Pulse-ox and dark skin

Q: Pulse oximetry readings usually ____________ the oxygen saturation in patients with darker skin? (select one)

A) overestimates

B) underestimates

Answer: A

Any kind of skin pigmentation including hyperbilirubinemia can falsely overestimate the pulse-ox reading. This may cause "hidden" hypoxemia. This may not be of concern in usual circumstances but given the recent COVID pandemic where clinicians are fighting for every single percent increase in pulse-ox level, this may be of bedside importance. This discrepancy can be up to 4 percent or more.  This“hidden” hypoxemia may lead to higher organ dysfunction scores and in-hospital mortality.

#procedures

#oxygenation

References:

1. Bickler PE, Feiner JR, Severinghaus JW. Effects of skin pigmentation on pulse oximeter accuracy at low saturation. Anesthesiology 2005; 102:715.

2. Sjoding MW, Dickson RP, Iwashyna TJ, et al. Racial Bias in Pulse Oximetry Measurement. N Engl J Med 2020; 383:2477.

3. Interim Clinical Guidance for Management of Patients with Confirmed Coronavirus Disease (COVID-19), February 16, 2021. https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guidance-management-patients.html (Accessed on April 12, 2022).

4. Wong AI, Charpignon M, Kim H, et al. Analysis of Discrepancies Between Pulse Oximetry and Arterial Oxygen Saturation Measurements by Race and Ethnicity and Association With Organ Dysfunction and Mortality. JAMA Netw Open 2021; 4:e2131674.