Informative Value of the Oxygenation Index in the Diagnosis of Acute Respiratory Distress Syndrome

Abstract

Objective: to study the informative value of the oxygenation index as a criterion for the diagnosis of acute respiratory distress syndrome (ARDS) of varying genesis. Subjects and methods. Seventy-two patients, including 27 women and 45 men, aged 19 to 65 years admitted to an intensive care unit for various diseases, in whom ARDS was diagnosed on the basis of the traditional criteria, were prospectively examined. The authors analyzed the causes of acute respiratory failure, the time course of changes in gas exchange and PaO2/FiO2, X-ray picture, and the time of respiratory support when respiratory and nonrespiratory treatments were performed. Results. After correction of the extrapulmonary causes of impaired gas exchange, optimization of respiratory support parameters, and use of aggressive artificial ventilation methods and nonrespiratory treatments, 45 (62.5%) of the 72 examinees diagnosed as having ARDS showed a considerable gas exchange improvement and a steady increase in the oxygenation index more than 300; thus, these patients stopped meeting the criteria of ARDS. Conclusion. The oxygenation index is a rather vulnerable sign of ARDS, the time course of changes in which depends on many pulmonary and extrapulmonary causes, which necessitates a comprehensive evaluation of the degree of lung injury, the causes and severity of respiratory failure and, evidently, the refinement and expansion of the criteria for establishing this diagnosis. Key words: acute lung injury, acute respiratory distress syndrome, acute respiratory failure, oxygenation index.