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Diagnosing brain death on ECMO

posted 28 Feb 2011, 16:49 by Oliver Flower
With the increasing use of ECMO, and with intracerebral haemorrhage being a feared and not uncommon complication of the accompanying anticoagulation, this issue is likely to become more common. This paper provides a useful modification of the apnoea test. I've been involved with two organ donations from similar situations and if brain death can be diagnosed, warm ischaemic time can be minimised for potential recipients.

Muralidharan R, Mateen FJ, Shinohara RT, Schears GJ, Wijdicks EF. 
Neurocrit Care. 2011 Feb 14

BACKGROUND: To identify a reliable method of performing apnea testing as part of brain death determination in adult patients who develop loss of brainstem reflexes while receiving extracorporeal membrane oxygenation (ECMO). ECMO provides extracirculatory support to patients in cardiorespiratory failure who would otherwise be expected to die. Many studies have reported brain death as a potential complication of adult ECMO, but none have cited how apnea testing was performed in these patients. 

METHODS: This retrospective review identified adults 15 years or older treated with ECMO at our institution (2002-2010) and the method of determination of brain death when complete loss of brainstem reflexes occurred. 

RESULTS: Loss of all brainstem reflexes was identified in three cases (3/87, 3.4%). The apnea test was not performed since it was deemed "difficult," leading to withdrawal of ECMO and intensive care. Ancillary tests such as cerebral flow studies were not used because they may not document absent cerebral arterial flow due to the ischemic nature of the injury. We propose the use of an oxygenated apnea test on ECMO using continuous positive airway pressure (CPAP) through the ventilator or anesthesia bag, with an inline manometer and an end tidal CO(2) device. 

CONCLUSION: Apnea testing is essential in the determination of brain death, but may not be employed in ECMO-treated adult patients. Apnea testing using the above protocol may assist in better decision making for adult ECMO patients at risk of brain death.

Image: A patient on ECMO being transported by helicopter