Resource Use and Clinical Outcomes in Infants with Supraventricular Tachycardia Monitored with the Owlet Smart Sock.

OBJECTIVES: To describe the prevalence of Owlet Smart Sock (OSS) use in infants with supraventricular tachycardia (SVT) and associated demographic and clinical characteristics of users and to analyze the association of OSS use on medical resource use and clinical outcomes from emergency department (ED) encounters for SVT. STUDY DESIGN: This was a single-center, retrospective cohort study of infants with confirmed SVT from 2015 to 2022. OSS users and nonusers were compared across clinical and demographic parameters. Medical resource use (phone calls, office visits, ED visits) and outcomes (need for intensive care, length of stay, echocardiographic function, clinical appearance) were compared between OSS users and nonusers. RESULTS: Of 133 infants with SVT, OSS was used by 31 of 133 (23%), purchased before SVT diagnosis in 5 in 31 (16%) of users. No demographic difference was found between OSS users and nonusers. OSS users had more phone notes than nonusers, (P = .002) and more ED visits (P = .03), but the number of office visits and medication adjustments did not differ. During ED presentation, OSS users had better preserved left ventricular ejection fraction on echocardiogram (P = .04) and lower length of hospital stay by a mean 1.7 days (P = .02). CONCLUSIONS: OSS is used by a portion of infants with SVT. It is associated with more frequent phone calls and ED visits but lower length of stay and better-preserved cardiac function upon presentation.

Racial and skin color mediated disparities in pulse oximetry in infants and young children.

Race-based and skin pigmentation-related inaccuracies in pulse oximetry have recently been highlighted in several large electronic health record-based retrospective cohort studies across diverse patient populations and healthcare settings. Overestimation of oxygen saturation by pulse oximeters, particularly in hypoxic states, is disparately higher in Black compared to other racial groups. Compared to adult literature, pediatric studies are relatively few and mostly reliant on birth certificates or maternal race-based classification of comparison groups. Neonates, infants, and young children are particularly susceptible to the adverse life-long consequences of hypoxia and hyperoxia. Successful neonatal resuscitation, precise monitoring of preterm and term neonates with predominantly lung pathology, screening for congenital heart defects, and critical decisions on home oxygen, ventilator support and medication therapies, are only a few examples of situations that are highly reliant on the accuracy of pulse oximetry. Undetected hypoxia, especially if systematically different in certain racial groups may delay appropriate therapies and may further perpetuate health care disparities. The role of biological factors that may differ between racial groups, particularly skin pigmentation that may contribute to biased pulse oximeter readings needs further evaluation. Developmental and maturational changes in skin physiology and pigmentation, and its interaction with the operating principles of pulse oximetry need further study. Importantly, clinicians should recognize the limitations of pulse oximetry and use additional objective measures of oxygenation (like co-oximetry measured arterial oxygen saturation) where hypoxia is a concern.

Pulse Wave Amplitude Drops Index: A Biomarker of Cardiovascular Risk in Obstructive Sleep Apnea.

Rationale: It is currently unclear which patients with obstructive sleep apnea (OSA) are at increased cardiovascular risk. Objective: To investigate the value of pulse wave amplitude drops (PWADs), reflecting sympathetic activations and vasoreactivity, as a biomarker of cardiovascular risk in OSA. Methods: PWADs were derived from pulse oximetry-based photoplethysmography signals in three prospective cohorts: HypnoLaus (N = 1,941), the Pays-de-la-Loire Sleep Cohort (PLSC; N = 6,367), and "Impact of Sleep Apnea syndrome in the evolution of Acute Coronary syndrome. Effect of intervention with CPAP" (ISAACC) (N = 692). The PWAD index was the number of PWADs (>30%) per hour during sleep. All participants were divided into subgroups according to the presence or absence of OSA (defined as ⩾15 or more events per hour or <15/h, respectively, on the apnea-hypopnea index) and the median PWAD index. Primary outcome was the incidence of composite cardiovascular events. Measurements and Main Results: Using Cox models adjusted for cardiovascular risk factors (hazard ratio; HR [95% confidence interval]), patients with a low PWAD index and OSA had a higher incidence of cardiovascular events compared with the high-PWAD and OSA group and those without OSA in the HypnoLaus cohort (HR, 2.16 [1.07-4.34], P = 0.031; and 2.35 [1.12-4.93], P = 0.024) and in the PLSC (1.36 [1.13-1.63], P = 0.001; and 1.44 [1.06-1.94], P = 0.019), respectively. In the ISAACC cohort, the low-PWAD and OSA untreated group had a higher cardiovascular event recurrence rate than that of the no-OSA group (2.03 [1.08-3.81], P = 0.028). In the PLSC and HypnoLaus cohorts, every increase of 10 events per hour in the continuous PWAD index was negatively associated with incident cardiovascular events exclusively in patients with OSA (HR, 0.85 [0.73-0.99], P = 0.031; and HR, 0.91 [0.86-0.96], P < 0.001, respectively). This association was not significant in the no-OSA group and the ISAACC cohort. Conclusions: In patients with OSA, a low PWAD index reflecting poor autonomic and vascular reactivity was independently associated with a higher cardiovascular risk.

