Corrected Minute Ventilation Is Associated With Mortality in ARDS Caused by COVID-19

BACKGROUND: The ratio of dead space to tidal volume (V_D/V_T) is associated with mortality in patients with ARDS. Corrected minute ventilation (V̇_Ecorr) is a simple surrogate of dead space, but, despite its increasing use, its association with mortality has not been proven. The aim of our study was to assess the association between V̇_Ecorr and hospital mortality. We also compared the strength of this association with that of estimated V_D/V_T and ventilatory ratio.

METHODS: We performed a retrospective study with prospectively collected data. We evaluated 187 consecutive mechanically ventilated subjects with ARDS caused by novel coronavirus disease (COVID-19). The association between V̇_Ecorr and hospital mortality was assessed in multivariable logistic models. The same was done for estimated V_D/V_T and ventilatory ratio.

RESULTS: Mean ± SD V̇_Ecorr was 11.8 ± 3.3 L/min in survivors and 14.5 ± 3.9 L/min in nonsurvivors (P < .001) and was independently associated with mortality (adjusted odds ratio 1.15, P = .01). The strength of association of V̇_Ecorr with mortality was similar to that of V_D/V_T and ventilatory ratio.

CONCLUSIONS: V̇_Ecorr was independently associated with hospital mortality in subjects with ARDS caused by COVID-19. V̇_Ecorr could be used at the patient’s bedside for outcome prediction and severity stratification, due to the simplicity of its calculation. These findings need to be confirmed in subjects with ARDS without viral pneumonia and when lung-protective mechanical ventilation is not rigorously applied.