Purpose
The correlation between tissue oxygen saturation (StO2) measured using time-resolved near-infrared spectroscopy (t-NIRS) and central venous blood oxygen saturation (ScvO2) remains unclear. This study aimed to verify whether ScvO2 could be noninvasively monitored and estimated using t-NIRS.
Methods
This observational study enrolled patients aged ≥ 18 years who had a central venous line catheter inserted through the internal jugular vein and entered the intensive care unit postoperatively. The study utilized t-NIRS to measure neck tissue oxygen saturation (StO2_neck) and thenar eminence tissue oxygen saturation (StO2_thenar), and ScvO2 was measured to analyze the correlation and concordance between the two.
Results
The coefficient of correlation between StO2_neck and ScvO2 was 0.43 (p < 0.05), whereas that between StO2_thenar and ScvO2 was 0.34 (p = 0.12). Bland–Altman analysis showed mean differences between StO2_neck and ScvO2, as well as between StO2_thenar and ScvO2 (± standard deviation, 95% limits of agreement) of 11. 8% (± 7.1%, -2.1–25.7%) and 14.4% (± 10.2%, -5.6–34.4%), respectively. The bias in StO2_neck was significantly associated with diastolic blood pressure and internal jugular vein diameter. However, no factors were found to be associated with the bias in the hands.
Conclusion
StO2 _neck demonstrated a significant correlation and concordance with ScvO2. However, a bias was observed that was associated with diastolic blood pressure and transverse length of the internal jugular vein. t-NIRS is an important measurement for respiratory and circulatory monitoring. Incorporating factors such as blood pressure and ultrasound findings can enhance the accuracy of ScvO2 estimation.
Trial registration
: This study was approved by the Research Ethics Committee of the Niigata University Medical and Dental Hospital (2023-0021, May 23rd, 2023).