The Role of Oxygenation Index as an Outcome Predictor in Mechanically Ventilated Acute Respiratory Distress Syndrome Patients

Background: Acute respiratory distress syndrome (ARDS) is associated with a significant mortality rate and a high likelihood of failing to wean from mechanical ventilation. Predicting such outcomes in such patients is crucial for the modification of appropriate treatment approaches and for facilitating family communication. Several studies have found that the oxygenation index is an early predictor of outcomes. This study aimed to assess the role of OI assessed on day 1 for predicting weaning outcomes and mortality within 28 days. Methods: This prospective observational study was done at Dhaka Medical College Hospital (DMCH) over a year. A total of 122 patients with ARDS admitted to the non-COVID intensive care unit (ICU) at the Department of Anesthesia, Pain, Palliative & Intensive Care were included in the study based on selection criteria, using a non-probability sampling technique after receiving informed written consent from the patient’s attendants. On day one, the oxygenation index (OI) was measured, and the outcomes were recorded. Results: An oxygenation index of ≥16.01 cm of H2O substantially increased the risk of mortality by 295.211 (95% confidence interval (CI): 28.163-3094.528) times and predicted mortality with 88.06% sensitivity and 87.27% specificity. The oxygenation index (≥11.11 cm of H2O) was found to independently and significantly increase the chance of weaning outcome (failure) by 35.094 (95% CI: 4.041-304.762) times and weaning failure was predicted with 95.45% sensitivity and 70.27% specificity. Conclusion: In ARDS patients on mechanical ventilation, the OI measure at day one can be used as a highly accurate, and independent predictor of death and weaning failure.