Pulse Oximeter Research Articles

Finger photopletysmography detects early acute blood loss in compensated blood donors: a pilot study.

Diagnosis of incipient acute hypovolemia is challenging as vital signs are typically normal and patients remain asymptomatic at early stages. The early identification of this entity would affect patients' outcome if physicians were able to treat it precociously. Thus, the development of a noninvasive, continuous bedside monitoring tool to detect occult hypovolemia before patients become hemodynamically unstable is clinically relevant. We hypothesize that pulse oximeter's alternant (AC) and continuous (DC) components of the infrared light are sensitive to acute and small changes in patient's volemia. We aimed to test this hypothesis in a cohort of healthy blood donors as a model of slight hypovolemia. We planned to prospectively study blood donor volunteers removing 450 mL of blood in supine position. Noninvasive arterial blood pressure, heart rate, and finger pulse oximetry were recorded. Data was analyzed before donation, after donation and during blood auto-transfusion generated by the passive leg-rising maneuver. Sixty-six volunteers (44% women) accomplished the protocol successfully. No clinical symptoms of hypovolemia, arterial hypotension (systolic pressure <90 mmHg), brady-tachycardia (heart rate <60 and >100 beats-per-minute) or hypoxemia (SpO2 <90%) were observed during donation. The AC signal before donation (median 0.21 and interquartile range 0.17 a.u.) increased after donation [0.26(0.19) a.u; p<0.001]. The DC signal before donation [94.05(3.63) a.u] increased after blood extraction [94.65(3.49) a.u; p<0.001]. When the legs' blood was auto-transfused during the passive leg-rising, the AC [0.21(0.13) a.u.; p=0.54] and the DC [94.25(3.94) a.u.; p=0.19] returned to pre-donation levels. &#xD;Significance. The AC and DC components of finger pulse oximetry changed during blood donation in asymptomatic volunteers. The continuous monitoring of these signals could be helpful in detecting occult acute hypovolemia. New pulse oximeters should be developed combining the AC/DC signals with a functional hemodynamic monitoring of fluid responsiveness to define which patient needs fluid administration.&#xD.

Examining Oxygen Saturation and Peak Volume Correlation in Respiratory Disorders: A Study at PCM/PCA Ciledug

Examining Oxygen Saturation and Peak Volume Correlation in Respiratory Disorders: A Study at PCM/PCA Ciledug

Smart Health Monitoring with Power-Aware IoT Using a Wireless Body Area Network

Smart health monitoring systems have become increasingly popular in recent years due to the growth of the Internet of Things (IoT) technology and its applications in healthcare. This project proposes an IoT-based smart health monitoring system that utilises an ESP32 Microcontroller, MAX30100 Pulse Oximeter Heart Rate Sensor Module, MLX90614 ESF Non-Contact Human Body Infrared Temperature Measurement Module, LCD 16*2, 3.7v 2000mAh Lithium Battery, TP4056 1A Li-Ion Lithium Battery charging Module, and some buttons. The system is designed to monitor the user's heart rate, blood oxygen level, and body temperature in real-time and display the readings on an LCD screen as well as an IoT web page. The project aims to provide an affordable, portable, and user-friendly smart health monitoring solution that can be used at home, in hospitals, or other healthcare settings. The project methodology involved a combination of hardware and software components, including circuit design and programming using the Arduino IDE. The system was tested and evaluated for its performance, accuracy, and usability using a sample population. The results showed that the system was effective in monitoring the user's vital signs and displaying the readings in real-time. The system was found to be accurate and reliable, with a high level of user satisfaction and ease of use. Overall, the IoT-based smart health monitoring system proposed in this project has significant implications for healthcare, particularly in terms of remote monitoring, telemedicine, and personalised healthcare. The system has the potential to improve patient outcomes, reduce healthcare costs, and increase access to healthcare services. The project also highlights the potential of IoT technology in healthcare and the need for further research and development in this area

Evaluation of novel indices of walking performance taking oxygen desaturation into account during six-minute walk test in cardiovascular disease patients.

