Measurement Of Oxygen Saturation Research Articles

European ILD registry algorithm for self-assessment in interstitial lung diseases (eurILDreg ASA-ILD).

Predicting progression and prognosis in Interstitial Lung Diseases (ILD), especially Idiopathic Pulmonary Fibrosis (IPF) and Progressive Pulmonary Fibrosis (PPF), remains a challenge. Integrating patient-centered measurements is essential for earlier and safer detection of disease progression. Home monitoring through e-health technologies, such as spirometry and oximetry connected to smartphone applications, holds promise for early detection of ILD progression or acute exacerbations, enabling timely therapeutic interventions. The European ILD Registry Algorithm for Self-Assessment in ILD (eurILDreg ASA-ILD), developed by all eurILDreg principal investigators, includes questionnaires on symptom burden, respiratory infections, and quality of life (EQ5D VAS, K-BILD, LCQ). The algorithm also incorporates spirometry and oxygen saturation measurements, both at rest and during exercise (one-minute sit-to-stand test, 1STST). This ASA-ILD algorithm is integrated into the patientMpower Ltd. smartphone application, used for patient-led monitoring, research, and clinical care since 2016, and available on both Apple and Android platforms. For patient-centered measurements, participants in the multicenter eurILDreg study will receive a patientMpower account, a handheld clinical-grade spirometer (Spirobank Smart, MIR, Italy), and a pulse oximeter (Nonin Medical, Inc. Plymouth, MN, USA), along with usage instructions. Artificial intelligence software (ArtiQ) will analyze spirometry maneuvers in real-time, ensuring compliance with recentERS/ATS criteria and providing automated feedback. Pulse oximetry is integrated into the exercise testing within the application, following an automated in-app protocol developed with clinician involvement for safety and accuracy. The application will send reminders to participants to complete patient-reported outcome measures (PROMs) according to the study protocol. This study is designed to explore the potential of e-Health technologies, such as home monitoring via spirometry and oximetry, integrated with the eurILDreg ASA-ILD algorithm and patientMpower app, to improve early detection and management of ILD. A pilot trial showed promising adherence to spirometry, indicating that digital health interventions could enhance patient care and outcomes in ILD. The ethics committee of the Justus-Liebig-University of Giessen has approved the eurILDreg and this substudy with the protocol reference number 111/08. The research was conducted strictly according to the principles of the Declaration of Helsinki. Patients were included into the registry upon having signed the informed consent. The eurIPFreg and eurIPFbank are listed in ClinicalTrials.gov (NCT02951416). EurILDreg is registered in German Clinical Trials Register, DRKS 00028968.

The Role of Continuous Monitoring of Venous Drainage Flow and Integrated Oxygen Extraction (ERiO2) via Bilateral Near-Infrared Spectroscopy in Cerebral Perfusion During Aortic Arch Surgery

Background and Objective: Effective cerebral perfusion monitoring is essential in aortic arch surgery, particularly when employing the Kazui technique under moderate hypothermia. Near-infrared spectroscopy (NIRS) provides real-time regional oxygen saturation (rSO2) measurements, while the continuous monitoring of venous drainage flow and oxygen extraction ratio (ERiO2) delivers additional insights into cerebral oxygenation and metabolic balance. This study investigates the correlation between NIRS-derived rSO2, venous drainage flow, and ERiO2 during selective antegrade cerebral perfusion (SACP) to better understand their interplay and clinical significance. Materials and Methods: This retrospective study analyzed data from 10 patients undergoing aortic arch surgery with the Kazui technique, including 4 patients with type I A dissections and 6 with aortic arch aneurysms. Bilateral NIRS (Masimo system) was used to measure rSO2, while venous drainage flow and ERiO2 were continuously monitored using the Landing system. Intraoperative parameters such as cardiopulmonary bypass (CPB) time, cooling and rewarming duration, venous return flow, and perfusion delivery rates were collected and analyzed. The correlations between rSO2, venous drainage flow, and ERiO2 were statistically evaluated. Results: The mean CPB time was 182 ± 15 min, with a mean cross-clamp time of 98 ± 12 min. Cooling to 20 °C was achieved in 29 ± 3 min, followed by a controlled rewarming phase of 10 ± 1.5 min. The venous return flow averaged 570 ± 25 mL/min, while the perfusion delivery rates exceeded 600 ± 30 mL/min. Bilateral NIRS monitoring revealed stable rSO2 values averaging 65 ± 5%, while ERiO2 averaged 28 ± 4%. A strong correlation (r = 0.91, p < 0.01) was observed between rSO2 and ERiO2, with venous drainage flow playing a critical role in maintaining this relationship. Conclusions: This study demonstrates a robust correlation between NIRS-derived rSO2, continuous venous drainage flow, and ERiO2 during SACP in aortic arch surgery.

