The end-tidal alveolar dead space fraction for risk stratification during the first week of invasive mechanical ventilation an observational cohort study

Abstract

The end-tidal alveolar dead space fraction (AVDSf = [PaCO2−PETCO2]/PaCO2) is a metric used to estimate alveolar dead space. Higher AVDSf on the first day of mechanical ventilation is associated with mortality and fewer ventilator-free days. It is not clear if AVDSf is associated with length of ventilation in survivors, how AVDSf performs for risk stratification beyond the first day of ventilation, or whether AVDSf adds predictive value to oxygenation (oxygenation index [OI]) or severity of illness (Pediatric Risk of Mortality [PRISM III]) markers.