# Detection of spontaneous breathing during an apnea test in a patient with suspected brain death using electrical impedance tomography: a case report

## TL;DR

This case report shows how electrical impedance tomography can detect subtle breathing efforts during a brain death test, improving accuracy beyond visual observation.

## Contribution

The study demonstrates the novel use of EIT to detect spontaneous breathing during an apnea test in a brain death evaluation.

## Key findings

- EIT detected spontaneous breathing movements not easily visible to the naked eye during the apnea test.
- EIT showed a shift in ventilation distribution, indicating initial recovery before returning to ventilatory dependence.
- The use of EIT may improve the sensitivity and accuracy of apnea test assessments.

## Abstract

The apnea test (AT) is a crucial procedure in determining brain death (BD), with detection of spontaneous breathing efforts serving as a key criterion. Numerous national statutes mandate complete disconnection of the patient from the ventilator during the procedure to open the airway directly to the atmosphere. These regulations mandate visual observation as an exclusive option for detecting breathing efforts. However, reliance on visual observation alone can pose challenges in identifying subtle respiratory movements.

This case report presents a 55-year-old morbidly obese male patient with suspected BD due to cerebral hemorrhage undergoing an AT. The AT was performed with continuous electrical impedance tomography (EIT) monitoring. Upon detection of spontaneous breathing movements by both visual observation and EIT, the AT was aborted, and the patient was reconnected to the ventilator. EIT indicated a shift in ventilation distribution from the ventral to the dorsal regions, indicating the presence of spontaneous breathing efforts. EIT results also suggested the patient experienced a slow but transient initial recovery phase, likely due to atelectasis induced by morbid obesity, before returning to a steady state of ventilatory support.

The findings suggest EIT could enhance the sensitivity and accuracy of detecting spontaneous breathing efforts, providing additional insights into the respiratory status of patients during the AT.