Excessive Oxygen Administration in High-Risk Patients Admitted to Medical and Surgical Wards Monitored by Wireless Pulse Oximeter.

The monitoring of oxygen therapy when patients are admitted to medical and surgical wards could be important because exposure to excessive oxygen administration (EOA) may have fatal consequences. We aimed to investigate the association between EOA, monitored by wireless pulse oximeter, and nonfatal serious adverse events (SAEs) and mortality within 30 days. We included patients in the Capital Region of Copenhagen between 2017 and 2018. Patients were hospitalized due to acute exacerbation of chronic obstructive pulmonary disease (AECOPD) or after major elective abdominal cancer surgery, and all were treated with oxygen supply. Patients were divided into groups by their exposure to EOA: no exposure, exposure for 1-59 min or exposure over 60 min. The primary outcome was SAEs or mortality within 30 days. We retrieved data from 567 patients for a total of 43,833 h, of whom, 63% were not exposed to EOA, 26% had EOA for 1-59 min and 11% had EOA for ≥60 min. Nonfatal SAEs or mortality within 30 days developed in 24%, 12% and 22%, respectively, and the adjusted odds ratio for this was 0.98 (95% CI, 0.96-1.01) for every 10 min. increase in EOA, without any subgroup effects. In conclusion, we did not observe higher frequencies of nonfatal SAEs or mortality within 30 days in patients exposed to excessive oxygen administration.

Decontamination Effect of Hypochlorous Acid Dry Mist on Selected Bacteria, Viruses, Spores, and Fungi as Well as on Components of Electronic Systems.

This publication presents the effect of hypochlorous acid dry mist as a disinfectant on selected bacteria, viruses, spores, and fungi as well as on portable Microlife OXY 300 finger pulse oximeters and electronic systems of Raspberry Pi Zero microcomputers. The impact of hypochlorous acid on microbiological agents was assessed at concentrations of 300, 500, and 2000 ppm of HClO according to PN-EN 17272 (Variant I). Studies of the impact of hypochlorous acid fog on electronic components were carried out in an aerosol chamber at concentrations of 500 ppm and 2000 ppm according to two models consisting of 30 (Variant II) and 90 fogging cycles (Variant III). Each cycle included the process of generating a dry mist of hypochlorous acid (25 mL/m3), decontamination of the test elements, as well as cleaning the chamber of the disinfectant agent. The exposure of the materials examined on hypochlorous acid dry mist in all variants resulted in a decrease in the number of viruses, bacteria, spores, and fungi tested. In addition, the research showed that in the variants of hypochlorous acid fogging cycles analyzed, no changes in performance parameters and no penetration of dry fog of hypochlorous acid into the interior of the tested medical devices and electronic systems were observed.

Preterm Infants off Positive Pressure Respiratory Support Have a Higher Incidence of Occult Cerebral Hypoxia.

