Oximetry Research Articles

Improvement of Quality and Patient Safety in Anaesthesia Practice in Low-Resource Settings

In modern healthcare system, health policy makers, healthcare professionals and organizations, and patients are becoming more aware of the importance of promoting quality care and safety practices. In anaesthesia practice, the specialty has come a long way since its establishment in Dhaka Medical College Hospital in Bangladesh in 1950s by the house surgeons at that time. In last few decades, there had been incredible innovations in anaesthesia, such as the introduction of sevoflurane, isoflurane, propofol, the laryngeal mask airway, pulse oximetry, HDU and ICU facilities and many more. However, in Bangladesh, being a low-resource country, there are still many challenges that the specialty must meet especially in quality of care and patient safety culture. Following some recent anaesthesia-related fatalities, concerns about anaesthesia flared up among patients, health professionals and policy makers. Therefore, different healthcare organizations, both public and private, are now looking at the resiliency analysis of the anaesthesia practice in order to improve quality and patient safety to enhance patient satisfaction and trust building. This review paper aims to discuss quality improvement and patient safety in anesthesia practice and their contributing factors, standardized practices, and strategies to facilitate safety with a focus on teamwork and communication in low-resource settings. However, the review does not seek to be exhaustive or systematic, but to highlight current areas of concern and some potential solutions. Mugda Med Coll J. 2024; 7(2): 127-134

Association of Intraoperative Occult Hypoxemia With 30-Day and 1-Year Mortality.

Despite the widespread use of pulse oximetry for intraoperative estimation of arterial oxygen saturation, there is growing evidence that certain patient populations may be vulnerable to inaccurate pulse oximetry measurements and that unrecognized hypoxemia is associated with end-organ damage and adverse outcomes. In this single-center retrospective cohort study, we sought to better elucidate the relationship between intraoperative occult hypoxemia and postoperative mortality among patients undergoing anesthesia and surgery. Data were collected from our departmental data warehouse for adult patients (≥18 years) undergoing anesthesia between 2008 and 2019 with at least 1 intraoperative arterial blood gas recorded. The number of occult hypoxemic events, defined as arterial oxygen saturation (Sao2) of <88% despite oxygen saturation measured by pulse oximetry (Spo2) >92%, were determined. Mortality data were obtained from the Social Security Death Master File and used to determine 30-day and 1-year postoperative mortality. Propensity score overlap-weighted Firth logistic regression and Cox proportional-hazard modeling were performed to analyze whether at least 1 occult hypoxemic event was predictive of 30-day and 1-year mortality. There were 25,234 patients and 62,707 paired readings included in the final analysis. There were 351 patients (1.4%) with at least 1 occult hypoxemic reading. The overall 30-day mortality rate was 3.3% and 1-year mortality rate was 10.2%. In the overlap-weighted models, patients who experienced at least 1 occult hypoxemic event had significantly higher odds of both 30-day mortality (odds ratio [OR] = 2.89, 95% confidence interval [CI], 1.46-5.72, P = .002) and 1-year mortality (hazard ratio [HR] = 1.90, CI, 1.48-2.43, P < .001). There was no significant interaction between occult hypoxemia and self-reported race/ethnicity for predicting mortality. Intraoperative occult hypoxemic events are associated with significantly higher odds of 30-day and 1-year mortality, independent of self-reported race/ethnicity.

