Veterinary Anesthesia- Small Animal

Front 1

What 3 values are measured by a blood gas machine? What are normal values for each parameter?

Back 1

pH: 7.35-7.45
PaO2: 80-110mmHg
PaCO2: 35-45mmHg

Front 2

What will PaO2 be under ideal situations on 100% O2?
At what Pa02 is an animal defined as hypoxemic?

Back 2

PaO2= 500mmHg
PaO2<60mmHg

Front 3

What are the 5 causes of hypoxemia in animals? Which one of these will not respond to supplemental oxygen?

Back 3

Shunt***
V/Q mismatch
hypoventilation
Diffusion Impairment
Low inspired oxygen fraction

Front 4

What values for PaCO2 are considered too high and too low? Why do we care if it's too low?

Back 4

>60mmHg is too high, though some hypercapnia is beneficial as it provides drive to breathe.
<20-25mmHg is too low, and will cause decreased cerebral blood flow to the brain.

Front 5

What are 3 categories of problems resulting in hypercapnia? What are some examples of each?

Back 5

1. Decreased CO2 elimination (hypoventilation, respiratory mm weakness from mm relaxants or hypokalemia, severe diffusion impairment)

2. Rebreathing (exhausted soda lime, excessive dead space eg long tube, broken 1-way valve)

3. Increased production (malignant hyperthermia, pyrexia)

Front 6

Normally, low CO2=reflex breathing. Which drug does not depress that relationship?

Back 6

ketamine.

Front 7

Name 2 anticholinergics. What receptors do they affect? What are 3 major reasons (2 major, 1 minor) to use them in anesthesia? What are some side effects (name at least 5)

Back 7

Atropine and glycopyrrolate hit the muscarinic receptors, inhibiting vagal bradycardia, decreasing salivation/airway secretions, and decreasing gastric acid secretion. They also cause sinus tachycardia, 2nd degree AV block, ventricular premature contraction, mydriasis, bronchodilation, decreased intestinal motility, decreased bladder and urethral tone

Front 8

What are two dissociatives? How do they act physiologically? What is the major use in anesthesia, plus 2 less-important uses?

Back 8

Ketamine and tiletamine are used for induction of short-term maintenance (in cats and dogs.) They interrupt ascending transmission from unconscious to conscious parts of the brain via depression of thalamocortex. They provide analgesia but very poorly, especially regarding viscera, and produce a VERY SUPERFICIAL sleep.

Front 9

Give 2 undesirable effects of dissociatives and discuss the effects on the heart.

Back 9

They cause increased intracranial pressure/cerebral bloodflow.and ketamine causes profuse salivation. They directly decrease CV function but this results in increased sympathetic tone, leading to increased cardiac output, tachycardia, increased arterial pressure, and sensitization to catecholamine-induced arrhythmias.

Front 10

Name 4 benzodiazepines. What receptor do they affect and how?

Back 10

Clonazapam, diazepam, midazolam, alprazolam; they enhance inhibitory NT GABA by binding to its receptor, activating chloride channels->hyperpolarization.

Front 11

What are 3 major uses for benzodiazepines in anesthesia and their undesirable effects. How do they effect the heart?

Back 11

Tranquilization, muscle relaxation, and anticonvulsion. Decreased cerebral bloodflow; MINIMAL cardiovascular effects.

Front 12

What are 4 alpha 2 agonists? How do they work?

Back 12

Medetomidine, xylazine, Clonidine, and methyldopa work by activating alpha 2 receptors in the dorsal horn of the spinal cord, inhibiting nociceptive transmitters from being released (eg substance P); also hit alpha 2 receptors elsewhere that cause sedation, and presynaptic ANS alpha 2s cause decreased NE release centrally and peripherally.

Front 13

What are the 3 major uses for alpha-2 agonists, and its undesirable effects?

Back 13

Analgesia, sedation, and muscle relaxation. They cause arrhythmias (atropine-responsive bradycardia, 1st and 2nd deg AV blocks, sinus arrest) decreased cardiac output, decreased GI motility/secretion, and variable effects on vascular resistance.

