The effect of pleural drainage on pulse oximetry in a post-operative thoracic surgery population.

BACKGROUND: Pleural effusions in post-operative thoracic surgery patients are common. Effusions can result in prolonged hospitalizations or readmissions, with prior studies suggesting mixed effects of pleural drainage on hypoxia. We aimed to define the impact of pleural drainage on pulse oximetry (SpO2) in post-thoracic surgery patients. METHODS: A retrospective study of post-operative thoracic surgery patients undergoing pleural drainage was performed. SpO2 and supplemental oxygen (FiO2) values were recorded at pre- and post-procedure. The primary outcome was difference in pre-procedural and post-procedural SpO2. RESULTS: We identified 95 patients with a mean age of 65 (SD - 13.8) years undergoing 122 pleural drainage procedures. Mean drainage volume was 619 (SD-423) mL and the majority of procedures (88.5 %) included a drainage of <1000 mL. SpO2 was associated with an increase from 94.0 % (SD-2.6) to 97.3 % (SD-2.0) at 24-h (p < 0.0001). FiO2 was associated with a decrease from 0.31 (SD-0.15) to 0.29 (SD-0.12) at 24-h (p = 0.0081). SpO2/FiO2 was associated with an increase from 344.5 (SD-99.0) to 371.9 (SD-94.7) at 24-h post-procedure (p < 0.0001). CONCLUSIONS: Pleural drainage within post-operative thoracic surgery patients offers statistically significant improvements in oxygen saturation by peripheral pulse oximetry and oxygen supplementation; however the clinical significance of these changes remains unclear. Pleural drainage itself may be requested for numerous reasons, including diagnostic (fevers, leukocytosis, etc.) or therapeutic (worsening dyspnea) evaluation. However, pleural drainage may offer minimal clinical impact on pulse oximetry in post-operative thoracic surgery patients.

Effect of near-infrared spectroscopy on postoperative delirium in cardiac surgery with cardiopulmonary bypass: a systematic review and meta-analysis.

Background: Postoperative delirium (POD) is a common anesthetic side effect in cardiac surgery. However, the role of oxygen saturation monitoring in reducing postoperative delirium has been controversial. Therefore, this meta-analysis aimed to analyze whether NIRS monitoring during cardiac surgery under cardiopulmonary bypass could reduce the incidence of postoperative delirium. Methods: PubMed, Web of Science, Cochrane Library, Embase and China National Knowledge Infrastructure (CNKI) databases were systematically searched using the related keywords for randomized-controlled trials (RCTs) published from their inception to March 16, 2024. This review was conducted by the Preferred Reporting Project and Meta-Analysis Statement (PRISMA) guidelines for systematic review. The primary outcome was postoperative delirium, and the second outcomes included the length of ICU stay, the incidence of kidney-related adverse outcomes, and the incidence of cardiac-related adverse outcomes. Results: The incidence of postoperative delirium could be reduced under the guidance of near-infrared spectroscopy monitoring (OR, 0.657; 95% CI, 0.447-0.965; P = 0.032; I2 = 0%). However, there were no significant differences in the length of ICU stay (SMD, 0.005 days; 95% CI, -0.135-0.146; P = 0.940; I2 = 39.3%), the incidence of kidney-related adverse outcomes (OR, 0.761; 95% CI, 0.386-1.500; P = 0.430; I2 = 0%), and the incidence of the cardiac-related adverse outcomes (OR, 1.165; 95% CI, 0.556-2.442; P = 0.686; I2 = 0%) between the two groups. Conclusion: Near-infrared spectroscopy monitoring in cardiac surgery with cardiopulmonary bypass helps reduce postoperative delirium in patients. Systematic Review Registration: PROSPERO, identifier, CRD42023482675.

[Catheter-assisted local lysis therapy for submassive pulmonary embolism]. / Kathetergestützte lokale Lysetherapie bei submassiven Lungenembolien.

