Prognostic value of plateau pressure below 30 cm H2O in septic subjects with acute respiratory failure.

BACKGROUND Ventilation with low tidal volume is recommended for patients with acute lung injury. Current guidelines suggest limiting plateau pressure (Pplat) to < 30 cm H2O for septic patients needing mechanical ventilation. The aim of this study was to determine whether Pplat within the first 24 h of ICU admission is predictive of outcome and whether Pplat < 30 cm H2O is associated with lower mortality rates. METHODS This study was a retrospective analysis of prospectively acquired clinical data from an ICU of a tertiary referral hospital in central Taiwan. Subjects were included if they were admitted due to sepsis and respiratory failure requiring mechanical ventilation from April 2008 to November 2009. RESULTS There were 220 subjects (188 males, 32 females) with a median age of 76 y and a mean Acute Physiology and Chronic Health Evaluation II score of 25.0 ± 6.5. Pneumonia was the major cause of sepsis (85.5%). The hospital mortality rate was 39.1%. Pplat was higher throughout the first 24 h of ICU admission in nonsurvivors. Higher Pplat was associated with higher mortality rates regardless of acute lung injury. In multivariate regression analysis, Pplat > 25 cm H2O at 24 h after admission was an independent risk factor for mortality (adjusted odds ratio of 2.33, 95% CI 1.10-4.91, P = .03 for hospital mortality). CONCLUSIONS Pplat within the first 24 h of ICU admission is predictive of outcome, with lower Pplat associated with lower mortality rates. There is no safety margin for Pplat. Limiting Pplat should be considered even at < 30 cm H2O in septic patients with acute respiratory failure.