Abstract
OBJECTIVES: To evaluate the performance of direct-to-consumer pulse oximeters under clinical conditions, with arterial blood gas measurement (SaO(2)) as reference standard. DESIGN: Cross-sectional, validation study. SETTING: Intensive care. PARTICIPANTS: Adult patients requiring SaO(2)-monitoring. INTERVENTIONS: The studied oximeters are top-selling in Europe/USA (AFAC FS10D, AGPTEK FS10C, ANAPULSE ANP 100, Cocobear, Contec CMS50D1, HYLOGY MD-H37, Mommed YM101, PRCMISEMED F4PRO, PULOX PO-200 and Zacurate Pro Series 500 DL). Directly after collection of a SaO(2) blood sample, we obtained pulse oximeter readings (SpO(2)). SpO(2)-readings were performed in rotating order, blinded for SaO(2) and completed <10 min after blood sample collection. OUTCOME MEASURES: Bias (SpO(2)-SaO(2)) mean, root mean square difference (A(RMS)), mean absolute error (MAE) and accuracy in identifying hypoxaemia (SaO(2) ≤90%). As a clinical index test, we included a hospital-grade SpO(2)-monitor (Philips). RESULTS: In 35 consecutive patients, we obtained 2258 SpO(2)-readings and 234 SaO(2)-samples. Mean bias ranged from -0.6 to -4.8. None of the pulse oximeters met A(RMS) ≤3%, the requirement set by International Organisation for Standardisation (ISO)-standards and required for Food and Drug Administration (FDA) 501(k)-clearance. The MAE ranged from 2.3 to 5.1, and five out of ten pulse oximeters met the requirement of ≤3%. For hypoxaemia, negative predictive values were 98%-99%. Positive predictive values ranged from 11% to 30%. Highest accuracy (95% CI) was found for Contec CMS50D1; 91% (86-94) and Zacurate Pro Series 500 DL; 90% (85-94). The hospital-grade SpO(2)-monitor had an A(RMS) of 3.0% and MAE of 1.9, and an accuracy of 95% (91%-97%). CONCLUSION: Top-selling, direct-to-consumer pulse oximeters can accurately rule out hypoxaemia, but do not meet ISO-standards required for FDA-clearance.