STEPPING OUTSIDE THE BOX: TAILORING EXERCISE TEST PROTOCOLS &amp; PROCEDURES

https://youtu.be/r8yQKiNeJWc INTRODUCTION The most frequently used exercise test protocol in the United States is the Bruce treadmill protocol. Using this standard protocol enables clinicians to report clinically useful information beyond myocardial ischemia, hemodynamic response, and rhythm, such as estimating prognosis with the Duke Treadmill Score and categorizing fitness by age and sex. However, some patients, especially highly fit aerobic-type athletes, might be better served with tailored exercise test procedures. CASE PRESENTATION A 22-year-old, apparently healthy male, collegiate track athlete complained of lightheadedness and profound fatigue after repeated intervals of 400-800 m. The referring physician ordered a cardiopulmonary exercise test in order to replicate his training regimen and symptoms. MANAGEMENT A plan was developed to perform a graded exercise test (GXT) on a treadmill with measurement of expired air, followed by a 3-min active cooldown, then up to 4 run/walk intervals of 1- and 2-min duration, respectively. Spirometry was performed before the GXT and repeatedly up to 20 min after the last run interval. The GXT protocol was based on the athlete’s self-reported pace during warmup (8:00/mile [4:58/km]) and a 10 km run (6:00/mile [3:44/km]) with a target duration of 10 min. The run intervals were based on his self-reported target time to complete 400 m (~65 s) during training. That time was converted to speed (13.8 miles/h [22.2 km/h]) and the associated metabolic equivalents of task (METs) were estimated (22 METs). Because the maximum speed of the laboratory treadmill is 12 miles/h (19.3 km/h), a 3% incline was used to achieve the target METs during the run intervals. A 12-lead ECG and pulse oximetry were monitored continuously during the GXT, the run/walk intervals, and through 6 min of recovery. Blood pressure (BP) was monitored via auscultation every 2 min through the initial 6 min of the GXT and recovery. BPs could not be obtained at higher running speeds. He did not use the handrail for support during testing. He reported that the run intervals were a similar level of exertion as during training. No abnormalities were noted during the GXT or the spirometry. His symptoms were reproduced during the 4th run interval. Total time in the laboratory was 1.5 hours. DISCUSSION Exercise testing on this patient could have been limited to a GXT (Bruce protocol or other), but the probability of reproducing his symptoms would have been low. As a young athlete, staff were confident that he could tolerate a GXT and several running intervals during the same encounter. Knowledge of METs allowed for an equivalent workload to be identified for the intervals despite limitations of the treadmill speed. It is not uncommon for laboratories to limit testing protocols to a few options (e.g. Bruce or modified Bruce). However, it can be beneficial to tailor procedures for select patients to increase the likelihood of reproducing patient-specific complaints or responses.

Implementation of Continuous Capnography Protocol in a Postanesthesia Care Unit for Adult Patients at High-risk of Postoperative Respiratory Depression

This project aimed to implement a continuous capnography protocol in the postanesthesia care unit (PACU) for postoperative adult patients who are at high risk for respiratory failure. A preintervention and postintervention quality improvement design with retrospective chart reviews evaluated patient demographics (age, weight, body mass index [BMI], perioperative fluid intake and output, use of intraoperative positive-end expiratory pressure), length of surgery, average length of PACU stay, incidence of respiratory events, and adherence to a PACU capnography protocol. Preimplementation data were collected from retrospective chart reviews over a 3-month period. A continuous capnography protocol was implemented for same-day surgery patients with a BMI of 35kg/m2 or greater and who received general anesthesia. Postimplementation data were collected over 3 months in addition to adherence to the capnography protocol. This was presented using descriptive statistics. Age, length of surgery, weight, BMI, perioperative fluid intake and output, and use of positive-end expiratory pressure did not impact PACU length of stay. The average PACU length of stay decreased from 76.76 to 71.82minutes postimplementation but was not statistically significant (P=.470). The incidence of respiratory events was 6% (n=3). After the implementation of the continuous capnography protocol, adherence to the continuous capnography monitoring was 86% (n=43). Patients who are at high risk for postoperative respiratory failure may benefit from continuous capnography monitoring in the PACU. Capnography monitoring may decrease PACU length of stay and provide earlier detection of pending respiratory depression or failure than pulse oximetry alone.

The prevalence of hypoxaemia in paediatric and adult patients in health-care facilities in low-income and middle-income countries: a systematic review and meta-analysis.

