Central venous oxygen saturation is not predictive of early complications in cancer patients presenting to the emergency department

Abstract

Central venous oxygen saturation (ScvO₂) is easily observable in oncology patients with long-term central venous catheters (CVC), and has been studied as a prognostic factor in patients with sepsis. We sought to investigate the association between ScvO₂ and early complications in cancer patients presenting to the ED. We prospectively enrolled adult cancer patients with pre-existing CVC who presented to the ED. ScvO₂ was measured on their CVC. The outcome was admission to the intensive care unit (ICU) or mortality by day 7. ScvO₂ was first studied as a continuous variable (%) with a ROC analysis and as a categorical variable (cut-off at < 70%) with a multivariate analysis. A total of 210 cancer patients were enrolled. At baseline, ScvO₂ showed no significant difference between patients who were admitted to the ICU or died before day 7, and patients who did not (67%; IQR 62-68% vs. 71%; IQR 65-78% respectively, P = 0.3). The ROC analysis showed the absence of discrimination accuracy for ScvO₂ to predict the outcome (AUC = 0.56). By multivariate analysis, ScvO₂ < 70% was not associated with the outcome (OR 1.67; 95% CI 0.64-4.36). Variables that were associated with ICU admission or death by day 7 included a shock-index (heart rate/systolic blood pressure) > 1 and a performance status > 2 (OR 4.76; 95% CI 1.81-12.52 and OR 6.23, 95% CI 2.40-16.17, respectively). This study does not support the use of ScvO₂ to risk stratify cancer patients presenting to the ED.

Keywords: Cancer; Central venous oxygen saturation (ScvO2); Emergency department; Neutropenia; Triage.