Evaluation of Apnea Test in Brain-Dead Patients

Document Type : Research Paper




ntroduction: Apnea testing is mandatory to confirm brain death. Serious side effects such as severe cardio-pulmonary complications, ICP elevation and pneumothoraces may occur during apnea testing. So, it should be performed as the last test after the other ones. However, its safety is a major issue .The aim of this study was to evaluate the results and complications of apnea test in brain dead patients in the course of three years.
Material and Methods: This cross sectional study was corried out from 2002 to 2005 at Mashhad University of Medical Sciences with a simple sampling method on 57 brain dead patients in whom apnea test was performed by the authors. After preoxygenation the test was done in 10 minutes during which the patients had been disconnected from the ventilator. ABG analysis proceeded in minutes 2, 5, 8 and 10. The test result assumed positive if PaCO2 was increased up to 60mmHg or more than 20mmHg from baseline value. All patients should had been preoxygenated. The test stopped whenever predefined complications occurred. All the data collected in a separated questionnaire. Statistical analysis was done using SPSS software and with ANNOVA test.
Results: From 57 brain dead patients in this study, 11 were female and 46 were male. The mean age of the patients was 25.28 years, ranging from 6 to 38 (SD= 14.3). Serious complications occurred in 11 patients including severe hypoxia in 10 and cardiac arrest in one. These complications were more common in patients, before testing, with an unstable cardiopulmonary condition than the ones with a stable condition (53.84% versus9.6%). The mean period from death time to apnea testing was between minimally 36 hours and maximally 11 days. It was 11 days in a patient aged 15. In all cases, the results of the tests were positive and supported by clinical diagnosis of brain death.
Conclusion:Apnea test is an invasive test. It may reduces the organ reservoirs and potentially induces tissue ischemia, due to severe cardio-pulmonary complications. Also, it is not able to reject brain death diagnosis, if it has already been confirmed by the other tests. It seems that an alternative test with a high index of safety should be considered or some modifications are needed. At least, it is suggested to be avoided in patients with an unstable cardiopulmonary condition.


1- Mori K, Shingu K, Nakao S. Brain Death. In: Miller RD. Miller’s anesthesia. 6th ed. Philadelphia: Elsevier;
2005. 2955-2970.
2- Paolin A, Manuali A, Di Paola F, Boccaletto F, Caputo P, Zanata R, et al. Reliability in diagnosis of brain
death. Intensive Care Med 1996 Aug; 22(8): 836-7.
3- Combes JC, Nicolas F, Lenfant F, Cros N, D’Athis P, Freysz M. Hemodynamic changes induced by apnea test
in patients with brain death . Ann Fr Anesth Reanim 1996; 15(8): 1173-7.
4- Levesque S, Lessard MR, Nicole PC, Langevin S, Leblanc F, Lauzier F, Brochu JG . Efficacy of a T-piece
system and a continues positive airway pressure system for apnea testing in the diagnosis of brain death. Crit Care
Med 2006 Mar 14; Publish Ahead of print.
5- Sharp MD, young GB, Harris C. The apnea test for brain death determination: an alternative approach
.Neurocrit Care 2004; (3):363-6.
6- Saponsik G, Rizzo G , Deluca JL. Pneumothorax and pneumoperitoneum during the apnea test: how safe is this
procedure? Arq Neuropsiquiatr 2000 Sep; 58(3B): 905-8.
7- Saponsik G , Rizzo G , Vega A, Sabbatiello R , Deluca JL . Problems associated with the apnea test in the
diagnosis of brain death. Neurol India 2004 Sep; 52(3): 342-5.
8- Ma PL, Yang MS, Li Q, Ou H, Peng Y, Su JW, Zhao JZ. Study on safety of apnea test in clinical determination
of brain death. Zhongguo Wei Zhong Bing Ji Jiu Yi Xue 2006 May; 18(5):260-3.
9- Ohno M. Cardiovascular effects of apnea test in the diagnosis of brain death. Masui 1990 Jul; 39(7): 822-6.
10- Maekawa T, Sadamitsu D, Tateishi A. Safety application in apnea test. Rinsho Shinkeigaku. 1993 Des; 33(12):
11- Su YY, Zhao H, Zhang Y, Wang XM, Hua Y. Studies on evaluation of brain death. Zhonghua Nei Ke Za Zhi
2004 Apr; 43(4):250-3.
12- Goudreau JI, Wijdicks EF, Emery SF. Complication during apnea testing in the determination of brain death:
Predisposing factor. Neurology 2000; 55:1954.