Test 3: 30: CV

Question 1

if pt on ACE inhibitor what to do day of surgery

Answer 1

hold
can cause hypotension from reduced afterload

enalapril, benazepril

Question 2

if pt on beta blocker what to do day of surgery

Answer 2

do not withhold- can cause rebound effect

beta blocker are used to decrease HR

atenolol, propranolol

Question 3

if pt on calcium channel blockers what to do day of surgery

Answer 3

ok to continue unless pt is hypotensive or bradycardic

calcium channel blockers are used to decrease BP

amlodipine

Question 4

if pt on pimobenden what to do day of surgery

Answer 4

Do NOT hold day of surgery

pimobendan is used to increase contractility and decrease afterload

Question 5

if pt on diuretic what to do day of surgery

Answer 5

case by case- hold day of surgery unless activly in heart failure

there is increase risk of hypotension and hypokalemia if they remain on the diuretic

furosemide

Question 6

what are some diagnostics tests for a cardiac workup before anesthesia

Answer 6

Bloodwork
* Complete Blood Count
* HCT
* Chemistry Screen
* BUN/Creatinine
* NTpro-BNP
* Troponin?

Other tests
* Blood Pressure
* ECG
* Chest Radiographs?
* Echocardiogram?
* Arterial Blood Gas?

Question 7

what is La:Ao

Answer 7

left atrium size compared to aortic root on echo

if left atrium much bigger can indicate volume overload and left sided heart failure

Question 8

as a cat ages there is a greater risk for what cardiac issue

Answer 8

HCM +/- a murmur

Question 9

what determines SV

Answer 9

stroke volume: ↑contractility, ↑preload ↓afterload

Question 10

MAP should be kept above —

Answer 10

MAP > 60 mmHg

Question 11

how to prevent exacerbation of cardiac disease during anesthesia

Answer 11

↓ fluid use
minimize stress
rapid intervention with ↓BP, HR or arrhythmias

Question 12

what oral premeds can be used for cardiac anesthetic protocol

Answer 12

Gabapentin

• Mild sedation in cats with mild impact on echocardiographic findings (remained in reference range)
• May reduce need for other premedications
• Improved cardiovascular stability in people

Trazodone

• Improved signs of anxiety in cats with no significant effect on physical exam findings
• Oral trazodone has minimal cardiovascular impacts in healthy dogs
• MAC sparing (17%)

Question 13

use acepromazine for cardiac pt?

Answer 13

not usually

• causes vasodilation via ⍺ blockade
• NOT reversible
• Contraindicated in patients with hypertrophic cardiomyopathy
• Low-dose may be tolerated in patients with mild mitral valve disease

acepromazine: dopamine 2 receptor antagonist and anti ANS(⍺1 and 2, m1, H1, 5HT2) → sedative, ↓BP, ↑spleen size, ↓temp, ↓vomiting

Question 14

can you use ⍺2 agonist for heart pts

Answer 14

⍺2 agonist will increase afterload and can cause reflex bradycardia → ↓ cardiac output

• should not be used in pt with decrease systolic function (DCM)
• may be beneficial in cats with HOCM
• reversible - atipamezole (antisedan)

dexmedetomidine, xylazine: cause sedation, analgesia, ↓SYM: ↓HR ↓BP

peripheral: vasoconstriction: ↑BP, reflex ↓HR
central: ↓SYM: ↓BP and ↓HR (can use atropine to counteract)

Question 15

can you use opioids for cardiac pt

Answer 15

yes- well tolerated

• Important to treat pain
• Minimal impacts on blood pressure
• Can cause vagally-mediated bradycardia- but can be treated with anticholinergics (atropine)
• MAC sparing
• Reversible with naloxone