BACKGROUND: Pulmonary embolism is the third most common cardiovascular disease. Interventional treatment options as an alternative to systemic lysis therapy of hemodynamically stable, submassive pulmonary embolisms have received an unprecedented boost in innovation in recent years. The treatment options are heterogeneous and can be roughly divided into local thrombolysis and local thrombectomy. For years in our center we have been carrying out catheter-assisted, locoregional lysis therapy with side-hole lysis catheters and a cumulative dose per pulmonary branch of 10 mg alteplase over 15 h for hemodynamically stable, submassive pulmonary emboli. AIM: The aim of this retrospective study was to review this therapeutic concept and to collect data on clinical endpoints and possible complications. METHODS: The study included data from 01/2018-03/2023. For this purpose, the patients were selected based on the OPS codes (8.838.60 and 1­276.0), and the data was collected using the medical records. Biometric data, data on previous illnesses and vital parameters, laboratory chemistry data, CT diagnostic data, echocardiographic data, data on drug treatment and data on complications were collected anonymously. RESULTS: There was a significant reduction in the strain on the right heart. Peripheral oxygen saturation also improved significantly and heart rate decreased significantly. The complication rate remained low and was almost exclusively limited to access-related problems. CONCLUSION: Catheter-assisted, locoregional lysis therapy is a safe and effective treatment method for submassive pulmonary embolism.

Effectiveness of Continuous Positive Airway Pressure in Alleviating Hypoxemia and Improving Exertional Capacity at Altitude.

Strickland, Brian, Elan Small, Mary Ryan, and Ryan Paterson. Effectiveness of continuous positive airway pressure in alleviating hypoxemia and improving exertional capacity at altitude. High Alt Med Biol. 00:000-000, 2024. Introduction: Decreased oxygen saturation and exercise tolerance are commonly experienced at high altitude. Continuous positive airway pressure (CPAP) devices have become increasingly portable and battery powered, providing a potentially unique new therapeutic modality for treatment of altitude-related illnesses. This study evaluated the potential use of CPAP devices to improve and maintain oxygen saturation at altitude, both at rest and with exertion, to evaluate the feasibility of using this device at altitude. Methods: Subjects were taken to Mount Blue Sky and monitored while they hiked to the summit (4,350 m), maintaining a consistent level of exertion. Subjects hiked for 0.7 km both with and without CPAP set to 10 cmH2O pressure. Continuous vital signs were collected during the hike and recovery period. Results: All subjects completed the hike wearing CPAP devices at a vigorous level of exertion. Mean oxygen saturation of the CPAP group (M = 83.8%, SD = 3.72) was significantly higher than that of the control group during exertion (M = 78.7%, SD = 2.97); p = 0.005. Recovery after exertion was quicker in the CPAP group than the control group. Three subjects experienced claustrophobia requiring a brief pause, but were able to complete their exercise trial without removing equipment or experiencing adverse events. When pauses from claustrophobia were excluded, there was no difference in completion time between the groups (p = 0.06). Conclusion: CPAP reliably improved oxygen saturation at rest and during vigorous exertion at high altitude. Its ability to correct hypoxemia, even with physical exertion, may prove useful after further study as a portable self-carried device to prevent and treat altitude-related illness, or to improve safety in high-altitude rescues.

The Impact of Using Nesting Care on Heart Rate, Oxygen Saturation, and Pain Among Premature Neonates in Neonatal Intensive Care Units in Saudi Arabia: A Quasi-Experimental Study.

