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BACKGROUND: The relationship between body mass index (BMI) and development of acute respiratory distress syndrome (ARDS) is unknown. METHODS: A cohort study of critically ill patients at risk for ARDS was carried out. BMI was calculated from admission height and weight. Patients were screened daily for AECC (American European Consensus Committee)-defined ARDS and 60-day ARDS mortality. RESULTS: Of 1795 patients, 83 (5%) patients were underweight (BMI <18.5 kg/m2), 627 (35%) normal (BMI 18.5–24.9), 605 (34%) overweight (BMI 25–29.9), 364 (20%) obese (BMI 30–39.9) and 116 (6%) severely obese (BMI 40). Increasing weight was associated with younger age (p<0.001), diabetes (p<0.0001), higher blood glucose (p<0.0001), lower prevalence of direct pulmonary injury (p<0.0001) and later development of ARDS (p = 0.01). BMI was associated with ARDS on multivariate analysis (ORadj1.24 per SD increase; 95% CI 1.11 to 1.39). Similarly, obesity was associated with ARDS compared with normal weight (ORadj1.66; 95% CI 1.21 to 2.28 for obese; ORadj1.78; 95% CI 1.12 to 2.92 for severely obese). Exploratory analysis in a subgroup of intubated patients without ARDS on admission (n = 1045) found that obese patients received higher peak (p<0.0001) and positive end-expiratory pressures (p<0.0001) than non-obese patients. Among patients with ARDS, increasing BMI was associated with increased length of stay (p = 0.007) but not with mortality (ORadj0.89 per SD increase; 95% CI 0.71 to 1.12). CONCLUSION: BMI was associated with increased risk of ARDS in a weight-dependent manner and with increased length of stay, but not with mortality. Additional studies are needed to determine whether differences in initial ventilator settings may contribute to ARDS development in the obese. [ABSTRACT FROM AUTHOR]

OBJECTIVE:: Clinical predictors for acute respiratory distress syndrome (ARDS) have been studied in few prospective studies. Although transfusions are common in the intensive care unit, the role of submassive transfusion in non-trauma-related ARDS has not been studied. We describe here the clinical predictors of ARDS risk and mortality including the role of red cell transfusion. DESIGN:: Observational prospective cohort. SETTING:: Intensive care unit of Massachusetts General Hospital. PATIENTS:: We studied 688 patients with sepsis, trauma, aspiration, and hypertransfusion. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: Two hundred twenty-one (32%) subjects developed ARDS with a 60-day mortality rate of 46%. Significant predictors for ARDS on multivariate analyses included trauma (adjusted odds ratio [ORadj] 0.22, 95% confidence interval [CI] 0.090.53), diabetes (ORadj 0.58, 95% CI 0.360.92), direct pulmonary injury (ORadj 3.78, 95% CI 2.455.81), hematologic failure (ORadj 1.84, 95% CI 1.053.21), transfer from another hospital (ORadj 2.08, 95% CI 1.333.25), respiratory rate >33 breaths/min (ORadj 2.39, 95% CI 1.513.78), hematocrit >37.5% (ORadj 1.77, 95% CI 1.142.77), arterial pH <7.33 (ORadj 2.00, 95% CI 1.313.05), and albumin =2.3 g/dL (ORadj 1.80, 95% CI 1.182.73). Packed red blood cell transfusion was associated with ARDS (ORadj 1.52, 95% CI 1.002.31, p = .05). Significant predictors for mortality in ARDS included age (ORadj 1.96, 95% CI 1.502.53), Acute Physiology and Chronic Health Evaluation III score (ORadj 1.78, 95% CI 1.162.73), trauma (ORadj 0.075, 95% CI 0.0060.96), corticosteroids before ARDS (ORadj 4.65, 95% CI 1.4714.7), and arterial pH <7.22 (ORadj 2.32, 95% CI 1.025.25). Packed red blood cell transfusions were associated with increased mortality in ARDS (ORadj 1.10 per unit transfused; 95% CI 1.041.17) with a significant dose-dependent response (p = .02). CONCLUSIONS:: Important predictors for the development of and mortality in ARDS were identified. Packed red blood cell transfusion was associated with an increased development of and increased mortality in ARDS. [ABSTRACT FROM AUTHOR]