Lactate clearance and volume status at cannulation are associated with survival in trauma VV ECMO patients

Background Veno-venous extracorporeal membrane oxygenation (VV ECMO) is an advanced therapy for patients with respiratory failure refractory to conventional management. Volume overload and elevated lactate levels have been associated with poor outcomes in medical patients with respiratory failure managed with VV ECMO, but this has not been studied in trauma patients. Methods This was a single-center retrospective study of trauma patients treated with VV ECMO between 2014 and 2024. Associations between in-hospital survival and (1) lactate trends before and after cannulation, and (2) fluid balance before and after cannulation were analyzed. We determined lactate clearance using linear regression of serial values, and assessed fluid balance in 12-h intervals normalized to the time of cannulation. Results Seventy-eight patients were included, with an overall survival rate of 69%. Survivors exhibited lower pre-cannulation lactate levels (4.7 mmol/L vs. 12.4 mmol/L, p < 0.001) and lower cumulative pre-ECMO fluid balance (2.1 L vs. 5.6 L, p = 0.03). Pre-cannulation lactate clearance was significantly greater among survivors (−0.37 ± 0.16 mmol/L per hour vs. +0.09 ± 0.12 mmol/L per hour, p = 0.02). Post-cannulation trends in lactate and volume status were not associated with mortality. Mortality risk increased sharply beyond a cumulative +3.5 L fluid balance at cannulation. Combined modeling showed lowest survival when lactate exceeded 10 mmol/L and fluid balance surpassed +3 L. Conclusions In trauma patients undergoing VV ECMO, both impaired lactate clearance and positive fluid balance prior to cannulation were associated with increased mortality, while post-cannulation changes were not. A pre-ECMO fluid balance exceeding +3.5 L was an inflection point associated with increased mortality risk. These findings suggest that lactate clearance and volume overload may have prognostic value before ECMO initiation in trauma populations.