BACKGROUND: Supportive positioning may mimic the intrauterine environment and enhance neonates' physiological and developmental outcomes. Limited research in Saudi Arabia examined the effect of supportive positioning aids (nesting) on infant outcomes in neonatal intensive care units (NICUs). OBJECTIVE: This study compared nesting care to non-nesting care in the short-term outcomes of premature neonates (heart rate, oxygen saturation, and pain) in Saudi NICUs. METHODS: A quasi-experimental design compared two groups of premature neonates from two NICUs regarding their heart rate, oxygen saturation, and pain level. Nesting was used in the first group, and not in the second group. Seventy premature neonates (35 per group) were recruited. An independent t-test was used to compare the two groups. RESULTS: Heart rate was significantly lower in the nesting group than the non-nesting group at baseline and after procedures (136bpm and 139bpm vs 144bpm and 148bpm, P ≤ 0.05). The pain level was significantly lower in the nesting group than the non-nesting group at baseline and after procedures (3.7 and 3.8 vs 4.7 and 4.6, P ≤ 0.05). There was no significant difference between the two groups in oxygen saturation. CONCLUSION: Nesting care supported premature neonates in the NICU. It helped stabilize the heart rate and pain. NICUs in Saudi Arabia would benefit from educating NICU nurses and informing NICU managers and policymakers of nesting care.

Type 2 diabetes foot inflammation prevention reminder socks.

It is not easy to determine the time between diagnosis and inflammation in patients with type 2 diabetes foot disease. In severe cases, it can lead to ulceration or even amputation. During the development of the inflammation, there will be changes in temperature and blood oxygen saturation in the sole of the foot. Therefore, early monitoring can be an effective prevention and reminder. By integrating flexible conductive fibres, conductive ink and fabric, six nodes on the sole of the foot are monitored. Blood oxygen is monitored above the thumb using photoelectric sensors. The monitoring data signals from these two areas are transmitted to the integrated sensor on the top of the socks and then to the mobile app via Bluetooth. Blood oxygen saturation and temperature can be displayed in real time, and the data is also uploaded to ports such as doctors, communities and hospitals for clinical diagnosis. This study can effectively monitor and remind the inflammatory changes after diabetic foot disease, and change the way of health monitoring by design. Although this study does not have the function of treatment, it is the greatest value of designing intervention medical health - prevention reminder.

Oxygenation Index and Oxygen Saturation Index for Predicting Postoperative Outcome in Patients Undergoing Emergency Surgery: A Prospective Cohort Study.

Background: The OI was originally evaluated as a prognostic tool for acute hypoxemic respiratory failure in children and was an independent predictor for mortality in adult patients with acute respiratory distress syndrome (ARDS). Methods: Oxygenation index and OSI of 201 adult patients undergoing emergency surgery were evaluated at different time points. The primary objective of this study was to find the correlation between OI and OSI. The secondary objectives were to find the prognostic utility of OI and OSI for postoperative mechanical ventilation and mortality. Results: Significant statistical correlation was found between OI and OSI both at the beginning (r 2 = 0.61; p < 0.001) and immediately after surgery (r 2 = 0.47; p < 0.001). Oxygen saturation index at the beginning [area under the receiver operating characteristics curve (AUROC) (95% CI) 0.76 (0.62-0.89); best cutoff 3.9, sensitivity 64% and specificity 45%] and immediately after surgery [AUROC (95% CI) 0.82 (0.72-0.92); best cutoff 3.57, sensitivity 79%, and specificity 62%] were reasonable predictors of the requirement of invasive ventilatory support. Exploratory analysis reported that older age (p = 0.02), higher total leukocyte count (p = 0.002), higher arterial lactate (p = 0.02), and higher driving pressure (p < 0.001) were independently associated with hospital mortality. Conclusion: In adult patients undergoing emergency laparotomy under general anesthesia, OI and OSI were found to be correlated. Both metrics demonstrated reasonable accuracy in predicting the need for invasive ventilatory support beyond 24 hours and hospital mortality. How to cite this article: Thakuria R, Ernest EE, Chowdhury AR, Pangasa N, Kayina CA, Bhattacharjee S, et al. Oxygenation Index and Oxygen Saturation Index for Predicting Postoperative Outcome in Patients Undergoing Emergency Surgery: A Prospective Cohort Study. Indian J Crit Care Med 2024;28(7):645-649.

Artificial neural networks trained on simulated multispectral data for real-time imaging of skin microcirculatory blood oxygen saturation.