Question 16

can you use benzodiazepines for cardiac pt

Answer 16

yes

• Minimal impact on cardiovascular function
• May not offer optimal sedation in most patients (can cause dysphoria) →need to combine with opioid or use as co-induction agent
• MAC sparing
• Reversible-flumazenil

diazepam, didazolam

Question 17

alfaxalone

Answer 17

steroid
sedation with no analgesia effect
rapid onset- can be IM for angry animals

can cause excitatory during recovery- give with sedation or analgesia (opioid) to prevent this

less CV effects then propofol
Resp: ↓RR and swallow reflex
Metabolism: liver but safe to use in sighthounds and cats

caution with animals with respiratory problems, CV disease (CHF)

Question 18

what drug protocol for fractious cardiac pt

Answer 18

• Oral premedication at home (gabapentin/ trazodone)
• Alfaxalone(sedation) /Butorphanol(opioid) IM
• Minimal impacts on cardiac output
• Mild impacts on echo findings in healthy cats and dogs
• Favorable compared to
  dexmedetomidine/butorphanol in cats

butorphanol: opioid: κ agonist + μ antagonist: minimal analgesia, mild sedation
alfaxalone: IM anesthetic, no analgesia, less CV effects then propofol, use with opioid to prevent excitability

Question 19

can you use propofol for cardiac pt

Answer 19

would not recommend

• Dose and rate dependent vasodilation → hypotension
• Dose and rate dependent hypoventilation → hypoxemia
• Minimize induction dose needed when possible
• Avoid in severely compromised patients (CHF)

Question 20

can you use alfaxalone for cardiac pts

Answer 20

better then propofol but still not great

• Dose dependent ↑HR and vasodilation in dogs, can cause ↓HR in cats
• Cardiac output typically maintained
• Minimize dose when possible
• May be preferable over propofol for mild cardiovascular disease
• Avoid in severe cardiac disease

Question 21

can you use ketamine in cardiac pt

Answer 21

• Increases sympathetic tone → increases HR, BP, afterload
• Contraindicated in HCM → increased work causes ↑O2 consumption, O2 runs out and cause ischemia → arrhythmias
• Direct myocardial depression
• Analgesic
• ↑SYM: may be beneficial in mild mitral valve disease

ketamine: dissociative anesthetic: block NMDA(excitatory glutamate receptor) → intense analgesia, light sleep, catalepsy(muscle rigidity), violent recovery, apneustic breathing, can cause ↑HR, CO, MAP in healthy pts, but in sick pts can have negative inotropic and vasodilatory effect →arrhythmia

Question 22

can you use etomidate for cardiac pts

Answer 22

yes- minimal cardiac effects

• side effect: adrenocortical suppression
• Always combine with sedation (benzodiazepine + opioid) to avoid muscle twitching

Question 23

once induced how to maintain anesthesia in cardiac pt

Answer 23

Inhalants cause dose-dependent hypotension → vasodilation and decreased contractility. Use lowest amount possible

TIVA with propofol or alfaxalone may cause less hypotension. But is Not as rapidly eliminated as inhaled drugs during cardiac arrest

MAC Sparing protocols
* Locoregional anesthesia when possible
* Opioid CRI →Fentanyl or remifentanil
* Lidocaine CRI →Reduces ventricular arrhythmias

Question 24

what monitoring is used for cardiac pt during procedure

Answer 24

Oxygenation

• Pulse oximetry and arterial blood gas analysis

Hemodynamics

• Invasive blood pressure when possible
• +/- Cardiac output monitoring
• +/- Transesophageal echo

Other

• ECG
• Capnography
• Temperature

Question 25

left sided systolic apical murmur usually means

Answer 25

mitral valve disease

Question 26

staging for mitral valve disease

Answer 26

**Stage A:** High risk of developing mitral valve disease **Stage B**: Structural heart disease but no failure * B1: Asymptomatic, no echo/radiographic changes * B2: Asymptomatic, echo/radiographic changes, **NEED treatment** **Stage C**: Heart Failure **Stage D**: Heart Failure refractory to standard treatment

