Factors influencing the transition phase in acute respiratory distress syndrome: an observational cohort study

Abstract

Background: Protective ventilation during the acute phase of ARDS and weaning from mechanical ventilation are well-established in current guidelines. However, the intermediate transition phase between these stages remains poorly characterized. Objectives: To describe the transition phase in moderate-to-severe ARDS and evaluate the factors associated with neuromuscular blockade (NMBA) weaning failure and pressure support ventilation (PSV) failure. Methods: This bicentric observational cohort study included patients with moderate-to-severe ARDS requiring NMBA continuous infusion within 72 h post-intubation. The transition phase was defined as the 72 h following the first NMBA weaning attempt. The main endpoints were the rates of NMBA reintroduction and PSV failure. Secondary outcomes included predictive factors for NMBA weaning failure and PSV failure and the impact of tidal volume on patient outcomes. Main results: A total of 196 patients were included. NMBA weaning failure occurred in 74 (38%) patients. COVID-19 (OR 3.98 [1.95–8.41], p < 0.001), pH (OR 0.50 [0.30–0.79], p = 0.004), PaO2/FiO2 ratio (OR 0.92 [0.87–0.97], p = 0.007), and high or low driving pressure before first NMBA weaning attempt (< 12 or ≥ 14 cmH2O) (OR 2.77 [1.16–7.14], p = 0.027) were significantly associated with NMBA reintroduction. PSV was initiated in 147 (75%) patients, with a failure rate of 57%, occurring after a median of 9 h [6–24]. Tidal volume (OR 1.28 [1.06–1.56], p = 0.012) was significantly associated with PSV failure. During PSV, 43% of patients exhibited high tidal volumes (> 8 mL/kg PBW). NMBA weaning failure was associated with fewer ventilator-free days and increased mortality at day 28. PSV failure was associated with fewer ventilator-free days. Conclusion: The transition phase represents a high-risk period in ARDS, with significant failure rates for NMBA weaning and PSV trials that may influence patient outcomes. The transition phase therefore represents a critical area for future research to optimize management during this vulnerable period.