Intermediate tidal volume is an acceptable option for ventilated patients with acute respiratory distress syndrome

OBJECTIVE: Evidence only proves low surpasses high tidal volume (V(T)) for acute respiratory distress syndrome (ARDS). Intermediate V(T) is a common setting for ARDS patients and has been demonstrated as effective as low V(T) in non-ARDS patients. The effectiveness of intermediate V(T) in ARDS has not been studied and is the objective of this study. DESIGN: A retrospective cohort study. SETTING: Five ICUs with their totally 130 beds in Taiwan. PATIENTS OR PARTICIPANTS: ARDS patients under invasive ventilation. INTERVENTIONS: No. MAIN VARIABLES OF INTEREST: 28-D mortality. RESULT: Totally 382 patients, with 6958 ventilator settings eligible for lung protection, were classified into low (mean V(T) = 6.7 ml/kg), intermediate (mean V(T) = 8.9 ml/kg) and high (mean V(T) = 11.2 ml/kg) V(T) groups. With similar baseline ARDS and ICU severities, intermediate and low V(T) groups did not differ in 28-D mortality (47% vs. 63%, P = 0.06) or other outcomes such as 90-D mortality, ventilator-free days, ventilator-dependence rate. Multivariate analysis revealed high V(T) was independently associated with 28-D and 90-D mortality, but intermediate V(T) was not significantly associated with 28-D mortality (HR 1.34, CI 0.92–1.97, P = 0.13) or 90-D mortality. When the intermediate and low V(T) groups were matched in propensity scores (n = 66 for each group), their outcomes were also not significantly different. CONCLUSION: Intermediate V(T), with its outcomes similar to small V(T), is an acceptable option for ventilated ARDS patients. This conclusion needs verification through clinical trials.