Pulse Oximeters and Violation of Federal Antidiscrimination Law.

This Viewpoint discusses how some pulse oximeters can provide incorrect oxygen saturation data for dark-skinned patients compared with light-skinned patients, describes the reasons that biased oximeters remained in use, and highlights why a rule recently proposed by the US Department of Health and Human Services may bring about needed change in the use of pulse oximetry for patients with dark skin.

Remote monitoring in telehealth care delivery across the U.S. cystic fibrosis care network.

BACKGROUND: Cystic fibrosis (CF) programs and people with CF (PwCF) employed various monitoring methods for virtual care during the COVID-19 pandemic. This paper characterizes experiences with remote monitoring across the U.S. CF community. METHODS: The CF Foundation (CFF) sponsored distribution of home spirometers (April 2020 to May 2021), surveys to PwCF and CF programs (July to September 2020), and a second program survey (April to May 2021). We used mixed methods to explore access, use, and perspectives regarding the use of remote monitoring in future care. RESULTS: By October 2020, 13,345 spirometers had been distributed, and 19,271 spirometers by May 2021. Programs (n=286) estimated proportions of PwCF with home devices increased over seven months: spirometers (30% to 70%), scales (50% to 70%), oximeters (5% to 10%) with higher estimates in adult programs for spirometers and oximeters. PwCF (n=378) had access to scales (89%), followed by oximeters (48%) and spirometers (47%), often using scales and oximeters weekly, and spirometers monthly. Over both surveys, some programs had no method to collect respiratory specimens for cultures associated with telehealth visits (47%, n=132; 41%, n=118). Most programs (81%) had a process for phlebotomy associated with a telehealth visit, primarily through off-site labs. Both PwCF and programs felt future care should advance remote monitoring and recommended improvements for access, training, and data collection systems. CONCLUSIONS: PwCF and programs experienced unprecedented access to remote monitoring and raised its importance for future care. Improvements to current systems may leverage these shared experiences to augment future care models.

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.

OBJECTIVES: To evaluate the performance of direct-to-consumer pulse oximeters under clinical conditions, with arterial blood gas measurement (SaO2) as reference standard. DESIGN: Cross-sectional, validation study. SETTING: Intensive care. PARTICIPANTS: Adult patients requiring SaO2-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 SaO2 blood sample, we obtained pulse oximeter readings (SpO2). SpO2-readings were performed in rotating order, blinded for SaO2 and completed <10 min after blood sample collection. OUTCOME MEASURES: Bias (SpO2-SaO2) mean, root mean square difference (ARMS), mean absolute error (MAE) and accuracy in identifying hypoxaemia (SaO2 ≤90%). As a clinical index test, we included a hospital-grade SpO2-monitor (Philips). RESULTS: In 35 consecutive patients, we obtained 2258 SpO2-readings and 234 SaO2-samples. Mean bias ranged from -0.6 to -4.8. None of the pulse oximeters met ARMS ≤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 SpO2-monitor had an ARMS 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.

The Performance of Digital Monitoring Devices for Oxygen Saturation and Respiratory Rate in COPD: A Systematic Review.

Healthcare access and delivery for individuals with chronic obstructive pulmonary disease (COPD) who live in remote areas or who are susceptible to contracting communicable diseases, such as COVID-19, may be a challenge. Telehealth and remote monitoring devices can be used to overcome this issue. However, the accuracy of these devices must be ensured before forming healthcare decisions based on their outcomes. Therefore, a systematic review was performed to synthesize the evidence on the reliability, validity and responsiveness of digital devices used for tracking oxygen saturation (SpO2) and/or respiratory rate (RR) in individuals with COPD, in remote settings. Three electronic databases were searched: MEDLINE (1996 to October 8, 2020), EMBASE (1996 to October 8, 2020) and CINAHL (1998 to October 8, 2020). Studies were included if they aimed to evaluate one or more measurement properties of a digital device measuring SpO2 or RR in individuals with COPD. Six-hundred and twenty-five articles were identified and after screening, 7 studies matched the inclusion criteria; covering 11 devices measuring SpO2 and/or RR. Studies reported on the reliability (n = 1), convergent validity (n = 1), concurrent validity (n = 2) and predictive validity (n = 2) of SpO2 devices and on the convergent validity (n = 1), concurrent validity (n = 1) and predictive validity (n = 1) of RR devices. SpO2 and RR devices were valid when compared against other respiration monitoring devices but were not precise in predicting exacerbation events. More well-designed measurement studies are needed to make firm conclusions about the accuracy of such devices.Supplemental data for this article is available online at https://doi.org/10.1080/15412555.2021.1945021 .

Smartphone Biosensor With App Meets FDA/ISO Standards for Clinical Pulse Oximetry and Can Be Reliably Used by a Wide Range of Patients.