Pulse oximetry at two sensor placement sites in conscious foals

BackgroundPulse oximetry has not been thoroughly evaluated for assessment of oxygenation in conscious foals. Compared with invasive arterial blood sampling, it is a painless and non-invasive method for real-time monitoring of blood oxygen saturation. The aim of this prospective clinical study was to evaluate the usability, validity, and reliability of pulse oximetry at two measuring sites (lip and caudal abdominal skin fold) for blood oxygen saturation measurement in conscious foals with and without respiratory compromise. Thirty-two foals under one month of age were used. Nineteen foals had normal respiratory and cardiovascular function, and 13 had pneumonia. Pulse oximetry with a transmittance sensor was performed in triplicate on each foal’s lip (n = 196 measurements) and/or skin fold (n = 338 measurements), and arterial blood sample was collected. The oxygen saturation values measured by pulse oximetry from the lip and skin fold were compared with each other (n = 58 measurement pairs) and with the calculated arterial oxygen saturation based on arterial blood samples (n = 93 measurement pairs). Furthermore, repeatability of the pulse oximetry measurements was assessed.ResultsMeasured blood oxygen saturation was clearly associated with the calculated saturation, but on average (± SD) it was 1.8 (± 3.3) percentage units higher from the lip and 5.7 (± 4.3) percentage units higher from the skin fold than the calculated saturation. In concurrent lip and skin fold measurements within a foal, the skin fold measurements were 2.4 (± 2.4) percentage units higher than the lip measurements. The repeatability of three pulse oximetry saturation measurement results was moderate to good and significantly improved when the measurement furthest from the middle-measured value was excluded. The most deviating measurement was often obtained first. Pulse oximetry in general was well tolerated and easy to perform, but as expected in conscious foals, movement and contact problems generated occasional technical difficulties in some individuals.ConclusionsIn conscious foals, pulse oximetry with a transmittance sensor attached to the lip (but not to the skin fold) is a clinically applicable and valid method for arterial blood oxygen saturation determination. Several measurements should be obtained and outliers discarded to obtain a reliable result.

Performance Evaluation of a Locally Produced Pulse Oximeter

Most aftermarket pulse oximeters (POs) sold usually have peripheral blood oxygen saturation (SpO2) sensors with short life spans and the lack of specialized personnel to carry out the repairs result in frequent failures and replacement of the device. The study aims to solve the problems by developing a cheap, durable, easy to operate, and enhanced reflectance pulse oximeter (RPO). The testing of the device involved the SpO2 and heart rate (HR) measurements of Forty (40) healthy volunteers. From the performance evaluation, the measured data and its accuracy were satisfactory with an average accuracy and error rates of 99.7 % and 0.3 % for SpO2 while that of the HR was 97.7 % and 2.3 % respectively. Furthermore, analysis from the Bland - Altman Plot for both the SpO2 and HR showed that the locally developed PO could be used as a substitute to measure oxygen saturation and pulse rate in patients.

Sex and age-related day-to-day variability in the skin microcirculation during post-occlusive reactive hyperemia.