Significance: Imaging blood oxygen saturation ( SO 2 ) in the skin can be of clinical value when studying ischemic tissue. Emerging multispectral snapshot cameras enable real-time imaging but are limited by slow analysis when using inverse Monte Carlo (MC), the gold standard for analyzing multispectral data. Using artificial neural networks (ANNs) facilitates a significantly faster analysis but requires a large amount of high-quality training data from a wide range of tissue types for a precise estimation of SO 2 . Aim: We aim to develop a framework for training ANNs that estimates SO 2 in real time from multispectral data with a precision comparable to inverse MC. Approach: ANNs are trained using synthetic data from a model that includes MC simulations of light propagation in tissue and hardware characteristics. The model includes physiologically relevant variations in optical properties, unique sensor characteristics, variations in illumination spectrum, and detector noise. This approach enables a rapid way of generating high-quality training data that covers different tissue types and skin pigmentation. Results: The ANN implementation analyzes an image in 0.11 s, which is at least 10,000 times faster than inverse MC. The hardware modeling is significantly improved by an in-house calibration of the sensor spectral response. An in-vivo example shows that inverse MC and ANN give almost identical SO 2 values with a mean absolute deviation of 1.3%-units. Conclusions: ANN can replace inverse MC and enable real-time imaging of microcirculatory SO 2 in the skin if detailed and precise modeling of both tissue and hardware is used when generating training data.

Comparing the Efficacy of Foot Reflexology and Benson's Relaxation on Anxiety and Physiologic Parameters After Cesarean Surgery.

OBJECTIVE: To compare the efficacy of foot reflexology and Benson's relaxation on anxiety and physiologic parameters after cesarean surgery. DESIGN: Randomized controlled trial with three parallel arms. SETTING: Gynecologic ward of the Persian Gulf Martyrs Hospital in Bushehr, Iran, in 2020. PARTICIPANTS AND INTERVENTIONS: Women undergoing cesarean surgery (n = 135) were selected by convenience sampling and divided via block randomization into three groups of foot reflexology, Benson's relaxation interventions, and control group (n = 45 in each group). Interventions were performed 2 hours after cesarean surgery. MEASUREMENTS: Spielberger's State-Trait Anxiety Inventory, mercury sphygmomanometer, and pulse oximeter were used to collect the data. Anxiety was measured before and 30 minutes after the intervention. Physiologic parameters were measured before the intervention and immediately, 30 minutes, and 60 minutes after the intervention. Data were analyzed using inferential statistics. RESULTS: The mean score of situational anxiety after the intervention was significantly lower than before the intervention in the reflexology (t = 5.66, 11.14; 95% confidence interval [CI] [5.66, 11.14]) and Benson's relaxation groups (t = 7.362; 95% CI [5.91, 9.85]). However, changes in the control group were not significant (t = 1.674; 95% CI [-0.24, 2.55]). Decreases in anxiety scores were similar in the two intervention groups. After intervention, in most measurement times, respiratory rate and pulse rate decreased in the two intervention groups compared to the control group, and arterial oxygen saturation and systolic blood pressure increased. CONCLUSION: Considering the effect of both interventions on decreasing anxiety and improving most physiologic parameters, it seems that foot reflexology and Benson's relaxation can be recommended after cesarean surgery.

The relationship between perioperative central venous oxygen saturation and postoperative complications in highly invasive gastroenterological surgery.

