Test 3: 30: CV Flashcards
if pt on ACE inhibitor what to do day of surgery
hold
can cause hypotension from reduced afterload
enalapril, benazepril
if pt on beta blocker what to do day of surgery
do not withhold- can cause rebound effect
beta blocker are used to decrease HR
atenolol, propranolol
if pt on calcium channel blockers what to do day of surgery
ok to continue unless pt is hypotensive or bradycardic
calcium channel blockers are used to decrease BP
amlodipine
if pt on pimobenden what to do day of surgery
Do NOT hold day of surgery
pimobendan is used to increase contractility and decrease afterload
if pt on diuretic what to do day of surgery
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
what are some diagnostics tests for a cardiac workup before anesthesia
Bloodwork
* Complete Blood Count
* HCT
* Chemistry Screen
* BUN/Creatinine
* NTpro-BNP
* Troponin?
Other tests
* Blood Pressure
* ECG
* Chest Radiographs?
* Echocardiogram?
* Arterial Blood Gas?
what is La:Ao
left atrium size compared to aortic root on echo
if left atrium much bigger can indicate volume overload and left sided heart failure
as a cat ages there is a greater risk for what cardiac issue
HCM +/- a murmur
what determines SV
stroke volume: ↑contractility, ↑preload ↓afterload
MAP should be kept above —
MAP > 60 mmHg
how to prevent exacerbation of cardiac disease during anesthesia
↓ fluid use
minimize stress
rapid intervention with ↓BP, HR or arrhythmias
what oral premeds can be used for cardiac anesthetic protocol
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%)
use acepromazine for cardiac pt?
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
can you use ⍺2 agonist for heart pts
⍺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)
can you use opioids for cardiac pt
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
can you use benzodiazepines for cardiac pt
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
alfaxalone
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)
what drug protocol for fractious cardiac pt
- 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
can you use propofol for cardiac pt
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)
can you use alfaxalone for cardiac pts
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
can you use ketamine in cardiac pt
- 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
can you use etomidate for cardiac pts
yes- minimal cardiac effects
- side effect: adrenocortical suppression
- Always combine with sedation (benzodiazepine + opioid) to avoid muscle twitching
once induced how to maintain anesthesia in cardiac pt
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
what monitoring is used for cardiac pt during procedure
Oxygenation
- Pulse oximetry and arterial blood gas analysis
Hemodynamics
- Invasive blood pressure when possible
- +/- Cardiac output monitoring
- +/- Transesophageal echo
Other
- ECG
- Capnography
- Temperature
left sided systolic apical murmur usually means
mitral valve disease
staging for mitral valve disease
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
stage A mitral valve disease
Stage A: High risk of developing mitral valve disease
stage B mitral valve disease
Stage B: Structural heart disease but no failure
- B1: Asymptomatic, no echo/radiographic changes
- B2: Asymptomatic, echo/radiographic changes, NEED treatment- pimodendan
stage C mitral valve disease
Stage C: Heart Failure
left sided systolic apical murmur
stage D mitral valve disease
Stage D: Heart Failure refractory to standard treatment
left sided systolic apical murmur
what is the most common heart disease in dogs
mitral valve disease → left sided systolic apical murmur
Most common in small breed dogs→ prevalence increases with age (85% by age 13)
what drug should a B2 mitral valve disease dog be on
pimodendan
B2: asymptomatic but has echo/xray changes
pimobendan can lengthen time to developing symptoms
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
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
goals for mitral valve disease
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
induction protocol for mitral valve disease pt
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
dilated cardiomyopathy causes
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
goals for DCM pts
- Maintain HR and preload
- Support contractility
- Maintain sinus rhythm
DCM can cause ↓systolic function and LV dilation → MR → Afib and ventricular arrhythmias
protocol for DCM pts
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
DCM can cause ↓systolic function and LV dilation → MR → Afib and ventricular arrhythmias (dobermans and grain free diets)
HCM causes
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)
— is the most common cardiac disorder in cats
HCM (15% increases with age)
HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM
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
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)
HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM
goals for HCM
- Minimize stress: sympathetic activation & tachycardia because it increases myocardial oxygen demand
- Avoid decreased afterload- do not want to vasodilate
- Avoid volume overload/underload
HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM
protocol for HCM pt
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)
HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM
— can have mild bradycardia acceptable, caution with anticholinergics
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
HCM: diastolic dysfunction → LA dilation → CHF, clots, iscemia and arrhythmias. Can progress to HOCM
DCM or HCM you should use dobutamine
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
why avoid ace and ketamine in HCM
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
should also avoid dobutamine and anticholinergics in HCM pts
why use anticholinergics in Mitral valve disease pts
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
mitral valve want to keep fast and loose, avoid bradycardia and increased afterload
— is the Most common congenital disease of large breed dogs
aortic stenosis
Aortic stenosis causes
Increased resistance to outflow → left ventricular hypertrophy → myocardial ischemia
syncope, ventricular arrhythmias, sudden death
goals of Aortic stenosis
similar to HCM cats cause AS causes LV hypertrophy
- Prevent tachycardia
- Prevent arrhythmias
- Maintain adequate blood pressure and cardiac output (coronary perfusion)
protocol for Aortic stenosis
- 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
pulmonary stenosis can lead to —
ventricular arrythmias or RV failure
goals for pulmonary stenosis
- Maintain preload/venous return
- Maintain myocardial contractility
- Prevent tachycardia or severe bradycardia
- Avoid increases in pulmonary vascular resistance
PS: ventricular arrhythmias and RV failure
protocol for pulmonary stenosis
- 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
PDA causes
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
if pulmonary HTN too high what direction will blood flow in PDA
will reverse. will go from pulmonary artery into the aorta, skipping the lungs → cyanosis
goals for PDA
- 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)
protocol for PDA
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
— is most common congenital defect in cat
VSD
VSD can cause
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
goals for VSD
- Prevent right to left shunting
- Maintain SVR
- Avoid increasing PVR (do not want shunt reversing)
protocol for VSD
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