OBJECTIVE: To use cerebral near-infrared spectroscopy (NIRS) to quantify occult cerebral hypoxia across respiratory support modes in preterm infants. STUDY DESIGN: In this prospective, longitudinal, observational study, infants ≤32 weeks gestation underwent serial pulse oximetry (oxygen saturation [SpO2]) and cerebral NIRS monitoring (4-6 hours per session) following a standardized recording schedule (daily for 2 weeks, every other day for 2 weeks, then weekly until 35 weeks corrected gestational age). Four calculations were made: median cerebral saturation, median cerebral hypoxia burden (proportion of NIRS samples below the hypoxia threshold [<67%]), median systemic saturation, and median systemic hypoxia burden (proportion of SpO2 samples below the desaturation threshold [<85%]). During each recording session, respiratory support mode was noted (room air, low-flow nasal cannula, high-flow nasal cannula, noninvasive positive pressure ventilation, continuous positive airway pressure, and invasive ventilation). RESULTS: There were 1013 recording sessions made from 174 infants with a median length of 6.9 hours. Although the systemic (SpO2) hypoxia burden was significantly greater for infants on the highest respiratory support (invasive and noninvasive positive pressure ventilation), the cerebral hypoxia burden was significantly greater during recording sessions made on the lowest respiratory support (8% for room air; 29% for low-flow nasal cannula). CONCLUSIONS: Premature infants on the highest levels of respiratory support have less cerebral hypoxia than those on lower respiratory support. These results raise concern about unrecognized cerebral hypoxia during lower acuity periods of neonatal intensive care unit hospitalization and adverse outcomes.

Parental Ability to Assess Pediatric Vital Signs.

OBJECTIVE: To evaluate parents' ability to accurately assess their child's heart and respiratory rates (RRs) in the context of potential utility for telehealth visits. STUDY DESIGN: In this controlled study of 203 child-parent pairs, parents measured their child's heart rate (HR) using 4 methods: palpation, auscultation, and 2 photoplethysmographic smartphone applications. Parents measured RR by inspecting the child and tapping the smartphone application. The gold standards were electrocardiogram for the HR and the child's breaths measured by a health care professional for 60 seconds for the RR. We plotted the measurements using a Bland-Altman plot with 95% limits of agreement. RESULTS: Parents underestimated HR by palpation with a calculated bias of -18 beats per minute (bpm) (SD, 19), with limits of agreement ranging from -56 to 19 bpm. Parents overestimated and underestimated HR by auscultation with limits of agreement ranging from -53 to 46 bpm. Smartphone applications did not improve the accuracy of measurements. The accuracy of parental RR measurements was low. For young children, bias was -0.8 breaths per minute (brpm) (SD, 9.8) with limits of agreement from -20 to 19 brpm, and for older children, bias was 0.9 brpm (SD 7.4) with limits of agreement from 6 to 15 brpm. The sensitivity of parental subjective opinion to recognize accelerated RR was 37% (95% CI, 25%-51%). CONCLUSION: Parents were not able to assess their child's RR or HR accurately. Digital remote assessment of children should not rely on parental measurements of vital signs.

Knowledge of pulse oximetry among emergency and critical care nurses.

BACKGROUND: The pulse oximeter is a simple, cost-effective and reliable device for estimating arterial blood oxygen saturation. Nurses are required to be knowledgeable in pulse oximeter use. Little is known about nurses' knowledge of pulse oximetry in the Middle East region. AIM: To assess nurses' knowledge of pulse oximetry among emergency and critical care nurses and to explore predictors of nurses' knowledge of pulse oximetry. METHODS: This is the second part of data analysis that was first presented in the 'proficiency in ECG' study conducted in Jordan. The original data used for both parts of analysis included a questionnaire with two tests; a knowledge of pulse oximeter test and an ECG proficiency test. Participants were asked to take, alone without receiving assistance, both tests. In this study, the second part of analysis, the focus is on the pulse oximeter test. The test consisted of 21 items that emphasize knowledge of basic physiological principles as well as device limitations; whether technical or interpretation. The test administration procedure also included asking participants to provide socio-demographic variables. In the original data collected in both parts of analysis, nurses working in the emergency department, cardiac care units or intensive care units from nine different hospitals (1 governmental, 6 private and 2 educational) and holding a bachelor degree or higher were asked to participate. RESULTS: The total number of participating nurses was 210; out of 247 approached (response rate, 85%). The mean score in the nurses' knowledge of pulse oximetry test was 12.33 out of 21, corresponding to 58.7%. The clinical area currently working in predicted the knowledge of pulse oximetry test score after controlling for all other variables. Emergency department and intensive care unit nurses scored higher than cardiac care unit nurses by 1.86 and 1.63 points respectively (58.2% and 60% respectively). CONCLUSION: Nurses consistently report inadequate education and training concerning pulse oximeter use and interpretation. A revision to hospital in-service education seminars and undergraduate nurses' curriculum to assure adequate preparation is needed. RELEVANCE TO CLINICAL PRACTICE: Knowledge of pulse oximetry among emergency and critical care nurses is modest. This is a challenge worldwide. Predictors of nurses' knowledge of pulse oximetery are the clinical area currently working in (ICU and ED nurses are more knowledgeable than CCU nurses), proficiency in electrocardiography and taking an advanced cardiac life support course.

