Initial oxygenation as early predictor of mortality in acute respiratory distress syndrome: a retrospective study

Introduction: Acute respiratory distress syndrome (ARDS) is a major contributor to mortality and morbidity of adult patients admitted to intensive care units (ICU). Numerous scoring systems have been developed for critically ill patients with the goal of more accurately predicting clinical outcomes. However, the variability in these scores among individual patients, and consequently, their individual predictive ability is quite limited. Aim: To evaluate the role of initial oxygenation as an early predictor of mortality in ARDS patients. Methodology: One hundred and six mechanically ventilated adult patients with ARDS were enrolled retrospectively. Baseline parameters from the day of ICU admission were recorded. The details of ventilation, inspired oxygen fraction required, positive end-expiratory pressure and number of days on ventilation along with duration of hospital stay were recorded. Similarly, the status of oxygenation was assessed using PaO2/FiO2 (P/F) ratio. Survival of the patients was correlated with the baseline status of oxygenation. Results: Of the 106 patients, 65 were males and 41 female. The mean (± SD) age was 44 years (16.08). The difference in the P/F ratio between survivors and nonsurvivors was statistically significant. The ROC curve showed a cutoff value for P/F ratio of 108. Among survivors, the ICU stay was shorter in patients in pulmonary group compared to extrapulmonary group. Conclusion: Mortality is high if the baseline P/F ratio at admission is below 108. There is no difference in mortality due to lung injury caused by pulmonary or extrapulmonary aetiologies. ICU stay is longer among survivors if cause of ARDS is extrapulmonary.