Time from first study transfusion to onset of mechanical ventilation for patients with diagnostic criteria for ARDS. The time (days) to the onset of mechanical ventilation after the first study platelet transfusion was determined for patients with a diagnosis of ALI meeting criteria for ARDS who required mechanical ventilation (N = 17). The distributions of time to onset of mechanical ventilation were significantly different between the Test group (dashed line) in comparison to the Reference group (solid line), P = .03. Reference patients were more likely to be mechanically ventilated sooner than Test patients.