ECMO Veno-Venous (VV) ECMO Management 5

Question 1

Which condition would most likely prompt conversion from VV to VA ECMO in a patient already on VV support?

Accepted Answer

Progressive cardiogenic shock with hemodynamic deterioration

Answer

VV ECMO provides only respiratory support; progressive cardiogenic shock requiring hemodynamic support necessitates conversion to VA ECMO, which also offloads the failing heart.

Question 2

A VV ECMO patient's sweep gas accidentally becomes disconnected for 3 minutes. What is the expected physiologic consequence?

Accepted Answer

Rapid hypoxemia and hypercapnia

Answer

Loss of sweep gas eliminates both O2 transfer and CO2 removal across the membrane, causing rapid hypoxemia and hypercapnia.

Question 3

During VV ECMO, thrombocytopenia and prolonged aPTT develop simultaneously. Anti-PF4 antibody is strongly positive. What is the recommended treatment?

Accepted Answer

Stop heparin and switch to a direct thrombin inhibitor (bivalirudin or argatroban)

Answer

Positive anti-PF4 antibody confirms heparin-induced thrombocytopenia; heparin must be stopped and replaced with a non-heparin anticoagulant such as bivalirudin.

Question 4

What is the significance of a 'chattering' or 'sucking' cannula during VV ECMO?

Accepted Answer

It signals that drainage is impaired, usually from hypovolemia or cannula malposition

Answer

Cannula chattering occurs when the circuit intermittently collapses venous inflow, indicating inadequate preload or a positional drainage issue requiring immediate attention.

Question 5

A VV ECMO patient with ARDS is being weaned. During a 4-hour trial with sweep gas at 0 L/min, PaO2 is 72 mmHg on FiO2 0.4. Ventilator settings are Vt 6 mL/kg, PEEP 10 cmH2O, RR 20. What is the appropriate next step?

Accepted Answer

Immediately decannulate the patient

Answer

PaO2 >65 mmHg on FiO2 ≤0.4 and acceptable ventilator parameters during a sweep-off trial indicate adequate native lung recovery and readiness for decannulation.

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO Veno-Venous (VV) ECMO Management 5