The accuracy of pulse oximetry in measuring oxygen saturation by levels of skin pigmentation: a systematic review and meta-analysis

Abstract

Background During the COVID-19 pandemic, there have been concerns regarding potential bias in pulse oximetry measurements for people with high levels of skin pigmentation. We systematically reviewed the effects of skin pigmentation on the accuracy of oxygen saturation measurement by pulse oximetry (SpO2) compared with the gold standard SaO2 measured by CO-oximetry. Methods We searched Ovid MEDLINE, Ovid Embase, EBSCO CINAHL, ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform (up to December 2021) for studies with SpO2–SaO2 comparisons and measuring the impact of skin pigmentation or ethnicity on pulse oximetry accuracy. We performed meta-analyses for mean bias (the primary outcome in this review) and its standard deviations (SDs) across studies included for each subgroup of skin pigmentation and ethnicity and used these pooled mean biases and SDs to calculate accuracy root-mean-square (Arms) and 95% limits of agreement. The review was registered with the Open Science Framework (https://osf.io/gm7ty). Results We included 32 studies (6505 participants): 15 measured skin pigmentation and 22 referred to ethnicity. Compared with standard SaO2 measurement, pulse oximetry probably overestimates oxygen saturation in people with the high level of skin pigmentation (pooled mean bias 1.11%; 95% confidence interval 0.29 to 1.93%) and people described as Black/African American (1.52%; 0.95 to 2.09%) (moderate- and low-certainty evidence). The bias of pulse oximetry measurements for people with other levels of skin pigmentation or those from other ethnic groups is either more uncertain or suggests no overestimation. Whilst the extent of mean bias is small or negligible for all subgroups evaluated, the associated imprecision is unacceptably large (pooled SDs > 1%). When the extent of measurement bias and precision is considered jointly, pulse oximetry measurements for all the subgroups appear acceptably accurate (with Arms < 4%). Conclusions Pulse oximetry may overestimate oxygen saturation in people with high levels of skin pigmentation and people whose ethnicity is reported as Black/African American, compared with SaO2. The extent of overestimation may be small in hospital settings but unknown in community settings. Review protocol registration https://osf.io/gm7ty

Agreement between pulse oximetry and arterial oxygen saturation measurement in critical care patients during COVID-19: a cross-sectional study

“…The impact of hypoxemia on the measure of SpO 2 is a well-known issue [ 34 ]. It has been reported that the poor quality of the measure of hypoxemic patients could be related 1/to the arteriolar dilation caused by tissue hypoxia that induces venous pulsation, which reduces the quality of the measure [ 9 , 35 ], 2/with the quality of the pulse oximeter being used [ 35 , 36 ] or high levels of skin pigmentation [ 14 , 37 , 38 ].…”

Proposal of a diagnostic algorithm based on the use of pulse oximetry in obstructive sleep apnea

“…AHI, however, proved to be equivalent regardless of the hypopnea criteria used in its definition (AASM 2012, Chicago) [ 43 ]. Fifth, we evaluated a white race population, so the diagnostic performance of oximetry cannot be extrapolated to subjects with dark skin pigmentation [ 44 ].…”

Pulse Oximeter Bias and Inequities in Retrospective Studies––Now What?

“…In a 2022 meta-analysis of 382 articles, only 15 articles assessed the impact of skin pigmentation on pulse oximeter accuracy. 8 The qualitative categories were not specific: light, medium, and dark. 8 Colorimeters and spectrophotometers, which measure erythema and melanin indices in addition to other relevant pigment parameters, are highly useful in parsing the mechanisms that drive the observed associations between skin pigment and pulse oximeter errors.…”

“…8 The qualitative categories were not specific: light, medium, and dark. 8 Colorimeters and spectrophotometers, which measure erythema and melanin indices in addition to other relevant pigment parameters, are highly useful in parsing the mechanisms that drive the observed associations between skin pigment and pulse oximeter errors. Most importantly, these quantitative data can inform efforts to improve pulse oximeter technology and hone regulatory approaches to address the observed biases.…”