Little is known about the day-to-day variability of different skin microcirculation parameters, and how this variability is influenced by age and sex. The aim was to examine the day-to-day variability of microcirculatory parameters in relation to age and sex. The cutaneous microcirculation was measured using a fiber optic probe integrating laser Doppler flowmetry (LDF) and diffuse reflectance spectroscopy (DRS) to measure oxygen saturation, red blood cell (RBC) tissue fraction, speed-resolved and conventional perfusion. Measurements at two separate days were compared during baseline, a 5-min occlusion and during the following post-occlusive reactive hyperemia (PORH) period on the volar forearm and dorsal foot in totally 48 men and women aged 20-30 and 50-60 years, respectively. Variability was expressed as the coefficient of variation CV and repeatability as the intraclass correlation coefficient ICC. Peak oxygen saturation during PORH had the lowest day-to-day variability for the forearm (CV = 2.1 %) and the foot (CV = 3.8 %) as well as an excellent repeatability (ICC = 0.80 and ICC = 0.82, respectively). Older women had a higher day-to-day variability in baseline conventional perfusion compared to younger women on the forearm (p = 0.007). On the foot, older women had a lower day-to-day variability than younger women for baseline oxygen saturation (p = 0.006) and peak RBC tissue concentration (p = 0.008). Older men had a lower day-to-day variability than younger men for baseline oxygen saturation (p = 0.012) but a higher variability for baseline and peak RBC tissue concentration (p = 0.008 and p = 0.002) on the foot. Peak oxygen saturation had the lowest day-to-day variability of the measured parameters. A lower value of peak oxygen saturation has previously been associated with increasing systematic coronary risk implying that this is a suitable parameter for measuring microcirculatory dysfunction. Sex and age only affected the day-to-day variability of very few parameters.

Investigation of a Novel Noninvasive Risk Analytics Algorithm With Laboratory Central Venous Oxygen Saturation Measurements in Critically Ill Pediatric Patients.

Accurate assessment of oxygen delivery relative to oxygen demand is crucial in the care of a critically ill patient. The central venous oxygen saturation (Svo2) enables an estimate of cardiac output yet obtaining these clinical data requires invasive procedures and repeated blood sampling. Interpretation remains subjective and vulnerable to error. Recognition of patient's evolving clinical status as well as the impact of therapeutic interventions may be delayed. The predictive analytics algorithm, inadequate delivery of oxygen (IDo2) index, was developed to noninvasively estimate the probability of a patient's Svo2 to fall below a preselected threshold. A retrospective multicenter cohort study was conducted using data temporally independent from the design and development phase of the IDo2 index. A total of 20,424 Svo2 measurements from 3,018 critically ill neonates, infants, and children were retrospectively analyzed. Collected data included vital signs, ventilator data, laboratory data, and demographics. The ability of the IDo2 index to predict Svo2 below a preselected threshold (30%, 40%, or 50%) was evaluated for discriminatory power, range utilization, and robustness. Area under the receiver operating characteristic curve (AUC) was calculated for each index threshold. Datasets with greater amounts of available data had larger AUC scores. This was observed across each configuration. For the majority of thresholds, Svo2 values were observed to be significantly lower as the IDo2 index increased. The IDo2 index may inform decision-making in pediatric cardiac critical care settings by providing a continuous, noninvasive assessment of oxygen delivery relative to oxygen demand in a specific patient. Leveraging predictive analytics to guide timely patient care, including support for escalation or de-escalation of treatments, may improve care delivery for patients and clinicians.

Sleep Disordered Breathing and Subsequent Neuroimaging Markers of Brain Health in Hispanic/Latino Adults.

Sleep disordered breathing (SDB) is a risk factor of stroke and Alzheimer disease and related dementias (ADRDs). Hispanic/Latino adults have higher risk of SDB and ADRDs, which emphasizes the need to better understand the association between SDB and brain health. Furthermore, results on SDB and brain aging are mixed, and there are limited data for Hispanic/Latino adults. The main goal of this study is to assess the association between SDB and brain MRI measures in a diverse Hispanic/Latino population. The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) is a community-based prospective cohort multisite (Bronx, Chicago, Miami, San Diego) study of diverse Hispanic/Latino adults in the United States. Participants underwent 1 night of unsupervised home testing with a sleep apnea test device at baseline. The SOL-Investigation of Neurocognitive Aging MRI, an ancillary study, recruited 2,667 HCHS/SOL participants (35-85 years) who underwent neuroimaging approximately 10 years after baseline sleep assessment. The main exposure was the respiratory event index (REI, 3% desaturation). Secondary exposures encompassed measures of oxygen saturation. Main outcomes included total brain, gray matter, white matter hyperintensity (WMH), and hippocampal volumes. Survey linear regression models were used to determine associations between SDB and brain MRI measures. The mean age was 67.6 years, with a body mass index of 29.7, and 58.3% were female. We found that increased REI was associated with larger hippocampal volumes (bhippocampus = 0.006 [0.001-0.012]). These results were consistent with oxygen levels (minimum SpO2%) during sleep (bhippocampus = -0.013 [-0.021 to -0.004]). Lower oxygen levels (mean SpO2) during sleep were associated with enlarged WMH volumes (bWMH = -0.095 [-0.164 to -0.025]). We found that SDB and worse oxygenation during sleep were linked to larger hippocampal volumes. These results underscore the complex relationships between sleep health and brain aging and warrant longitudinal follow-up, starting in middle age or earlier.

