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

Abstract

ObjectiveEvidence only proves low surpasses high tidal volume (VT) for acute respiratory distress syndrome (ARDS). Intermediate VT is a common setting for ARDS patients and has been demonstrated as effective as low VT in non-ARDS patients. The effectiveness of intermediate VT in ARDS has not been studied and is the objective of this study.DesignA retrospective cohort study.SettingFive ICUs with their totally 130 beds in Taiwan.Patients or participantsARDS patients under invasive ventilation.InterventionsNo.Main variables of interest28-D mortality.ResultTotally 382 patients, with 6958 ventilator settings eligible for lung protection, were classified into low (mean VT = 6.7 ml/kg), intermediate (mean VT = 8.9 ml/kg) and high (mean VT = 11.2 ml/kg) VT groups. With similar baseline ARDS and ICU severities, intermediate and low VT 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 VT was independently associated with 28-D and 90-D mortality, but intermediate VT 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 VT groups were matched in propensity scores (n = 66 for each group), their outcomes were also not significantly different.ConclusionIntermediate VT, with its outcomes similar to small VT, is an acceptable option for ventilated ARDS patients. This conclusion needs verification through clinical trials.