Utilization patterns and patient outcomes associated with use of rescue therapies in acute lung injury.

Abstract

To investigate the practice patterns and clinical outcomes associated with use of rescue therapies in patients with acute lung injury. Secondary analysis of multicentered, randomized, controlled trial data from the National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome Clinical Trials Network. Intensive care units of Acute Respiratory Distress Syndrome Clinical Trials Network centers across the United States. Subjects enrolled in six Acute Respiratory Distress Syndrome Clinical Trials Network trials occurring between 1996 and 2005. None. One hundred sixty-six of 2632 (6.3%) subjects received rescue therapy, defined as prone positioning (97 of 166 [58%]), inhaled vasodilators (47 of 166 [28%]), high-frequency ventilation (12 of 166 [7%]), or extracorporeal membrane oxygenation (10 of 166 [6%]). Use of inhaled vasodilators increased whereas use of prone position decreased over time (p for trend = 0.04 and 0.0013, respectively). Multivariate predictors for use of rescue therapy included age (odds ratio per 10 yrs and 95% confidence interval: 0.88; 0.78-0.99; p = .049), positive end-expiratory pressure (odds ratio per 5-cm H2O increase: 1.33; 95% confidence interval, 1.05-1.69; p = .019), Pao2/Fio2; odds ratio per 5-cm H2O increase: 0.98; 95% confidence interval, 0.96-0.99; p = .017), peak airway pressure (odds ratio per 5-cm H2O increase: 1.11; 95% confidence interval, 1.001-1.237; p = .047), and study order (odds ratio per subsequent Acute Respiratory Distress Syndrome Clinical Trials Network study: 1.21; 95% confidence interval, 1.03-1.41; p = .02). Cox proportional hazards analysis of propensity score-matched subjects showed no difference in survival for those who received rescue therapy vs. those who did not (hazard ratio for death after rescue therapy or index date, 1.10; 95% confidence interval, 0.67-1.78; p = .72). No differences in survival were found between those who received prone positioning vs. inhaled vasodilators (propensity score-adjusted hazard ratio for prone 0.87; 95% confidence interval, 0.86-2.10; p = .76). Rescue therapies are utilized in younger patients with more severe oxygenation deficits. Patterns of rescue therapy utilization appear to be changing over time. Within the limits of an observational study design, we did not find evidence of a survival benefit with use of rescue therapies in acute lung injury.