Children with Congenital Central Hypoventilation Syndrome Do Not Wake up to Ventilator Alarms.

PURPOSE: Congenital Central Hypoventilation Syndrome (CCHS) requires lifelong ventilatory support during sleep. Subjects with CCHS are vulnerable to sleep disturbances associated with treatments, monitoring alarms, and care they receive. We hypothesized that sleep would be disrupted in patients  with CCHS due to ventilatory support and other treatments at night. METHODS: An anonymous survey of patients with CCHS, age up to 17 years was conducted through REDCAP. Subjects were recruited in person, by flyer, email, and social media. Data collected included demographics, PHOX2B genotype, ventilatory support, treatments, nursing, and sleep parameters. RESULTS: We received 23 responses (35% female, 8.1 years ± 5.6). PHOX2B genotypes were 20/24 PARM (2), 20/25 PARM (4), 20/26 PARM (2), 20/27 PARM (9), ≥ 20/28 PARM (2), and NPARM (2). Two subjects did not indicate the PHOX2B genotype. 13/23 were ventilated by PPV via tracheostomy, 7 by NIPPV, 2 by diaphragm pacing, and 1 did not indicate. Additional treatments received at night included suctioning (9), aerosol (1), G-tube feeding (2), and none (11). Only 9 received nursing at night. 13 used pulse oximetry for monitoring, and 9 used both pulse oximetry and end tidal CO2 monitor. 17/23 rarely woke up due to ventilator or monitor alarms. 11/23 usually or sometimes woke up at least once a night; only 2/11 woke up due to alarms. 5/17 who rarely woke up to the alarms had night nursing. CONCLUSION: Most subjects with CCHS did not awaken to ventilator or monitoring alarms and a majority of these patients did not have nighttime nursing. (Mathur et al. in Sleep 43(Supplement_1):A333, 2020).

Evaluation of the routine implementation of pulse oximeters into integrated management of childhood illness (IMCI) guidelines at primary health care level in West Africa: the AIRE mixed-methods research protocol.

BACKGROUND: The AIRE operational project will evaluate the implementation of the routine Pulse Oximeter (PO) use in the integrated management of childhood illness (IMCI) strategy for children under-5 in primary health care centers (PHC) in West Africa. The introduction of PO should promote the accurate identification of hypoxemia (pulse blood oxygen saturation Sp02 < 90%) among all severe IMCI cases (respiratory and non-respiratory) to prompt their effective case management (oxygen, antibiotics and other required treatments) at hospital. We seek to understand how the routine use of PO integrated in IMCI outpatients works (or not), for whom, in what contexts and with what outcomes. METHODS: The AIRE project is being implemented from 03/2020 to 12/2022 in 202 PHCs in four West African countries (Burkina Faso, Guinea, Mali, Niger) including 16 research PHCs (four per country). The research protocol will assess three complementary components using mixed quantitative and qualitative methods: a) context based on repeated cross-sectional surveys: baseline and aggregated monthly data from all PHCs on infrastructure, staffing, accessibility, equipment, PO use, severe cases and care; b) the process across PHCs by assessing acceptability, fidelity, implementation challenges and realistic evaluation, and c) individual outcomes in the research PHCs: all children under-5 attending IMCI clinics, eligible for PO use will be included with parental consent in a cross-sectional study. Among them, severe IMCI cases will be followed in a prospective cohort to assess their health status at 14 days. We will analyze pathways, patterns of care, and costs of care. DISCUSSION: This research will identify challenges to the systematic implementation of PO in IMCI consultations, such as health workers practices, frequent turnover, quality of care, etc. Further research will be needed to fully address key questions such as the best time to introduce PO into the IMCI process, the best SpO2 threshold for deciding on hospital referral, and assessing the cost-effectiveness of PO use. The AIRE research will provide health policy makers in West Africa with sufficient evidence on the context, process and outcomes of using PO integrated into IMCI to promote scale-up in all PHCs. TRIAL REGISTRATION: Trial registration number: PACTR202206525204526 retrospectively registered on 06/15/2022.

