362: USE OF AIRWAY PRESSURE RELEASE VENTILATION IN ACUTE RESPIRATORY DISTRESS SYNDROME

Abstract

Introduction: Acute Respiratory Distress Syndrome (ARDS) is a disease process with high morbidity and mortality. Airway Pressure Release Ventilation (APRV) has been shown to potentially protect against the development of ARDS. We hypothesized that APRV is protective against the development of ARDS in the surgical critical care population. Methods: IRB approved, prospective observational cohort study of all ventilated patients admitted to the surgical intensive care unit at a single tertiary, academic center over a 6 month period. Patients were randomized to APRV or conventional ventilation (CV). ARDS was defined using the Berlin criteria. Lung injury prediction scores (LIPS) were calculated for all enrolled patients, with higher LIPS representing increased risk of developing ARDS. Primary outcomes include development of ARDS. LIPS score was used to predict patients at high risk for ARDS. Secondary outcomes included the ability of APRV to protect against ARDS in septic patients, and the ability of APRV to decrease overall mortality. Univariate and multivariate logistic regression models were performed using SAS 9.2. Statistical significance was set at p<0.05. Results: 268 total patients enrolled, 141 (52.6%) with ARDS and 127 (47.4%) without ARDS. 119 (44.4%) patients were on APRV and 149 (55.6%) were on CV. There was no statistically significant difference in the rate of ARDS in patients on APRV versus CV (p=0.862). This result is consistent despite LIPS. APRV was also not found to be protective against the development of ARDS in a subset of septic patients. 108 (40.3%) patients were septic with 49 (45.4%) on APRV and 59 (54.6%) on CV. 33 (30.6%) of APRV patients with sepsis and 37 (34.3%) of CV sepsis patients developed ARDS. After adjusting for multiple comparisons, there were no statistical significances between groups. APRV trended toward a higher mortality than CV in patients with ARDS, but this did not reach statistical significance (OR 1.64, p=0.144). Conclusions: APRV is not protective against the development of ARDS, even when a patient is high risk based on the LIPS system. APRV also does not protect against ARDS in septic patients nor does it decrease overall mortality. Additional studies are required to extrapolate this data to nonsurgical critical care patients.