Association of Ventilatory Ratio with Acute Cor Pulmonale and Mortality in COVID-19 ARDS: A Cohort Study

Abstract

Purpose

An elevated ventilatory ratio (VR) and acute cor pulmonale (ACP) are associated with mortality in ARDS patients. The primary aim of this study was to assess the association between VR and ACP in patients with COVID-19-related ARDS (C-ARDS). The secondary objectives were to analyze the association between VR and ICU mortality, describe VR temporal behavior in survivors and non-survivors, and evaluate the association between VR and pulmonary embolism.

Materials and Methods

We studied a cohort of patients with C-ARDS. The VR was calculated using a validated formula. Echocardiography was used to diagnose ACP, and CT pulmonary angiography was performed to identify PE. To evaluate the associations between VR and ACP, mortality, and PE, a generalized logistic regression model was used.

Results

Of the 140 subjects, 60 (43%) had a VR < 2, while 80 (57%) had a VR ≥ 2. Patients with a VR ≥2 had a higher risk of developing ACP than those with a VR <2 (Odds Ratio (OR), 3.77; 95% CI: 1.30 - 8.72). The ICU mortality rate was 29%. Of the 40 patients who died, 30 (75%) had a VR ≥ 2. Mortality was significantly associated with VR ≥ 2 and driving pressure ≥ 15 cm H₂O. In non-survivor patients with a VR < 2 at ICU admission, a significant increase in VR was observed over the 7-day observation period. No significant association was observed between PE and VR (p = .118).

Conclusion

Elevated VR was associated with ACP in patients with C-ARDS. VR ≥ 2 combined with driving pressure ≥ 15 cm H₂O significantly improved the ability to identify patients at risk for ACP. Additionally, at ICU admission, elevated VR values and initially low values that increased over the first week were associated with higher ICU mortality.