Cardiac Surgery

Question 1

What does hypothermia during CPB do?

Answer 1

Decrease cerebral metabolic rate

Alkaline drift decreasing the PaCO2.

Question 2

What is alpha stat management?

Answer 2

It allows the natural alkaline drift without correction

Question 3

What is ph stat management?

Answer 3

It corrects the alkaline drift by adding CO2 to the oxygenation or sweeping the CO2 out.

Question 4

What are the advantages of ph stat management?

Answer 4

1. Improved oxygen delivery to tissues by counteracting the leftward shift of the oxygen dissociation curve due ton alkalosis
2. Increased speed of homogenous cerebral cooling thru vasodilation
3. Decreased CMRO2
4. Increased CBF

Question 5

During bypass, what is the most likely cause of activated clotting time variability?

Answer 5

Hemo dilution

Question 6

What is activated clotting time?

Answer 6

Test of heparin’s effect

Question 7

How is ACT tested?

Answer 7

Whole blood is added to a test tube with activator in it, diatomaceous earth or kaolin which stimulates the intrinsic coagulation pathway.

When clot forms it slows the descent of a plunger and increases the number generated the longer it takes the clot to form.

Question 8

What factors can alter the ACT?

Answer 8

Hypothermia
Hemo dilution
TCP - Platelets < 30-50
Drugs affecting platelets (Asa, Plavix, prostacyclin)

Question 9

Why are pediatric patients more likely to have variability with ACT?

Answer 9

Because they have increased consumption of heparin

Question 10

What determines heart rate after transplant?

Answer 10

The donor atrium

Question 11

What is the initial response to hypovolemia in a transplanted heart?

Answer 11

An increase in stroke volume dependent on adequate preload

Question 12

What drugs have no action on the transplanted heart?

Answer 12

Anticholinergics

Question 13

Why do you sometimes see 2 P waves on the EKG of a transplanted heart

Answer 13

Because the recipient atrium is still present and remains innervated, but signal don’t cross the suture line

Question 14

What does a transplanted heart respond to?

Answer 14

Direct acting agents : isoproterenol, Epi, norepinephrine, dopamine, dobutamine

Question 15

What is the fastest way to cool someone?

Answer 15

Endovasculqr cooling

Question 16

When is then highest risk to patients when cooled?

Answer 16

During the rewarming process due to rapid rewarming. Must be done over 24 hours.
Can cause electrolyte shifts, increased ICP and arrhythmias

Question 17

What is one of the complications of PAC use involving non-heparin coated catheters?

Answer 17

Endocarditis

Question 18

What is the most common complication of PAC placement?

Answer 18

Arrhythmia

Question 19

What are the complications associated with PAC use?

Answer 19

Pulmonary infarction 
PA rupture
Thromboembolism
Endocardium damage
Tricuspid valve injury
Pseudo aneurysm

Question 20

What factors increase the risk of PA rupture?

Answer 20

Anti coagulation
Old age
Hypothermia
Pulmonary hypertension

Question 21

Why do we use a double lumen tube when repairing a PA?

Answer 21

To prevent the other lung from contamination

Question 22

Which anastomosis is done last in a CABG?

Answer 22

LAD