Purpose: Operations for malignant diseases of the bile duct, pancreas, and esophagus are the most invasive gastroenterological surgeries. The frequency of complications after these surgeries is high, which affects the postoperative course and mortality. In patients who undergo these types of surgeries, continuous monitoring of the perioperative central venous oxygen saturation (ScvO2) is possible via a central venous catheter. We aimed to investigate the relationship between continuously monitored perioperative ScvO2 values and postoperative complications. Methods: The medical records of 115 patients who underwent highly invasive gastroenterological surgeries and ScvO2 monitoring from April 2012 to March 2014 were analyzed. Sixty patients met the inclusion criteria, and their ScvO2 levels were continuously monitored perioperatively. The relationship between ScvO2 levels and major postoperative complications, defined as Clavien-Dindo grade ≥ III, was examined using uni- and multivariate analysis. Results: Thirty patients developed major postoperative complications. The adequate cut-off value derived from receiver operating curves of the postoperative average ScvO2 levels for predicting major complications was 75%. Multivariate analysis revealed that low average postoperative ScvO2 levels (p = 0.016) and blood loss ≥ 1000 mL (p = 0.039) were significant predictors of major postoperative complications. Conclusions: Low perioperative ScvO2 values were associated with an increased risk of major postoperative complications. Continuous ScvO2 monitoring will help prevent postoperative complications.

Pulse oximetry in patients with pigmented skin: What I should know.

Pulse oximetry is widely used to non-invasively estimate the oxygen saturation of haemoglobin in arterial blood (SpO2). It is used widely throughout healthcare and was used extensively during the Covid-19 pandemic to detect and treat hypoxic patients. Research has suggested that pulse oximetry is less accurate in patients with darker skin. This led the US Food and Drug Administration agency (FDA) to issue a safety statement warning that pulse oximeters may be inaccurate when patients have pigmented skin. Evidence suggests that the oxygen saturation of arterial blood (SaO2) may be being overestimated by measuring SpO2 in those with pigmented skin. The degree of overestimation increases as SaO2 decreases especially when SpO2 reads below 80%. We review how pulse oximetry works and consider the implications for a patient's health when interpreting SpO2 in individuals with pigmented skin.

The Effects of Head Elevation on Intracranial Pressure, Cerebral Perfusion Pressure, and Cerebral Oxygenation Among Patients with Acute Brain Injury: A Systematic Review and Meta-Analysis.

BACKGROUND: Head elevation is recommended as a tier zero measure to decrease high intracranial pressure (ICP) in neurocritical patients. However, its quantitative effects on cerebral perfusion pressure (CPP), jugular bulb oxygen saturation (SjvO2), brain tissue partial pressure of oxygen (PbtO2), and arteriovenous difference of oxygen (AVDO2) are uncertain. Our objective was to evaluate the effects of head elevation on ICP, CPP, SjvO2, PbtO2, and AVDO2 among patients with acute brain injury. METHODS: We conducted a systematic review and meta-analysis on PubMed, Scopus, and Cochrane Library of studies comparing the effects of different degrees of head elevation on ICP, CPP, SjvO2, PbtO2, and AVDO2. RESULTS: A total of 25 articles were included in the systematic review. Of these, 16 provided quantitative data regarding outcomes of interest and underwent meta-analyses. The mean ICP of patients with acute brain injury was lower in group with 30° of head elevation than in the supine position group (mean difference [MD] - 5.58 mm Hg; 95% confidence interval [CI] - 6.74 to - 4.41 mm Hg; p < 0.00001). The only comparison in which a greater degree of head elevation did not significantly reduce the ICP was 45° vs. 30°. The mean CPP remained similar between 30° of head elevation and supine position (MD - 2.48 mm Hg; 95% CI - 5.69 to 0.73 mm Hg; p = 0.13). Similar findings were observed in all other comparisons. The mean SjvO2 was similar between the 30° of head elevation and supine position groups (MD 0.32%; 95% CI - 1.67% to 2.32%; p = 0.75), as was the mean PbtO2 (MD - 1.50 mm Hg; 95% CI - 4.62 to 1.62 mm Hg; p = 0.36), and the mean AVDO2 (MD 0.06 µmol/L; 95% CI - 0.20 to 0.32 µmol/L; p = 0.65).The mean ICP of patients with traumatic brain injury was also lower with 30° of head elevation when compared to the supine position. There was no difference in the mean values of mean arterial pressure, CPP, SjvO2, and PbtO2 between these groups. CONCLUSIONS: Increasing degrees of head elevation were associated, in general, with a lower ICP, whereas CPP and brain oxygenation parameters remained unchanged. The severe traumatic brain injury subanalysis found similar results.