In pulmonary disease patients since oxygen desaturation during 6-min walk test (6MWT) affects walk distance (6MWD), some novel indices such as desaturation/distance ratio [DDR, oxygen desaturation area (DAO2)/6MWD] and distance-saturation product [DSP, 6MWD × minimum peripheral oxygen saturation (SpO2)] are evaluated. However, there has been no study examining these indices that consider exercise-induced desaturation (EID) in patients with cardiovascular disease. In 94 cardiovascular disease patients without pulmonary complications, 6MWT and echocardiography were performed at the entry of cardiac rehabilitation. SpO2 was measured during 6MWT using a continuously monitorable pulse oximeter, and DSP and DDR were calculated using minimum SpO2 and DAO2 [sum of (100-SpO2) per second during 6MWT], respectively. EID was defined as SpO2 decrease of ≥ 4% or minimum SpO2 of < 90% during 6MWT. DSP was slightly lower and DDR was markedly higher in patients with EID than in those without. When examining correlations of DSP and DDR with their components, DSP was correlated with 6MWD much closely than minimum SpO2, while DDR was correlated as closely with DAO2 as 6MWD. Furthermore, DAO2, but not minimum SpO2, had a direct correlation with 6MWD. As for associations with cardiac function, DSP was correlated with several cardiac parameters, but DDR was not correlated with any of these parameters. Our findings suggest that oxygen desaturation during 6MWT affects walking distance in cardiovascular disease patients even without pulmonary complications and that DDR is more appropriate than DSP as an index of walking performance that takes EID into consideration, independently of cardiac function.

Transcutaneous Discrimination of Fetal Heart Rate from Maternal Heart Rate: A Fetal Oximetry Proof-of-Concept.

Intrapartum care uses electronic fetal heart rate monitoring (EFHRM) for over 50years to indirectly assess fetal oxygenation. However, this approach has been associated with an increase in cesarean delivery rates and limited improvements in neonatal hypoxic outcome. To address these shortcomings, a novel transabdominal fetal pulse oximeter (TFO) is being developed to provide an objective measurement of fetal oxygenation. Previous studies have evaluated the performance of TFO on pregnant ewe. Building on the animal model, this study aims to determine whether TFO can successfully capture human fetal heart rate (FHR) signals during non-stress testing (NST) as a proof-of-concept. Eight ongoing pregnancies meeting specific inclusion criteria (18-40years old, singleton, and at least 36weeks' gestation) were enrolled with consent. Each study session was 15 to 20min long. Reference maternal heart rate (MHR) and FHR were obtained using finger pulse oximetry and cardiotocography for subsequent comparison. The overall root-mean-square error was 9.7BPM for FHR and 4.4 for MHR, while the overall mean-absolute error was 7.6BPM for FHR and 1.8 for MHR. Bland-Altman analysis displayed a mean bias ± standard deviation between TFO and reference of -3.9 ± 8.9BPM, with limits of agreement ranging from -21.4 to 13.6 BPM. Both maternal and fetal heart rate measurements obtained from TFO exhibited a p-value < 0.001, showing significant correlation with the reference. This proof-of-concept study successfully demonstrates that TFO can accurately differentiate maternal and fetal heart signals in human subjects. This achievement marks the initial step towards enabling fetal oxygen saturation measurement in humans using TFO.

