Continuous monitoring of ScvO₂ by a new fibre-optic technology compared with blood gas oximetry in critically ill patients: A multicentre study

Objective: The aim of this study was to compare the accuracy of the CeVOX monitor measuring continuous central venous saturation (ScvO₂) with laboratory blood gas oximetry under clinical circumstances. Design: Prospective, multicentre, observational study. Setting: Five adult general intensive care units. Patients and participants: Fifty-three critically ill patients. Interventions: The fibre-optic probe was inserted into an ordinary central venous catheter's distal lumen. Blood samples were taken from this line via a Y-adapter every 8 h and ScvO₂ was measured with a laboratory co-oximeter. Patients were observed for a maximum of 5 days. Results were compared using linear regression and the Bland and Altman plots. Measurements and results: The 526 matched pairs of ScvO₂ showed a significant correlation between the two methods (r = 0.79, p< 0.001). Bland-Altman plots showed an overall mean bias of -0.3% and moderate agreement (lower and upper levels of agreement: -13.2% and 12.5%). Correlation for the first time point, and for differences between the first two time points for each method revealed good correlation: (n = 53): r = 0.79, p< 0.001; (n = 50): r = 0.58, p< 0.001, respectively. Conclusion: These results in a heterogeneous group of critically ill patients show that continuous ScvO₂ monitoring by the CeVOX technology yielded results comparable with those obtained by laboratory co-oximetry and therefore can be relied on in everyday clinical practice.