Lower tidal volume at initiation of mechanical ventilation may reduce progression to acute respiratory distress syndrome: a systematic review
1 Department of Anesthesiology, Division of Critical Care, Division of Emergency Medicine, Washington University in St. Louis School of Medicine, 660 South Euclid Avenue, St. Louis, MO, USA
2 Department of Emergency Medicine, Department of Anesthesia, Division of Critical Care, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA, USA
3 Department of Anesthesiology, Division of Critical Care, Washington University in St. Louis School of Medicine, 660 South Euclid Avenue, St. Louis, MO, USA
4 Division of Emergency Medicine, Washington University in St. Louis School of Medicine, 660 South Euclid Avenue, St. Louis, MO, USA
Critical Care 2013, 17:R11 doi:10.1186/cc11936
Please see related commentary by Kilickaya et al., http://ccforum.com/content/17/2/123Published: 18 January 2013
The most appropriate tidal volume in patients without acute respiratory distress syndrome (ARDS) is controversial and has not been rigorously examined. Our objective was to determine whether a mechanical ventilation strategy using lower tidal volume is associated with a decreased incidence of progression to ARDS when compared with a higher tidal volume strategy.
A systematic search of MEDLINE, EMBASE, CINAHL, the Cochrane Library, conference proceedings, and clinical trial registration was performed with a comprehensive strategy. Studies providing information on mechanically ventilated patients without ARDS at the time of initiation of mechanical ventilation, and in which tidal volume was independently studied as a predictor variable for outcome, were included. The primary outcome was progression to ARDS.
The search yielded 1,704 studies, of which 13 were included in the final analysis. One randomized controlled trial was found; the remaining 12 studies were observational. The patient cohorts were significantly heterogeneous in composition and baseline risk for developing ARDS; therefore, a meta-analysis of the data was not performed. The majority of the studies (n = 8) showed a decrease in progression to ARDS with a lower tidal volume strategy. ARDS developed early in the course of illness (5 hours to 3.7 days). The development of ARDS was associated with increased mortality, lengths of stay, mechanical ventilation duration, and nonpulmonary organ failure.
In mechanically ventilated patients without ARDS at the time of endotracheal intubation, the majority of data favors lower tidal volume to reduce progression to ARDS. However, due to significant heterogeneity in the data, no definitive recommendations can be made. Further randomized controlled trials examining the role of lower tidal volumes in patients without ARDS, controlling for ARDS risk, are needed.
2013 Fuller et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0 webcite), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.