Retinal vessel flicker light responsitiviness and its relation to analysis protocols, static and metabolic data in healthy subjects

Aims/Purpose: To assess agreement between different analysis protocols for determination of retinal vessel dilation response to flicker light (FL) and its relation to static‐ and metabolic parameters of retinal vessels in healthy subjects.Methods: 24 right eyes of 24 healthy controls (mean age: 35.87 ±SD 14.20 years), who underwent dynamic‐ and static retinal diameter‐ and oxygen saturation measurements on Retinal Vessel Analyser were included (RVA, Imedos, Jena, Germany). Using repeated video analyses, responses to FL were measured within the superior‐temporal (ST) area. Taking the length and the location into account, the FL data were evaluated in 3 groups: length < 1 optic disc (OD) (group 1); length > 1OD: close to the OD (group 2) and within the VesselMap area (group 3).For comparability, the static‐ (CRA, CRV, AVR) and oxygen saturation parameters (A‐V SO2, V‐SO2, A‐V SO2) were calculated in the ST peripapillary area using the VesselMap tool of RVA and were evaluated in relation to the corresponding dynamic ones (group 3).Results: In all groups, vascular FL response of arteries was less pronounced compared to venules (p = 0.023). Event thought, FL responses (mean ±SD: FL‐A; FL‐V, %) in group 1 to be more pronounced (mean 3.36 ±2.31; 4.42 ±1.69) compared to those in groups 2 (mean: 2.97 ±2.40; 4.08 ±1.55) and 3 (2.84 ±2.29; 4.21± 2.03) they did not reach statistically significant values (p > 0.44).The mean flicker response of venules showed negative correlations to the corresponding static‐ and metabolic parameters: CRV (r = ‐0.489; p = 0.015) and V‐SO2 (r = ‐0.375; p = 0.001).Conclusions: Our study confirms, that flicker light response, even showing slight difference about its length and location, allows agreeable measurements. However, even in healthy subjects, the effect of the static‐ and metabolic retinal vessel measurements on retinal venular flicker response should be taken in consideration.

Retinal vessel flicker light responsitiviness and its relation to analysis protocols, static and metabolic data in healthy subjects

Aims/Purpose: To assess agreement between different analysis protocols for determination of retinal vessel dilation response to flicker light (FL) and its relation to static‐ and metabolic parameters of retinal vessels in healthy subjects.Methods: 24 right eyes of 24 healthy controls (mean age: 35.87 ± SD 14.20 years), who underwent dynamic‐ and static retinal diameter‐ and oxygen saturation measurements on Retinal Vessel Analyser were included (RVA, Imedos, Jena, Germany). Using repeated video analyses, responses to FL were measured within the superior‐temporal (ST) area. Taking the length and the location into account, the FL data were evaluated in 3 groups: length < 1 optic disc (OD) (group 1); length > 1OD: close to the OD (group 2) and within the VesselMap area (group 3).For comparability, the static‐ (CRA, CRV, AVR) and oxygen saturation parameters (A‐V SO2, V‐SO2, A‐V SO2) were calculated in the ST peripapillary area using the VesselMap tool of RVA and were evaluated in relation to the corresponding dynamic ones (group 3).Results: In all groups, vascular FL response of arteries was less pronounced compared to venules (p = 0.023). Event thought, FL responses (mean ± SD: FL‐A; FL‐V, %) in group 1 to be more pronounced (mean 3.36 ± 2.31; 4.42 ± 1.69) compared to those in groups 2 (mean: 2.97 ± 2.40; 4.08 ± 1.55) and 3 (2.84 ± 2.29; 4.21 ± 2.03) they did not reach statistically significant values (p > 0.44).The mean flicker response of venules showed negative correlations to the corresponding static‐ and metabolic parameters: CRV (r = ‐0.489; p = 0.015) and V‐SO2 (r = ‐0.375; p = 0.001).Conclusions: Our study confirms, that flicker light response, even showing slight difference about its length and location, allows agreeable measurements. However, even in healthy subjects, the effect of the static‐ and metabolic retinal vessel measurements on retinal venular flicker response should be taken in consideration.

