High Positive End Expiratory Pressure is Associated with Improved Survival in Obese Patients with Acute Respiratory Distress Syndrome

• Published in: The American journal of medicine Vol. 130; no. 2; pp. 207 - 213
• Main Authors: Bime, Christian, MD, MSc, Fiero, Mallorie, PhD, Lu, Zhenqiang, PhD, Oren, Eyal, PhD, MS, Berry, Cristine E., MD, MHS, Parthasarathy, Sairam, MD, Garcia, Joe G.N., MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2017; Elsevier Sequoia S.A
• Subjects: Adult; ARDS; Female; Humans; Internal Medicine; Male; Middle Aged; Mortality; Obesity; Obesity - complications; Obesity - mortality; PEEP; Positive-Pressure Respiration - methods; Respiratory diseases; Respiratory Distress Syndrome, Adult - complications; Respiratory Distress Syndrome, Adult - mortality; Respiratory Distress Syndrome, Adult - physiopathology; Respiratory Distress Syndrome, Adult - therapy; Retrospective Studies; Survival; Tidal Volume; mortality; adult; PEEP; ARDS; obesity; survival; Obesity; Adult; Survival; Mortality
• DOI: 10.1016/j.amjmed.2016.09.029
• ISSN: 0002-9343

Abstract Background In acute respiratory distress syndrome, minimizing lung injury from repeated collapse and reopening of alveoli by applying a high positive end expiratory pressure improves oxygenation without influencing mortality. Obesity causes alveolar atelectasis thus suggesting that a higher positive end expiratory pressure might be more protective among the obese. We hypothesized that the effect of applying a high positive end expiratory pressure on mortality from acute respiratory distress syndrome would differ by obesity status. Methods This was a retrospective analysis of 505 patients from the Assessment of Low tidal Volume and elevated End-expiratory volume to Obviate Lung Injury Trial, a multicenter randomized trial that compared a higher versus a lower positive end expiratory pressure ventilatory strategy in acute respiratory distress syndrome. We examined the relationship between positive end expiratory pressure strategy and 60-day mortality stratified by obesity status. Results Among obese patients with acute respiratory distress syndrome, those assigned to a high positive end expiratory pressure strategy experienced lower mortality compared to those assigned to a low strategy (18% vs 32%; p = 0.04). Among the non-obese, those assigned to high positive end expiratory pressure strategy experienced similar mortality with those assigned to low strategy (34% vs 23 %; p = 0.13). Multivariate analysis demonstrated an interaction between obesity status and the effect of positive end expiratory pressure strategy on mortality (p <0.01). Conclusions Ventilation with higher levels of positive end expiratory pressure was associated with improved survival among the subgroup of patients with acute respiratory distress syndrome who are obese.