Modern intensive care unit interventions such as low-tidal volume mechanical ventilation may result in short-term improvements in acute respiratory distress syndrome (ARDS) survival, but less is known about the epidemiology of long-term survival. Chen Wang et al conducted a study to quantify the gap between in-hospital and 1-year ARDS mortality rates, and to identify risk factors and causes of death at one year among patients with ARDS.
Patients were selected from an ongoing prospective, multi-unit acute lung injury (ALI) biomarker study (VALID) at a single institution (Vanderbilt University Medical Center, Nashville, TN, USA). Those who met the American European Consensus Committee criteria for ALI/ARDs were included. A sensitivity analysis was also performed to include patients who met the Berlin criteria for ARDS. All were followed until death or for at least 1 year after study enrollment. Logistic regression was used to analyze associations between risk factors and death.
In two meta-analyses and one previous observational study, prone positioning was associated with improved survival for patients with severely hypoxemic acute respiratory distress syndrome (ARDS). However, the findings in these studies were in contradistinction to previously conducted randomized trials. To further evaluate the effectiveness of early prone positioning in severe ARDS, Guerin and colleagues from the PROSEVA Study Group designed a randomized controlled trial comparing early application of prone positioning versus supine positioning for patients with severe ARDS. Results were published in a recent issue of The New England Journal of Medicine.
There were 229 patients assigned to the supine group and 237 assigned to the prone group. Patients were similar within the two groups with the exception of a higher Sequential Organ Failure Assessment (SOFA) score and more vasopressor use in the supine group, as well as more neuromuscular blocker use in the prone group. Mortality at day 28 was significantly lower in the prone group (16%) compared to the supine group (32.8%; p<0.001). After adjustment for the SOFA score, patients in the prone group had a lower hazard of death compared to the supine group (hazard ratio = 0.42; 95% confidence interval [CI], 0.26-0.66; p<0.001). Patients in the prone group also had improved 90-day survival and more ventilator-free days compared to the supine group. The external generalizability of this work may be limited in centers where technical and logistical expertise for prone positioning is limited. Read the full Concise Critical Appraisal.