A New Approach to Retinal Oxygen Extraction Measurement Based on Laser Speckle Flowgraphy and Retinal Oximetry.

Currently, no standard for the measurement of retinal oxygen extraction exists. Here, we present a novel approach for measurement of retinal oxygen extraction based on two commercially available devices, namely laser speckle flowgraphy (LSFG) and retinal oximetry. The study was conducted in a randomized, double-masked design. Two study days were scheduled for each healthy participant. On one study day, measurements were performed during breathing of 100% oxygen to induce hyperoxia and on the other study day during breathing of 12% oxygen in nitrogen to induce hypoxia. To obtain data for short- and long-term reproducibility, baseline measurements during breathing of room air were performed twice on both study days. Retinal oxygen extraction was calculated from retinal oxygen saturation measurements using the oxygen module of the dynamic vessel analyzer (Imedos, Jena, Germany) and retinal blood flow measurements using LSFG (Nidek, Tokyo, Japan). As expected, breathing of 100% oxygen induced a significant decrease in retinal oxygen extraction of 36% ± 17% (P < 0.001). During hypoxia, retinal oxygen extraction did not change from baseline (P = 0.153). For short-term reproducibility, the intraclass correlation coefficient was excellent (0.910) and good (0.879) for long-term reproducibility. Coefficient of variation between measurements was 9.8% ± 7.0% for short-term and 10.4% ± 8.8% for long-term reproducibility. The data obtained in the present experiments show that the new approach to measure retinal oxygen extraction is valid and reproducible in healthy volunteers. The technique may become a valuable tool in studying retinal hypoxia in a wide variety of ocular and systemic diseases in the future.

Spiral cardiac quantitative susceptibility mapping for differential cardiac chamber oxygenation-Initial validation in relation to invasive blood sampling.

To develop a breath-hold cardiac quantitative susceptibility mapping (QSM) sequence for noninvasive measurement of differential cardiac chamber blood oxygen saturation (ΔSO2). A non-gated three-dimensional stack-of-spirals QSM sequence was implemented to continuously sample the data throughout the cardiac cycle. Measurements of ΔSO2 between the right and left heart chamber obtained by the proposed sequence and a previously validated navigator Cartesian QSM sequence were compared in three cohorts consisting of healthy volunteers, coronavirus disease 2019 survivors, and patients with pulmonary hypertension. In the pulmonary-hypertension cohort, Bland-Altman plots were used to assess the agreement of ΔSO2 values obtained by QSM and those obtained by invasive right heart catheterization (RHC). Compared with navigator QSM (average acquisition time 419 ± 158 s), spiral QSM reduced the scan time on average by over 20-fold to a 20-s breath-hold. In all three cohorts, spiral QSM and navigator QSM yielded similar ΔSO2. Among healthy volunteers and coronavirus disease 2019 survivors, ΔSO2 was 17.41 ± 4.35% versus 17.67 ± 4.09% for spiral and navigator QSM, respectively. In pulmonary-hypertension patients, spiral QSM showed a slightly smaller ΔSO2 bias and narrower 95% limits of agreement than that obtained by navigator QSM (1.09% ± 6.47% vs. 2.79% ± 6.99%) when compared with right heart catheterization. Breath-hold three-dimensional spiral cardiac QSM for measuring differential cardiac chamber blood oxygenation is feasible and provides values in good agreement with navigator cardiac QSM and with reference right heart catheterization.

Quantification of hemi-hepatic ischemia using real-time multispectral oxygenation imaging with single snapshot imaging of optical properties (SSOP)

