Pulse Oximetry and Race in Critically Ill Adults

For critically ill adults, oxygen saturation is continuously monitored using pulse oximetry (Spo₂) as a surrogate for arterial oxygen saturation (Sao₂). Skin pigmentation may affect accuracy of Spo₂ by introducing error from statistical bias, variance, or both. We evaluated relationships between race, Spo₂, Sao₂, and hypoxemia (Sao₂ < 88%) or hyperoxemia (Pao₂ > 150 mm Hg) among adults receiving mechanical ventilation in a medical ICU.

Single-center, observational study.

Medical ICU at an academic medical center.

Critically ill adults receiving mechanical ventilation from July 2018 to February 2021, excluding patients with COVID-19, with race documented as Black or White in the electronic medical record, who had a pair of Spo₂ and Sao₂ measurements collected within 10 minutes of each other.

None.

We included 1,024 patients with 5,557 paired measurements within 10 minutes, of which 3,885 (70%) were within 1 minute. Of all pairs, 769 (14%) were from Black patients and 4,788 (86%) were from White patients. In analyses using a mixed-effects model, we found that across the range of Spo₂ values of 92-98%, the associated Sao₂ value was approximately 1% point lower for Black patients compared with White patients. Among patients with a Spo₂ value between 92% and 96%, Black patients were more likely to have both hypoxemia (3.5% vs 1.1%; p = 0.002) and hyperoxemia (4.7% vs 2.4%; p = 0.03), compared with White patients.

Among patients with a measured Spo₂ of 92-96%, greater variation in Sao₂ values at a given Spo₂ resulted in a higher occurence rate of both hypoxemia and hyperoxemia for Black patients compared with White patients.