Question 27

stage A mitral valve disease

Answer 27

**Stage A:** High risk of developing mitral valve disease

Question 28

stage B mitral valve disease

Answer 28

**Stage B**: Structural heart disease but no failure * B1: Asymptomatic, no echo/radiographic changes * B2: Asymptomatic, echo/radiographic changes, **NEED treatment- pimodendan**

Question 29

stage C mitral valve disease

Answer 29

**Stage C**: Heart Failure ## Footnote left sided systolic apical murmur

Question 30

stage D mitral valve disease

Answer 30

**Stage D**: Heart Failure refractory to standard treatment ## Footnote left sided systolic apical murmur

Question 31

what is the most common heart disease in dogs

Answer 31

mitral valve disease → left sided systolic apical murmur Most common in small breed dogs→ prevalence increases with age (85% by age 13)

Question 32

what drug should a B2 mitral valve disease dog be on

Answer 32

pimodendan B2: asymptomatic but has echo/xray changes pimobendan can lengthen time to developing symptoms

Question 33

Which of the following would you select as an anesthetic protocol for a 12 year old female toy poodle with B2 mitral valve disease undergoing anesthesia for a mastectomy? A) Dexmedetomidine, ketamine/midazolam, isoflurane B) Fentanyl, midazolam, alfaxalone, epidural, isoflurane +/- fentanyl CRI C) Acepromazine, hydromorphone, propofol, isoflurane D) Etomidate, isoflurane

Answer 33

**B:** alfaxolone has less CV effects, combined with opioid (fentanyl and benzo- midazolam) to prevent excitabolity, then use local epidural, and maintain on iso with CRI opioid-fentanyl as needed would not use A: dexmedatomidine (⍺2 agonist) counterindicated cause it ↑ afterload, also no opioid used for pain control C: could use for B1(no echo changes) excitable dog: ace (sedation), hydro (opioid) D: etomidate is great but needs to be combined with benzo to prevent excitability, also no opioid for pain relief

Question 34

goals for mitral valve disease

Answer 34

leaky valve: fast and loose * Maintain HR → **Avoid bradycardia** do not want more diastolic fill time, because when heart contracts that mean even more blood would go backwards * Maintain contractility * Maintain blood pressure → **Avoid increased afterload**

Question 35

induction protocol for mitral valve disease pt

Answer 35

keep fast and loose * Premedicate or co-induce with **opioid, benzodiazepine** * Minimize propofol or alfaxalone dose * Minimize inhalant * Liberal use of **anticholinergics** (do not tolerate bradycardia →try to keep HR up) * Judicious/↓ use of fluids * Support blood pressure with dopamine/dobumatine

Question 36

dilated cardiomyopathy causes

Answer 36

Decreased systolic function and left ventricular dilation →mitral annular stretch → mitral regurgitation (**most do not have murmur**) can cause arrhythmias: Afib and Ventricular arrhythmia * Doberman or grain free, taurine deficiency

Question 37

goals for DCM pts

Answer 37

* Maintain HR and preload * Support contractility * Maintain sinus rhythm ## Footnote DCM can cause ↓systolic function and LV dilation → MR → Afib and ventricular arrhythmias

Question 38

protocol for DCM pts

Answer 38

very similar to mitral valve disease pts * Opioid based premedication * Induction with midazolam + alfaxalone/etomidate * Dobutamine for inotropic support * Lidocaine for sudden onset Afib/ Vtach * Consider electro-cardioversion if unresponsive Afib & hemodynamically unstable ## Footnote DCM can cause ↓systolic function and LV dilation → MR → Afib and ventricular arrhythmias (dobermans and grain free diets)

Question 39

HCM causes

Answer 39

ventricular hypertrophy → **diastolic dysfunction (can't relax)** this can lead to LA dilation → **CHF and clot formation** in the LA, **myocardiac ischemia and arrhythmias** can have systolic anterior motion of the mitral valve (SAMI) →**HOCM** (mitral valve sucked into aorta)

Question 40

--- is the most common cardiac disorder in cats

Answer 40

HCM (15% increases with age) ## Footnote HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM

Question 41

Which of the following would you select as an anesthetic protocol for a fractious 13 year old MC DSH with HCM without evidence of heart failure undergoing anesthesia for dental extractions? A) Dexmedetomidine IM, induce with ketamine/midazolam, maintain on isoflurane B) Acepromazine + hydromorphone IM, induce with propofol, maintain on isoflurane C) Alfaxalone + methadone IM, induce with propofol + midazolam, maintain on isoflurane, perform dental blocks D) induce with Etomidate, maintain on isoflurane

Answer 41

A) Dexmedetomidine IM, induce with ketamine/midazolam, maintain on isoflurane (NO opioid, dexmed (⍺2agonist) Contraindicated in pts with **decreased systolic function** because it decreases cardiac output by increasing afterload and reflex ↓HR. Ketamine will cause ↑HR which is bad cause HCM can cause arrhythmias) B) Acepromazine + hydromorphone IM, induce with propofol, maintain on isoflurane (ace and propofol will drop BP which may decrease perfusion to very thick myocardium →ischemia) **C: Alfaxalone + methadone IM, induce with propofol + midazolam, maintain on isoflurane, perform dental blocks** (alfaxalone have ↓CV effects and can be given IM for angry cat, opioid good for pain. prop + midazolam together will not need as much meds and will have less ↓ in BP, use of local blocks will decrease other meds needed) D: induce with Etomidate, maintain on isoflurane (etomidate needs to be given IV, this is angry cat- will not work, no opioid, need benzo for etomidate to avoid excitability) ## Footnote HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM

Question 42

goals for HCM

Answer 42

* **Minimize stress**: sympathetic activation & tachycardia because it increases myocardial oxygen demand * Avoid decreased afterload- do not want to vasodilate * Avoid volume overload/underload ## Footnote HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM

Question 43

protocol for HCM pt

Answer 43

**Premedication** with alfaxalone +opioid * Can consider low dose dexmedetomidine especially if HOCM * **Avoid** acepromazine **Induction with**: * Alfaxalone + midazolam * Etomidate + midazolam * Propofol +midazolam * **Avoid** ketamine/tiletamine cause they cause ↑SYM (↑HR) **Other** * Maintain on inhalant with locoregional when possible, consider MAC sparing opioid * Low dose IV crystalloids (~3ml/kg/hr) * **Mild bradycardia acceptable**, caution with anticholinergics * Treat hypotension with dopamine/norepinephrine (**avoid dobutamine**- do not need heart to pump harder, their systolic function is normal okay) ## Footnote HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM

Question 44

--- can have mild bradycardia acceptable, caution with anticholinergics

Answer 44

HCM- the lower HR will allow more time for heart to fill this is opposite to mitral valve disease where lower HR = more blood = more regurg ## Footnote HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM

Question 45

DCM or HCM you should use dobutamine

Answer 45

**DCM: dobutamine for inotropic support**(↑ systolic). DCM have ↓ systolic function and LV dilation and MR and Afib. HCM: do not use dobutamine: treat ↓BP with dopamine/NE: HCM have ↓ diastolic function but normal systolic function do not need dobutamine to make it pump harder

Question 46

why avoid ace and ketamine in HCM

Answer 46

HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM **Acepromazine**- cause vasodilation which decreases blood back to heart, not reversible **Ketamine**: increases symp tone (↑HR, BP and afterload) HCM cats have normal systolic function and increased HR will limit filling time → ischemia and arrhythmias ## Footnote should also avoid dobutamine and anticholinergics in HCM pts

Question 47

why use anticholinergics in Mitral valve disease pts

Answer 47

want to prevent bradycardia if slower HR, then more blood into ventricle and when heart pumps then more blood will regurg. use atropine to increase HR and avoid bradycardia ## Footnote mitral valve want to keep fast and loose, avoid bradycardia and increased afterload