BackgroundIdentifying liver ischemia is crucial in liver surgery. This study aimed to develop a hemi-hepatic ischemia model for assessing liver ischemia using single snapshot imaging of optical properties (SSOP), a noninvasive optical imaging modality that provides real-time measurements of tissue oxygen saturation (StO2).Materials and methodsTwelve swine were randomly assigned to two groups: One undergoing total vascular inflow occlusion (TVIO) and the other undergoing hepatic artery occlusion (HAO). Preoperative 3D CT scans were used to locate the left-sided hepatic arteries and portal veins, which were clamped during surgery. Real-time SSOP imaging was conducted to measure StO2 in three lobes—the left lateral lobe (LL), left medial lobe (LM), and right medial lobe (RM)—as well as capillary lactate levels and Doppler blood flow. Measurements were recorded at baseline (T0), during ischemia (T1, 30 min after clamping), and during reperfusion (T2, 30 min after declamping).ResultsIn the TVIO group, SSOP imaging revealed a distinct demarcation line on the liver surface. StO2 levels measured by SSOP significantly decreased from T0 to T1, dropping by 29.8% in the LL (46.0 ± 5.1 vs. 16.2 ± 5.1%, p = 0.011) and 36.3% in the LM (42.7 ± 5.9 vs. 6.4 ± 4.0%, p = 0.001). Additionally, capillary lactate levels increased substantially in the LL (1.3 ± 0.4 vs. 8.5 ± 2.4 mmol/L, p = 0.041) and in the LM (1.3 ± 0.4 vs. 8.2 ± 2.1 mmol/L, p = 0.021). In contrast, the HAO group showed a less pronounced reduction in StO2: 13.6% in the LL (32.7 ± 6.4 vs. 19.1 ± 5.4%, p = 0.007) and 19.8% in the LM (35.3 ± 8.2 vs. 15.5 ± 5.8%, p = 0.011), with no significant increase in capillary lactate levels. An inverse correlation was found between StO2 and capillary lactate levels (r = − 0.76, p < 0.001).ConclusionSSOP is a real-time, contrast-free imaging technique that effectively evaluates liver ischemia by accurately measuring tissue oxygenation, as validated by perfusion biomarkers.

The Effect of Surgical Mask Use on Respiratory Functions of Healthcare Professionals at Different Physical Activity Levels

Objectives: We aimed to show the effect of surgical mask use on pulmonary functions in healthy healthcare workers at different physical activity levels. Methods: This analytical cross-sectional study included healthy and active sports physicians and sports physiotherapists. Participants were subjected to respiratory function tests and arterial oxygen saturation (SpO2 ) measurements at rest and after the non-inclined treadmill activities at constant speeds of 3 km/h and 6.5 km/h with a surgical mask. Results: SpO2 measurements taken immediately after the participants’ physical activities at a speed of 6.5 km/h were significantly lower than the basal SpO2 measurements (p=0.045) as well as 1st second of forced expiration (FEV1 )/forced vital capacity (FVC), and FEV1 /FVC% in pulmonary function test measurements were significantly higher than baseline measurements (p=0.005; p=0.012, respectively). The flow velocity value in the last quarter of the forced expiration (FEF75) and its percentile were (FEF%75) found to be significantly higher than the measurements taken at rest after walking at 6.5 km/h (p=0.005 vs. p=0.004, respectively). The differences between the ERV values obtained after the participants’ physical activities at two speeds (3 km/h vs. 6.5 km/h) were significant (p=0.045). Conclusion: Using surgical masks by health workers while performing their low-moderate occupational activities may cause changes in respiratory parameters due to the microenvironment formed in the mask and increased respiratory resistance.

Estimation of Venous Oxygen Saturation Through Non-Invasive Optical Sensing at the Jugular Veins

Abstract Non-invasive, real-time venous oxygen saturation (SvO2) measurements provide the potential to improve health outcomes in transfusions, ventilator care, and in the intensive care unit. Current methods use catheters which are invasive, expensive, and pose potential high-risk, with only discrete measurements from a jugular vein obtained. This research designed, developed, and tested a proof-of-concept optical sensor similar to a pulse oximeter for non-invasive, continuous SvO2 monitoring at the external jugular vein (EJV). Testing on three subjects met the aim of correctly identifying the EJV waveform and provided an SvO2 estimation within the usual healthy range of 60-90%. SvO2 estimates from the EJV pulse of 71.1%, 72.2%, and 70.4% and breathing pulse of 74.7%, 75.3%, and 74.1%, all fall within range, with trials capturing clear EJV waveforms from the single-point sensor. Further research is necessary to calibrate and validate the device against gold-standard blood gas analysers. However, the initial results prove the sensor’s reliability and potential in detecting and estimating SvO2 non-invasively, which has the potential to benefit patients across a wide range of clinical settings.

Sex-specific NLRP3 activation in neutrophils promotes neutrophil recruitment and NETosis in the murine model of diffuse alveolar hemorrhage.