Evaluation of the effects on SpO2 of N95 mask (FFP2) on dental health care providers: a cross-sectional observational study.

OBJECTIVE: The purpose of this cross-sectional observational study was to evaluate the effects of SpO2 in a sample of dental health care providers who wear a N95 mask or Filtering Face Piece (FFP2) for four consecutive hours, measured by a pulse oximeter before donning the mask and again after four hours of work and to offer some strategies to minimize discomfort and improve communication with their patients while wearing the mask. MATERIALS AND METHODS: A 17-item questionnaire was sent via Google Drive to various practitioners in Italy and the USA. A sample of 162 questionnaires were returned from dentists, orthodontists, dental hygienists and dental assistants who committed to wearing a FFP2 for 4 consecutive hours during a work day and then measuring the oxygen saturation by way of a pulse oximeter before and after the 4 working hours. The final analysis was performer on 147 viable questionnaires returned. The sample was composed of 62 males and 85 females with an average age of 42.9 ± 12.0 years. RESULTS: For the entire sample population, the baseline saturation was 98.6 ± 1.2 and, after four hours of mask wearing, there was a significant decrease in oxygen saturation to 97.0 ± 2.9 (p < 0.01). No statistical differences in SpO2 were found across specialties or across types of procedures performed during the 4 h. Heart rates were not significantly different before and after the 4 h in all categories. The 3 most frequent reported complaints were: fatigue (64%), headache (36%) and external ear pain (31%). The most common additional personal protective equipment (PPE) was a mask shield (78%) and those who wore the mask continuously reported more communication difficulty with patients, compared with those who took the mask off more often, in fact, 64% of the subjects reported that using the mask influenced their communication with their patients. Based on the results of the questionnaire, a list of breathing and vocal folds health strategies was devised and proposed, along with strategies to augment communication with patients. CONCLUSIONS: This study highlights a significant decrease in oxygen saturation after only 4 h of work (except for smokers) while wearing a FFP2, and confirms the widespread symptoms of fatigue, headache and pain behind the ears that dental professionals experience. But it also highlighted how mask wearing impaired communication with patients and wearing additional masks and a facial shield may add to those communications difficulties. This aspect and the need for better communication can lead the operators to remove the mask to improve breathing and communication, thus putting themselves at a risk of infection. Of all the aspects explored in this study, the most interesting was indeed the impact on fatigue and communication and the strategies proposed in this article can easily be implemented to reduce headache and fatigue by improving breathing efficiency and by aiding communication while donning a mask by improving voice quality and by using augmentative communication tools.

The Use of Wearable Pulse Oximeters in the Prompt Detection of Hypoxemia and During Movement: Diagnostic Accuracy Study.

BACKGROUND: Commercially available wearable (ambulatory) pulse oximeters have been recommended as a method for managing patients at risk of physiological deterioration, such as active patients with COVID-19 disease receiving care in hospital isolation rooms; however, their reliability in usual hospital settings is not known. OBJECTIVE: We report the performance of wearable pulse oximeters in a simulated clinical setting when challenged by motion and low levels of arterial blood oxygen saturation (SaO2). METHODS: The performance of 1 wrist-worn (Wavelet) and 3 finger-worn (CheckMe O2+, AP-20, and WristOx2 3150) wearable, wireless transmission-mode pulse oximeters was evaluated. For this, 7 motion tasks were performed: at rest, sit-to-stand, tapping, rubbing, drinking, turning pages, and using a tablet. Hypoxia exposure followed, in which inspired gases were adjusted to achieve decreasing SaO2 levels at 100%, 95%, 90%, 87%, 85%, 83%, and 80%. Peripheral oxygen saturation (SpO2) estimates were compared with simultaneous SaO2 samples to calculate the root-mean-square error (RMSE). The area under the receiver operating characteristic curve was used to analyze the detection of hypoxemia (ie, SaO2<90%). RESULTS: SpO2 estimates matching 215 SaO2 samples in both study phases, from 33 participants, were analyzed. Tapping, rubbing, turning pages, and using a tablet degraded SpO2 estimation (RMSE>4% for at least 1 device). All finger-worn pulse oximeters detected hypoxemia, with an overall sensitivity of ≥0.87 and specificity of ≥0.80, comparable to that of the Philips MX450 pulse oximeter. CONCLUSIONS: The SpO2 accuracy of wearable finger-worn pulse oximeters was within that required by the International Organization for Standardization guidelines. Performance was degraded by motion, but all pulse oximeters could detect hypoxemia. Our findings support the use of wearable, wireless transmission-mode pulse oximeters to detect the onset of clinical deterioration in hospital settings. TRIAL REGISTRATION: ISRCTN Registry 61535692; http://www.isrctn.com/ISRCTN61535692. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1136/bmjopen-2019-034404.

