Chapters 141-153 Cardiac Anesthesia

Question 1

Describe what “demand ischemia” is.

Answer 1

in cases without plaque rupture, increased O2 demand from elevated catecholamines during perioperative period from surgical stress and hypercoagulable period cause ischemia in setting of severe preexisting CAD

Question 2

Describe difference in terms of where the problem is in relation to the coronary artery for STEMI an NSTEMI.

Answer 2

STEMI- total coronary occlusion; NSTEMI- subtotal occlusion although many other factors such as preexisting collaterals, coronary vasospasm, O2 level can alter this generalization

Question 3

What can you use intraopeatively to assess for ACS?

Answer 3

Multi lead EKG, Pulmonary artery occlusion pressure and TEE

Question 4

In settings other than ACS when might you see elevated troponins?

Answer 4

A fib RVR, PE, cardiac trauma, stress cardiomyopathy, acute neurologic disease, critical illness

Question 5

Patients that have HITT have an antibody to what?

Answer 5

Heparin-platelet factor 4 complex

Question 6

What can you use for anticoagulation in patients with HITT?

Answer 6

Direct-acting thrombin inhibitor such as Bivalirudin or Argatraban.

Question 7

What are compensatory mechanisms the body does to try to improve CO with heart failure?

Answer 7

Activation of the renin-angiotensin-aldosterone system, natriuretic peptide to increase fluid retension, cause peripheral vasoconstriction and ventricular remodeling

Question 8

When should you consider putting in an ICD in patients with heart failure

Answer 8

When the EF

Question 9

What at the various types of VADs in terms of left/right, type of mechanism. location and goal therapy?

Answer 9

Right and left VADS
pulsatile or nonpulsatile
location: paracorpally, intracorpareally
Goals: recovery (short term), bridge to transplant or destination therapy

Question 10

Describe the 1st generation VAD

Answer 10

pulsatile pumps with valves located paracorpally; for short to intermediate term use; for bridge to transplant or bridge to recovery; portable

Question 11

Describe the 1st generation VAD and their use

Answer 11

pulsatile pumps with valves located paracorporeally; for short to intermediate term use; for bridge to transplant or bridge to recovery; portable

Question 12

Describe 2nd generation VAD and their use

Answer 12

intracorporeal, nonpulsitile, without valves; used for bridge to transplant and destination therapy

Question 13

Describe 3rd generation VAD and their use

Answer 13

intracorporeal, bearingless that use magnetics and hydrodynamics to suspend impellers; bridge to transplant

Question 14

What cardiac anatomic anomolies must be repaired before implanting a VAD?

Answer 14

PFO must be repaired- beca se LAVD will creaed negative pressure and this will prevent paradoxical embolism.

Aortic insuffiency- it might create a flow loop of blood flowing from device into aortic root and is drawn back through the incompetent valve back into device

Mitral regurgitation- decrease effectiveness

Question 15

How can you treat hypotension in patient with total artifical heart

Answer 15

Avoid iontropes–duh.

Fluid and vasopressors

Question 16

What are common abnormalities that patients may get with nonpulsatile LVADs?

Answer 16

GI bleeding from AV malformations in GI tract and bladder

Question 17

How do you measure blood pressure in patient with 2nd or 3rd generation VAD?

Answer 17

need invasive A line because there is no pulsatile flow

Question 18

What is mechanism of action of aspirin?

Answer 18

Irreversibly acetaylates platelet cyclooxygenase 1 preventing formation of thromboxane A2 and therefore platelet aggregation

Question 19

What is mechanism of action of clopidogrel?

Answer 19

P2y12 Receptor antagonist- irreversible conformational change in the P2Y12 receptor for adeosone diphostate (ADP) and inhibit platelet aggregation by limiting ADP mediated conversion of glycoprotein II2-IIIa to active form

Question 20

What is antiplatelet therapy guidelines for BMS and DES?

Answer 20

BMS- 4-6 weeks and DES at least 12 months

Question 21

What are advantages of minimally invasive direct coronary artery bypass and off-pump CAB?

Answer 21

• avoidance of median sternotomy (wound infection)
• avoid SIRS response to pump
• avoid cross clamping aorta- no risk of aortic dissection or neurlogic sequeale
• decreased risk of perioperative stroke
• decreased atrial fibrillation postop

Question 22

What are disadvantages to minimally invasive direct coronary artery bypass and off-pump CAB?

Answer 22

• lack of optimal exposure (with MIDCAB only IMA to LAD)
• MIDCAB- more trauma to costal cartilages and increased postop pain
• increased hemodynamic instability– pressure surgeon to hasten work and result in questionable anastomosis
• OPCAB compared to on pump CABG- with pump higher graft patency and lower mortality

Question 23

What are disadvantages to minimally invasive direct coronary artery bypass and off-pump CAB?

Answer 23

• lack of optimal exposure (with MIDCAB only IMA to LAD)
• MIDCAB- more trauma to costal cartilages and increased postop pain (double lumen tube)
• increased hemodynamic instability– pressure surgeon to hasten work and result in questionable anastomosis
• OPCAB compared to on pump CABG- with pump higher graft patency and lower mortality

Question 24

What are disadvantages to minimally invasive direct coronary artery bypass and off-pump CAB?

Answer 24

• lack of optimal exposure (with MIDCAB only IMA to LAD)
• MIDCAB- more trauma to costal cartilages and increased postop pain (double lumen tube)
• increased hemodynamic instability– pressure surgeon to hasten work and result in questionable anastomosis
• OPCAB compared to on pump CABG- with pump higher graft patency and lower mortality

Question 25

What are special anesthetic considerations with minimally invasive direct coronary artery bypass and off-pump CAB?

Answer 25

avoid antifibrinolytic agents- may contribute to graft thrombosis

induced bradycardia facilitates surgical field and reduces myocardial O2 demand

Increased risk of arrhythmias intraoperatively from ischemia and manipulation and reperfusion

Question 26

What are special anesthetic considerations with minimally invasive direct coronary artery bypass and off-pump CAB?

Answer 26

avoid antifibrinolytic agents- may contribute to graft thrombosis

induced bradycardia facilitates surgical field and reduces myocardial O2 demand

Increased risk of arrhythmias intraoperatively from ischemia and manipulation and reperfusion

Surgical exposure requires heart lifted and rotation which decreased preload– need vasoconstrictors

Question 27

What do you use for heparin dosing in minimally invasive direct coronary artery bypass and off-pump CAB?

Answer 27

200 u/kg with goal ACT of 300 seconds