Air or Oxygen for Infant Resuscitation: A Prospective Cohort Study of Moderate-Late Preterm Infants Requiring Delivery Room Resuscitation.

INTRODUCTION: Due to concerns of oxidative stress and injury, most clinicians currently use lower levels of fractional inspired oxygen (FiO2, 0.21-0.3) to initiate respiratory support for moderate to late preterm (MLPT, 32-36 weeks gestation) infants at birth. Whether this practice achieves recommended oxygen saturation (SpO2) targets is unknown. METHODS: We aimed to determine SpO2 trajectories of MLPT infants requiring respiratory support at birth. We conducted a prospective, opportunistic, observational study with consent waiver. Preductal SpO2 readings were obtained during the first 10 min of life from infants between 32 and 36 weeks gestation requiring respiratory support in the delivery room. Primary outcome was reaching a minimum SpO2 80% at 5 min of life. The study was prospectively registered (ACTRN12620001252909). RESULTS: A total of 76 eligible infants were recruited between February 2021 and March 2022 from 5 hospitals in Australia. Most (n = 58, 76%) had respiratory support initiated with FiO2 0.21 (range 0.21-1.0) using CPAP (92%). Median SpO2 at 5 min was 81% (interquartile range [IQR] 67-90) and 93% (IQR 86-96) at 10 min. At 5 min, 18/43 (42%) infants had SpO2 below 80% and only 8/43 (19%) reached SpO2 80-85%. CONCLUSIONS: Many MLPT infants requiring respiratory support do not achieve recommended SpO2 targets. In very preterm infants, SpO2 <80% at 5 min of life increases risk of death, intraventricular haemorrhage, and neurodevelopmental impairment. The implications on this practice on the health outcomes of MLPT infants are unclear and require further research.

Automatic Segmentation for Analysis of Murine Cardiac Ultrasound and Photoacoustic Image Data Using Deep Learning.

OBJECTIVE: Although there are methods to identify regions of interest (ROIs) from echocardiographic images of myocardial tissue, they are often time-consuming and difficult to create when image quality is poor. Further, while myocardial strain from ultrasound (US) images can be estimated, US alone cannot obtain functional information, such as oxygen saturation (sO2). Photoacoustic (PA) imaging, however, can be used to quantify sO2 levels within tissue non-invasively. METHODS: Here, we leverage deep learning methods to improve segmentation of the anterior wall of the left ventricle and apply both strain and oxygen saturation analysis via segmentation of murine US and PA images. RESULTS: Data revealed that training on US/PA images using a U-Net deep neural network can be used to create reproducible ROIs of the anterior wall of the left ventricle in a murine image dataset. Accuracy and Dice score metrics were used to evaluate performance of the neural network on each image type. We report an accuracy of 97.3% and Dice score of 0.84 for ultrasound, 95.6% and 0.73 for photoacoustic, and 96.5% and 0.81 for combined ultrasound and photoacoustic images. CONCLUSION: Rapid segmentation via such methods can assist in quantification of strain and oxygenation.

Multispectral Imaging-Based System for Detecting Tissue Oxygen Saturation With Wound Segmentation for Monitoring Wound Healing.

