metabolism
answer
barbituates and propofol
question
Even though mask induction is used in small rumis, what are they much more likely to do?
answer
regurgitate
question
What is essential in order to intubate a small rumi
answer
laryngoscope
question
What are the 2 ways you can intubate small rumis
answer
visual and blind
question
What drugs make ET intubation in small rumis easier?
answer
'hypnotic' anesthesthetics rather than ketamine
question
In order to intubate a small rumi, what may you need in order to place the tube into the trachea?
answer
a 'stiffener'
question
Maitenance of anesthesia in small ruminants is achieved through
answer
inhalants mainly TIVA - barbituates TIVA - propofol TIVA - alfaxalone TIVA - ketamine combinations
question
How should ruminants be placed during anesthetic recovery? Why?
answer
place in sternal recumbency in order to eructate
question
Do not remove an ET tube in ruminants until
answer
they can maintain sternal recumbency
question
Where is the best target for IV access in camelids?
answer
right jugular vein, high up
question
Why is it difficult to thread a catheter in camelids?
answer
veins have valves
question
Instead of hitting the jugular vein in a camelid, what might you hit instead because it's so close?
answer
carotid artery
question
How think is a male camelids skin? Why do we care?
answer
up to 1 cm really hard to get IV access
question
Besides the jugular, what are the next best veins to access in camels?
answer
cephalic or saphenous
question
If you can't hit a vein in a camelid to administer anesthetics, what should you do?
answer
IM injection is generally a good idea
question
Before nintubation of a llama/alpaca, what should you do?
answer
desensitize the larynx with lidocaine
question
What is essential for the intubation of llamas and alpacas? why?
answer
intubation is difficult! need a guide wire and laryngoscope
question
How long and wide should your ET tube be for a llama/alpaca?
answer
35-40 cm long 8-10 mm diameter wide
question
Llama/alpacas are more or less sensitive to xylazine than other ruminants?
answer
less sensitive to xylazine
question
What can you administer to improve the sedative and analgesia in llamas/alpacas?
answer
opioids
question
During anesthesia, what problems are llamas and alpacas prone to?
answer
hypoxemia
question
During anesthetic recovery, llamas and alpacas shhould be monitored for? what should they be given?
answer
monitor for respiratory obstuction supplement with oxygen
question
When does rumination begin in calves/lambs/kids/creas? Therefore how do you change your anesthetic protocol?
answer
begins at 8-12 weeks old so therefore you shouldn't starve them for too long before that or else risk hypoglycemia
question
What are the best sedatives for baby ruminants?
answer
diazepam/midazolam
question
What gas inhalant is used for mask induction in baby ruminants?
answer
sevoflurane
question
For short anesthetic procedures, what is the best combination to use for TIVA?
answer
xylazine/ketamine