Front 14

Name 2 phenothiazines and their mechanism of action.

Back 14

Chlorpromazine, acepromazine; they hit the basal ganglia, hypothalamus, limbic, and RAS systems, blocking 5-HT (dopamine) receptors and dopaminergic actions.

Front 15

Name 5 uses for phenothiazines in anesthesia, as well as 2 undesirable effects, one desirable but not "important" effect, and describe the effect on cardiac contractility.

Back 15

Used for tranquilization, premedication, sedation, antiemesis, and antihistamine effects. Get decreased vasomotor reflexes (blocking alpha-mediated vasoconstriction->hypotension and reflex tachycardia, hypotheria), decreased GI motility. It usually does NOT affect cardiac contractility, and is an ANTIARRTHYMIC (blocks alpha-1 effects on myocardium)

Front 16

Name 2 opiods that start with M

Back 16

morphine, MEPERIDINE

Front 17

Where does butorphanol work?

Back 17

MIXED AGONIST-- kappa agonist, mu antagonist

Front 18

Where does buprenorphine work?

Back 18

Partial mu agnoist

Front 19

What are the major effects of mu receptor stimulation?

Back 19

supraspinal and spinal analgesia, euphoria, sedation.

Front 20

What are the major effects of kappa receptor stimulation?

Back 20

spinal analgesia, dysphoria, sedation.

Front 21

What are the major benefits of morphine? What are some undesired effects? Which effect is different in cats vs dogs?

Back 21

Analgesia and sedation. Undesirable effects: dose-depending CV depression (atropine-responsive bradycardia), delayed gastric emptying, decreased small intestinal propulsion, urinary retention, diarrhea/constipation. miOsis in dOgs, mydriAsis in cAts.

Front 22

What is an undesirable effect of fentanyl and morphine?

Back 22

Salivation

Front 23

What are some undesirable effects of meperidine on the cardiovascular system? Which of these effects does morphine share?

Back 23

If given rapidly IV->histamine release and hypotension (morphine too!), trachycardia.

Front 24

Name 3 barbiturates and their mechanism of action

Back 24

Thiopental, phenobarpital and pentobarbital bind the GABA receptor and decrease the rate of dissociation of inhibitory neurotransmitters, inhibiting effects of glutamate (which is excitatory) and also alters synaptic transmission by inhibiting sodium and calcium channels while potentiating potassium channels. The upshot is that it prevents passage of impulses to the cerebral cortex.

Front 25

What is the anesthetic use of barbiturates? What are 3 undesirable effects, and a positive effect of one of them?

Back 25

RAPID induction, also maintenance of anesthesia. Dose-dependent cardiovascular despression (transient hypotension->secondary tachycardia), arrhythmias (VPCs, etc), decreased cerebral blood flow and metabolism. Pentobarb is an anticonvulsant.

Front 26

What do we use propofol for? What are 4 undesirable effects?

Back 26

Induction or maintenance of anesthesia. Causes direct myocardial depression, peripheral vasodilation/venodilation, decreased MAP/CO (dose-dependent); heart rate may go up or remain unchanged.

Front 27

Name the side effects of gas inhalants.

Back 27

DDCVS (lower contractility, output, MAP, stroke volume), peripheral vasodilation, myocardial sensitization to catecholamine arrhythmias (esp halothane). Also decreased renal blood flow, increased cerebral bloodflow (dilation of cerebral vessels.)

Front 28

Name 3 sympathomimetics, and describe the various receptors to them and the effects of each receptor.

Back 28

Dopamine, dobutamine, epinephrine. B1: positive inotrope.
D1, D2: vasodilation of renal/mesenteric avsculature.
a1: vasoconstriction

Front 29

Why would you use sympathomimetics in anesthesia?

Back 29

Inotropic support; maintenance of renal bloodflow, treatment for shock, hypotension, restoration of heart activity after arrest, treating bradycardia that won't respond to anticholinergics