Revolutionizing Heart Monitoring with Oximetry

Innovative medical gadgets are now critically needed to monitor and analyze the situation, especially in light of the COVID-19 pandemic. In light of this, a portable, affordable, IOT-based heart rate and SpO2/level sensor device with effective performance has been developed. In order to publish data to a software web page and display data on the OLED, the suggested system has an integrated LED with basic internet access. Its mobility, user-friendliness, and distinctive method of sending collected data are its key qualities. data online, enabling it to perform better than the solutions that are currently on offer in a number of ways. The project is designed in such a way that the analogue quantities which are to be recorded continuously are taken and converted into corresponding digital values using a six-channel ADC. Here we consider temperature and monitor the heart rate. The processed data from ADC is sent to the microcontroller. With the help of a six-channel ADC, the project's architecture transforms the analogue numbers that must be continuously recorded into equivalent digital values. Here, we keep an eye on the heart rate and take the temperature into account. The microcontroller receives the data from the ADC that has been processed. The microcontroller is designed to continuously monitor the status of the sensors. To transfer sensor data to the server web page in the form of a database, the microcontroller and the Wifi Module will be interfaced using serial connection. Monitoring physiological data, such as electrocardiogram (ECG) signals, offers a new avenue for ease of control and prevention in modern healthcare. Consequently, a new era of proactive, intelligent healthcare would emerge—especially considering the major barrier of scarce medical resources. It was shown how to use a mobile ECG monitoring service hosted in the cloud. With the use of a pulse oximeter and a wireless transmission method like WI-FI, these may identify ECG signals and display them on a screen. IOT based on ECG monitoring has been the subject of various works.

Hospital Environmental Factors That Influence Peripheral Oxygen Saturation Measurements: A Cross-Sectional Study.

Pulse oximetry is a non-invasive, cost-effective, and generally reliable instrument measuring pulse rate and peripheral oxygen saturation (SpO2). However, these measurements can be affected by the patient's internal or external factors, including the type of pulse oximeter device (POD). (1) This study's objective was to identify potential environmental factors that may impact the measurements taken by three PODs. (2) Methods: A descriptive-analytical cross-sectional study was designed. The patients' SpO2 levels were measured using a standard monitor and two PODs owned by the professionals. The measurements were taken on the patients' fingers. Concurrently, we evaluated the surrounding environmental conditions, encompassing temperature, humidity, illuminance, and noise. (3) Results: This study involved 288 adult participants in the sample. For each 20-decibel increment in noise, there was a reduction in SpO2 by an average of 1%, whereas for every additional degree of ambient temperature, SpO2 decreased by an average of 2% (4) Conclusions: Significant correlations between SpO2 and age, as well as with noise and ambient temperature, were observed. No significant differences between oxygen saturation and lighting or humidity were observed. This study was prospectively registered with the Clinical Research Ethics Committee of Gran Canaria at the Dr. Negrín University Hospital, with protocol code 2019-247-1, and approved on 24 May 2019.

Neonatal Resuscitation Practices in Portuguese Delivery Rooms: A Cross-Sectional Study.

Data from previous studies have demonstrated inconsistency between current evidence and delivery room resuscitation practices in developed countries. The primary aim of this study was to assess the quality of newborn healthcare and resuscitation practices in Portuguese delivery rooms, comparing current practices with the 2021 European Resuscitation Council guidelines. The secondary aim was to compare the consistency of practices between tertiary and non-tertiary centers across Portugal. An 87-question survey concerning neonatal care was sent to all physicians registered with the Portuguese Neonatal Society via email. In order to compare practices between centers, participants were divided into two groups: Group A (level III and level IIb centers) and Group B (level IIa and I centers). A descriptive analysis of variables was performed in order to compare the two groups. In total, 130 physicians responded to the survey. Group A included 91 (70%) and Group B 39 (30%) respondents. More than 80% of participants reported the presence of a healthcare professional with basic newborn resuscitation training in all deliveries, essential equipment in the delivery room, such as a resuscitator with a light and heat source, a pulse oximeter, and an O2 blender, and performing delayed cord clamping for all neonates born without complications. Less than 60% reported performing team briefing before deliveries, the presence of electrocardiogram sensors, end-tidal CO2 detector, and continuous positive airway pressure in the delivery room, and monitoring the neonate's temperature. Major differences between groups were found regarding staff attending deliveries, education, equipment, thermal control, umbilical cord management, vital signs monitoring, prophylactic surfactant administration, and the neonate's transportation out of the delivery room. Overall, adherence to neonatal resuscitation international guidelines was high among Portuguese physicians. However, differences between guidelines and current practices, as well as between centers with different levels of care, were identified. Areas for improvement include team briefing, ethics, education, available equipment in delivery rooms, temperature control, and airway management. The authors emphasize the importance of continuous education to ensure compliance with the most recent guidelines and ultimately improve neonatal health outcomes.

