%0 Journal Article %A Richard H Kallet %A James A Alonso %A Jean-François Pittet %A Michael A Matthay %T Prognostic Value of the Pulmonary Dead-Space Fraction During the First 6 Days of Acute Respiratory Distress Syndrome %D 2004 %J Respiratory Care %P 1008-1014 %V 49 %N 9 %X BACKGROUND: The ratio of pulmonary dead space to tidal volume (VD/VT) in acute respiratory distress syndrome (ARDS) is reported to be between 0.35 and 0.55. However, VD/VT has seldom been measured with consideration to the evolving pathophysiology of ARDS. METHODS: We made serial VD/VT measurements with 59 patients who required mechanical ventilation for ≥ 6 days. We measured VD/VT within 24 h of the point at which the patient met the American-European Consensus Conference criteria for ARDS, and we repeated the VD/VT measurement on ARDS days 2, 3, and 6 with a bedside metabolic monitor during volume-regulated ventilation. We analyzed the changes in VD/VT over the 6-day period to determine whether VD/VT has a significant association with mortality. RESULTS: VD/VT was significantly higher in nonsurvivors on day 1 (0.61 ± 0.09 vs 0.54 ± 0.08, p < 0.05), day 2 (0.63 ± 0.09 vs 0.53 ± 0.09, p < 0.001), day 3 (0.64 ± 0.09 vs 0.53 ± 0.09, p < 0.001), and day 6 (0.66 ± 0.09 vs 0.51 ± 0.08, p < 0.001). CONCLUSION: In ARDS a sustained VD/VT elevation is characteristic of nonsurvivors, so dead-space measurements made beyond the first 24 hours may have prognostic value. %U https://rc.rcjournal.com/content/respcare/49/9/1008.full.pdf