Development and Internal Validation of a Novel Prognostic Score to Predict Mortality in Acute Respiratory Distress Syndrome - Driving Pressure, Oxygenation and Nutritional Evaluation - "DRONE Score"

Introduction: There are few scores for mortality prediction in acute respiratory distress syndrome (ARDS) incorporating comprehensive ventilatory, acute physiological, organ dysfunction, oxygenation, and nutritional parameters. This study aims to determine the risk factors of ARDS mortality from the above-mentioned parameters at 48 h of invasive mechanical ventilation (IMV), which are feasible across most intensive care unit settings. Methods: Prospective, observational, single-center study with 150 patients with ARDS defined by Berlin definition, receiving IMV with lung protective strategy. Results: Our study had a mortality of 41.3% (62/150). We developed a 9-point novel prediction score, the driving pressure oxygenation and nutritional evaluation (DRONE) score comprising of driving pressure (DP), oxygenation accessed by the ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO(2)) ratio and nutritional evaluation using the modified nutrition risk in the critically ill (mNUTRIC) score. Each component of the DRONE score with the cutoff value to predict mortality was assigned a particular score (the lowest DP within 48 h in a patient being always >= 15 cmH(2)O a score of 2, the highest achievable PaO2/FiO(2) <208 was assigned a score of 4 and the mNUTRIC score >= 4 was assigned a score of (3). We obtained the DRONE score >= 4, area under the curve 0.860 to predict mortality. Cox regression for the DRONE score >4 was highly associated with mortality (P < 0.001, hazard ratio 5.43, 95% confidence interval [2.94-10.047]). Internal validation was done by bootstrap analysis. The clinical utility of the DRONE score >= 4 was assessed by Kaplan-Meier curve which showed significance. Conclusions: The DRONE score >= 4 could be a reliable predictor of mortality at 48 h in ARDS patients receiving IMV.