ASA Continues Push to Identify Role of Skin Tone in Pulse Oximeter Performance

ASA Continues Push to Identify Role of Skin Tone in Pulse Oximeter Performance

Use of an Artificial Intelligence Device for Evaluating Blood Loss in Complex Major Orthopaedic Surgery Procedures

BackgroundAn artificial intelligence algorithm that analyzes the pulse oximeter waveform in the fingertip can be used to determine the compensatory reserve index (CRI) in trauma patients. This measurement shows the remaining cardiovascular capacity and is known to be more specific and sensitive in detecting blood loss than are routine vital signs. We hypothesized that the CRI measurement could predict loss of reserve cardiovascular capacity in patients undergoing major orthopaedic surgery, and therefore could help in their management. MethodsA total of 304 patients undergoing lower extremity arthroplasty consented to participate in waveform monitoring. Pulse oximeter waveforms were sensed with a fingertip probe and processed with a tablet computer that remained with the patient during surgery and recovery in the hospital. The CRI, systolic blood pressure (SBP), and heart rate (HR) were evaluated throughout the postoperative period. ResultsThe CRI measurement identified a group of patients who were significantly more likely to require transfusions and emergency medical care (P = 0.000021). Patients who had morbid obesity were especially likely to have low CRI results and a high percentage of clinical events. A CRI of 0.40 or higher was evaluated retrospectively as the criterion for withholding transfusion in 54 patients, but that group had a significantly higher incidence of transfusion later in treatment than did the cohort as a whole. The SBP and HR were not useful in predicting the need for transfusion until late in treatment. ConclusionsThis study suggests that the CRI measurement can identify patients at risk for transfusion and the need for urgent medical care and may aid in the management of blood loss and transfusion in major orthopaedic surgery.

IOT Based Remote Patient Monitoring System

Abstract: A remote monitoring technique that can accurately track human physiological indicators has applications in virtual reality, sports science, medicine, rehabilitation, and surveillance. The majority of systems now in use for tracking bodily parameters in humans need wiring that limits natural movement. In order to get over this restriction, a wearable wireless sensor network that monitors physiological human body characteristics has been built using an accelerometer, a pulse oximeter, a heart-rate sensor, a temperature sensor, and a galvanic skin response sensor. The individual is being tracked wirelessly using his own location. It would be simple to modify this system to watch athletes and young children. Unlike a tethered monitoring equipment, the wireless feature allows the human body to move freely, making the system genuinely portable, quick, and dependable. The portable and the designed sensor node's small size makes it simple to attach to the body.

E Wheel: A Smart Wheelchair

Abstract: In this project, we propose the development of an innovative smart electric wheelchair tailored to address the needs of individuals with mobility impairments. The primary objective is to enhance their quality of life and promote independence through the integration of cutting-edge technologies. The wheelchair's standout feature lies in its incorporation of advanced control mechanisms, notably head gesture control. This intuitive navigation system allows users to maneuver the wheelchair effortlessly, while also offering joystick controls. Furthermore, the wheelchair integrates a pulse oximeter sensor, enabling realtime health monitoring. This functionality is crucial for individuals with mobility impairments who may require continuous monitoring of vital signs such as oxygen saturation and heart rate. The inclusion of Blink facilitates remote monitoring and caregiver alerts, providing peace of mind to both users and their caregivers. Safety is paramount in the design of this wheelchair. To ensure safe navigation in various environments, the wheelchair is equipped with obstacle detection and protection mechanisms.

