Pre-bypass

Question 1

What are components of goal directed therapy

Answer 1

• optimize myocardial oxygen supply/demand balance
• optimize ventricular pressure-volume relationship
• maintain contractility and CO
• control heart rate and rhythm

Question 2

what is it important to protect against pre-bypass

Answer 2

ischemia

Question 3

Periods of high stimulation

Answer 3

• incision
• sternotomy
• pericardiotomy

Question 4

periods of low stimulation

Answer 4

• pre-incision
• IMA harvest
• cannulation of aorta

Question 5

Why do you bring systolic own to 90 during cannulation of aorta

Answer 5

to prevent embolic incidents

Question 6

Risks of redo sternotomy

Answer 6

• be prepared to crash on bypass

- adhesions of vessels to posterior side of sternum, auricular appendage

Question 7

Two common risks with sternotomy

Answer 7

IMA dissection and brachial plexus injury

Question 8

Other risks with sternotomy

Answer 8

• retractor compression of left subclavian artery
• radial nerve injury from post supporting the pittman retractor
• risk of sternal fracture
• papaverine - hypotension and anaphylaxis

Question 9

Sources for graft

Answer 9

• IMA
• Radial artery
• saphenous vein
• gastroepiploic artery

Question 10

common issues pre-bypass

Answer 10

• ischemia
• hypotension
• hypertension
• rate probelms
• hyperglycemia

Question 11

What reduces the incidence of perioperative MI before bypass

Answer 11

prevention and rapid treamtent of ischemia

Question 12

major risk factor for ischemia?

Answer 12

tachycardia

Question 13

considerations for why the patient is ischemic

Answer 13

tachycardia
hypertension
hypotension
hypoxia

Question 14

How can you alter your anesthetic plan to remedy ischemia

Answer 14

• lighten/deepen your anesthetic
• vasodilator
• BBlocker
• pressor/inotrope (with caution)

Question 15

Nitroglycerine mechanism of action on preload and afterload

Answer 15

Decrease preload through venodilation resulting in decreased LV filling pressures and decreased diastolic chamber size

Decreased afterload with decreases systolic pressures, decreases SVR and improves coronary circulation

Question 16

Nitrates role in coronary circulation

Answer 16

• epicardial cornoary artery dilation
• reactive areas only
• athermatous vessels do not react/dilate
• increase collateral coronary artery flow and vessel diameter
• improves subendocardial flow
• reversal and prevention of coronary vasospasm and vasoconstriction

Question 17

Beta blockers role in ischemia

Answer 17

• reduce myocardial 02 consumption
• decrease HR and contractility
• improve coronary artery blood flow
• prolong diastolic time
• improves both collateral flow and ischemic flow
• overall improves myocardial supply/demand ratio
• reduce mortality post-MI

Question 18

Calcium channel blockers and their role in preventing ischemia

Answer 18

• slow the ventricular response rate in afib/aflutter
• cornary vasodialtors
• depress contractility and vascular tone, decrease SV

Question 19

Verapamil

Answer 19

-ca channel blocker best for tachyarrhythmias

Question 20

nifedipine and diltiazem

Answer 20

ca channel blocker best for vasodilation

Question 21

benefit of diltiazem

Answer 21

ca channel blocker vasodilates with the least myocardial depression

Question 22

Potential causes of hypotension

Answer 22

mechanical (surgical)
technical
deep anesthesia
occult blod loss into chest
typically hpovolemia

Question 23

Treatment of hyotension

Answer 23

fluid bolus (colloid, crystalloid)
vasopressors
inotropes (w/ caution)

Question 24

causes of hypertension

Answer 24

most commonly light anesthesia
hypoxia (consider ET position)
hypercarbia
hypervolemia

Question 25

Treatment of hypertension

Answer 25

increase depth of anesthesia resolve ventilation problems beta blockers

Question 26

HR problems: SB

Answer 26

common causes: narcotic effect, ischemia, myocardial supply/demand

Question 27

HR problems: ST

Answer 27

``` much more ominous than SB most common cause of ischemia light anesthesia? ventilation problems? treat with narcotics or beta blockers ```

Question 28

efffects of hyperglycemia

Answer 28

- impaired leukocytes and immune function - impaired endothelial vasodilation - inhibits development of collateral coronary blood flow - higher mortality rate from MI - impaired wound healing - increased infection rate

Question 29

CBP causes a temporary state of insulin ______

Answer 29

resistance

Question 30

Heparin dosing

Answer 30

300 u/kg (3 mg/kg)

Question 31

heparin administration

Answer 31

give via central line | aspirate before and after

Question 32

heparin and act

Answer 32

draw act 3 min after dose | ACT must be >400

Question 33

AT-III deficiency

Answer 33

heparin resistance - inability to get adequate anticoagulation despite conventional heparin doses more common in those who have been on heparin preoperatively

Question 34

How to tx AT-III deficiency

Answer 34

usually responds to increased dosing may give 1,000 units of AT-III or 2-4 units of FFP to restore AT-III activity

Question 35

HIT type 1

Answer 35

usually of little clinical significance

Question 36

HIT type II patho

Answer 36

IGE antibodies develop to heparin-platelet factor 4 complexes on the surfaces of the platelets and endothelial cells. Complex activation and platelet aggregation

Question 37

symptoms of HIT II

Answer 37

throbocytopenia, heparin tachyphlaxis, bleeding, thrombosis

Question 38

treatment of HIT II

Answer 38

discontinue heparin, aspirin thereapy Alt: LMWH, Heparinoids (dermatan sulfate and danapariod) direct thrombin inhibitors plasmapheresis (wait until antibodies disappear)

Question 39

direct thrombin inhibitors

Answer 39

hirudin, bivalirudin and agatroban, ancrod

Question 40

Are you ready to go on pump?

Answer 40

``` LAMPS labs anesthetic (midaz, narc, relaxant) monitors patient/pump support ```