ECMO ECMO in Neonatal and Pediatric Populations 3 — Questions and Answers
Question 1: Which blood gas parameter is primarily controlled by adjusting the sweep gas flow rate in pediatric VV-ECMO?
- PaO2
- PaCO2 (Correct answer)
- pH directly
- Bicarbonate (HCO3)
Correct answer: PaCO2
Increasing sweep gas flow enhances CO2 removal across the oxygenator membrane, directly lowering PaCO2 and raising pH.
Question 2: In VA-ECMO, 'differential hypoxia' (also called North-South syndrome) refers to:
- Higher SpO2 in the right hand compared to the left
- Upper body hypoxia from native cardiac output while lower body receives oxygenated ECMO return (Correct answer)
- Unequal oxygen saturation at pre- and post-membrane sites
- Hypoxia in watershed zones of the brain
Correct answer: Upper body hypoxia from native cardiac output while lower body receives oxygenated ECMO return
In VA-ECMO, the failing native heart may eject deoxygenated blood into the ascending aorta while ECMO return enters the descending aorta, causing the upper body to be hypoxic.
Question 3: The primary goal of ECMO support in pediatric myocarditis is:
- Providing permanent cardiac replacement
- Bridging to myocardial recovery or cardiac transplantation (Correct answer)
- Eliminating the need for inotropic medications
- Treating the viral cause directly
Correct answer: Bridging to myocardial recovery or cardiac transplantation
Myocarditis can cause fulminant cardiac failure, and ECMO provides hemodynamic support while awaiting spontaneous recovery or listing for transplantation.
Question 4: The typical ECMO blood flow rate target in neonates to achieve adequate oxygen delivery is approximately:
- 50–75 mL/kg/min
- 100–150 mL/kg/min (Correct answer)
- 150–200 mL/kg/min
- 200–250 mL/kg/min
Correct answer: 100–150 mL/kg/min
Neonatal ECMO flows of 100–150 mL/kg/min provide sufficient cardiac output equivalent to support systemic oxygen delivery in the normal range.
Question 5: To reduce intracranial pressure risk in neonates on ECMO, the recommended head and body positioning is:
- Flat supine with neck in neutral alignment
- Head of bed elevated 30° with head in midline position (Correct answer)
- Trendelenburg (head-down) position
- Right lateral decubitus to protect the carotid cannula site
Correct answer: Head of bed elevated 30° with head in midline position
30° head-of-bed elevation with midline neck positioning promotes cerebral venous drainage and reduces ICP without compromising ECMO cannula function.
Question 6: A neonate on femoral VA-ECMO develops progressive ipsilateral lower extremity ischemia. The most appropriate intervention is:
- Increase ECMO flow rate to improve peripheral perfusion
- Insert a distal perfusion catheter into the superficial femoral artery (Correct answer)
- Immediately decannulate and transition to VV-ECMO
- Administer systemic vasodilators to improve limb perfusion
Correct answer: Insert a distal perfusion catheter into the superficial femoral artery
A distal perfusion catheter (DPC) inserted antegrade into the superficial femoral artery restores distal limb perfusion while maintaining ECMO support.
ECMO ECMO in Neonatal and Pediatric Populations 3
Which blood gas parameter is primarily controlled by adjusting the sweep gas flow rate in pediatric VV-ECMO?