Efficacy of pulmonary telerehabilitation on exercise tolerance, fatigue, perceived exertion, depression, and quality of life in COVID-19 survivors

INTRODUCTION: Telerehabilitation advanced significantly with the emergence of COVID-19 and the recommendation of limiting physiotherapist-patient contact time whenever practicable. The effectiveness of telerehabilitation on those who had a longer stay in hospital and on oxygen support following discharge is still under question. OBJECTIVES: To evaluate the effects after six weeks of pulmonary telerehabilitation on exercise tolerance, fatigue level, perceived exertion, symptoms of depression and quality of life in patients surviving COVID-19. MATERIALS AND METHODS: A quasi-experimental study was conducted on 25 post-COVID-19 patients following discharge in a home environment setting. The participants were advised to prepare equipment such as oxygen concentrator, B-type oxygen cylinder (backup), lengthy oxygen tubes, finger pulse oximeter, mini static pedal exerciser, incentive spirometry, weight cuffs or water bottles and sandbags. After six weeks of telerehabilitation, the patients underwent assessments including initial oxygen saturation (SPO2), heart rate, peak oxygen demand during exercise to maintain baseline SPO2, peak heart rate, maximum drop in SPO2, recovery time to baseline SPO2 measured with a pulse oximeter and stopwatch, peak perceived exertion using the Borg Dyspnea Scale, peak fatigue score using the visual analog scale (VASF), quality of life assessed with the SF-36 questionnaire, and mental health status evaluated with the Hamilton Depression Scale (HAMD). One-way repeated measure ANOVA and paired t-test were used. RESULTS: Significant improvements following the intervention on the initial SPO2 (F (2.12, 23.13) = 21.0, p&lt;0.05) and heart rate (F (1.839, 20.23) = 43.73, p&lt;0.05), peak maximum oxygen demand during exercise to maintain baseline SPO2 (F (1.487, 16.36) = 8.96, p&lt;0.05), peak maximum perceived exertion (F (5, 55) = 112.51, p&lt;0.05), peak maximum fatigue score (F (1.755, 19.30) = 67.44, p&lt;0.05), peak heart rate (F (1.798, 19.78) = 50.99, p&lt;0.05), peak drop in SPO2 (F (2.467, 27.14) = 41.46, p&lt;0.05) and peak recovery time to achieve baseline SPO2 (F (5, 55) = 78.89, p&lt;0.05). Six-week post-analysis on the depressive symptoms (mean difference =11.25, p&lt; 0.05) and quality of life also showed significant improvement (mean difference =29.92, p&lt; 0.05). CONCLUSION: Six weeks of comprehensive pulmonary telerehabilitation with simple equipment improved tolerance to exercise, fatigue, perceived exertion, symptoms of depression and quality of life for post-COVID-19 patients.

Pulse oximeter bench tests under different simulated skin tones.

Pulse oximeters' (POs) varying performance based on skin tones has been highly publicised. Compared to arterial blood gas analysis, POs tend to overestimate oxygen saturation (SpO2) values for people with darker skin (occult hypoxemia). The objective is to develop a test bench for assessing commercial home and hospital-based POs in controlled laboratory conditions. A laboratory simulator was used to mimic different SpO2 values (~ 70 to 100%).Different neutral density and synthetic melanin filters were used to reproduce low signal and varying melanin attenuation levels. Six devices consisting of commercial home (Biolight, N = 13; ChoiceMMed, N = 18; MedLinket, N = 9) and hospital-based (Masimo Radical 7 with Neo L, N = 1; GE B450 Masimo SET with LNCS Neo L, N = 1; Nonin 9550 Onyx II™, N = 1) POs were reviewed and their response documented. Significant variations were observed in the recorded SpO2 values among different POs when exposed to identical simulated signals. Differences were greatest for lower SpO2 (< 80%) where empirical data is limited. All PO responses under low signal and melanin attenuation did not change across various simulated SpO2 values. The bench tests do not provide conclusive evidence that melanin does not affect in vivo SpO2 measurements. Research in the areas of instrument calibration, theory and design needs to be further developed.

Development of a Web-Based Oxygenation Dashboard for Preterm Neonates: A Quality Improvement Initiative

Background: Preterm neonates are extensively monitored to require strict oxygen target attainment for optimal outcomes. In daily practice, detailed oxygenation data are hardly used and crucial patterns may be missed due to the snapshot presentations and subjective observations. This study aimed to develop a web-based dashboard with both detailed and summarized oxygenation data in real-time and to test its feasibility to support clinical decision making. Methods: Data from pulse oximeters and ventilators were synchronized and stored to enable real-time and retrospective trend visualizations in a web-based viewer. The dashboard was designed based on interviews with clinicians. A preliminary version was evaluated during daily clinical rounds. The routine evaluation of the respiratory condition of neonates (gestational age < 32 weeks) with respiratory support at the NICU was compared to an assessment with the assistance of the dashboard. Results: The web-based dashboard included data on the oxygen saturation (SpO2), fraction of inspired oxygen (FiO2), SpO2/FiO2 ratio, and area < 80% and > 95% SpO2 curve during time intervals that could be varied. The distribution of SpO2 values was visualized as histograms. In 65% of the patient evaluations (n = 86) the level of hypoxia was assessed differently with the use of the dashboard. In 75% of the patients the dashboard was judged to provide added value for the clinicians in supporting clinical decisions. Conclusions: A web-based customized oxygenation dashboard for preterm neonates at the NICU was developed and found feasible during evaluation. More clear and objective information was found supportive for clinicians during the daily rounds in tailoring treatment strategies.

Assessment of fluid infusion rate using a pulse oximeter: a pilot study.

Assessment of fluid infusion rate using a pulse oximeter: a pilot study.

Advances in pediatric anesthesia services over the past 10 years in French-speaking sub-Saharan Africa.

To improve and maintain quality and safety in anesthesia, standards have been proposed regarding human resources, facilities and equipment, medications and intravenous fluids, monitoring, and the conduct of anesthesia. Compliance with these standards remains a challenge in French-speaking sub-Saharan Africa (SSA) and results in high morbidity and mortality particularly in children. This aim of this study was to assess the progress made in improving the pediatric anesthesia infrastructures, human resources, education, medications, and equipment in French-speaking SSA over the past 10 years (2013-2022). This is a descriptive, multicenter, cross-sectional study with retrospective data collection, conducted from September 1 to November 5, 2023. Comparative data from 2012 to 2022 were collected through an online survey. Descriptive statistics were used to summarize data. Data were obtained from 12 countries out of 14. The number of hospitals providing pediatric surgery and anesthesia rose from 94 in 2012 to 142 in 2022 (+51%). The total number of physician anesthesiologists rose from 293 (0.1 physician anesthesiologists/100 000 inhabitants) in 2012 to 597 (0.2 physician anesthesiologists/100 000 inhabitants) in 2022 (+103.7%). Five (0.006 physician anesthesiologists/100 000 children) had completed a fellowship in pediatric anesthesia and intensive care in 2012, and 15 (0.01 physician anesthesiologists/100 000 children) in 2022 (+200%). Five physician anesthesiologists had an exclusive pediatric anesthesia practice in 2012, whereas they were 32 in 2022 (+540%). There is no specialized training in pediatric anesthesia and intensive care in any of these countries. Halothane was always available in 81.5% of the hospitals in 2012, and in 50.4% of the hospitals in 2022. Sevoflurane was always available in 5% of the hospitals in 2012, and in 36.2% in 2022. Morphine was always available in 32.2% in 2012, whereas it was available in 52.9% of them in 2022. Pediatric pulse oximeter sensors were available in 36% of the hospitals in 2012, and in 63.4% in 2022. Capnography was available in 5.3% of the hospitals in 2012, and in 48% in 2022. Progress have been made over the last 10 years in French-speaking SSA to improve infrastructures, human resources, education, medications, and equipment for pediatric anesthesia in French-speaking SSA. However, major efforts must be continued. Standards adapted to the local context should be formulated.

