Assessment of Microcirculatory Dysfunction by Measuring Subcutaneous Tissue Oxygen Saturation Using Near-Infrared...

Area of Science:

• Critical care medicine
• Biomedical engineering
• Physiology

Background:

• Circulatory failure presents high mortality and necessitates microcirculation assessment.
• Hemodynamic improvements do not always resolve persistent microcirculatory dysfunction.
• Near-infrared spectroscopy (NIRS) offers a method to evaluate microcirculation via subcutaneous regional tissue oxygen saturation (rSO2).

Purpose of the Study:

• To evaluate the utility of NIRS-measured rSO2 in assessing microcirculatory dysfunction in patients with circulatory failure.
• To determine the correlation between knee rSO2 and the Sequential Organ Failure Assessment (SOFA) score.

Main Methods:

• NIRS was used to measure rSO2 at multiple sites, including the knee, in healthy volunteers and ICU patients.
• Circulatory failure was defined by specific systolic blood pressure and lactate thresholds.
• Prospective, single-center study comparing patients with and without circulatory failure upon ICU admission.

Main Results:

• Healthy volunteers showed approximately 58% rSO2 across measured sites.
• Patients with circulatory failure exhibited significantly lower knee rSO2 compared to those without.
• Knee rSO2 demonstrated a significant negative correlation with SOFA scores over the initial days in the ICU.

Conclusions:

• Subcutaneous knee rSO2 serves as a valuable indicator of microcirculatory dysfunction.
• Knee rSO2 is associated with SOFA score, reflecting the severity of organ damage in circulatory failure.