Mechanism of injury influences quality of life in survivors of acute respiratory distress syndrome

Objective: Growing evidence suggests that acute respiratory distress syndrome (ARDS) occurring as a consequence of primary (direct) lung injury differs from that resulting from secondary (indirect) lung injury in terms of radiographic appearance, response to interventions, and outcomes. We examined whether there are differences in quality of life (QOL) in survivors of ARDS attributable to the mechanism of underlying lung injury. Design and setting: Prospective observational cohort study in 54 intensive care units in Canada and the United States. Patients and participants: Survivors of ARDS (n = 73) were grouped according to underlying cause of ARDS (i.e., primary vs. secondary lung injury) and followed prospectively for 12 months. Measurements and results: QOL was assessed using the Medical Outcomes Study 36-item Short Form Health Survey (SF-36) and the St. George's Respiratory Questionnaire (SGRQ), and spirometry was performed at each outpatient follow-up visit. At 3 months mortality and QOL outcomes were similar between the groups, but by 12 months patients with primary lung injury had significantly better QOL scores in four of eight SF-36 domains and in two of three domains of the SGRQ. Differences were not attributable to duration of ICU or hospital length of stay, duration of mechanical ventilation, comorbidities prior to the index illness, or differences in spirometry during the follow-up period. Conclusions: QOL in survivors of ARDS appears to be influenced by the mechanism of lung injury (primary vs. secondary), lending support to the concept that ARDS is a heterogeneous condition.