Topic 4: CPG and MUF

Question 1

Choosing a CPG system what are 4 characteristics we want?

Answer 1

Small prime
Good heat exchange
Air handling capabilities
A versatile system

Question 2

Retrograde CPG – what pressure need to be maintained and where??

Answer 2

Flow should be titrated to maintain a coronary sinus pressure of 30-40 mmHg

DO NOT EXCEED 40 mmHg on kidlets

Question 3

Myocardial-protection strategy aims to do what two things?

Answer 3

1. To halt the mechanical contractions of the heart and to allow intracardiac procedures to be performed in a motionless, bloodless field.
2. Designed to sufficiently reduce myocardial oxygen consumption, so that myocardial function can resume at the end of the procedure with minimal dysfunction

Question 4

Action Potential

Phase 0

Answer 4

Na+ influx

intracellular
Blocking this is the mechanism of Na arrest

Question 5

Action Potential

Phase 1

Answer 5

Transient K+ efflux

Question 6

Action Potential

Phase 2

Answer 6

Ca++ influx

Question 7

Action Potential

Phase 3

Answer 7

K+efflux

Blocking this is the mechanism of K Arrest

Question 8

Action Potential

Phase 4

Answer 8

Na/K ATPase

Question 9

What are the %s that blood CPG and crystalloid CPG are used in US?

Answer 9

86% Blood based CP

14% Crystalloid based

Question 10

Most popular blood based CPG used ?

Answer 10

Del Nido solution (1:4) —–38%

Question 11

Most popular crystalloid based CPG?

Answer 11

Custodiol (7% out of the 14%)

Question 12

Moderate (28° to 31°C) hypothermic cardiopulmonary bypass is more common with what population?

Answer 12

in neonates and infants

Question 13

Longer intervals between cardioplegia doses were associated with what solutions?

Answer 13

surgeons using del Nido and Custodiol solutions (these solutions were commonly administered with a single dose regardless of aortic cross-clamp time)

Question 14

Del Nido Osmolarity?

Answer 14

Osmolarity 340 mOsm/L

Question 15

Del Nido Dosing: Arrest? Maintenace?

Answer 15

Dosing: 20 mL/kg arrest

10 mL/kg maintenance

Question 16

Del Nido Delivery mL/min?

Answer 16

Deliver at 90-180 mL min

Question 17

Ingredients in St. Vincents CPG solution?

Answer 17

Dextrose 5%
THAM
Citrate Phosphate Dextrose Solution

Question 18

CUSTODIAL SOLUTION (BRETSCHNEIDER)
what mechanism is arrest ?

Answer 18

Intracellular solution
Low Na arrest
Single administration: up to 2 hours

Question 19

CUSTODIAL SOLUTION (BRETSCHNEIDER)
ingredients ?

Answer 19

Histidine:buffer-against acidosis during XC
Trytophan:stabilizes cell membrane
Ketoglutarate:improves ATP production during reperfusion

Question 20

Histidine does what?

Answer 20

buffer-against acidosis during XC

Question 21

Trytophan does what?

Answer 21

stabilizes cell membrane

Question 22

Ketoglutarate does what?

Answer 22

improves ATP production during reperfusion

Question 23

Why would Mg be added to CPG solution?

Answer 23

May provide a protective effect on the hypoxic-ischemic immature heart.

Mg is exchanged for calcium during reperfusion

Question 24

How does Mg help protect the hypoxic-ischemic immature heart?

Answer 24

This effect probably due to the antiarrhythmic effect of Mg, inhibited entry of calcium into the myocytes, and decreased uptake of Na by myocytes during ischemia.
Mg is exchanged for calcium during reperfusion

Question 25

MUF allows?

Answer 25

To allow recovery of the pump blood for the patient, while allowing the patient to be in a hemodynamic state to accept the volume is the a significant advance for pediatric perfusionists

Question 26

who was MUF developed by?

Answer 26

Developed Mr. Martin Elliott (Great Ormand | Street/Hospital for Sick Children London UK) in 1985

Question 27

MUF does what 7 things

Answer 27

A. Raising Hct B. Extravascular fluid crosses (rapid, large increase in COP and OSMO) 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 28

What Complement activation factors cross in MUF?

Answer 28

C3a, sC56-9, C3 bound

Question 29

Pulmonary effects > Systemic effects with what factors when MUF is used?

Answer 29

IL-6, IL-8, and TNF

Question 30

How long is MUF after CPB in infants sustained?

Answer 30

results in immediate improvements in both static and dynamic pulmonary compliance, but the effect was not sustained after admission to the PICU or 24 hours after the operation.

Question 31

Why is MUF not sustained in infants? (3 main things?)

Answer 31

--Possibly - pulmonary compliance is affected both by excess fluid from the hemodilutional effect of bypass, As well as by the systemic inflammatory response --decreases total body water and removes inflammatory cytokines. (However, the initiation of the systemic inflammatory response most likely occurs during rewarming) (MUF starts after the inflammatory cascade has been activated) --Maybe that the salutary effects of hemoconcentration and removal of water after bypass by MUF are unable to overcome the ongoing effects of capillary leak possibly caused by an activated ongoing inflammatory response.

Question 32

MUF setup?

Answer 32

Using the MUF technique, an ultrafilter is interposed in the CPB circuit between the aortic arterial line and the venous. After weaning from CPB, the blood is removed from the patient via the aortic canula and fed through the ultrafilter. The outlet of the ultrafilter is fed to the right atrium of the patient.

Question 33

Max BF through the MUF?

Answer 33

approximates 20mL/kg/min max.

Question 34

When suction is applied to MUF what is the ultrafiltration rate?

Answer 34

ultrafiltration rate of 100 to 150 mL per minute. A constant left atrial or right atrial pressure is maintained, achieving continued hemodynamic stability in the patient.

Question 35

What is the end point time or HCT level that we want to achieve during ultrafiltration ?

Answer 35

with the end point being either time (10– 20 minutes) or the achievement of a hematocrit value of approximately 40-50

Question 36

Benefits of MUF ? (5)

Answer 36

- 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 37

Possible negatives of MUF? (5)

Answer 37

-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 38

What does filtration do to total-body weight post-op?

Answer 38

have smaller increases in total-body weight

Question 39

Hemofiltration increases the hematocrit which does what for the body?

Answer 39

which translates into increased oxygen-carrying capacity

Question 40

MUF is associated to what clinically ?

Answer 40

-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