Benefit of a single recruitment maneuver after an apnea test for the diagnosis of brain death

INTRODUCTION Many potential lung transplants are lost because of hypoxemia during donor management. We hypothesized that the apnea test, necessary to confirm the diagnosis of brain death in potential lung donors, was involved in the decrease in the ratio of partial pressure of arterial O₂ to fraction of inspired O₂ (PaO₂/FiO₂) and that a single recruitment maneuver performed just after the apnea test can reverse this alteration. METHODS In this case-control study, we examined the effectiveness of the recruitment maneuver with a comparison cohort of brain dead patients who did not receive the maneuver. Patients were matched one-to-one on the basis of initial PaO₂/FiO₂ and on the duration of mechanical ventilation before the apnea test. PaO₂/FiO₂ was measured before (T1), at the end (T2) and two hours after apnea test (T3). RESULTS Twenty-seven patients were included in each group. The apnea test was associated with a significant decrease in PaO₂/FiO₂ from 284 ± 98 to 224 ± 104 mmHg (P < 0.001). The decrease in PaO₂/FiO₂ between T1 and T3 was significantly lower in the recruitment maneuver group than in the control group (-4 (-68-57) vs -61 (-110--18) mmHg, P = 0.02). The number of potential donors with PaO₂/FiO₂ > 300 mmHg decreased by 58% (95% CI: 28-85%) in the control group vs 0% (95% CI: 0-34%) in the recruitment maneuver group (P < 0.001). CONCLUSIONS The apnea test induced a decrease in PaO₂/FiO₂ in potential lung donors. A single recruitment maneuver performed immediately after the apnea test can reverse this alteration and may prevent the loss of potential lung donors.