Diffuse alveolar hemorrhage (DAH) is a life-threatening complication of systemic lupus erythematosus and small vessel vasculitis. We previously showed that neutrophil extracellular traps (NETs) were associated with the pathogenesis of pristane-induced DAH and demonstrated that neutrophil NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome assembly participated in NET generation under sterile stimulation. We investigated whether NLRP3 inflammasome assembly in neutrophils may drive pulmonary NETosis in a mouse model of pristane-induced DAH. C57BL/6J mice received a single intraperitoneal injection of 0.5mL of pristane. Neutrophil NLRP3 inflammasome assembly and NETs were characterized by immunofluorescence staining of apoptosis-associated speck-like protein a CARD (ASC), co-staining of DNA, and citrullinated histones, respectively. Clinical status of mice was assessed 11 days after pristane injection by measurement of arterial oxygen saturation and of weight loss; severity of lung injury was determined using a quantification score from hematoxylin-eosin-stained slides. Pristane induced ASC speck formation in neutrophils and we confirmed that NLRP3 inflammasome was involved in NET generation after pristane stimulation in vitro. NLRP3 deficiency reduced the severity of pristane-induced DAH in female, but not male mice. Interestingly, NLRP3 deficiency reduced the number of neutrophils and NETs in the lungs of females compared to males. Our results suggest a link between female sex-specific NLRP3 inflammasome activation and subsequent pulmonary NETosis in the development of pristane-induced DAH. Therefore, we identified NLRP3 inflammasome as a potential new therapeutic target in this severe complication of pro-female autoimmune disease for which specific inhibitors of NLRP3 are currently developed.

Inverse linear association between blood haemoglobin and oxygen saturation accuracy measured by pulse oximetry: a cross-sectional analysis in individuals with COVID-19 infection

BackgroundPulse oximetry measures oxygen saturation non-invasively by using differential absorption of infrared signals which are dependent on the oxyhaemoglobin:deoxyhaemoglobin ratio. We tested the hypothesis that pulse oximetry error in measurements...

The effect of vo2max on muscle oxygen saturation (SMO2) in University Badminton Athletes

Muscle oxygen saturation (SmO2) is an additional physiological parameter that helps identify the transition from aerobic to anaerobic workload. Additionally, it can be used to predict performance by calculating Vo2 and energy expenditure. Muscle oxygen saturation (SmO2) is a measure of oxygen saturation in muscle tissue that can be used to evaluate metabolic zones, training intensity, and athlete performance. An athlete's muscle oxygen saturation (SMO2) is a measure of how well their muscles use oxygen, which is important for evaluating performance and creating training programs. This research is a week-long experimental study with a one-shot case study design, research intends to look at the effect of Vo2Max on muscle oxygen saturation (SMO2) in university badminton athletes. The subjects of this research are student athletes who actively practice badminton. There were 6 respondents who were willing to be research subjects and had met the specified criteria, namely actively exercising three times a week and being in good health. Then the author took data on athletes who had the highest and lowest Vo2Max to analyze SMO2 optimization, which was the focus of this research. The results of the analysis show that there is a significant influence between Vo2max and SMO2 optimization; this can be seen by the difference through the t test with a sig (2-tailed) value of 0.000 &lt; 0.05. Another finding is that athletes with higher Vo2max show better SMO2 recovery results. better than athletes with low Vo2max; in this study, athletes with higher Vo2max showed a 37% increase in SMO2 over two minutes, while athletes with lower Vo2max showed a 21% increase. This is an interesting finding for coaches and athletes regarding the importance of Vo2 max capacity in optimizing SMO2.

Validity of a Consumer-Based Wearable to Measure Clinical Parameters in Patients With Chronic Obstructive Pulmonary Disease and Healthy Controls: Observational Study.

