Popular direct-to-consumer pulse oximeters can accurately rule out hypoxaemia but have some notable limitations, according to results of a recent study published in BMJ Open Respiratory Research.
The cross-sectional validation study compared blood gas (SpO2) readings taken by 10 top-selling direct-to-consumer pulse oximeters with arterial blood gas measurements (SaO2) derived from patient blood samples, using a cohort of 35 patients in the intensive care unit (ICU) of a community hospital in the Netherlands. From these 35 patients, researchers obtained 2258 SpO2 readings and 234 SaO2 samples. Readings from the commercial oximeters were also compared with those of a hospital-grade pulse oximetry device.
Outcome measures included mean bias (peripheral–arterial), root mean square difference, mean absolute error, and accuracy in identifying hypoxaemia (arterial blood gas ≤90%). Investigators found that mean bias ranged from −0.6 to −4.8. None of the direct-to-consumer pulse oximeters met root mean square difference of 3% or less, a requirement set by International Organisation for Standardisation (ISO; a Geneva, Switzerland-based nongovernmental organization) and a requirement for Food and Drug Administration clearance. For hypoxaemia, negative predictive values were 98% to 99%. However, positive predictive values ranged from 11% to 30%.
Researchers found that the hospital-grade SpO2 monitor performed slightly better than the consumer devices. Investigators recommended using a hospital-grade device to confirm a below-normal SpO2 reading from a consumer oximeter used for home monitoring.
The study authors concluded that the consumer pulse oximeters tested can rule out hypoxaemia but are not reliable in confirming hypoxaemia and most do not meet FDA requirements. However, investigators added, these devices’ ability to rule out hypoxaemia in the vast majority of patients “is particularly relevant in community-based populations with a low a priori hypoxaemia risk.”
Harskamp RE, Bekker L, Himmelreich JCL, et al. Performance of popular pulse oximeters compared with simultaneous arterial oxygen saturation or clinical-grade pulse oximetry: a cross-sectional validation study in intensive care patients. BMJ Open Respir Res. 2021;8(1):e000939. doi:10.1136/bmjresp-2021-000939