Coronary Artery Revascularization Ap2

Front 1

What are the goals of induction?

Back 1

Maintenance of hemodynamics- avoid exacerbation of ischemial with a slow, smooth, controlled induction

Front 2

What is a graded induction?

Back 2

anesthetic agents given is small increments to avoid hypotension. A series a challenges used to judge when anesthetic depth will allow for intubation without a marked sypmathetic response.

Front 3

What are the 3 challenges to assess sympathetic response and readiness for intubation?

Back 3

1. oral airway
2. foley catheter
3. Laryngoscopy

Front 4

What is the most important advantage of use of volatile agents for maintenance of anesthesia?

Back 4

Titratability

Front 5

T/F all inhaled anesthetics depress baroreceptor responses.

Back 5

True - E>H>I
Vasomotor responses are also blunted

Front 6

What is an even greater stimulation than skin incision?

Back 6

strnotomy
Disconnect pt form vent to allow lung to deflate- take off exp limb, APL open,low TV 1-2L O2 flow

Front 7

What is important to have drawn up and ready for a redo sternotomy?

Back 7

full heparinization dose 300-400 units/kg

Front 8

If a massive bleed occurs with redo sternotomy what is the order of interventions:

Back 8

1. Heparinize the pt - for immediate bypass
2. Resuscitate - pressors, blood
3. Surgeon will prepare for emerg CPB - sucker bypass -sxn becomes cannula

Front 9

Name 2 low stimulation times when hypotension may be encountered.

Back 9

prepping and draping and conduit harvesting

Front 10

Compare vein and artery conduits.

Back 10

Vein - easy to harvest - cut to fit length, plaque formation; duration 5-10 yrs
Artery - prone to spasm during manipulation, longer patency rates.
Synthetic - still evolving - prone to clot r/t diameter

Front 11

What is the easiest artery to use for grafting?

Back 11

Left internal mammary artery
LIMA to LAD

Front 12

What are the heparin doses for midcab, offpump, CABG with bypass?

Back 12

100 units/kg Midcab
200 units/kg Off pump
300-400 units/kg CABG/CPB

Front 13

Which vein is commonly used for grafting?

Back 13

Saphenous vein

Front 14

T/F Pt on heparin therapy decreases the ability to anticoag pt.

Back 14

True - AT3 used up - rely on liver for production of more AT3 for Heparin to bind to. T1/2 90 min. Admin 2 units of FFP(contains AT3) to correct

Front 15

List causes of heparin resistance

Back 15

AT3 deficiency:
Congenital (not manufactured by body) or aquired (heparin infusion, cirrhosis of liver, nephrotic syndrome)

Front 16

Contact of blood with the foreign surface of the bypass circuit may activate?

Back 16

White cells and platelets, complement system, coagulation system, kinin generation, fibrinolytic system

Front 17

Name 3 antifibrolytics that prevent clots from breaking down once formed:

Back 17

Epsilon-aminocaproic acid (Amicar)
Tranexamic acid
Aprotinin (Trasylol) - off market

Front 18

Describe the action of Aproptinin, Amicar and tranexamic acid

Back 18

Aprotinin - inhibits plasmin (fibrin breakdown slowed)
Amicar/TxA - prevents the breakdown of fibrin by preventing attachment of plasmin to fibrin

Front 19

What is the best time to admin antifibrinolytics?

Back 19

Before anticoagulation - best efficacy before clooting cascade begins( before incision)
After anticoagulation - reduce incident of thrombotic complications

Front 20

What is the recommended dosing regimen of Epsilon- Aminocaproic Acid ( Amicar)?

Back 20

Bolus infusion - 5-10 gm over 30 min
Infusion 1-2 gm/hr into ICU

Front 21

What is the recommended dosing regimen of Tranexamic Acid?

Back 21

<70 kg: Bolus 500 mg over 20 min - Infusion 500 mg over 10 hours
>70 kg: Bolus 1 gram over 20 minutes. Infusion 1 gram over 10 hours.

Front 22

Why was Aprotinin removed from the market?

Back 22

Renal failure, anaphylactic reaction due to reexposure within 6 months

Front 23

At what temp is the greatest absolute decrease in myocardial O2 consumption obtained?

Back 23

25 degrees celcius

Front 24

What are the 2 purposes of cardioplegia?

Back 24

arrest heart for still surface and minimize myocardial damage

Front 25

What are the components of cardioplegia solution?

Back 25

Blood, THAM, bicarb, mannitol, nitroglycerine, calcium channel blockers, Mg etc

Front 26

What type of cardaic arrest is achieved with cardioplegia?

Back 26

Diastolic arrest - by producing depolarization of the membrance and inhibiting repolarization. Increases RMP.
Ion (K 30 Meq/L) to arrest the heart

Front 27

Describe retrograde and antegrade delivery of cardioplegia:

Back 27

Antegrade - infused intermittently via coronary arteries - osteo off aorta
Retrograde - infused intermittently through coronary sinus - monitor line to measure pressure (don't exceed 30-50 torr)
*Infused in coronary sinus and out coronary arteries
With high grade atheroscloerosis, antegrade cardioplegia may not reach distal areas = risk of ischemia or infarct.

Front 28

What should pre CPB ACT level be?

Back 28

ACT>400

Front 29

Why is additional anesthetics and muscle relaxants required with initiation of CPB?

Back 29

Volume of distribuation is increased allowing for a dilution effect - additional 1.5 L added to circulatory volume.

Front 30

Why do we stop ventilation when CPB full flow?

Back 30

To prevent delivery of hypoxic mixture with a parallel circuit