A study on the prevalence of direct vs indirect etiology, prognostic determinants and mortality in ARDS

Abstract

Objective: The objective of this study is to determine the etiology and risk factors for the development of acute respiratory distress syndrome (ARDS) and also the association between clinical and laboratory parameters and outcome in patients with ARDS. Methodology: This was an observational prospective study conducted in the intensive care units of Narayana Medical College and Hospital, Nellore between November 2015 and May 2016. Patients who fulfilled the AECC definition for ARDS and who were mechanically ventilated for more than a 24 h period were selected for the study. Results: Fifty patients who met the predefined criteria were enrolled for the study. Of these 50 cases, females (52%) were slightly more than the male patients and the most common age group was 31–50 years. ARDS was mostly secondary to infectious causes (92%) and the most common etiology for ARDS in our study was direct cause (52%) followed by indirect cause (48%). Factors associated with poor outcome and high mortality are low PaO2/FiO2 (P value <0.001), high SAPS II score (P value <0.001), high SOFA scores (P value 0.001), high max SOFA scores (P value 0.001), and severe lung injury scores (P value <0.001). High procalcitonin levels and C-reactive protein (CRP) levels less than 226 mg/mL showed more number of nonsurvivors (71.8%). There was significant increase in the mortality among patients who were prescribed inotropic support when compared to those who were not (P <0.001). Of the 50 patients enrolled in the study, 33 patients succumbed to their illness with the mortality of 66%. Conclusion: Direct etiology by pulmonary infection was the most common cause for ARDS. Prognostic determinants like PaO2/FiO2 and clinical scores like SOFA, maxSOFA, SAPS II, and LIS had a statistically significant association with mortality. Laboratory parameters like serum albumin were associated with significant mortality whereas CRP and procalcitonin did not show a statistically significant correlation with mortality. The use of a combination of clinical factors and biological markers is a promising strategy that needs to be prospectively validated.