OBJECTIVE: Blood circulation is an important indicator of wound healing. In this study, a tissue oxygen saturation detecting (TOSD) system that is based on multispectral imaging (MSI) is proposed to quantify the degree of tissue oxygen saturation (StO2) in cutaneous tissues. METHODS: A wound segmentation algorithm is used to segment automatically wound and skin areas, eliminating the need for manual labeling and applying adaptive tissue optics. Animal experiments were conducted on six mice in which they were observed seven times, once every two days. The TOSD system illuminated cutaneous tissues with two wavelengths of light - red ([Formula: see text] nm) and near-infrared ([Formula: see text] nm), and StO2 levels were calculated using images that were captured using a monochrome camera. The wound segmentation algorithm using ResNet34-based U-Net was integrated with computer vision techniques to improve its performance. RESULTS: Animal experiments revealed that the wound segmentation algorithm achieved a Dice score of 93.49%. The StO2 levels that were determined using the TOSD system varied significantly among the phases of wound healing. Changes in StO2 levels were detected before laser speckle contrast imaging (LSCI) detected changes in blood flux. Moreover, statistical features that were extracted from the TOSD system and LSCI were utilized in principal component analysis (PCA) to visualize different wound healing phases. The average silhouette coefficients of the TOSD system with segmentation (ResNet34-based U-Net) and LSCI were 0.2890 and 0.0194, respectively. CONCLUSION: By detecting the StO2 levels of cutaneous tissues using the TOSD system with segmentation, the phases of wound healing were accurately distinguished. This method can support medical personnel in conducting precise wound assessments. Clinical and Translational Impact Statement-This study supports efforts in monitoring StO2 levels, wound segmentation, and wound healing phase classification to improve the efficiency and accuracy of preclinical research in the field.

Thirty-second chair stand test in older adults with chronic health conditions is associated with lower limb oxygen extraction capacity.

BACKGROUND: The 30-s chair stand test (CS-30) is a well-known measure of muscle strength in older adults. However, factors other than muscle strength may also be involved in older adults with chronic health conditions who require support and care in daily living. PURPOSE: To test the hypothesis that the CS-30 in older adults with chronic health conditions is associated with lower limb muscle oxygen extraction capacity. METHODS: Twenty-seven older adults with chronic health conditions (those who needed support and care in daily living because of stroke, musculoskeletal disease, etc.) were recruited. Tissue and percutaneous oxygen saturations of the right vastus lateralis muscle were measured during CS-30 measurements, and muscle oxygen extraction rate (MOER) was calculated. Knee extension strength, skeletal muscle mass index (SMI), and phase angle (PhA) were measured. In a multiple regression analysis with CS-30 as the dependent variable, results were calculated for model 1 with SMI, PhA, and ΔMOER as independent variables and model 2 with knee extension muscle strength added to model 1. RESULTS: Phase angle (model 1, ß = 0.46, p = .014; model 2, ß = 0.46, p = .016) and ΔMOER (model 1, ß = 0.39, p = .032; model 2, ß = 0.40, p = .039) were significantly associated in both models. Adjusted R2 was 0.26 (Model 1) and 0.23 (Model 2). CONCLUSION: The CS-30 in older adults with chronic health conditions may be related to muscle oxygen extraction capacity. This indicates that CS-30 also considers lower limb endurance assessment in this population.

Machine learning-based prediction of cerebral oxygen saturation based on multi-modal cerebral oximetry data.

This study develops machine learning-based algorithms that facilitate accurate prediction of cerebral oxygen saturation using waveform data in the near-infrared range from a multi-modal oxygen saturation sensor. Data were obtained from 150,000 observations of a popular cerebral oximeter, Masimo O3™ regional oximetry (Co., United States) and a multi-modal cerebral oximeter, Votem (Inc., Korea). Among these observations, 112,500 (75%) and 37,500 (25%) were used for training and test sets, respectively. The dependent variable was the cerebral oxygen saturation value from the Masimo O3™ (0-100%). The independent variables were the time of measurement (0-300,000 ms) and the 16-bit decimal amplitudes values (infrared and red) from Votem (0-65,535). For the right part of the forehead, the root mean square error of the random forest (0.06) was much smaller than those of linear regression (1.22) and the artificial neural network with one, two or three hidden layers (2.58). The result was similar for the left part of forehead, that is, random forest (0.05) vs logistic regression (1.22) and the artificial neural network with one, two or three hidden layers (2.97). Machine learning aids in accurately predicting of cerebral oxygen saturation, employing the data from a multi-modal cerebral oximeter.

The Effect of Static Apnea Diving Training on the Physiological Parameters of People with a Sports Orientation and Sedentary Participants: A Pilot Study.

