Feasibility and safety of ultra-low volume ventilation (≤ 3 ml/kg) combined with extra corporeal carbon dioxide removal (ECCO2R) in acute respiratory failure patients

Abstract

Background: Ultra-protective ventilation is the combination of low airway pressures and tidal volume (Vt) combined with extra corporeal carbon dioxide removal (ECCO2R). A recent large study showed no benefit of ultra-protective ventilation compared to standard ventilation in ARDS (Acute Respiratory Distress Syndrome) patients. However, the reduction in Vt failed to achieve the objective of less than or equal to 3 ml/kg predicted body weight (PBW). The main objective of our study was to assess the feasibility of the ultra-low volume ventilation (Vt ≤ 3 ml/kg PBW) facilitated by ECCO2R in acute respiratory failure patients. Methods: Retrospective analysis of a prospective cohort of patients with either high or low blood flow veno-venous ECCO2R devices. A session was defined as a treatment of ECCO2R from the start to the removal of the device (one patient could have one more than one session). Primary endpoint was the proportion of sessions during which a Vt less or equal to 3 ml/kg PBW at 24 h after the start of ECCO2R was successfully achieved for at least 12 h. Secondary endpoints were respiratory variables, rate of adverse events and outcomes. Results: Forty-five ECCO2R sessions were recorded among 41 patients. Ultra-low volume ventilation (tidal volume ≤ 3 ml/kg PBW, success group) was successfully achieved at 24 h in 40.0% sessions (18 out of 45 sessions, confidence interval 25.3–54.6%). At 24 h, tidal volume in the failure group was 4.1 [3.8–4.5] ml/kg PBW compared to 2.1 [1.9–2.5] in the success group (p < 0.001). After multivariate analysis, blood flow rate was significantly associated with success of ultra-low volume ventilation (adjusted OR per 100 ml/min increase 1.51 (95%CI 1.21–1.90, p = 0.0003). Conclusion: Ultra-low volume ventilation (≤ 3 ml/kg PBW) was feasible in 18 out of 45 sessions. Higher blood flow rates were associated with the success of ultra-low volume ventilation.