DOI: 10.1097/cce.0000000000001437 ISSN: 2639-8028

Apnea Testing for Brain Death/Death by Neurologic Criteria in Adults: A Prospective Multicenter Observational Study Assessing the Relationship Between Methodology, Safety, and Duration

Sean Cuninghame, John Basmaji, James Duffin, Andrew Healey, Beth Paltser, Michelle Snyder-Salehi, Alexander Yoshiki, J. Gordon Boyd, Michael Hartwick, Karim Soliman, Jeffrey M. Singh, David Katz, Janice Beitel, Ebenezer Ogunsakin, Marat Slessarev
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IMPORTANCE:

Apnea testing is an integral component of brain death (BD) assessments. The optimal method of Apnea Testing is currently not known.

OBJECTIVES:

To describe the current use of apnea test methods, and compare the effect of the chosen apnea test method (passive oxygenation, continuous positive airway pressure [CPAP], or exogenous C

o
2 ) on safety and duration of apnea test in adult BD/death by neurologic criteria (DNC) organ donors.

DESIGN:

A prospective multicenter observational study.

SETTING:

Seventy-four ICUs in Ontario, Canada, who participate in organ donation practices.

PATIENTS:

All BD/DNC assessments in Ontario, Canada, from July 2023 to August 2024.

INTERVENTIONS:

None.

MAIN OUTCOMES AND MEASURES:

Outcomes included the rate of apnea test attempts, completions, and adverse events. We also measured the incidence of each method used and the duration of the apnea test.

RESULTS:

During the 1-year study period, a total of 368 BD/DNC assessments were performed, of which 361 (98%) attempted an apnea test. Of the 361 apnea tests attempted, 236 (65%) used passive oxygenation (tracheal insufflation), 103 (29%) used CPAP-based methods, and 22 (6%) used exogenous C

o
2 . Nine tests were not completed: seven were terminated due to adverse events (all with passive oxygenation; five hypoxemia, two hemodynamic instability) and two due to observed respiratory effort. All adverse events occurred with the passive oxygenation method ( p = 0.20). No statistically significant differences were seen in apnea test duration between methods. The median test durations were 12 minutes (interquartile range [IQR], 10–17 min), 12 minutes (IQR, 8–15 min), and 15 minutes (IQR, 11–25 min) for passive oxygenation, positive pressure, and exogenous C
o
2 , respectively.

CONCLUSIONS AND RELEVANCE:

In this large multicenter study, passive oxygenation was associated with a nonsignificant increase in adverse events compared with CPAP-based and exogenous C

o
2 methods. Exogenous C
o
2 did not shorten apnea test time. These findings support further investigation of CPAP-based methods as an alternative approach to apnea testing and refinement of C
o
2 delivery parameters.

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