Timing of Low Tidal Volume Ventilation and ICU Mortality in ARDS: A Prospective Cohort Study.
Am J Respir Crit Care Med. 2014 Dec 5;
Authors: Needham DM, Yang T, Dinglas VD, Mendez-Tellez PA, Shanholtz C, Sevransky JE, Brower RG, Pronovost PJ, Colantuoni E
Rationale: Reducing tidal volume decreases mortality in ARDS. However, the effect of the timing of low tidal volume ventilation is not well understood. Objectives: To evaluate the association of ICU mortality with initial tidal volume and with tidal volume change over time. Methods: Multivariable, time-varying Cox regression analysis of a multi-site, prospective study of 482 ARDS patients with 11,558 twice-daily tidal volume assessments (evaluated in ml/kg of Predicted Body Weight [PBW]) and daily assessment of other mortality predictors. Measurements and Main Results: An increase of 1 ml/kg PBW in initial tidal volume was associated with a 23% increase in ICU mortality risk (adjusted hazard ratio 1.23, 95% confidence interval [CI] 1.06--1.44, p=0.008). Moreover, a 1 ml/kg PBW increase in subsequent tidal volumes compared to the initial tidal volume was associated with a 15% increase in mortality risk (adjusted hazard ratio 1.15, 95% CI 1.02--1. 29, p=0.019). Compared to a prototypical patient receiving 8 days with a tidal volume of 6 ml/kg PBW, the absolute increase in ICU mortality (95% CI) of receiving 10 and 8 ml/kg PBW, respectively, across all 8 days was 7.2% (3.0 - 13.0%) and 2.7% (1.2-4.6%). In scenarios with variation in tidal volume over the 8-day period, mortality was higher when a larger volume was used earlier. Conclusions: Higher tidal volumes shortly after ARDS onset were associated with a greater risk of ICU mortality compared to subsequent tidal volumes. Timely recognition of ARDS and adherence to low tidal volume ventilation is important for reducing mortality. Clinicaltrials.gov NCT00300248.
PMID: 25478681 [PubMed - as supplied by publisher]