Noninvasive Non-Contact SpO2 Monitoring Using an Integrated Polarization-Sensing CMOS Imaging Sensor.

BACKGROUND: In the diagnosis and primary health care of an individual, estimation of the pulse rate and blood oxygen saturation (SpO2) is critical. The pulse rate and SpO2 are determined by methods including photoplethysmography (iPPG), light spectroscopy, and pulse oximetry. These devices need to be compact, non-contact, and noninvasive for real-time health monitoring. Reflection-based iPPG is becoming popular as it allows non-contact estimation of the heart rate and SpO2. Most iPPG methods capture temporal data and form complex computations, and thus real-time measurements and spatial visualization are difficult. METHOD: In this research work, reflective mode polarized imaging-based iPPG is proposed. For polarization imaging, a custom image sensor with wire grid polarizers on each pixel is designed. Each pixel has a wire grid of varying transmission axes, allowing phase detection of the incoming light. The phase information of the backscattered light from the fingertips of 12 healthy volunteers was recorded in both the resting as well as the excited states. These data were then processed using MATLAB 2021b software. RESULTS: The phase information provides quantitative information on the reflection from the superficial and deep layers of skin. The ratio of deep to superficial layer backscattered phase information is shown to be directly correlated and linearly increasing with an increase in the SpO2 and heart rate. CONCLUSIONS: The phase-based measurements help to monitor the changes in the resting and excited state heart rate and SpO2 in real time. Furthermore, the use of the ratio of phase information helps to make the measurements independent of the individual skin traits and thus increases the accuracy of the measurements. The proposed iPPG works in ambient light, relaxing the instrumentation requirement and helping the system to be compact and portable.

Perfusion index as an objective measure of postoperative pain in children undergoing adenotonsillectomy: a cohort study.

Postoperative pain in children is usually undertreated because of their inability to complain. While several pain assessment scales have been developed, they have shortcomings such as subjectivity and being observer-dependent. This study aimed to assess the validity of the perfusion index as an objective measure of postoperative pain in children undergoing adenotonsillectomy. Children aged 3-7 years were enrolled. The Children's Hospital of Eastern Ontario Scale (CHEOPS) was used to assess postoperative pain. The perfusion index was measured at the same time intervals as CHEOPS. The highest CHEOPS before rescue analgesia was administered and CHEOPS when the patients became pain-free were recorded with the corresponding perfusion index. The primary outcome was the correlation between the postoperative CHEOPS and the corresponding postoperative perfusion index. The secondary outcomes were the ability of perfusion index changes to predict the presence of postoperative pain and patients' response to analgesics. The postoperative perfusion index was negatively correlated with CHEOPS at 30 and 90 min postoperatively. The change in the preoperative baseline perfusion index (ΔPI-pre) was moderately correlated with the highest CHEOPS (CHEOPS-1) (r = 0.61, p = 0.001). The change in the postoperative perfusion index (ΔPI-po) was negatively correlated with the change in the CHEOPS (ΔCHEOPS) (r = - 0.53, P = 0.0001). The ΔPI-pre was an excellent predictor of postoperative pain (AUROC 0.83 with 71% sensitivity, 83% specificity, and a cut-off value of ≥ 0.26). The perfusion index is a good objective measure for predicting the presence of postoperative pain in children undergoing adenotonsillectomy under general anesthesia. Trial registration: ClinicalTrials.gov; ID: (NCT03854604) registered on February 2019.

