The same trend was observed with decreased levels in the tertiles for the end-tidal-to-arterial PCO 2 ratio. As ARDS severity increased, mortality increased with successive tertiles of dead space fraction by Harris–Benedict and by direct estimation, and with an increase in the VR.

The end-tidal-to-arterial PCO 2 ratio was lower in non-survivors than in survivors ( p < 0.001). Estimations of wasted ventilation such as the estimated dead space fraction (by Harris–Benedict and direct method) and ventilatory ratio were significantly higher in non-survivors than survivors at baseline and during the following days of mechanical ventilation ( p < 0.001).

ResultsĪ total of 927 consecutive patients admitted with COVID-19-related ARDS were included in this study. The aim was to quantify the dynamics and determine the prognostic value of surrogate markers of wasted ventilation in patients with COVID-19-related ARDS. Consecutive patients aged at least 18 years were eligible for participation if they had received invasive ventilation for COVID-19 at a participating ICU during the first month of the national outbreak in the Netherlands. The PRoVENT-COVID is a national, multicenter, retrospective observational study done at 22 intensive care units in the Netherlands. Secondary analysis from the PRoVENT-COVID study.

Estimates for dead space ventilation have been shown to be independently associated with an increased risk of mortality in the acute respiratory distress syndrome and small case series of COVID-19-related ARDS.

Dead space ventilation