Evaluation of the new modified apnea test in confirmation of brain death.

Abstract

Background: Apnea testing is mandatory to confirm brain death; however, it is unsafe for patients who have substantial hypoxemia without ventilator support. We used a new modified apnea test without the need to disconnect the patient from the ventilator in the present study and compared the outcomes and complications of the new method to the widely used old method.

Materials and methods: The current study was conducted on people suspected of having brain death. Both the old and new apnea tests were carried out on the same individual. In the new modified method, instead of hyperventilating and then separating the brain death from the ventilator, the induced hypercapnia method was used, and instead of performing repeated arterial blood gas (ABG), the target ETCO₂ was obtained, and at the time of the target ETCO₂, ABG was also checked followed by comparing ETCO₂ with PaCO₂.

Results: Thirty patients, including 25 (83.3%) males and 5 (16.75%) females, were included in the study. The results showed significant improvement in terms of O₂ saturation and heart rate (HR) using the new modified apnea test compared to the common test. Systolic blood pressure, diastolic blood pressure, and the frequency of complications were improved in the new modified test.

Conclusion: The modified apnea test produced better results in terms of O₂ saturation, HR, and other clinical factors, while it does not require disconnection from the ventilator and repeated ABG assessment. Therefore, it can be used to successfully diagnose brain death in high-risk individuals suffering from severe hypoxia.