CCP Neonatal & Pediatric Perfusion 3 — Questions and Answers
Question 1: A 4 kg infant on CPB has a hematocrit of 18%. The most appropriate perfusionist action is:
- Transfuse packed red blood cells into the circuit (Correct answer)
- Increase pump flow to compensate
- Add crystalloid to dilute further
- Administer albumin 5%
Correct answer: Transfuse packed red blood cells into the circuit
A hematocrit below 20–24% in neonates warrants PRBC transfusion to ensure adequate oxygen-carrying capacity during hypothermic CPB.
Question 2: Which anatomical characteristic of the neonatal coronary circulation most influences cardioplegia delivery technique?
- High coronary-to-aorta flow ratio requiring lower delivery pressures (Correct answer)
- Larger coronary ostia requiring higher flow rates
- Absence of collateral circulation requiring longer intervals
- Dominant right coronary system requiring bicaval cannulation
Correct answer: High coronary-to-aorta flow ratio requiring lower delivery pressures
Neonatal coronary vessels are small and have high flow relative to aortic pressure, so cardioplegia should be delivered at lower pressures (40–60 mmHg) to avoid barotrauma.
Question 3: During pediatric CPB, cerebral near-infrared spectroscopy (NIRS) shows a drop in rSO2 from 72% to 48%. The most appropriate immediate action is:
- Increase pump flow and check cannula position (Correct answer)
- Administer methylprednisolone
- Reduce temperature further
- Begin phenylephrine infusion
Correct answer: Increase pump flow and check cannula position
A significant NIRS drop suggests inadequate cerebral perfusion; increasing pump flow and verifying cannula positioning are the immediate corrective steps.
Question 4: What is the typical safe duration of deep hypothermic circulatory arrest (DHCA) at 18°C before significant neurological risk increases in neonates?
- 30–40 minutes (Correct answer)
- 60–75 minutes
- 10–15 minutes
- 50–60 minutes
Correct answer: 30–40 minutes
At 18°C, approximately 30–40 minutes of DHCA is considered the threshold beyond which neurological injury risk increases substantially.
Question 5: In neonatal perfusion, the estimated blood volume (EBV) for a neonate is approximately:
- 80–85 mL/kg (Correct answer)
- 60–65 mL/kg
- 100–110 mL/kg
- 50–55 mL/kg
Correct answer: 80–85 mL/kg
Neonates have an EBV of approximately 80–85 mL/kg, which is higher than older children and adults, making hemodilution calculations critically important.
Question 6: Which congenital heart defect most commonly requires the use of antegrade cerebral perfusion (ACP) during aortic arch reconstruction in neonates?
- Hypoplastic left heart syndrome (HLHS) (Correct answer)
- Tetralogy of Fallot
- Transposition of the great arteries
- Total anomalous pulmonary venous return
Correct answer: Hypoplastic left heart syndrome (HLHS)
HLHS requiring Norwood Stage I involves complex aortic arch reconstruction where ACP is used to provide cerebral blood flow during the period of systemic circulatory arrest.
Question 7: During pediatric CPB, which electrolyte abnormality is most likely to cause arrhythmias after cardioplegia administration?
- Hyperkalemia (Correct answer)
- Hyponatremia
- Hypophosphatemia
- Hypomagnesemia
Correct answer: Hyperkalemia
Cardioplegia solutions contain high concentrations of potassium for arrest; systemic hyperkalemia from cardioplegia washout can trigger ventricular arrhythmias on reperfusion.
CCP Neonatal & Pediatric Perfusion 3
A 4 kg infant on CPB has a hematocrit of 18%.
The most appropriate perfusionist action is: