1. This retrospective cohort study demonstrated that for a given blood oxygen hemoglobin saturation, Black, Asian, and Hispanic patients in the intensive care unit had higher pulse oximetry readings than White patients.
2. The disparity between blood oxygen hemoglobin saturation and pulse oximetry performance in different racial and ethnic groups was associated with reduced administration of oxygen supplementation among Black, Asian, and Hispanic patients.
Evidence Rating Level: 2 (Good)
Study Rundown: Near-infrared pulse oximetry (SpO2) probes allow for noninvasive arterial hemoglobin oxygen saturation monitoring. Given its mechanism of action using spectrophotometry, it is affected by pigmentations, such as skin melanin and nail polish. This could lead to falsely high SpO2 readings in different racial groups, resulting in hidden hypoxemia. Higher SpO2 readings may alter management strategies, such as reducing ventilation and supplemental oxygen administration. This retrospective cohort study investigated whether there are racial and ethnic disparities in the administration of supplemental oxygen in the intensive care unit (ICU) and whether these are based on differences in pulse oximetry readings. There were 3069 patients included in the study (White: n = 2667; Black: n = 207; Asian: n = 83; Hispanic: n = 112). Black patients had significantly lower blood hemoglobin oxygen saturation than White patients, yet higher SpO2 readings. Despite no significant differences in average blood hemoglobin oxygen saturation between White patients and Hispanic or Asian patients, Hispanic and Asian patients demonstrated higher SpO2 values. Black, Hispanic, and Asian patients all demonstrated higher SpO2 values for a given hemoglobin oxygen saturation. Furthermore, Black, Asian, and Hispanic patients received lower oxygen delivery rates than White patients after controlling for several confounding variables. Oxygen delivery differences appeared to be associated with discrepancies between SpO2 and the true blood hemoglobin oxygen saturation. Overall, this study demonstrated that SpO2 performance in Black, Asian, and Hispanic patients was higher than their White counterparts for a known blood hemoglobin oxygen saturation, which resulted in reduced administration of supplemental oxygen. The methodology was robust, and the cohort size included in this study permitted evaluation and control of multiple variables. One limitation of this study is that hemoglobin oxygen saturation and SpO2 data were not temporally matched.
Relevant Reading: Racial bias in pulse oximetry measurement
In-Depth [retrospective cohort]: This study was conducted between 2008 and 2019 at the Beth Israel Deaconess Medical Center and utilized the Medical Information Mart for Intensive Care (MIMIC)-IV critical care data set. This study assessed the association between SpO2 performance and hemoglobin oxygen saturation among White, Black, Asian, and Hispanic patients. Patients were included if they were admitted to the ICU without requiring respiratory support for at least 12 hours. Patients were excluded if there was no documentation of race or ethnicity (Asian, Black, Hispanic, or White). The primary outcome was the time-weighted average supplemental oxygen rate. A multivariable linear regression model was used to determine associations between SpO2 and hemoglobin oxygen saturation, as well as whether these discrepancies were associated with differences in the administration of oxygen supplementation. For a given hemoglobin oxygen saturation compared to White patients, Black (coefficient: 0.919 [95% CI: 0.698-1.140]; p< 0.001), Hispanic (coefficient: 0.622 [95% CI: 0.329-0.915]; p< 0.001), and Asian (coefficient: 0.602 [95% CI: 0.263-0.941]; p= 0.001) patients were associated with a higher SpO2 readings. Additionally, Black (coefficient: -0.294 [95% CI: -0.460 to -0.128]; p= 0.001), Asian (coefficient: -0.291 [95% CI: -0.546 to -0.035]; p= 0.03), and Hispanic (coefficient: -0.242 [95% CI: -0.463 to -0.020]; p= 0.03) patients were associated with reduced average oxygen delivery rates by approximately 0.2-0.3 L/min compared to White patients.
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