Objectives: To compare noninvasive external jugular vein oxygen saturations (SjvO₂ ) and central venous oxygen saturation (ScvO₂ ) from a blood sample in patients admitted to the intensive care unit.

Design: A prospective, comparative, monocentric clinical trial design was used.

Setting: The study was performed in the Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva (Switzerland).

Participants: A total of 79 patients were enrolled; patients with confirmed COVID-19 infection requiring invasive mechanical ventilation (patients with COVID-19, n = 36) and patients after liver transplantation (posttransplant patients, n = 43).

Interventions: Simultaneous measurement of SjvO₂ by near-infrared spectroscopy and ScvO₂ from central venous blood samples using a blood gas analyzer in stable hemodynamic conditions.

Measurements and main results: A strong linear correlation was evidenced in both the COVID-19 and posttransplant patient groups between the 2 modalities. The Bland-Altman analysis showed low bias in accordance with low percentage error in both groups (0.57% and 8.09% for patients with COVID-19; 0.00% and 13.72% for posttransplant patients).

Conclusions: Central venous oxygen saturation can be estimated reasonably by the continuous noninvasive measurement of SjvO₂ using near-infrared spectroscopy.