Hypoxaemia (low oxygen saturation in blood) is a key predictor of in-hospital mortality, affecting people of all ages with many different conditions. Early detection and treatment of hypoxaemia are critical, but there are few data to quantify hypoxaemia burden outside the child pneumonia population. We aimed to estimate hypoxaemia prevalence for adults and children with acute illness attending health facilities in low-income and middle-income countries (LMICs). We conducted a systematic review and meta-analysis, searching MEDLINE, PubMed, Embase, Cumulated Index in Nursing and Allied Health Literature, Index Medicus, and Google Scholar for studies reporting hypoxaemia prevalence among patients attending health facilities. We included articles with original data on peripheral blood oxygen saturation (SpO2), from an LMIC, published between Jan 1, 1998, and Jan 10, 2023. We included studies in acutely unwell people of any age and with any condition, but excluded those admitted to intensive care units, receiving perioperative care, or attending hospital for preventive or chronic care. We assessed study quality using Joanna Briggs Institute's Checklist for Prevalence Studies. Two reviewers independently conducted title and abstract screening, full-text review, data extraction, and quality assessment, requesting summary data from authors. We reported pooled prevalence of hypoxaemia (typically defined as SpO2 <90%) overall and by condition, using a random-effects meta-analysis model. This study is registered with PROSPERO, CRD42019136622. We identified 9173 unique records from searches and included 213 in meta-analyses involving 601 757 participants. The majority of studies were from the World Bank regions of sub-Saharan Africa (108 [51%] of 213) or south Asia (58 [27%]). The pooled prevalence of hypoxaemia among admitted patients was 24·5% (95% CI 19·9-29·4) for neonates (aged 0-28 days), 12·1% (10·0-14·4) for children (aged 1 month-17 years), and 10·8% (4·9-18·7) for adults (aged ≥18 years). Hypoxaemia prevalence was highest in neonatal and primary respiratory conditions but still common in many other conditions. Hypoxaemia was associated with 4·84 (95% CI 4·11-5·69) times higher odds of death than no hypoxaemia. Hypoxaemia is common across all age groups and a range of primary respiratory and other critical illnesses and is strongly associated with death. These estimates will inform oxygen-related strategies and programmes, and integration of pulse oximetry and oxygen into clinical guidelines, service structures, and strategies for maternal, neonatal, child, adolescent, and adult health. Bill & Melinda Gates Foundation, the ELMA Foundation, and Unitaid.

Hypoxemia During Bronchoscopy and The Risk Factors Related

Background: Hypoxemia, a common complication of bronchoscopy, often occurs even with oxygen supplementation, particularly during procedures performed under sedation, with reported incidences ranging from 2.5% to 69%. Hypoxemia during bronchoscopy which is defined as desaturation under 90% or more than 5% decreasing of basal SpO2, becomes a concern due to possible fatal complications. This study aims to determine the incidence of hypoxemia during bronchoscopy and identify its predisposing risk factors. Methods: An analytic observational study with a cross-sectional design was held in our center from October 2022 until June 2023. As many as 100 consecutive patients who underwent bronchoscopy and met inclusion criteria were evaluated prospectively. The patient’s oxygen saturation was monitored by finger pulse oximetry during the procedure. Demographic characteristics, comorbidities, lung function, PaO2 value, ASA score, types of intervention, sedative agents, duration of sedation and procedure were recorded. The risk factors for hypoxemia during bronchoscopy were evaluated. Results: The incidence of hypoxemia during bronchoscopy in our center was 15%. Bivariate analysis showed pleural effusion as a comorbidity (9 patients; 60%), restrictive-obstructive lung function test (10 patients; 66.7%) and PaO2 value (76.87±8.219) were statistically significant (P&lt;0.05) related to the existence of hypoxemia during bronchoscopy. Three other factors such as age, ASA score and duration of procedure with P&lt;0.25 were included in multivariate analysis and found that the most influencing factor was the restrictive-obstructive lung function test (P=0.001; OR=13.845). Conclusion: Comorbidity (pleural effusion), lung function (restrictive-obstructive) and PaO2 value were some factors significantly related to hypoxemia during bronchoscopy with lung function being the most influencing factor.

Incorporating an Elevated Perfusion Index in the Right Hand Enhanced Screening Sensitivity for Critical Aortic Arch Obstruction in Newborn Infants.

Newborn infants with critical aortic arch obstruction are often undiagnosed at discharge, despite screening. This study investigated if adding the perfusion index improved early detection. We retrospectively studied 38 newborn infants with critical aortic arch obstruction, who were routinely screened in 2014-2019 by 13 Swedish hospitals using pulse oximetry and the perfusion index. They were identified through surgery records and national mortality databases. The controls were 512 healthy newborn infants from one hospital. Optimal perfusion index cut-offs were determined using frequency distribution analysis. The groups had similar median gestational ages and birth weight. No infants with critical aortic arch obstruction were diagnosed just because of a positive perfusion index result. However, the right-hand perfusion index was significantly higher in the cases than in controls (p < 0.001). A perfusion index of > 3%, or positive pulse oximetry or positive physical examination, yielded 76% sensitivity and 85% specificity, with an area under the receiver operating characteristic curve of 0.81 (range 0.73-0.89, p < 0.0001). Pulse oximetry and just neonatal physical examinations had a lower sensitivity (45%, p = 0.009). A high perfusion index in the right hand enhanced critical aortic arch obstruction screening and repeated measurements should be explored to minimise false positives.

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.

