To investigate the impact of body mass index (BMI) on neurologic outcomes in venoarterial extracorporeal membrane oxygenation (VA-ECMO)

Retrospective observational study

Single center

Adults

VA-ECMO

Obese (BMI≥30 kg/m²) and nonobese (BMI<30 kg/m²) patient groups were compared. The primary outcome was neurologic outcomes at discharge, with “good” (modified Rankin Scale [mRS] score 0-3) and “poor” (mRS score 4-6). Secondary outcomes were acute brain injury (ABI) and mortality. Multivariable Cox regression was used to investigate risk factors for poor neurologic outcomes, adjusting for demographics, comorbidities, pre-ECMO PaO₂, pericannulation PaCO₂ change, lactate, central cannulation, and ABI. Spline regression was performed to assess the relationship between BMI and neurologic outcomes. The Kaplan-Meier estimator was used to evaluate 90-day survival. Among 214 patients (median age 58 years, 63% male), 104 were obese (median BMI, 35.4; interquartile range [IQR], 32.2-39.9), and 110 were nonobese (median BMI, 25; IQR, 23.2-27.5). Obese patients had higher rates of poor neurologic outcomes (91% vs 69%; p < 0.001) and ABI (50% vs 36%; p = 0.04). The Cox model identified associations of obesity (adjusted hazard ratio [aHR], 1.63, 95% confidence interval [CI], 1.15-2.31; p = 0.006) and ABI (aHR, 1.41; 95% CI, 1.01-1.96; p = 0.04) were associated with increased hazards of poor neurologic outcomes. Spline regression showed a fairly linear relationship between BMI and poor neurologic outcomes. Kaplan-Meier analysis suggested that the obese patients had a lower 90-day survival probability (p < 0.0001, log-rank test).

Obesity increased the hazard of poor neurologic outcomes, ABI, and mortality in this cohort of patients undergoing VA-ECMO, highlighting the importance of standardized neuromonitoring and early ABI detection, especially for obese patients. Further research is needed to explore the impact of obesity on neurologic outcomes independent of ABI.