BACKGROUND: Millions of smartphones contain a photoplethysmography (PPG) biosensor (Maxim Integrated) that accurately measures pulse oximetry. No clinical use of these embedded sensors is currently being made, despite the relevance of remote clinical pulse oximetry to the management of chronic cardiopulmonary disease, and the triage, initial management, and remote monitoring of people affected by respiratory viral pandemics, such as severe acute respiratory syndrome coronavirus 2 or influenza. To be used for clinical pulse oximetry the embedded PPG system must be paired with an application (app) and meet US Food and Drug Administration (FDA) and International Organization for Standardization (ISO) requirements. RESEARCH QUESTION: Does this smartphone sensor with app meet FDA/ISO requirements? Are measurements obtained using this system comparable to those of hospital reference devices, across a wide range of people? STUDY DESIGN AND METHODS: We performed laboratory testing addressing ISO and FDA requirements in 10 participants using the smartphone sensor with app. Subsequently, we performed an open-label clinical study on 320 participants with widely varying characteristics, to compare the accuracy and precision of readings obtained by patients with those of hospital reference devices, using rigorous statistical methodology. RESULTS: "Breathe down" testing in the laboratory showed that the total root-mean-square deviation of oxygen saturation (Spo2) measurement was 2.2%, meeting FDA/ISO standards. Clinical comparison of the smartphone sensor with app vs hospital reference devices determined that Spo2 and heart rate accuracy were 0.48% points (95% CI, 0.38-0.58; P < .001) and 0.73 bpm (95% CI, 0.33-1.14; P < .001), respectively; Spo2 and heart rate precision were 1.25 vs reference 0.95% points (P < .001) and 5.99 vs reference 3.80 bpm (P < .001), respectively. These small differences were similar to the variation found between two FDA-approved reference instruments for Spo2: accuracy, 0.52% points (95% CI, 0.41-0.64; P < .001) and precision, 1.01 vs 0.86% points (P < .001). INTERPRETATION: Our findings support the application for full FDA/ISO approval of the smartphone sensor with app tested for use in clinical pulse oximetry. Given the immense and immediate practical medical importance of remote intermittent clinical pulse oximetry to both chronic disease management and the global ability to respond to respiratory viral pandemics, the smartphone sensor with app should be prioritized and fast-tracked for FDA/ISO approval to allow clinical use. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT04233827; URL: www.clinicaltrials.gov.

Randomised study of heart rate measurement in preterm newborns with ECG plus pulse oximetry versus oximetry alone.

AIM: To determine whether the IntelliVue monitor (ECG plus Masimo pulse oximeter (PO)) displays heart rate (HR) at birth more quickly than Nellcor PO (PO alone) among infants of 29-35 weeks' gestational age. METHODS: Unmasked parallel group randomised (1:1) study. RESULTS: We planned to enrol 100 infants; however, the study was terminated due to the COVID-19 pandemic when 39 infants had been enrolled (17 randomised to IntelliVue, 22 to Nellcor). We found no differences between the groups in the time to first HR display (median (IQR) IntelliVue ECG 49 (33, 71) vs Nellcor 47 (37, 86) s, p>0.999), in the proportion who had a face mask applied for breathing support, or in the time at which it was applied. Infants monitored with IntelliVue were handled more frequently and for longer. CONCLUSION: IntelliVue ECG did not display HR more quickly than Nellcor PO in preterm infants. We found no differences in the rate of or time to intervention between groups. Our study was terminated early so these findings should be interpreted with caution. TRIAL REGISTRATION NUMBER: ISRCTN16473881.

In-Ear SpO2: A Tool for Wearable, Unobtrusive Monitoring of Core Blood Oxygen Saturation.

The non-invasive estimation of blood oxygen saturation (SpO2) by pulse oximetry is of vital importance clinically, from the detection of sleep apnea to the recent ambulatory monitoring of hypoxemia in the delayed post-infective phase of COVID-19. In this proof of concept study, we set out to establish the feasibility of SpO2 measurement from the ear canal as a convenient site for long term monitoring, and perform a comprehensive comparison with the right index finger-the conventional clinical measurement site. During resting blood oxygen saturation estimation, we found a root mean square difference of 1.47% between the two measurement sites, with a mean difference of 0.23% higher SpO2 in the right ear canal. Using breath holds, we observe the known phenomena of time delay between central circulation and peripheral circulation with a mean delay between the ear and finger of 12.4 s across all subjects. Furthermore, we document the lower photoplethysmogram amplitude from the ear canal and suggest ways to mitigate this issue. In conjunction with the well-known robustness to temperature induced vasoconstriction, this makes conclusive evidence for in-ear SpO2 monitoring being both convenient and superior to conventional finger measurement for continuous non-intrusive monitoring in both clinical and everyday-life settings.

COVID-19: Pulse oximeters in the spotlight.

From home to intensive care units, innovations in pulse oximetry are susceptible to improve the monitoring and management of patients developing acute respiratory failure, and particularly those with the coronavirus disease 2019 (COVID-19). They include self-monitoring of oxygen saturation (SpO2) from home, continuous wireless SpO2 monitoring on hospital wards, and the integration of SpO2 as the input variable for closed-loop oxygen administration systems. The analysis of the pulse oximetry waveform may help to quantify respiratory efforts and prevent intubation delays. Tracking changes in the peripheral perfusion index during a preload-modifying maneuver may be useful to predict preload responsiveness and rationalize fluid therapy.