Effects of Songs Recorded by Parents on the Vital Signs of Preterm Infants: A Randomized Controlled Trial

Background: Preterm infants often have unstable vital signs and prolonged hospital stays that can hinder parent–infant bonding, especially under COVID-19 restrictions. This study aimed to evaluate whether listening to songs recorded by parents was effective in stabilizing the condition of premature infants. Methods: This randomized controlled study was conducted at the University of Miyazaki Hospital from October 2022 to March 2024 during the COVID-19 pandemic period. The participants were preterm infants born at less than 33 weeks gestation and their parents, all of whom recorded songs. The recorded songs were played daily to the infants in the intervention group, while the control group received usual care. Primary outcomes included vital signs (respiratory rate, pulse oximetry saturation, heart rate) and activity level. Results: Data for 33 preterm infants (intervention, n = 17 [total 749 sessions]; control, n = 16 [total 721 sessions]) were analyzed for changes in vital signs and activity levels. The intervention reduced infants’ respiratory rates (4.1 [95% CI: 2.5–5.6], p &lt; 0.001) and slightly but statistically significantly increased pulse oximetry saturation (0.6 [95% CI: 0.02–1.2], p &lt; 0.044). Conclusions: Recorded parental songs were found to safely stabilize the respiratory status of preterm infants and may serve as an accessible intervention to support parent–infant attachment, particularly in settings with restricted parental visitation.

Hypoxemia and Postoperative Monitoring After Anesthesia: A Prospective Observational Study Using Portable Pulse Oximetry in a Resource-Limited Setting in Guatemala

Hypoxemia and Postoperative Monitoring After Anesthesia: A Prospective Observational Study Using Portable Pulse Oximetry in a Resource-Limited Setting in Guatemala

Pulse Oximetry and the Seriously-Ill Homebound Older Adult: A Retrospective Review of Telephone Triage Calls.

Pulse Oximetry and the Seriously-Ill Homebound Older Adult: A Retrospective Review of Telephone Triage Calls.

Managing home oxygen and nasogastric feeds post-NICU discharge: PCP practices and perspectives.

NICU graduates are frequently technology dependent including home oxygen, pulse oximetry, and/or nasogastric (NG) feedings. Primary care provider (PCP) perceptions, practices, and barriers to managing these infants are not well described, especially at altitude. We sought to 1) describe PCP comfort and 2) determine practices and barriers in managing this technology at higher altitude. This cross-sectional survey assessed Colorado and Wyoming PCP perceptions and practices surrounding technology in NICU graduates. We explored bivariate analysis between clinic altitude, location, and provider's experience with comfort caring for infants discharged with technology using chi-squared or fisher's exact tests. Significant relationships were modeled using logistic regression for odds ratios and 95% confidence intervals. Among 200 respondents, 82% were pediatricians and 86% practiced in urban/suburban environments. Clinic altitude ranged 2,500-9,000 feet. PCPs endorsed comfort managing oxygen in term (92%) and moderately/late preterm infants (82%), versus 52% comfort in very/extremely preterm infants. 62% utilized an oxygen weaning algorithm. Comfort managing oxygen was greater in suburban versus urban locations (OR 4.4, 95% CI 1.6-11.7) and providers practicing for > 10 versus < 5 years (OR 3.5, 95% CI 1.5, 8.4). 60% found pulse oximetry useful, though 70% perceived caregiver stress. 69% accepted infants on NG feeds, though 61% endorsed discomfort with management. PCPs are comfortable managing home oxygen in moderately preterm to term infants but find caring for the most preterm infants challenging. Discomfort in managing NG feeds is prevalent. This highlights peri-discharge barriers and improvement opportunities for high-risk, technology-dependent infants.

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.

Heterogeneity of Intermediate Care Organization Within a Single Healthcare System.

Intermediate care (IC) is prevalent nationwide, but little is known about how to best organize this level of care. Using a 99-item cross-sectional survey assessing four domains (hospital and physical IC features, provider and nurse staffing, monitoring, and interventions/services), we describe the organizational heterogeneity of IC within a five-hospital healthcare system. Surveys were completed by nurse managers from 12 (86%) of 14 IC settings. Six IC settings (50%) were embedded within acute care wards, four (33%) were stand-alone units, and two (17%) were embedded within an ICU. All had a nurse-to-patient ratio of 1:3, provided continuous cardiac telemetry, continuous pulse oximetry, high-flow nasal oxygen, and bedside intermittent hemodialysis. Most (> 50%) permitted arterial lines, frequent nursing assessments (every 2 hr), and noninvasive ventilation or mechanical ventilation via a tracheostomy. Vasopressors were less often permitted (< 25% of settings). Models of IC vary greatly within a single healthcare system.

