Performance of the new SmartCardia wireless, wearable oximeter: a comparison with arterial SaO2 in healthy volunteers

Abstract

Background: Our goal was to evaluate the performance of a new wearable arm located pulse oximeter.

Methods: Twelve volunteers were monitored with three pulse oximeters and underwent desaturation to 70% SaO₂. We compared the accuracy of SpO₂ reading from the SmartCardia system with SpO₂ using two well established devices (Masimo and Nellcor) as reference. Oximetry was performed at different level of oxygen saturation varying from 70 to 100%. Bias, ARMS and precision were evaluated using Bland-Altman plots.

Results: The mean (SD) differences between SaO₂ compared to SpO₂ and the devices were as follows: SaO₂ versus Masimo 2,12 ± 1,01% (95% CI 1,45 to 2,79), SaO₂ versus Nellcor 0,78 ± 0,58% (95% CI - 0,29 to 1,65) and SaO₂ versus SmartCardia 0,42 ± 0,24% (95% CI - 0,64 to 1,46). The bias between SmartCardia, Masimo, Nellcor devices and SaO₂ was 0.16 (95% CI 0.05 to 0.33) and LoA (level of agreements) 2.96 (95% CI - 2,68 to 2,89) for SmartCardia, 2,02 (95% CI 1,49 to 2,54) and LoA - 6 to 11 for Masimo, and 0,76 (95% CI 0,5 to - 1) and LoA - 3,5 to 5,0 for Nellcor. ARMS for the 70-100% SaO₂ range was 1,4 for SmartCardia, 5,0 for Masimo and 2,31 for Nellcor.

Conclusions: The new wireless SmartCardia SpO₂ measurement system demonstrated in-line results, bias, ARMS and precision in healthy volunteers, when compared with the gold standard SaO2 and with two well established systems, Masimo and Nellcor.

Trial registration: The present trial was prospectively registered at UCSF record (registration number:10-00437), on March 8, 2021.

Keywords: Masimo device; Nellcor device; Oximetry; SmartCardia; SpO2 measurement.