Near-infrared Spectroscopy and Skin Tone in Children: A Prospective Cohort Study

Area of Science:

• Biomedical Engineering
• Medical Devices
• Clinical Research

Background:

• Pulse oximetry is known to overestimate saturation in individuals with darker skin tones.
• Near-infrared spectroscopy (NIRS) uses similar optical principles, but its accuracy across different skin tones is less understood.
• Investigating NIRS performance in relation to skin tone is crucial for ensuring equitable patient monitoring.

Purpose of the Study:

• To quantify the impact of skin tone on the accuracy of Near-infrared spectroscopy (NIRS) measurements.
• To compare NIRS-derived regional oxygen saturation with mixed venous saturation across varying skin tones.
• To identify potential biases in NIRS technology related to skin pigmentation.

Main Methods:

• A cohort of 110 pediatric patients undergoing cardiac catheterization was studied.
• Skin tone was objectively measured using spectrophotometry and categorized by Individual Typology Angle (ITA).
• Regional oxygen saturation was measured using a Medtronic INVOS 5100C NIRS device and compared to mixed venous saturation, with multivariable regression analyzing ITA's effect.

Main Results:

• A significant bias was observed in NIRS measurements, with larger mean differences for darker skin tones (ITA 5-6: -12.8%) compared to lighter skin tones (ITA 3-4: -2.5%; ITA 1-2: 0.3%).
• Individual Typology Angle (ITA) was significantly associated with NIRS bias (coefficient 0.173, p<0.001).
• The observed bias indicates that NIRS tends to report lower values than mixed venous saturation in individuals with darker skin.

Conclusions:

• Darker skin tone is associated with poorer performance and underestimation of oxygen saturation by the Medtronic INVOS 5100C NIRS system.
• This performance disparity may contribute to disparities in patient care and clinical outcomes.
• There is a need for enhanced validation guidelines for NIRS devices to ensure equitable performance across all skin tones.