The apnea test is a cornerstone of the clinical determination of brain death: it confirms the absence of a respiratory drive in response to a rising arterial carbon dioxide level. In patients supported by extracorporeal membrane oxygenation (ECMO), the circuit continuously removes carbon dioxide, so the expected rise in CO2 is blunted or delayed. This makes the conventional apnea test slow, difficult to interpret, and sometimes inconclusive.
The Hacettepe carbon monoxide–based apnea test procedure provides a standardised way to perform the test under ECMO support by controlling the gas exchange of the circuit during the testing window, allowing the threshold stimulus to be reached in a predictable and safe manner so the examination can be completed reliably.
Why it matters
- Makes the apnea test feasible while the patient remains on ECMO.
- Reduces inconclusive or repeated examinations.
- Provides a standardised, reproducible bedside procedure.
- Supports timely and rigorous brain-death determination.
This page summarises the concept of the procedure. Detailed methodology and supporting data will be added as the work is published.