Pilot Study: Using Reflectance as a Proxy for Skin Pigmentation to Assess Pulse Oximeter Accuracy

Area of Science:

• Biomedical Engineering
• Clinical Medicine
• Pediatric Critical Care

Background:

• Pulse oximetry is a critical tool for monitoring oxygen saturation.
• Skin pigmentation can affect pulse oximeter accuracy, but objective measurements are needed.
• Previous studies often used subjective skin tone classifications.

Purpose of the Study:

• To objectively investigate the correlation between skin pigmentation and pulse oximeter reading accuracy in pediatric intensive care unit patients.
• To utilize a novel reflectance-based method for quantifying skin pigmentation.

Main Methods:

• A prospective observational study with retrospective data review was conducted.
• Skin reflectance was measured using a Photovolt reflectance meter in 32 pediatric ICU patients.
• Arterial blood gas (Sao2) and pulse oximetry (Spo2) values were collected and analyzed using regression models.

Main Results:

• Skin reflectance varied from 12% to 40%, with lower values indicating darker skin.
• Pulse oximetry (Spo2) overestimated arterial oxygen saturation (Sao2) in patients with lower skin reflectance, particularly near 90% Sao2.
• A 10-unit decrease in reflectance was associated with a 1% increase in the Spo2-Sao2 difference, indicating overestimation in darker skin.

Conclusions:

• Pulse oximeters tend to overestimate oxygen saturation in pediatric patients with darker skin tones (lower reflectance).
• The discrepancy between Spo2 and Sao2 increases significantly as skin reflectance decreases.
• Objective measurement of skin pigmentation is crucial for understanding and potentially mitigating pulse oximetry inaccuracies in diverse pediatric populations.