Determining factors of pulse oximetry accuracy: a literature review

Abstract

Objective: Identify and reach consensus on the variables that affect the measurement of oxygensaturation using pulse oximetry.

Methods: We applied inclusion and exclusion criteria to select relevant studies in databasessuch as Ebsco and PubMed. The search strategies, carried out until December 2023, focused onpublications that addressed the technology of pulse oximeters and variables that influence theiraccuracy. We assessed the risk of bias of the included studies and used standardized methodsfor synthesis of results.

Results: 23 studies were included. The synthesis of the results highlighted that equipment withtetrapolar technology showed greater precision in oxygen saturation measurements. Increasedskin pigmentation, hemoglobinopathies and high skin temperatures can lead to an overesti-mation of SpO2, while factors such as low perfusion, cold skin temperature, nail polish ortattoos, hypoxemia, anemia and high altitude training, they may underestimate it. On theother hand, motion artifacts, light pollution, frequency >150 beats per minute, electromag-netic interference and location of the sensor can cause distortion of the photoplethymographysignal.

Conclusions: The synthesis of the results highlighted that skin pigmentation and light inter-ference can lead to an overestimation of SpO2, while other factors such as low perfusion andaltitude tend to underestimate it. The studies presented variability and heterogeneity in theirdesigns, evidencing limitations in the consistency and precision of the evidence. Despite these limitations, the results underscore the importance of considering multiple variables when interpreting pulse oximetry measurements to ensure their reliability. The findings have significant implications for clinical practice and future research.