Cardiac III pathophysiology Flashcards
6 general risk factors for perioperative cardiac morbidity and mortality for non-cardiac surgery?
High risk surgery
Hx of ischemic heart disease
Hx of CHF
Hx of cerebrovascular disease
DM
Serum creatinine > 2mg/dL
What issue confers the greatest risk of perioperative MI?
Unstable angina (angina at rest)
What are ACC/AHA guidelines for minimum time before elective surgery if a patient has had an acute MI, and why?
Minimum of 4-6 weeks from acute infarction should pass before elective surgery.
The highest risk of reinfarction is greatest within 30 days of an acute MI.
AHA/ ACC guidelines based on surgical procedure classify which surgical procedures as high risk ( risk > 5 percent)?
Emergency surgery (especially in the elderly)
Open aortic surgery
Peripheral vascular surgery
Long surgical procedure with significant volume shifts and/or blood loss.
Factors that reduce oxygen delivery?
Decreased Coronary Flow
Decreased Ca02
Decreased Oxygen extraction
Factors that increase oxygen demand?
Tachycardia Hypertension SNS stimulation Increased wall tension Increased end diastolic volume Increased afterload Increased contractility
Decreased coronary flow reduces oxygen delivery, what variables cause decreased coronary flow?
increased HR
increased end diastolic pressure
decreased aortic pressure
decreased vessel diameter (spasm or hypocapnia)
The failing ventricle must have a defect in its ability to do what two things? (Heart failure)
fill and/or empty
What is systolic heart failure?
The ventricle does not empty well
What is diastolic heart failure?
The ventricle does not fill properly
When the myocardium’s pumping action fails to satisfy the body’s metabolic demands this is known as?
Heart Failure
What is the hallmark of systolic heart failure? (2)
decreased EF with an increased end-diastolic volume.
What commonly causes systolic heart failure?
Volume overload
What is the defining characteristic of diastolic dysfunction?
symptomatic heart failure with a normal EF
The heart is unable to relax and accept the incoming volume because ventricular compliance is reduced, this is known as?
diastolic heart failure
Cardiac remodeling can be reversed by what two type of drugs?
ACE inhibitors (-pril drugs)
Aldosterone inhibitors (spironolactone)
What induction medication can cause issues as it reduces SNS tone while simultaneously reducing myocardial contractility in the CHF patient?
Propofol
if a drug ends in -sartan then it is most likely what kind of drug?
angiotensin II receptor antagonist (ARB)
if a drug ends in -pril then it is most likely what kind of drug?
ACE inhibitor
If a drug ends in -dipine then it is most likely what kind of drug?
Calcium channel blocker
If a drug ends in -zosin then it is most likely what kind of drug?
alpha adrenergic receptor blocker
If a drug ends in -lol then it is most likely what kind of drug?
beta adrenergic receptor blocker
How do a1 antagonists decrease blood pressure?
decrease vascular calcium leading to vasodilation
decreased SVR (afterload)
What is inotropy?
contractility
what is chronotropic?
heart rate
what is dromotropy?
conduction velocity
what are the cardio selective B1 antagonists?
MAABE
metoprolol, acebutolol, atenolol, bisoprolol, esmolol
name the mixed a1/b1/b2 antagonist drugs (3)
carvedilol
labetalol
bucindolol
what is labetalol a:B antagonistic potency:
IV
PO
IV = 1:7 PO = 1:3
How do Beta blockers that block B1 receptors work (this would be all the beta blockers)
DECREASED: inotropy, chronotropy, dromotropy.
Decreased renin release by juxtaglomerular apparatus
All of the clinically used CCBs bind to what subunit of what channel?
alpha-1 subunit of the L- type calcium channel
If you want to reduce the HR in a patient with tachycardia, a-fib, or atrial flutter what two CCB would be your pick?
verapamil and diltiazem
Which two CCB target the myocardium mostly (compared to the vascular smooth muscle)?
verapamil
diltiazem
Which calcium channel blockers are known to cause vasodilation which leads to decreased SVR?
end in -pine
Which CCB target vascular smooth muscle mostly?
end in -pine
In what type of patient would you want to preserve contractility while reducing the heart rate?
reduced EF patient
ranked from highest to lowest which CCB impair contractility?
verapamil
nifedipine
diltiazem
nicardipine
If a patient has decreased contractility which drug is a better choice than verapamil?
diltiazem
Which CCB is the only CCB proven to reduce M&M from cerebral vasospasm?
Nimodipine
which CCB is useful as a coronary antispasmodic?
Nicardipine
Which three vasodilators (CCB) are best used in the treatment of hypertension from elevated SVR?
Nifedipine
Amlodipine
Nicardipine
What is the preferred technique for pericardiocentesis?
Local anesthetic