Cardiac Surgery

Question 1

Cardiac Cycle

Answer 1

Systole: ventricles contraction and ejection
Diastole: ventricles relax and fill
CO: SV x HR
Frank-starling relationshi

Question 2

Preload

Answer 2

Volume of blood in ventricle before systole

Used to estimate LV end diastolic volume

Question 3

After lost

Answer 3

Resistance to ejection of blood by each ventricle

Question 4

Cardiac perfusion pressure

Answer 4

Aortic diastolic BP - LVEDP

Question 5

Starlings law

Answer 5

Contractility depends on muscle fiber length

Question 6

Cardiac index

Answer 6

CO/BSA

Question 7

SVR

Answer 7

(MAP-CVP)x80]/CO

Question 8

Determinants of myocardial perfusion

Answer 8

Supply: CPP, HR, PaO2, coronary diameter
Demand: myocardial O2 consumption, HR, LV wall tension, contractility, conduction, relaxation

Question 9

HTN

Answer 9

Goal is to keep it within 20% of baseline

BP cuff or art-line

Question 10

Mitral Stenosis

Answer 10

Pathophys: high LA pressure -> pulmonary edema->LV hypertrophy 
- develop pulmonary HTN 
-atrial kick provides 40% of filling
-SV fixed
Anesthesia: maintain preload, SV, HR
- prevent high PVR

Question 11

Mitral Regurg

Answer 11

Pathophys: regurgitate fraction (volume or MR/total LV SV) >0.6 =severe
-acute MR: high pulmonary pressure and congestion
-chronic MR: increased LA size and compliance
Anesthesia: maintain normal HR, avoid myocardial depression, avoid high SVR

Question 12

Corona ties

Answer 12

LAD- anterior 2/3 of IV septum, anterior papillary muscle, anterior of LV
Circumflex-lateral and posterior wall of LV
Right main-RV, AV and SA node
PDA-inferior and posterior ventricles and posterior 1/3 of IV septum

Question 13

Aortic Stenosis

Answer 13

Pathophys: blood flow obstructed during systole->concentric LV hypertrophy->dependence on atrial kick->SV fixed->ischemia
Anesthesia: maintain HR, avoid low SVR->will cause CO to drop because SV fixed
-avoid myocardial depression
-consider art-line and per cutaneous pacing

Question 14

Aortic Regurgitation

Answer 14

Pathophys: acute=surgical emergency->acute pulmonary edema and congestion
-chronic=LV compensates with dilation and hypertrophy which leads to heart failure
Anesthesia:maintain HR, avoid high SVR->worsens regurg, consider vasodilator to decrease after load