Optimization of conditions for apnea testing in a hypoxemic brain dead patient

Abstract

We report the case of a patient in whom brain death was suspected and associated with atelectasis and moderate to severe hypoxemia even though the patient was subjected to protective ventilation, a closed tracheal suction system, positive end-expiratory pressure, and recruitment maneuvers. Faced with the failure to obtain an adequate partial pressure of oxygen for the apnea test, we elected to place the patient in a prone position, use higher positive end-expiratory pressure, perform a new recruitment maneuver, and ventilate with a higher tidal volume (8mL/kg) without exceeding the plateau pressure of 30cmH 2 O. The apnea test was performed with the patient in a prone position, with continuous positive airway pressure coupled with a T-piece. The delay in diagnosis was 10 hours, and organ donation was not possible due to circulatory arrest. This report demonstrates the difficulties in obtaining higher levels of the partial pressure of oxygen for the apnea test. The delays in the diagnosis of brain death and in the organ donation process are discussed, as well as potential strategies to optimize the partial pressure of oxygen to perform the apnea test according to the current recommendations.

Apnea Testing for the Determination of Brain Death: A Systematic Scoping Review

“…Other, single case modifications aimed at improved oxygenation and/or ability to conduct and complete AT described a pre-AT recruitment maneuver with incremental titration of PEEP and maintenance of PEEP via a CPAP valve [30], prolonged AT for 110 min due to suspected cardiac ventilations resulting in a very slow increase in carbon dioxide levels [31] and successful use of prone positioning with CPAP and T-piece in a severely hypoxic patient [32].…”

Use of CPAP as an alternative to the apnea test during the determination of brain death in hypoxemic patients. Report of two cases

“…( 10 ) Recently, a case was reported that showed the possibility of performing the apnea test in a prone position and with the CPAP valve coupled to a T-piece. ( 11 )…”

“…Additionally to providing safety to patients with hypoxic respiratory failure, the apnea test with CPAP is being used as part of a lung preservation strategy for transplantation and includes a tidal volume of 6 to 8mL/kg and a PEEP of 8 to 10cmH 2 O, in addition to alveolar recruitment maneuvers. ( 13 - 15 ) Although recruitment maneuvers ( 8 , 11 , 13 - 15 ) are suggested by some studies, their potential complications must be considered, such as hypotension, decreased SaO 2 , arrhythmias and barotrauma. Also, maintenance of the FRV promoted by CPAP is likely sufficient to maintain oxygenation.…”