A Bayesian Reanalysis of the Overall and Sex-Disaggregated Results of the Neonatal Oxygenation Prospective Meta-Analysis (NeOProM)

Data from the Neonatal Oxygenation Prospective Meta-analysis (NeOProM) indicate that targeting a higher (91–95%) versus lower (85–89%) pulse oximeter saturation (SpO2) range may reduce mortality and necrotizing enterocolitis (NEC) and increase retinopathy of prematurity (ROP). Aiming to re-evaluate the strength of this evidence, we conducted a Bayesian reanalysis of the NeOProM data. We used Bayes factors (BFs) to evaluate the likelihood of the data under the combination of models assuming the presence vs. absence of effect, heterogeneity, and moderation by sex. The Bayesian reanalysis showed moderate evidence in favor of no differences between SpO2 targets (BF10 = 0.30) in death or major disability, but moderate evidence (BF10 = 3.60) in favor of a lower mortality in the higher SpO2 group. Evidence in favor of differences was observed for bronchopulmonary dysplasia (BPD) (BF10 = 14.44, lower rate with lower SpO2), severe NEC (BF10 = 9.94), and treated ROP (BF10 = 3.36). The only outcome with moderate evidence in favor of sex differences was BPD. This reanalysis of the NeOProM trials confirmed that exposure to a lower versus higher SpO2 range is associated with a higher mortality and risk of NEC, but a lower risk of ROP and BPD. The Bayesian approach can help in assessing the strength of evidence supporting clinical decisions.

Hemodynamic Bedside Monitoring Instrument with Pressure and Optical Sensors: Validation and Modality Comparison.

Results from two independent clinical validation studies for measuring hemodynamics at the patient's bedside using a compact finger probe are reported. Technology comprises a barometric pressure sensor, and in one implementation, additionally, an optical sensor for photoplethysmography (PPG) is developed, which can be used to measure blood pressure and analyze rhythm, including the continuous detection of atrial fibrillation. The capabilities of the technology are shown in several form factors, including a miniaturized version resembling a common pulse oximeter to which the technology could be integrated in. Several main results are presented: i) the miniature finger probe meets the accuracy requirements of non-invasive blood pressure instrument validation standard, ii) atrial fibrillation can be detected during the blood pressure measurement and in a continuous recording, iii) a unique comparison between optical and pressure sensing mechanisms is provided, which shows that the origin of both modalities can be explained using a pressure-volume model and that recordings are close to identical between the sensors. The benefits and limitations of both modalities in hemodynamic monitoring are furtherdiscussed.

Validation of Polar ElixirTM Pulse Oximeter against Arterial Blood Gases during Stepwise Steady State Inspired Hypoxia.

The purpose of this study was to evaluate the accuracy of peripheral oxygen saturation (SpO2) measurements from Polar ElixirTM pulse oximetry technology compared to arterial oxygen saturation (SaO2) measurements during acute stepwise steady state inspired hypoxia at rest. A post hoc objective was to determine if SpO2 measurements could be improved by recalibrating the Polar ElixirTM algorithm with SaO2 values from a random subset of participants. The International Organization for Standardization (ISO) protocol (ISO 80601-2-61:2017) for evaluating the SpO2 accuracy of pulse oximeter equipment was followed whereby five plateaus of SaO2 between 70-100% were achieved using stepwise reductions in inspired O2 during supine rest. Blood samples drawn through a radial arterial catheter from 25 participants were first used to compare SaO2 to SpO2 measurements from Polar ElixirTM. Then the Polar ElixirTM algorithm was recalibrated using SaO2 data from 13 random participants and SpO2 estimates were recalculated for the other 12 participants. For SaO2 values between 70-100%, root mean square error (RMSE), intraclass correlations (ICC), Pearson correlations, and Bland-Altman plots were used to assess the accuracy, agreement, and strength of relationship between SaO2 values and SpO2 values from Polar ElixirTM. The initial RMSE for Polar ElixirTM was 4.13%. After recalibrating the algorithm, the RMSE was improved to 2.67%. The ICC revealed excellent levels of agreement between SaO2 and Polar ElixirTM SpO2 values both before (ICC(3,1) = 0.837, df = 574, p < 0.001) and after (ICC(3,1) = 0.942, df = 287, p < 0.001) recalibration. Relative to ISO standards, Polar ElixirTM yielded accurate SpO2 measurements during stepwise inspired hypoxia at rest when compared to SaO2 values, which were improved by recalibrating the algorithm using a subset of the SaO2 data.