Moreover, up to 50% of patients admitted to an ICU with sepsis develop ALI [2].Patients with sepsis-induced ALI have a higher case fatality rate than patients with other risk factors for ALI [1,3]. However, it is unclear if the Pancreatic cancer higher case fatality rate is related to patient’s co-morbidities, severity of illness, or the etiology of ALI. For example, patients with trauma versus sepsis as their risk factor for ALI tend to have lower case fatality rates. However, patients with trauma-related ALI also tend to be younger, with fewer co-morbid conditions and lower severity of illness compared with patients with sepsis-induced ALI [4,5].A recent study has suggested that that sepsis is not independently associated with mortality from ALI [6].

Our objective is to evaluate whether a risk factor of sepsis is independently associated with mortality in a large cohort of racially diverse ALI patients. A secondary objective is to evaluate clinical and treatment characteristics in this cohort. We have previously demonstrated that in patients with sepsis-induced ALI, a pulmonary versus nonpulmonary source of infection is not independently associated with patient mortality. [7]. Hence, we considered all sources of sepsis-induced ALI together in this evaluation. The purpose of this study is to examine whether the presence of sepsis as a risk factor for ALI is independently associated with mortality in a large representative multi-site cohort of ALI patients.Materials and methodsStudy populationThis is a retrospective analysis of consecutive ALI patients enrolled into a multi-site prospective cohort study during a three-year period ending in October 2007 [8].

In this study, 12 ICUs at 4 teaching hospitals enrolled consecutive mechanically ventilated patients who met the American-European consensus criteria for ALI [9]. Relevant exclusion criteria included: pre-existing illness with a life expectancy of less than six months; transfer to a study site ICU with pre-existing ALI of more than 24 hours’ duration; more than five days of mechanical ventilation prior to ALI diagnosis; and limitations in ICU care (e.g. no vasopressors) at eligibility.Primary outcome and exposure variablesThe primary study outcome was in-hospital mortality. The primary exposure variable was sepsis versus non sepsis as the etiology of ALI with this classification prospectively obtained based on documentation in the medical record for the ICU physicians.

Patients with pulmonary or non-pulmonary infections were classified as having sepsis. Any uncertainty in the classification of the primary exposure variable was addressed by an ICU investigator at each study site based on review of the medical record and discussion with the treating ICU physicians.Patient GSK-3 demographic and severity of illness variablesPatient-related exposures of interest (independent variables) included patient demographics and several measures of severity of illness.