Laboratory evaluation of performance of pulse oximeters from six different manufacturers during motion artifacts produced by Fluke 2XL SpO2 simulator.

We performed laboratory evaluation of six pulse oximeters from different manufacturers using the Fluke 2XL SpO2 simulator. The pulse oximeter probes were labeled 1 through 6 and tested using the two pre-programed preset functions of the Fluke 2XL SpO2 simulator, level 01 and level 02, for their performance in the presence of motion artifacts. The pulse oximeters were also tested at low perfusion index (PI) settings. The accuracy of the individual probes was ranked as good, mediocre, or poor based on the degree of deviation of the measured SpO2 and pulse rate (PR) by the probes from that generated by the simulator in both the presence and absence of motion artifacts and at lower PI. In preset level 01, probes numbered 1, 2, and 6 performed flawlessly, probes numbered 3, 4, and 5 performed poorly. In preset level 02, all probes performed well in the absence of motion artifacts. When probes were attached in the absence of motion, but readings were recorded after the emergence of motion artifacts, probes 1, 2, and 6 continued to perform well. However, the performance of probes 3, 4, and 5 deteriorated. When probes were attached directly in the presence of motion artifacts, probes 2 and 6 performed well, whereas all other probes performed poorly. Successively lowering the PI degraded performance of probes 3, 4, and 5 at extremely low PI. It is observed that during motion and/or low PI conditions, multiple probes see deterioration in performance.

Influence of cuff pressures of automatic sphygmomanometers on pulse oximetry measurements.

Information about blood arterial oxygen saturation (SpO2) is crucial in critical care settings or home health monitoring during the COVID-19 pandemic. Also, we need to identify the factors that affect the SpO2 measurement. In this paper, the effect of compression of the cuff during noninvasive blood pressure (NIBP) measurement on the SpO2 results was investigated. A custom-made system was used for simultaneous measurement of NIBP and SpO2. The study was conducted on 213 subjects aged between 21 and 93, with a systolic blood pressure of (94 to 194) mmHg, diastolic blood pressure of (52-98) mmHg, and 994 NIBP readings were used for the analysis. During the NIBP measurement, momentary changes in SpO2 can reach ±17% and are in most cases positive (mean 2.9%). The change was not correlated with sex, age, height, body weight, BMI, HR and blood pressure. The obtained results show that frequent NIBP measurements may lead to wrong conclusions about SpO2. In our study, pressure measurements mainly caused the increase of blood oxygenation level.

"Oxygen Pheriwala:" An innovative model for SARS-CoV-2 screening in resource-limited settings.

The second wave of SARS-CoV-2 infection came as a hypoxic emergency and situation became worse in rural India, where undiagnosed COVID-19 patients died without any diagnosis or intervention. The primary aim of this innovative model was the early diagnosis of suspected SARS-CoV-2 cases, providing empirical treatment and timely referral to appropriate COVID care facilities. Fever was measured with infrared thermometer and oxygen saturation level with pulse oximeter. A total of 8203 people were screened, of which 274 persons were febrile and 69 (25%) were hypoxic too. Sixty-four out of 69 (93%) patients turned COVID-19 positive on reverse transcription-polymerase chain reaction. At the end of 3 weeks, 48/64 (75%) patients were successfully discharged. This model can be easily implemented in resource-limited regions to identify and prioritize the patients not only in this pandemic but also in outbreak of other communicable diseases.

Validation of the Withings ScanWatch as a Wrist-Worn Reflective Pulse Oximeter: Prospective Interventional Clinical Study.

