Chapters 141-153 Cardiac Anesthesia Flashcards
Describe what “demand ischemia” is.
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
Describe difference in terms of where the problem is in relation to the coronary artery for STEMI an NSTEMI.
STEMI- total coronary occlusion; NSTEMI- subtotal occlusion although many other factors such as preexisting collaterals, coronary vasospasm, O2 level can alter this generalization
What can you use intraopeatively to assess for ACS?
Multi lead EKG, Pulmonary artery occlusion pressure and TEE
In settings other than ACS when might you see elevated troponins?
A fib RVR, PE, cardiac trauma, stress cardiomyopathy, acute neurologic disease, critical illness
Patients that have HITT have an antibody to what?
Heparin-platelet factor 4 complex
What can you use for anticoagulation in patients with HITT?
Direct-acting thrombin inhibitor such as Bivalirudin or Argatraban.
What are compensatory mechanisms the body does to try to improve CO with heart failure?
Activation of the renin-angiotensin-aldosterone system, natriuretic peptide to increase fluid retension, cause peripheral vasoconstriction and ventricular remodeling
When should you consider putting in an ICD in patients with heart failure
When the EF
What at the various types of VADs in terms of left/right, type of mechanism. location and goal therapy?
Right and left VADS
pulsatile or nonpulsatile
location: paracorpally, intracorpareally
Goals: recovery (short term), bridge to transplant or destination therapy
Describe the 1st generation VAD
pulsatile pumps with valves located paracorpally; for short to intermediate term use; for bridge to transplant or bridge to recovery; portable
Describe the 1st generation VAD and their use
pulsatile pumps with valves located paracorporeally; for short to intermediate term use; for bridge to transplant or bridge to recovery; portable
Describe 2nd generation VAD and their use
intracorporeal, nonpulsitile, without valves; used for bridge to transplant and destination therapy
Describe 3rd generation VAD and their use
intracorporeal, bearingless that use magnetics and hydrodynamics to suspend impellers; bridge to transplant
What cardiac anatomic anomolies must be repaired before implanting a VAD?
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
How can you treat hypotension in patient with total artifical heart
Avoid iontropes–duh.
Fluid and vasopressors
What are common abnormalities that patients may get with nonpulsatile LVADs?
GI bleeding from AV malformations in GI tract and bladder
How do you measure blood pressure in patient with 2nd or 3rd generation VAD?
need invasive A line because there is no pulsatile flow
What is mechanism of action of aspirin?
Irreversibly acetaylates platelet cyclooxygenase 1 preventing formation of thromboxane A2 and therefore platelet aggregation
What is mechanism of action of clopidogrel?
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
What is antiplatelet therapy guidelines for BMS and DES?
BMS- 4-6 weeks and DES at least 12 months
What are advantages of minimally invasive direct coronary artery bypass and off-pump CAB?
- 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
What are disadvantages to minimally invasive direct coronary artery bypass and off-pump CAB?
- 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
What are disadvantages to minimally invasive direct coronary artery bypass and off-pump CAB?
- 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
What are disadvantages to minimally invasive direct coronary artery bypass and off-pump CAB?
- 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
What are special anesthetic considerations with minimally invasive direct coronary artery bypass and off-pump CAB?
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
What are special anesthetic considerations with minimally invasive direct coronary artery bypass and off-pump CAB?
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
What do you use for heparin dosing in minimally invasive direct coronary artery bypass and off-pump CAB?
200 u/kg with goal ACT of 300 seconds
