Cardiac

Question 1

When cross-clamping the aorta, when is the most critical time?

Answer 1

Release of cross-clamp

Clamping the aorta greatly increases LV after load and can induce L heart failure

However, when you release the clamp, there is a large drop in after load + vasodilators and blood loss from surgery –> all lead to profound hypotension

Question 2

On TEE, how can you identify the 3 cusps of aortic valve?

Answer 2

Non-coronary cusp = always next to inter-atrial septum

Question 3

How does cardioplegia help cardiac function during bypass?

Answer 3

Causes demand of O2 consumption of myocardium to drastically decrease

Allows surgeon to operate on “still” heart

Question 4

How do you determine dominance of the heart?

Answer 4

Where does the Posterior Descending Artery originate from? L or R coronary artery

70% R dominant
20% L dominant
10% co-dominant

Question 5

What physiologic parameters do you want to avoid in aortic stenosis?

Answer 5

Avoid tachycardia (inadequate stroke volume)
Avoid low BP (drop in afterload will cause heart to reduce stroke volume)

Keep HR slow
Keep BP high

Question 6

Anginal pain can be from what 2 sources?

Answer 6

Aortic stenosis

Coronary disease

Question 7

What 2 variables comprise MAP?

Answer 7

CO x SVR

Question 8

Calculation for coronary perfusion pressure?

Answer 8

Diastolic BP - LVEDP

Question 9

Best way to increase oxygenation?

Answer 9

Hgb –> O2 content formula has Hgb increasing by factor of 1.34

Question 10

How is coronary flow affected with aortic regurgitation?

Answer 10

Overtime have increased LVEDP - this expansion will compress coronaries if left untreated

Question 11

Signs of mitral stenosis?

Answer 11

Hoarseness: distended L atrium and pulmonary artery can compress L recurrent laryngeal nerve
*A-Fib: one of 4 common triggers for A-fib (HEMP)

Question 12

Calculating MAP?

Answer 12

(Pulse pressure / 3) + diastolic bp

Pulse pressure= systolic - diastolic