Controversies in pediatric perfusion / test 3 / 3

Question 1

pH stat strategy

Aim:
Total CO2 content:
Intracellular state:
Enzyme structure & function:

Answer 1

Aim: Constant pH
Total CO2 content: Increases
Intracellular state: Acidotic
Enzyme structure & function: Altered & decreased activity

Question 2

Alpha - Stat strategy

Aim:
Total CO2 content:
Intracellular state:
Enzyme structure & function:

Answer 2

Aim: Constant OH/H+
Total CO2 content: Constant
Intracellular state: Neutral
Enzyme structure & function: Normal & activity is maximized

Question 3

Anaerobic metabolism produces what?

Answer 3

Lactic Acid

Question 4

Normoxia with Alpha Stat management leads to what ?

Answer 4

Increased Acid production

Question 5

Hyperoxia with pH Stat management leads to what ?

Answer 5

Decreased Acid production

Question 6

GUCHs ?

Answer 6

Grown Up Congenital Hearts

Question 7

By keeping total CO2 stores constant, net protein charge states are kept constant as temperature changes, this regulation is termed ?

Answer 7

Alpha-Stat Management

Question 8

net protein charge states ?

Answer 8

(termed “alpha”)

Question 9

The “alpha” refers to an important charged species ?

Answer 9

the alpha imidazole ring on the histidine amino acid

Question 10

Normal protein structure and function, especially enzyme function, depends on what ?

Answer 10

a constant and usually neutral electrochemical environment

Question 11

Alpha-stat management maintains a PaCO2 level of ?

Answer 11

40 mmHg when measured at 37° C

Temperature uncorrected

Question 12

Advantages of Alpha-Stat Management ?

Answer 12

• Neutral Intracellular electrochemical neutrality
• Maintains a more normal cerebral flow/metabolism
  relationship.
• Limited luxuriant cerebral blood flow during CPB

Question 13

Disadvantages of Alpha-Stat Management ?

Answer 13

less effective cooling of the brain =
↓ suppression of cerebral metabolism =
↓ cerebral protection

Question 14

pH-Stat Management

Answer 14

pH-stat management keeps the pH constant when measured at the actual blood temperature

Question 15

potent cerebral vasodilator during nonpulsatile cardiopulmonary bypass.

Answer 15

CO2

Question 16

Because CO2 solubility increases with temperature, total body CO2 stores must be what while using pH Stat Management ?

Answer 16

increased during cooling to maintain a “normal” corrected value.

Question 17

pH-stat management maintains a PaCO2 level of 40 mmHg when measured at ?

Answer 17

actual blood temperature

Temperature corrected

Question 18

Advantages of pH-Stat Management ?

Answer 18

-Luxuriant cerebral perfusion
-Improved brain cooling
Especially in the presence of aortopulmonary collaterals or shunts

Question 19

Disadvantages of pH-Stat Management

Answer 19

• Luxuriant cerebral flow may increase embolic material to the brain
  > Cerebral flow/metabolism uncoupling
• Less intracellular electrochemical neutrality (Acidic environment)

Question 20

Describe the Combination Strategy ?

CPB Initiation:
Prior to DHCA:
During DHCA:
Rewarming:

Answer 20

CPB Initiation: pH Stat
Prior to DHCA: pH Stat
During DHCA: Alpha Stat
Rewarming: Alpha Stat

Question 21

The use of pH-stat strategy during initial cooling to 14 C followed by a switch to Alpha-Stat strategy just before arrest results in ?

Answer 21

A better recovery of cerebral metabolism after DHCA compared with the recovery with either strategy used alone.

Question 22

What gas management strategy is utilized mainly for pediatrics ?

Answer 22

Combination Strategy

Question 23

electrochemical charge states and binding are largely responsible for what?

Answer 23

maintaining normal protein conformational structure

Question 24

What kind of gas management would improve brain cooling in patients with Aortopulmonary collaterals or shunts ?

Answer 24

pH Stat Management