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 (SaO) in pediatric patients.However, concerns have emerged about its accuracy across different skin tones, with darker pigmentation potentially leading to overestimation of arterial SaO.Objectives: This study aims to evaluate the diagnostic accuracy of pulse oximetry (peripheral oxygen saturation [SpO]) 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 6-month period on 300 children aged 1 month to 18 years undergoing clinically indicated ABG sampling.Skin tone was classified using the Fitzpatrick scale, which divides children into three groups of 100, including light skin (types I-II), medium skin (types III-IV), and dark skin (types V-VI).Simultaneous SpO and SaO measurements were obtained, and mean difference (SpO-SaO), root mean square error (RMSE), and frequency of clinically significant overestimation (SpO 92% when SaO<88%) were analyzed.Multivariable regression was used to adjust for confounders.Results: Pulse oximetry overestimated SaO in all groups, with the greatest bias observed in the dark skin group (mean difference=1.9%,RMSE=2.6)compared to the light-skin peers (mean difference=0.8%,RMSE=1.6;P<0.001).Clinically significant overestimation occurred in 35% of dark-skinned children with SaO<88%, compared to 8% in light-skinned children (P=0.004).Dark skin tone (=1.04;P<0.001).and medium skin tone (=0.51,P=0.011) were the predictors of SpO bias after adjusting for age and oxygen supplementation.Skin tone classification showed excellent inter-rater agreement (Cohen's >0.88). Conclusions:Pulse oximetry significantly overestimates arterial SaO 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.