Neurologic Outcome After Venoarterial Extracorporeal Membrane Oxygenation in Rats: A Description of a Long‐Term Survival Model

BACKGROUND: Neurological impairments seriously affect the quality of life in patients with venoarterial extracorporeal membrane oxygenation (VA-ECMO). However, the underlying mechanisms have been restricted to a satisfactory animal model with determined support and recovery time. This study aimed to establish a rodent VA-ECMO model with different durations, assessing the feasibility of a long-term surviving model with determined recovery time. METHODS: Thirty-six Sprague-Dawley rats were divided into five groups: sham group (n = 10), ECMO-2 h group (n = 5), ECMO-3 h group (n = 5), ECMO-4 h group (n = 11) and ECMO-6 h group (n = 5). The ECMO-4 h group was further assigned to the surviving time of postoperative day 7 (n = 6) to perform the Morris water maze. VA-ECMO was established through the right external jugular vein-right atrium for venous drainage and tail artery for arterial infusion. The branch of the left femoral artery was cannulated for arterial blood pressure monitoring and blood gas analyses. Thereafter, the brains were fixed for histopathological assessment. RESULTS: All VA-ECMO processes were successfully achieved, and one rat in the ECMO-4 h group died 2 h after ECMO. The physiologic variables of all rats were stable. Histologic deficits (pathological score, surviving neurons, and loss of dendritic spines) were detectable after more than 3 h of support, and functional deficits were observed after 4 h of exposure, which persisted for 3 days. CONCLUSION: We established a reproducible and long-term recovery model of VA-ECMO in rats with cerebral histologic deficits depending on support duration. The neurocognitive performance was impaired after 4-h VA-ECMO exposure with the 3-day recovery time frame.