Defining the Resolution of Acute Respiratory Distress Syndrome: A Delphi Consensus Study

OBJECTIVES: There are no established criteria to define the resolution of acute respiratory distress syndrome (ARDS). We aimed to develop an expert consensus definition of ARDS resolution. DESIGN: Modified Delphi consensus study with three iterative rounds. SETTING: Electronic surveys. SUBJECTS: A panel of 19 ARDS experts participated in the Delphi process. Experts were identified using prespecified criteria. INTERVENTIONS: The Delphi process was conducted over three rounds. Item generation was performed in round 1 with all panelists invited to suggest defining characteristics for resolution of ARDS with corresponding operational definitions, which were then voted on by the panel. Item refinement in rounds 2 and 3. Thresholds for agreement were specified a priori and set at 70%. MEASUREMENTS AND MAIN RESULTS: Nineteen panelists submitted complete responses to the first round with 16 panelists contributing to the final definition that met a priori consensus criteria after the third round questionnaire. The panel agreed on the following elements: 1) resolution of hypoxemia, defined as ratio of Pa o2 /F io2 greater than 300 (or ratio of oxygen saturation to F io2 > 315) for more than 24 hours and 2) normalization of level of respiratory support, defined as "if still intubated, this is for primarily nonrespiratory reasons (e.g. altered mental state, ICU-acquired weakness) and ventilatory assistance is minimal (i.e., positive end-expiratory pressure less than or equal to 5 cm H 2 O, and no adjunctive interventions); if maximal respiratory support was continuous positive airway pressure (CPAP) or noninvasive ventilation (NIV), then no longer requiring CPAP or NIV; if maximal respiratory support was oxygen via high-flow nasal cannula (HFNC), then no longer requiring HFNC; and if maximal respiratory support was standard oxygen, then longer receiving oxygen." CONCLUSIONS: A high level of consensus was achieved on criteria defining the resolution of ARDS. Future work is required to explore the epidemiology and performance characteristics of this definition.