Diver training improves physical and mental fitness, which can also benefit other sports. This study investigates the effect of eight weeks of static apnea training on maximum apnea time, and on the physiological parameters of runners, swimmers, and sedentary participants, such as forced vital capacity (FVC), minimum heart rate (HR), and oxygen saturation (SpO2). The study followed 19 participants, including five runners, swimmers, sedentary participants, and four competitive divers for reference values. The minimum value of SpO2, HR, maximum duration of apnea, and FVC were measured. Apnea training occurred four times weekly, consisting of six apneas with 60 s breathing pauses. Apnea duration was gradually increased by 30 s. The measurement started with a 30 s apnea and ended with maximal apnea. There was a change in SpO2 decreased by 6.8%, maximum apnea length increased by 15.8%, HR decreased by 9.1%, and FVC increased by 12.4% for the groups (p < 0.05). There were intra-groups changes, but no significant inter-groups difference was observed. Eight weeks of apnea training improved the maximum duration of apnea, FVC values and reduced the minimum values of SpO2 and HR in all groups. No differences were noted between groups after training. This training may benefit cardiorespiratory parameters in the population.

Validation of a Novel Noninvasive Technology to Estimate Blood Oxygen Saturation Using Green Light: Observational Study.

BACKGROUND: Pulse oximeters work within the red-infrared wavelengths. Therefore, these oximeters produce erratic results in dark-skinned subjects and in subjects with cold extremities. Pulse oximetry is routinely performed in patients with fever; however, an elevation in body temperature decreases the affinity of hemoglobin for oxygen, causing a drop in oxygen saturation or oxyhemoglobin concentrations. OBJECTIVE: We aimed to determine whether our new investigational device, the Shani device or SH1 (US Patent 11191460), detects a drop in oxygen saturation or a decrease in oxyhemoglobin concentrations. METHODS: An observational study (phase 1) was performed in two separate groups to validate measurements of hemoglobin and oxygen concentrations, including 39 participants recruited among current university students and staff aged 20-40 years. All volunteers completed baseline readings using the SH1 device and the commercially available Food and Drug Administration-approved pulse oximeter Masimo. SH1 uses two light-emitting diodes in which the emitted wavelengths match with absorption peaks of oxyhemoglobin (hemoglobin combined with oxygen) and deoxyhemoglobin (hemoglobin without oxygen or reduced hemoglobin). Total hemoglobin was calculated as the sum of oxyhemoglobin and deoxyhemoglobin. Subsequently, 16 subjects completed the "heat jacket study" and the others completed the "blood donation study." Masimo was consistently used on the finger for comparison. The melanin level was accounted for using the von Luschan skin color scale (VLS) and a specifically designed algorithm. We here focus on the results of the heat jacket study, in which the subject wore a double-layered heated jacket and pair of trousers including a network of polythene tubules along with an inlet and outlet. Warm water was circulated to increase the body temperature by 0.5-0.8 °C above the baseline body temperature. We expected a slight drop in oxyhemoglobin concentrations in the heating phase at the tissue level. RESULTS: The mean age of the participants was 24.1 (SD 0.8) years. The skin tone varied from 12 to 36 on the VLS, representing a uniform distribution with one-third of the participants having fair skin, brown skin, and dark skin, respectively. Using a specific algorithm and software, the reflection ratio for oxyhemoglobin was displayed on the screen of the device along with direct hemoglobin values. The SH1 device picked up more minor changes in oxyhemoglobin levels after a change in body temperature compared to the pulse oximeter, with a maximum drop in oxyhemoglobin concentration detected of 6.5% and 2.54%, respectively. CONCLUSIONS: Our new investigational device SH1 measures oxygen saturation at the tissue level by reflectance spectroscopy using green wavelengths. This device fared well regardless of skin color. This device can thus eliminate racial disparity in these key biomarker assessments. Moreover, since the light is shone on the wrist, SH1 can be readily miniaturized into a wearable device.