test 1 part 4

Question 1

What we want in pediatrics for cardioplegia:

Answer 1

• Small prime
• Good heat exchange
• Air handling capabilities
• A versatile system

Question 2

Cardioplegia circuits may include:

Answer 2

• Blood shunt
• Crystalloid component
• Blood component
• Heat exchanger
• Bubble trap
• Air detector

Question 3

CSC 14 heat exchanger

Answer 3

• has a stopcock on the bottom
  - used for priming
  - while priming, stopcock pointing up and the fluid can go straight through the bottom and the prime will go up through the filter and purge back into the reservoir
  - when you go on bypass, you flip the stopcock down and the fluid will go up through the filter and back down which allows the air to be removed
• priming volume of 30 cc

Question 4

Aortic root cardioplegia cannula selection by weight in Kg

Answer 4

• DLP 18 gauge = 0-7 kg

- DLP 16 gauge = 7-20 kg

Question 5

Retrograde CPG delivery

Answer 5

Retrograde cardioplegia is given into the coronary sinus. A balloon is inflated or self inflated and provides two functions:
 Prevents backflow
 Holds cannula in place
- Flow should be titrated to maintain a coronary sinus pressure of 30-40 mmHg.
- only delivers to the left side of the heart and not the right

Question 6

High K+/Low K+ ANTEGRADE DELIVERY

Answer 6

Initial dose: 30 mL/kg

Maintenance doses: 15 mL/kg every 15-30 minutes

Question 7

Custodiol ANTEGRADE DELIVERY

Answer 7

Initial dose: 30-50 mL/kg (up to 2 L)
Maintenance dose: 10 mL/kg every 2 hours
- Deliver at LINE pressure ~125 mmHg until arrest, then drop to line pressure of ~80 – 90 mmHg

Question 8

Del Nido ANTEGRADE DELIVERY

Answer 8

Initial dose: 20 mL/kg (up to 1 L)

• 10 mls/kg maintenance
• delivery at 90-180 mls/min

Question 9

MECHANISM OF POTASSIUM ARREST

Answer 9

• stops phase 3
• prevents repolarization
• extracellular

Question 10

CUSTODIOL SOLUTION (BRETSCHNEIDER, HTK)

Answer 10

• Intracellular solution
• Low Na arrest
• hyperpolarizing of myocytes and plasma membrane
• Histidine: buffer- against acidosis during XC
• Tryptophan: stabilizes cell membrane
• Ketoglutarate: improves ATP production during reperfusion

Question 11

TEMPERATURE AND CARDIOPLEGIA

Answer 11

Cold (<10°C) cardioplegia most common

Question 12

Magnesium addition

Answer 12

• The addition of magnesium may provide a protective effect on the hypoxic-ischemic immature heart.
• This effect probably due to the antiarrhythmic effect of magnesium, inhibited entry of calcium into the myocytes, and decreased uptake of sodium by myocytes during ischemia.

Question 13

MODIFIED ULTRAFILTRATION (MUF)

Answer 13

Utilization of a hemoconcentrator at a specific point post CPB

Question 14

What’s really happening at the hemoconcentrator level while MUFing

Answer 14

A. Raising Hct
B. Extravascular fluid crosses ( rapid, large increase in COP) (noncellular or non protein volume)
C. Removes inflammatory mediators
D. C-Reactive Proteins cross
E. Protein reactive cytokines cross
F. Complement activation factors cross (C3a, sC56-9, C3 bound)
G. Pulmonary effects > Systemic effects with IL-6, IL-8, and TNF

Question 15

MUF overview

Answer 15

• After CPB
• blood removed from patient by aortic cannula and goes through hemoconcentrator and fed back into patients right atrium
  • Suction is applied to the filter port of the hemoconcentrator, resulting in an ultrafiltration rate of 20 to 30 mL per minute
  • Ultrafiltration is carried out with the end point being either time (10–20 minutes) or the achievement of a hematocrit value of approximately 40-50.

Question 16

Blood flow through the hemoconcentrator approximately

Answer 16

20mL/kg/min max

Question 17

Beneficial effects of MUF:

Answer 17

 total body water is reduced as a direct result of removing the ultrafiltrate.
 Reduced edema
 Reduced hospital stay
 Reduced ventilation times
 Reduced incidence of pleural and pericardial effusions.

Question 18

Arguments against MUF:

Answer 18

 Possible air embolism
 Remember that air would be entering
venous side
 Circuit complexity and cost
 Prolonged exposure to foreign surface
 “Patient can be concentrated before coming of CPB”

Question 19

CLINICAL STUDIES HAVE DEMONSTRATED THAT MUF IS ASSOCIATED WITH

Answer 19

• Increased ventricular systolic function;
• Improved cerebral blood flow (CBF), cerebral metabolic activity, cerebral oxygen delivery
• Pulmonary function, decreased postoperative ventilation
• Decreased postoperative bleeding, chest-tube drainage, pleural effusions
• They equal short hospital stays

Question 20

MUF circuit

Answer 20

DRAW IT