LAUSR

Introduction/Hypothesis: The apnea test is a fundamental component of determination of death by neurologic criteria (DNC). The objective was to determine the incidence of adverse events during apnea testing using continuous positive airway pressure (CPAP) in children. We hypothesized that adverse events would occur during <5% of apnea tests. Methods: Medical record review of children evaluated for DNC between 2013 and 2018 at an academic children’s hospital where CPAP is the institutional standard for apnea testing. Abstracted information included number of apnea tests performed, vital signs and arterial blood gases during apnea testing, and outcome for each patient. Adverse events were defined as early termination of the apnea test due to desaturation, hypotension, or other significant event (e.g. arrhythmia, cardiac arrest). We used oxygenation index and presence of vasopressors to determine pre-apnea test cardiopulmonary dysfunction. Patient demographics and clinical characteristics were summarized by medians (interquartile range [IQR]) for continuous variables, and counts for categorical variables. Results: 73 patients (age 7 [2.7-13.2] years, 48% male) underwent 123 apnea tests. 5 (7%) patients had apnea tests deferred by a pediatric intensivist due to cardiopulmonary instability. Vasopressors were in use for 108 (88%) tests and pre-test oxygenation index was 3.5 [2.4-4.7]. CPAP with a flow-inflating bag was used in 106 (86%), CPAP via ventilator in 5 (4%), and undocumented in 12 (10%) apnea tests. Apnea test duration was 10 [7-12] minutes. PaCO2 increased from 44 [39-48] to 78 [71-85] mmHg. Pre-apnea test PaO2 was 358 [224-473] mmHg. At apnea test completion, PaO2 had increased in 45 (38%) and decreased in 75 (62%) tests with a median PaO2 decline of 23% [13-40%]. Adverse event rate was 0.8%. One apnea test was terminated early due to hypotension and none due to desaturation. No other adverse events were reported. 122 (99%) apnea tests were consistent with DNC. 69 (95%) patients were declared dead by neurologic criteria and 4 (5%) patients had care withdrawn prior to completing the DNC evaluation. Conclusions: Apnea testing can be safely performed in children using CPAP. Further studies are needed to determine specific cardiopulmonary parameters where apnea testing can be performed safely.