CCP CCP Temperature Management & Hypothermia 2 — Questions and Answers
Question 1: What is the primary advantage of alpha-stat blood gas management during hypothermic CPB?
- Maintains pH at 7.40 regardless of temperature
- Preserves cerebrovascular autoregulation and enzyme function (Correct answer)
- Increases cerebral blood flow by adding CO2
- Prevents hemodilution
Correct answer: Preserves cerebrovascular autoregulation and enzyme function
Alpha-stat management preserves cerebrovascular autoregulation and intracellular enzyme function by maintaining temperature-uncorrected pH values.
Question 2: pH-stat blood gas management during hypothermia results in which primary cerebral effect?
- Reduced cerebral blood flow
- Increased cerebral blood flow due to elevated CO2 (Correct answer)
- Normal cerebrovascular autoregulation
- Decreased cerebral oxygen delivery
Correct answer: Increased cerebral blood flow due to elevated CO2
pH-stat management adds CO2 to maintain pH 7.40 at actual body temperature, causing cerebral vasodilation and increased cerebral blood flow.
Question 3: Which pH management strategy is preferred for neonates and infants undergoing DHCA?
- Alpha-stat
- pH-stat (Correct answer)
- Neither; normothermia is used
- Both are equally effective
Correct answer: pH-stat
pH-stat is preferred in neonates and infants because increased cerebral blood flow improves uniform brain cooling before circulatory arrest.
Question 4: The 'afterdrop' phenomenon after CPB rewarming refers to:
- A drop in pump flow after separation from bypass
- Continued fall in core temperature after rewarming is stopped (Correct answer)
- Sudden hypotension immediately post-bypass
- Reduction in hemoglobin after transfusion
Correct answer: Continued fall in core temperature after rewarming is stopped
Afterdrop is the continued decrease in core temperature after active rewarming stops, caused by cold blood returning from peripheral tissues.
Question 5: During normothermic CPB, what core temperature range is targeted?
- 35-37°C (Correct answer)
- 32-34°C
- 28-30°C
- 38-40°C
Correct answer: 35-37°C
Normothermic CPB targets core temperatures of 35-37°C to maintain near-physiologic metabolic conditions throughout the procedure.
Question 6: To prevent neurological injury, the arterial blood outflow temperature during rewarming should not exceed:
- 37°C
- 38°C (Correct answer)
- 39°C
- 40°C
Correct answer: 38°C
Arterial outflow temperature should be kept at or below 37-38°C during rewarming to prevent cerebral hyperthermia and thermal neurological injury.
CCP CCP Temperature Management & Hypothermia 2
What is the primary advantage of alpha-stat blood gas management during hypothermic CPB?