Diagnostic Accuracy of Pulse Oximetry in Children With Different Skin Tones: A Cross-sectional Study

Background: Pulse oximetry is a widely used non-invasive method for monitoring oxygen saturation (SaO₂) in pediatric patients. However, concerns have emerged about its accuracy across different skin tones, with darker pigmentation potentially leading to overestimation of arterial SaO₂.  Objectives: This study aims to evaluate the diagnostic accuracy of pulse oximetry (peripheral oxygen saturation [SpO₂]) in children with different skin tones, using arterial blood gas (ABG) analysis as the reference standard.  Methods: This prospective, cross-sectional study was conducted at a tertiary pediatric hospital in India over a ۶-month period on ۳۰۰ children aged ۱ month to ۱۸ years undergoing clinically indicated ABG sampling. Skin tone was classified using the Fitzpatrick scale, which divides children into three groups of ۱۰۰, including light skin (types I–II), medium skin (types III–IV), and dark skin (types V–VI). Simultaneous SpO₂ and SaO₂ measurements were obtained, and mean difference (SpO₂–SaO₂), root mean square error (RMSE), and frequency of clinically significant overestimation (SpO₂ ≥۹۲% when SaO₂<۸۸%) were analyzed. Multivariable regression was used to adjust for confounders.  Results: Pulse oximetry overestimated SaO₂ in all groups, with the greatest bias observed in the dark skin group (mean difference=۱.۹%, RMSE=۲.۶) compared to the light-skin peers (mean difference=۰.۸%, RMSE=۱.۶; P<۰.۰۰۱). Clinically significant overestimation occurred in ۳۵% of dark-skinned children with SaO₂<۸۸%, compared to ۸% in light-skinned children (P=۰.۰۰۴). Dark skin tone (β=۱.۰۴; P<۰.۰۰۱). and medium skin tone (β=۰.۵۱, P=۰.۰۱۱) were the predictors of SpO₂ bias after adjusting for age and oxygen supplementation. Skin tone classification showed excellent inter-rater agreement (Cohen’s κ>۰.۸۸). Conclusions: Pulse oximetry significantly overestimates arterial SaO₂ in children with darker skin tones, increasing the risk of unrecognized hypoxemia. These findings highlight a critical issue in pediatric monitoring and indicate the need for more inclusive device calibration, clinical vigilance, and confirmatory testing in dark-skinned children.

کلیدواژه ها:

Pulse oximetry ، Diagnostic accuracy ، Skin tone ، Fitzpatrick scale ، Pediatric hypoxemia ، Oxygen saturation (SaO₂) ، Arterial blood gas (ABG)