Challenges and limitations of using ventilator-free days as an outcome in critical care trials - Critical Care Science (CCS)

Challenges and limitations of using ventilator-free days as an outcome in critical care trials | The use of ventilator-free days (VFDs) as an outcome measure is increasingly popular in critical care research.^(-) This composite outcome simultaneously reflects patient survival and the time not spent on mechanical ventilation (MV) within a specified timeframe, which usually extends from randomization up to Day 28. For patients who do not survive this period, VFDs are recorded as zero. Composite outcomes, such as those combining death, myocardial infarction, or stroke, are commonly used in fields such as cardiology due to their ability to enhance the statistical power of clinical trials while focusing on patient-relevant events. In intensive care, where the key outcomes often include the duration of MV, other organ support measures, and hospital stay, the necessity of integrating binary outcomes such as mortality with these continuous variables becomes apparent. The measure of VFDs was proposed more than 20 years ago to effectively merge these outcome types. It has been the most widely used composite outcome in trials of MV and acute respiratory distress syndrome (ARDS). However, in recent years, several authors have called attention about the limitations of VFDs, and potential alternative statistical approaches have been proposed.^(-) [...]