Anestheitc Induction

Question 1

What is the induction of anesthesia?

Answer 1

Transition from a conscious state to unconsciousness

Question 2

What are the top priorities when inducing anesthesia?

Answer 2

Rapidly secure airways and give oxygen

Maintain cardiovascular function

Induce/maintain anesthesia

Question 3

Why is induction in an inhalation agent via mask not recommended?

Answer 3

Breath hold- longer uptake

Longer to induce and intubation-> chance of aspiration

Slow induction-> can resist handling in excitement phase, stressful and chance for injury

Question 4

Propofol, etomidate, alphaxalone and thiopental all work on what receptor?

Answer 4

GABA agonist

Question 5

What is the most common injectable anesthetic in small animals?

Answer 5

Propofol

Question 6

T/F: propofol can only be used IV

Answer 6

True

Question 7

What effects does propoffol have on the CV system?

Answer 7

Vasodilation and hypotension

not ideal in hemodynamically unstable patient

High dose- may have neg inotropic effect

Question 8

What effect does propofol have on the respiratory system?

Answer 8

Strong depression -apnea possible

Decrease RR
Decreases tidal volume

Question 9

What effect does propofol have on the CNS

Answer 9

Decrease cerebral metabolic O2 consumption

Cause cerebral vasoconstriction

Reduced ICP and volume

Can terminate or induce seizure :O

Question 10

T/F: propofol has an analgesic effect

Answer 10

FALSE

Question 11

How can we keep intracranial pressure low during anesthesia?

Answer 11

Choose your drugs wisely

Increase ICP. -> ketamine and inhalants

Decrease ICP-> all other injectable (propofol, etomidate, alfaxalone)

Question 12

What things should you avoid to keep ICP low?

Answer 12

Hypercapnia or hypoxia 
Hypertension 
Coughing/vomiting 
Head down position
Jugular vein compression

Question 13

What are special considerations if you use propofol in cats?

Answer 13

Slower metabolism
Recovery may be delayed

Pain during IV (small veins0

Repeated admin- hemolysis and heinz body anemia

Question 14

What is the most common induction agent in small animals?

Answer 14

Propofol

Question 15

What is the most common component of TIVA in small animals

Answer 15

Propofol

Question 16

What is the drug of choice for C-section?

Answer 16

Propofol

Question 17

When is propofol contraindicated?

Answer 17

Hemodynamically unstable patients

-hypovolemia and negative inotropic effect

Question 18

What are the CV effects of alfaxalone?

Answer 18

Minimal when given at low doses

Question 19

T/F: alfaxalone causes a dose dependent respiratory depression

Answer 19

True

Question 20

T/F: alfaxalone causes good muscle relaxation and analgesia

Answer 20

False

Good muscle relaxation
No analgesia

Question 21

What is the onset and duration of alfaxalone ?

Answer 21

Rapid onset and short duration

Question 22

Which is better as a CRI, propofol and alfaxalone?

Answer 22

Alfaxalone -> no accumulation

Question 23

What are the routes of admin for alfaxalone

Answer 23

IM and IV

Question 24

Alfaxan is an new formulation of alfaxalone, which benefit does it provide over old formations life Saffan?

Answer 24

No histamine release

Question 25

What is the number one choice for induction of hemodynamically unstable patients?

Answer 25

Etomidate - almost no C effects

Question 26

T/F: etomidate provides no analgesia

Answer 26

True

Question 27

How is etomidate administered?

Answer 27

IV Formulated in propylene glycol/lipid emulsion -> painful if give IM

Question 28

How is etomidate metabolized?

Answer 28

Hepatic and plasma esterases | -> short duration of action (5-10mins)

Question 29

T/F: like alfaxalone, etomidate is a good drug for CRI?

Answer 29

False Contraindicated CRI because of - adrenal suppression - propylene glycol accumulation

Question 30

What effect does etomidate have on ICP?

Answer 30

Similar to propofol Decrease ICP and decrease metabolic demand of O2

Question 31

What opioid could you pair etomidate with to decrease vomiting as a side effect?

Answer 31

Fentanyl -> crosses BBB to inhibit vomiting

Question 32

What type of onset and distribution does thiopental have?

Answer 32

Fast onset, short duration Fast redistribution -> rapid recover But slow distribution - accumulation after repeated doses

Question 33

In what order of compartments does thiopental distribute?

Answer 33

Vessel rich group (CNS)-> rapid induction of anesthesia Muscle group-> redistribution here leads to rapid recovery Fat group

Question 34

Where is thiopental metabolized?

Answer 34

Liver **very slow! Redistribution from muscles and fat is slow -> bad recovery with repeated doses or CRI

Question 35

Can etomidate be used for C-sections

Answer 35

Nope

Question 36

What effects does thiopental have on the CV system>

Answer 36

``` Negative inotropy (more than propofol) Vasodilation (less than propofol) ``` Arrhythmogenic Reflex tachycardia

Question 37

What effects does thiopental have on the CNS and respiratory system?

Answer 37

Similar to propofol decrease ICP Respiratory depression -better muscle relaxation and does not cause twitching

Question 38

Which drug is a dissociative anesthetic?

Answer 38

Ketamine

Question 39

T/F: ketamine has an analgesic effect

Answer 39

True NMDA antagonist

Question 40

Can ketamine be used on its own to induce anesthesia?

Answer 40

Nope Causes catatonic state and catalepsy —> use with benzodiazepine or a2 agonist

Question 41

How can ketamine be administered?

Answer 41

IM or IV

Question 42

Ketamine causes a catatonic state, how does this relate to monitoring anesthetic depth?

Answer 42

- eyes remain open - pupils dilated - palpebral reflex or active - nystagmus - swallowing reflex intact - increased muscle tone —> must use other signs to mentor anesthetic depth

Question 43

What is the MOA of ketamine?

Answer 43

NMDA antagonist -> anesthetic and analgesic effects

Question 44

What are the CV effects of ketamine?

Answer 44

Indirect: Catecholamine release -> increase HR and contractility Direct: negative inotropic * if catecholamines are depleted, negative inotropic effect may dominate

Question 45

What effects does ketamine have on the respiratory system?

Answer 45

Less resp depression Apneustic breathing - breath hold at full inspiration Bronchodilation

Question 46

What are the CNS effects of ketamine?

Answer 46

Cerebral vasodilation: increase intracerebral volume and pressure Increase O2 requirement

Question 47

T/F: ketamine is the drug of choice for induction of anesthesia during ocular surgery

Answer 47

FALSE Contraindicated! Intraocular pressure increases -> may cause rupture with corneal damage

Question 48

How is ketamine metabolized?

Answer 48

To active metabolite in liver Norketamine excreted in urine *cats-> minimally metabolized, mostly directly excreted in kidney—> caution if renal function is reduced

Question 49

When is ketamine indicated?

Answer 49

Most risk patients tolerated in small doses Asthma Initial phase of hypovolemia shock Chemical immobilizing of aggressive animals (good with a2 agonsit)

Question 50

When is ketamine contraindicated?

Answer 50

Brain trauma or tumor (increased ICP) Eye injury HCM and other heart disease Seizure Hepatic and renal insufficiency

Question 51

What is in telazol?

Answer 51

Tiletamine (like ketamine) and zolazepam (benzo)

Question 52

When is telazol useful?

Answer 52

Aggressive small or wild animals Longer acting Formulated as powder and can be diluted as needed