Question 48

--- is the Most common congenital disease of large breed dogs

Answer 48

aortic stenosis

Question 49

Aortic stenosis causes

Answer 49

Increased resistance to outflow → left ventricular hypertrophy → myocardial ischemia syncope, ventricular arrhythmias, sudden death

Question 50

goals of Aortic stenosis

Answer 50

similar to HCM cats cause AS causes LV hypertrophy * Prevent tachycardia * Prevent arrhythmias * Maintain adequate blood pressure and cardiac output (coronary perfusion)

Question 51

protocol for Aortic stenosis

Answer 51

* **Avoid stress** (consider oral premedication if needed) * **Avoid anticholinergics** (unless severe bradycardia) and acepromazine * Dexmedetomidine controversial (low dose may be acceptable) * **avoid ketamine** (do not want to increase HR) * Opioid, BZD, alfaxalone/propofol/etomidate * Lidocaine CRI * Opioid CRI

Question 52

pulmonary stenosis can lead to ---

Answer 52

ventricular arrythmias or RV failure

Question 53

goals for pulmonary stenosis

Answer 53

* Maintain preload/venous return * Maintain myocardial contractility * Prevent tachycardia or severe bradycardia * **Avoid increases in pulmonary vascular resistance** ## Footnote PS: ventricular arrhythmias and RV failure

Question 54

protocol for pulmonary stenosis

Answer 54

* Premedicate if needed (opioid)-avoid tachycardia * Induce with opioid, benzodiazepine, lidocaine + low dose propofol or alfaxalone or etomidate * **avoid** ketamine (causes ↑HR) * Can use **higher fluid rates** (5ml/kg/hr) to maintain preload * **Avoid** hypercapnia, hypoxia, acidosis, hypothermia, pain

Question 55

PDA causes

Answer 55

shunt from descending aorta to pulmonary artery → more blood in left side of heart Left sided CHF (50% dead in 1 year) if PDA bad enough pulmonary HTN will cause shunt to reverse → cyanosis

Question 56

if pulmonary HTN too high what direction will blood flow in PDA

Answer 56

will reverse. will go from pulmonary artery into the aorta, skipping the lungs → cyanosis

Question 57

goals for PDA

Answer 57

* **Maintain CO and HR** (want to keep HR ↑ to decrease amount of blood that leaks through during diastole) * **Minimize reductions in SVR** * **Minimize increases in PVR** (shunt can reverse cause hypoxemia)

Question 58

protocol for PDA

Answer 58

**Premedication** with opioid +/- benzodiazepine +/- alfaxalone +/- ketamine * Utilize anticholinergic if bradycardic * Pre-oxygenate to avoid hypoxemia → increased PVR (want to avoid shunt reversal) **Induce with**: benzodiazepine + ketamine or etomidate or alfaxalone or low dose propofol * Maintain HR * Treat hypoventilation rapidly, prevent desaturation **Maintain** with inhalant + opioid CRI * Treat bradycardia * Treat hypotension with dopamine **Fluid restrictive** (~2ml/kg/hr) **2 pulse oximeters** →Caudal pulse oximeter can detect shunt reversal sooner as PDA on descending aorta

Question 59

--- is most common congenital defect in cat

Answer 59

VSD

Question 60

VSD can cause

Answer 60

shunts blood from left to right if it gets very bad: RV hypertrophy will cause shunt to reverse to right to left →cyanosis and poor prognosis

Question 61

goals for VSD

Answer 61

* Prevent right to left shunting * Maintain SVR * Avoid increasing PVR (do not want shunt reversing)

Question 62

protocol for VSD

Answer 62

**Premedication** with opioid +/- benzodiazepine * **Avoid acepromazine**—systemic hypotension **Pre-oxygenate** to avoid hypoxemia → increased PVR **Induce with**: benzodiazepine + ketamine or etomidate or alfaxalone or low dose propofol * Maintain HR * Treat hypoventilation rapidly, prevent desaturation **Maintain** with inhalant + opioid CRI * Treat hypotension with dopamine