PT - JOURNAL ARTICLE AU - Richard H Kallet AU - Hanjing Zhuo AU - Kathleen D. Liu AU - Carolyn S. Calfee AU - Michael A Matthay TI - THE ASSOCIATION BETWEEN PHYSIOLOGIC DEAD-SPACE FRACTION AND MORTALITY IN PATIENTS WITH THE ACUTE RESPIRATORY DISTRESS SYNDROME ENROLLED INTO A PROSPECTIVE MULTI-CENTERED CLINICAL TRIAL AID - 10.4187/respcare.02593 DP - 2013 Dec 31 TA - Respiratory Care PG - respcare.02593 4099 - http://rc.rcjournal.com/content/early/2013/12/31/respcare.02593.short 4100 - http://rc.rcjournal.com/content/early/2013/12/31/respcare.02593.full AB - Objective: To test the association between pulmonary dead-space fraction (VD/VT) and mortality in patients with ARDS (Berlin Definition, PaO2/FiO2 ≤ 300 mm Hg; PEEP ≥ 5 cm H2O) enrolled into a clinical trial incorporating lung-protective ventilation. Design: Prospective, multi-center study. Setting: Medical-surgical intensive care units in the United States. Subjects: 126 ALI patients enrolled into a phase III randomized, placebo-controlled study of aerosolized albuterol. Interventions: None Measurements and Main Results: VD/VT and pulmonary mechanics were measured within 4 hours of enrollment and repeated daily on study days 1 and 2 in subjects requiring arterial blood gases for clinical management. At baseline, non-survivors had a trend towards higher VD/VT compared to survivors (0.62 ± 0.11 vs. 0.56 ± 0.11 respectively, p = 0.08). Differences in VD/VT between non-survivors and survivors became significant on study days 1 (0.64 ± 0.12 vs. 0.55 ± 0.11 respectively, p = 0.01) and 2 (0.67 ± 0.12 vs. 0.56 ± 0.11 respectively, p=0.004). Likewise, the association between VD/VT and mortality was significant on study day 1 (odds ratio per 0.10 change in VD/VT [95% confidence interval]: 6.84 [1.62-28.84] p = 0.01; and study day 2: 4.90 [1.28-18.73] p = 0.02) after adjusting for VD/VT, PaO2/FiO2, oxygenation index, vasopressor use and the primary risk for ARDS. Using a Cox proportional hazard model, VD/VT was associated with a trend towards higher mortality (HR = 4.37 [CI: 0.99 – 19.32]; p = 0.052) that became significant when the analysis was adjusted for daily oxygenation index (HR = 1.74 [95% CI: 1.12 – 3.35] p = 0.04). Conclusions: Markedly elevated VD/VT (≥ 0.60) in early ARDS is associated with higher mortality. Measuring VD/VT may be useful in identifying ARDS patients at increased risk of death who are enrolled into a therapeutic trial.