The apnea test used for brain death certificationhas been placed into a debate, with regard to whether informed consent is warranted. This discussion on the apnea test appeared because of concerns about associated risks. A study was carried out, following the procedure indicated in the American Academy of Neurology guidelines of 2010. Patients are put on 100% oxygen at 6 l/min. The apnea test starts when PaO2>200%. Hypotension is defined as <90/60 mmHg, and hypoxia as PaO2<60%.
Of 147 patients evaluated over 10 years, 4 were withdrawn due to family desire to withdraw life support. 129 were declared brain dead and 14 waited for a circulatory death protocol. Neurointensivists carried out evaluations in 118 patients; neurologists in 7; intensivists in 3; a neurosurgeon in 1. The test was not attempted in 13 cases and aborted in 3 due do systemic complications. All patients had had blood pressure suppport due to brain stem dysfunction, but 16% were not on suppport immediately prior to the apnea test. In 30% elevation of dose of vascular support was necessary during the apnea test.
In summary, only in 2% of the patients the test was terminated due to complications. There were no cardiac arrythmias, arrests or pneumothorax associated with the apnea test. In earlier publications from the same hospital and others the rate of termination due to complication was 10-20%. The authors conclude that the apnea test is simple and safe. Furthermore, it is part of a medical diagnostic procedure, not an indication for specific informed consent.
Daneshmand, Rabinstein and Wijdicks. Neurology 2019, 92:386-387
Wijdicks et al Neurology 2010, 74:1911-1918
Bernat and Brust. Neurology 2019, 92:401-402
The real problem is that oly 25% of brain death evaluations follow standard procedures as that recommended by the AAN in 2010, or the landmark paper in JAMA 1968, 205:337-340. His has led to a loss pf public confidence that physicians can properly declare death. A number of law suits in the USA have taken place threatening organized neurology. This is most likely a similar situation in other countries where Medicine is privately organized, and thus multiple medical and legal societies have infuence on practice. This is the case of Brazil.
Dr Paulo Bittencourt
