Apnea testing using the oxygen insufflation method for diagnosis of brain death may compromise pulmonary function

Abstract Introduction The aim of our study was to compare the reliability and safety of the classical I-AT with the continuous positive airway pressure apnea test (CPAP-AT). Material and methods In the group of 48 patients (group O), an I-AT was performed at the end of BD diagnostic procedures, and approximately 1–1.5 h later CPAP-AT with 100% FiO 2 and CPAP of 10 cm H 2 O, provided by ventilator in CPAP mode. After pre‑oxygenation with 100% FiO 2 for 10 min, the PaO 2 /FiO 2 ratio was recorded prior to I-AT at time-point one (T1) and prior to CPAP-AT at time-point two (T2). Group O was categorized into subgroup N-H (non-hypoxemic), consisting of 41 patients with good lung function, and subgroup H (hypoxemic) consisting of 7 patients with poor lung function. Within each subgroup PaO 2 /FiO 2 at T1 and T2 were compared. Results In Group O, PaO 2 /FiO 2 decreased from 321 ± 128 mm Hg at T1 to 291 ± 119 mm Hg at T2 (p = 0.004). In subgroup N-H, PaO 2 /FiO 2 declined from 355 ± 103 to 321 ± 100 mm Hg (p = 0.008), and in subgroup H, PaO 2 /FiO 2 remained almost unchanged. Additionally, in 4 patients from subgroup N-H, PaO 2 /FiO 2 decreased below 200 mm Hg at T2. Conclusions Our study indicates that I-AT may compromise pulmonary function and this may support the recommendation of safer CPAP-AT alternative.