Consumer-based wearables are becoming more popular and provide opportunities to track individual's clinical parameters remotely. However, literature about their criterion and known-groups validity is scarce. This study aimed to assess the validity of the Fitbit Charge 4, a wrist-worn consumer-based wearable, to measure clinical parameters (ie, daily step count, resting heart rate [RHR], heart rate variability [HRV], respiratory rate [RR], and oxygen saturation) in patients with chronic obstructive pulmonary disease (COPD) and healthy controls in free-living conditions in Belgium by comparing it with medical-grade devices. Participants wore the Fitbit Charge 4 along with three medical-grade devices: (1) Dynaport MoveMonitor for 7 days, retrieving daily step count; (2) Polar H10 for 5 days, retrieving RHR, HRV, and RR; and (3) Nonin WristOX2 3150 for 4 nights, retrieving oxygen saturation. Criterion validity was assessed by investigating the agreement between day-by-day measures of the Fitbit Charge 4 and the corresponding reference devices. Known-groups validity was assessed by comparing patients with COPD and healthy controls. Data of 30 patients with COPD and 25 age- and gender-matched healthy controls resulted in good agreement between the Fitbit Charge 4 and the corresponding reference device for measuring daily step count (intraclass correlation coefficient [ICC2,1]=0.79 and ICC2,1=0.85, respectively), RHR (ICC2,1=0.80 and ICC2,1=0.79, respectively), and RR (ICC2,1=0.84 and ICC2,1=0.77, respectively). The agreement for HRV was moderate (healthy controls: ICC2,1=0.69) to strong (COPD: ICC2,1=0.87). The agreement in measuring oxygen saturation in patients with COPD was poor (ICC2,1=0.32). The Fitbit device overestimated the daily step count and underestimated HRV in both groups. While RHR and RR were overestimated in healthy controls, no difference was observed in patients with COPD. Oxygen saturation was overestimated in patients with COPD. The Fitbit Charge 4 detected significant differences in daily step count, RHR, and RR between patients with COPD and healthy controls, similar to those identified by the reference devices, supporting known-groups validity. Although the Fitbit Charge 4 shows mainly moderate to good agreement, measures of clinical parameters deviated from the reference devices, indicating that monitoring patients remotely and interpreting parameters requires caution. Differences in clinical parameters between patients with COPD and healthy controls that were measured by the reference devices were all detected by the Fitbit Charge 4.

CMOS Pulse Oximeter

Abstract: This paper presents the design and implementation of a non-invasive pulse oximeter based on Complementary MetalOxide-Semiconductor (CMOS) technology, aimed at enhancing the accuracy and accessibility of blood oxygen saturation measurements. Pulse oximetry is a critical tool in clinical and personal health monitoring, providing vital information about respiratory function. The integration of CMOS technology allows for miniaturization and energy efficiency, facilitating the development of compact, wearable devices capable of continuous monitoring. The proposed system utilizes advanced signal processing techniques, including lock-in detection and dual-wavelength illumination, to improve the reliability of photoplethysmographic (PPG) signal acquisition under various conditions. Experimental validation demonstrates the device's capability to deliver accurate SpO2 readings even in the presence of motion artifacts and ambient light interference. Furthermore, the calibration methods employed ensure that measurements are consistent and precise across different users. By leveraging the advantages of CMOS technology, this study not only highlights the potential for improved patient comfort and compliance but also opens new avenues for the application of pulse oximetry in diverse environments. The findings underscore the effectiveness of CMOS-based pulse oximeters in advancing non-invasive health monitoring solutions, ultimately contributing to enhanced patient care and outcomes.

The Relative Indirect Effects of Technology Bias and Implicit Bias on Racial Disparity in Service Delivery and Sepsis Mortality

Racism at the individual and societal levels has been identified as a cause of disparity in healthcare outcomes in the United States but reducing disparity has been slow. This study disentangles the relative effects of two types of racism on inpatient service delivery and hospital mortality: technology bias and implicit bias. Drawing on clinical data from intensive care unit (ICU) patients with sepsis, we use propensity score matching to balance groups of White and nonwhite patients and run a causal mediation analysis to test our model, which links patient race to hospital mortality through two mediating variables related to service delivery: (1) discrepancies in blood oxygen saturation measurements due to technology bias embedded in the medical device (i.e., pulse oximeter) and (2) administration of supplemental oxygen, which could be impacted by clinicians’ implicit bias. We first replicate prior findings that (a) higher discrepancies between oximeter readings and laboratory tests for nonwhite patients compared to Whites and (b) a higher discrepancy lowers the likelihood of patients receiving supplemental oxygen during the ICU stay. We make a unique contribution by finding that nonwhite patients with sepsis have a 79% higher risk of hospital mortality in the ICU compared to Whites, with nearly half of the racial disparity in mortality stemming from technology bias and less than a fifth from clinicians’ implicit bias. Eliminating these two biases would help save thousands of lives annually among racial/ethnic minorities with sepsis in the United States. Our findings indicate that technology bias exerts a greater negative impact on mortality than does implicit bias, highlighting the importance of device approval standards and clinicians' ability to customize decision criteria for supplemental oxygen.