Decreased CO 2 Levels as Indicators of Possible Mechanical Ventilation-Induced Hyperventilation in COVID-19 Patients: A Retrospective Analysis

摘要

Background: Six months since the outbreak of coronavirus disease (COVID-19), the pandemic continues to grow worldwide, although the outbreak in Wuhan, the worst-hit area, has been controlled. Thus, based on the clinical experience in Wuhan, we hypothesized that there is a relationship between the patient's CO 2 levels and prognosis. Methods: COVID-19 patients' information was retrospectively collected from medical records at the Leishenshan Hospital, Wuhan. Logistic and Cox regression analyses were conducted to determine the correlation between decreased CO 2 levels and disease severity or mortality risk. The Kaplan-Meier curve analysis was coupled with the log-rank test to understand COVID-19 progression in patients with decreased CO 2 levels. Curve fitting was used to confirm the correlation between computed tomography scores and CO 2 levels. Results: Cox regression analysis showed that the mortality risk of COVID-19 patients correlated with decreased CO 2 levels. The adjusted hazard ratios for decreased CO 2 levels in COVID-19 patients were 8.710 [95% confidence interval (CI): 2.773–27.365, P 0.001], and 4.754 (95% CI: 1.380–16.370, P = 0.013). The adjusted odds ratio was 0.950 (95% CI: 0.431–2.094, P = 0.900). The Kaplan-Meier survival curves demonstrated that patients with decreased CO 2 levels had a higher risk of mortality. Conclusions: Decreased CO 2 levels increased the mortality risk of COVID-19 patients, which might be caused by hyperventilation during mechanical ventilation. This finding provides important insights for clinical treatment recommendations.