To explore whether reducing airflow and maintaining blood flow can improve the success rate of the apnea test (AT) and whether two auxiliary test strategies can improve the completion rate of brain death determination (BDD). To perform a multicenter retrospective analysis of the effect of reducing air flow and maintaining constant blood flow during extracorporeal membrane oxygenation (ECMO) on AT parameters and the role of auxiliary detection in the absence of an AT. Among the 31 BDD patients, 18, 10, and 3 had hypoxic-ischemic encephalopathy, stroke, and traumatic brain injury, respectively. All patients received V-V ECMO (3 patients) or V-A ECMO support (28 patients). The median gas flow before and after the AT was 3.5 (3.0–4.0) vs. 0.5 (0.5–1) L/min (p < 0.01); PaCO₂ and pH in the right radial artery and the postoxygenator circuit met the AT-positive criteria after AT. All patients had at least two auxiliary tests that met the positive criteria for BDD. Twenty-five patients (81%) donated organs. Precise regulation of ECMO gas flow and blood flow can improve the completion rate of the AT. Performing at least two positive auxiliary tests increases BDD completion rates and the likelihood of organ donation.