ConclusionsĪVDSf is associated with mortality and length of ventilation in survivors throughout the first week of invasive mechanical ventilation. AVDSf did not improve mortality risk stratification when added to PRISM III but did improve mortality risk stratification when added to the gas exchange components of PRISM III (minimum 12-h PaO 2 and maximum 12-h PCO 2) ( p < 0.00001).

The maximum AVDSf within 12 h of intensive care unit admission demonstrated good risk stratification for mortality (AUC 0.768 ). An AVDSf > 0.3 was associated with a higher mortality than an AVDSf < 0.2 within each pediatric acute respiratory distress syndrome severity category. When using standardized variables, AVDSf effect estimates were generally higher than OI for mortality, whereas OI effect estimates were generally higher than AVDSf for the length of ventilation in survivors. Higher OI was not associated with increased mortality until ≥ 48 h of ventilation after controlling for AVDSf and PRISM III. Higher AVDSf was associated with mortality and longer length of ventilation in survivors throughout the first week of ventilation after controlling for OI and PRISM III. There were 2335 children and young adults (median age 5.8 years ) enrolled with 8004 analyzed AVDSf values. In those with arterial or capillary blood gases, AVDSf was calculated at the time of every blood gas for the first week of mechanical ventilation.

Retrospective single-center observational cohort study of children and young adults receiving invasive mechanical ventilation.

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 ) or severity of illness (Pediatric Risk of Mortality ) markers. Higher AVDSf on the first day of mechanical ventilation is associated with mortality and fewer ventilator-free days. The end-tidal alveolar dead space fraction (AVDSf = /PaCO 2) is a metric used to estimate alveolar dead space.

Volume alveolar dead space