Clinical diagnostic criteria of the adult respiratory distress syndrome in the intensive care unit

Objectives: To determine the use of commonly used diagnostic criteria for adult/acute respiratory distress syndrome (ARDS), evaluate physiologic variables of most value in diagnosing ARDS, and assess the frequency of newly diagnosed ARDS. Design: Self administered questionnaire by mail. Setting: Hospital intensive care units (ICUs). Subjects: Intensive care physicians (n = 923) in the United States listed as ICU directors in the Society of Critical Care Medicine Membership Directory. Interventions: None. Measurements and Main Results: A total of 448 (48.5%) physicians responded, with 301 questionnaires completed. Bilateral infiltrates on chest radiograph, the Pao(2)/F10(2) ratio, and pulmonary artery occlusion pressure were the most commonly used diagnostic criteria. However, the actual values used to diagnose ARDS were highly variable. The most important clinical physiologic variable used in determining the respiratory status of the ARDS patient was the Pao(2)/F10(2) ratio, followed by shunt fraction, alveolar-arterial oxygen tension gradient, F10(2), pao(2), respiratory system compliance, and minute ventilation. Respondents indicated that 9% of ICU beds at their institutions were occupied by a patient diagnosed with ARDS within the previous 7 days and 18.6% of all mechanically ventilated patients had ARDS by their own criteria. Based on the total number of ICU beds, the predicted incidence of ARDS would be similar to 275,000 patients per year in the United States. Conclusion: A wide range of diagnostic criteria are utilized by clinicians in the diagnosis of ARDS.