BACKGROUND: A decrease in the level of pulse oxygen saturation as measured by pulse oximetry (SpO2) is an indicator of hypoxemia that may occur in various respiratory diseases, such as chronic obstructive pulmonary disease (COPD), sleep apnea syndrome, and COVID-19. Currently, no mass-market wrist-worn SpO2 monitor meets the medical standards for pulse oximeters. OBJECTIVE: The main objective of this monocentric and prospective clinical study with single-blind analysis was to test and validate the accuracy of the reflective pulse oximeter function of the Withings ScanWatch to measure SpO2 levels at different stages of hypoxia. The secondary objective was to confirm the safety of this device when used as intended. METHODS: To achieve these objectives, we included 14 healthy participants aged 23-39 years in the study, and we induced several stable plateaus of arterial oxygen saturation (SaO2) ranging from 100%-70% to mimic nonhypoxic conditions and then mild, moderate, and severe hypoxic conditions. We measured the SpO2 level with a Withings ScanWatch on each participant's wrist and the SaO2 from blood samples with a co-oximeter, the ABL90 hemoximeter (Radiometer Medical ApS). RESULTS: After removal of the inconclusive measurements, we obtained 275 and 244 conclusive measurements with the two ScanWatches on the participants' right and left wrists, respectively, evenly distributed among the 3 predetermined SpO2 groups: SpO2≤80%, 80%

Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry.

Calculation of peripheral capillary oxygen saturation [Formula: see text] levels in humans is often made with a pulse oximeter, using photoplethysmography (PPG) waveforms. However, measurements of PPG waveforms are susceptible to motion noise due to subject and sensor movements. In this study, we compare two [Formula: see text]-level calculation techniques, and measure the effect of pre-filtering by a heart-rate tuned comb peak filter on their performance. These techniques are: (1) "Red over Infrared," calculating the ratios of AC and DC components of the red and infrared PPG signals,[Formula: see text], followed by the use of a calibration curve to determine the [Formula: see text] level Webster (in: Design of pulse oximeters, CRC Press, Boca Raton, 1997); and (2) a motion-resistant algorithm which uses the Discrete Saturation Transform (DST) (Goldman in J Clin Monit Comput 16:475-83, 2000). The DST algorithm isolates individual "saturation components" in the optical pathway, which allows separation of components corresponding to the [Formula: see text] level from components corresponding to noise and interference, including motion artifacts. The comparison we provide here (employing the two techniques with and without pre-filtering) addresses two aspects: (1) accuracy of the [Formula: see text] calculations; and (2) computational complexity. We used both synthetic data and experimental data collected from human subjects. The human subjects were tested at rest and while exercising; while exercising, their measurements were subject to the impacts of motion. Our main conclusion is that if an uninterrupted high-quality heart rate measurement is available, then the "Red over Infrared" approach preceded by a heart-rate tuned comb filter provides the preferred trade-off between [Formula: see text]-level accuracy and computational complexity. A modest improvement in [Formula: see text] estimate accuracy at very low SNR environments may be achieved by switching to the pre-filtered DST-based algorithm (up to 6% improvement in [Formula: see text] level accuracy at -10 dB over unfiltered DST algorithm and the filtered "Red over Infrared" approach). However, this improvement comes at a significant computational cost.

The Effect of Nail Polish and Henna on the Measures of Pulse Oximeters in Healthy Persons.

PURPOSE: The aim of the study was to determine the effects of nail polish and henna on pulse oximetry measurements in healthy individuals. METHODS: The study was designed as quasi-experimental and cross-sectional study. The population consisted of 682 women studying in a university's nursing department in the Mediterranean region during the academic year of 2016 to 2017. The sample consisted of 103 female students who agreed to participate in the study and met the inclusion criteria. The data were collected using a personal information form prepared in light of the literature. A single layer of nail polish of the same brand was applied; white on the thumb, red on the ring finger, and black on the little finger of the left hand, while henna was applied on the index finger of the left hand of the students. The middle finger was considered as the control group. A portable Nellcor (N-65) pulse oximeter was used for oxygen saturation measurements. The data were analyzed using means, SD, and paired-samples t test. FINDINGS: There was no statistically significant difference between oxygen saturation measurements of fingers with henna and red nail polish and the control finger (P > .05). However, oxygen saturation levels of fingers with black and white nail polish were lower than the control group's levels, and the difference was statistically significant (P < .05). CONCLUSIONS: The results demonstrated that white and black nail polish had an impact on oxygen saturation measurements, whereas henna and red nail polish had no effect on the measurements. Based on these findings, nurses may be advised to remove patients' nail polish before measuring oxygen saturation using the finger. In addition, conducting new studies investigating the effects of nail polish, henna, and false nails, which are increasingly used today, on SpO2 values, is suggested.