Obstructive sleep apnea is a common diagnosis in patients admitted at the memory clinic: Please screen for it!

Obstructive sleep apnea (OSA) affects a large portion of middle-aged and older adults. It has been linked to increased risk of cognitive decline and Alzheimer's disease. OSA can impair cognitive performance and patients with cognitive complaints can frequently present with this sleep disorder. Although instruments able for correctly screening patients with cognitive impairment and OSA exist, there is no evidence about utility and feasibility of their use in the memory clinics. The study by Lam et al. showed that, in case of impossibility of performing polysomnography-that is the gold standard for OSA diagnosis, pulse oximetry can represent a good instrument for screening patients with cognitive impairment for OSA, and they do not advice for using sleep interview or STOP-Bang questionnaire for screening this sleep disorder.

Hepatopulmonary syndrome from liver disease associated with autosomal recessive polycystic kidney disease.

Hepatopulmonary syndrome (HPS) is a life-threatening complication of chronic liver disease (CLD) that currently can be managed only by liver transplant. Though uncommon, some children with kidney disease have coexistent CLD and hence are at risk of developing HPS. Paediatric cases of HPS are rarely described in the nephrology literature. We present a patient with autosomal recessive polycystic kidney disease (ARPKD) and persistent hypoxaemia diagnosed as HPS and successfully managed with a liver transplant. We suggest that nephrologists caring for children with kidney and concomitant CLD consider routine screening for HPS with pulse oximetry.

Diagnostic accuracy of combined screening algorithm for early detection of congenital heart disease among term newborns in India.

To determine the validity of a screening algorithm based on combination of clinical examination and pulse oximetry, for early detection of congenital heart disease (CHD) in term newborns. CHD is the most frequent major congenital anomaly, with prevalence of 6-12 per 1000 live births. Clinical examination alone may fail to detect CHD in more than 50% of affected newborns. Recent studies have concluded that pulse oximetry has a high sensitivity and specificity as a screening tool for critical CHD. JSS Hospital, Mysuru, Karnataka, India. In this prospective observational study, all term neonates delivered at the hospital were included. The screening algorithm consisted of seven clinical parameters and pulse oximetry screening guidelines recommended by the American Academy of Paediatrics. Term newborns with the presence of any one of the above parameters in the algorithm were considered screen-positive. Echocardiography was done in all screen positives. Newborns were classified into those with and without CHD, based on echocardiography findings at birth and clinical examination and echocardiography findings at follow-up at 6 weeks. Among 1009 term neonates included in the study, CHD was detected in 57 (5.6%) with cyanotic CHD in 12. The sensitivity and specificity of combined screening to detect CHD was 71.93% and 95.8%, respectively. The positive predictive value was 50.62% and the negative predictive value was 98.28%. Screening for CHD with a simple comprehensive algorithm, integrating clinical evaluation and pulse oximetry, has moderate sensitivity and high specificity in detecting CHD in term newborns. Further work is needed to evaluate this form of screening.

Monte Carlo Simulation of the Effect of Melanin Concentration on Light-Tissue Interactions in Reflectance Pulse Oximetry.

Over the past ten years, there has been an increasing demand for reliable consumer wearables as users are inclined to monitor their health and fitness metrics in real-time, especially since the COVID-19 pandemic. Reflectance pulse oximeters in fitness trackers and smartwatches provide convenient, non-invasive SpO2 measurements but face challenges in achieving medical-grade accuracy, particularly due to difficulties in capturing physiological signals, which may be affected by skin pigmentation. Hence, this study sets out to investigate the influence of skin pigmentation, particularly in individuals with darker skin, on the accuracy and reliability of SpO2 measurement in consumer wearables that utilise reflectance pulse oximeters. A Monte Carlo model is developed to assess the effect on simulated reflectance pulse oximetry measurements across light, moderate, and dark skin types for oxygen saturation levels between 70 and 100%. The results indicate that a one-algorithm-fits-all calibration approach may be insufficient, and root mean square errors (RMSEs) of at least 0.3956%, 0.9132%, and 8.4111% for light, moderate, and dark skin are observed when compared to transmittance calibration algorithms. Further research is required to validate these findings and improve the performance of reflectance pulse oximeters in real-world applications, particularly in the context of consumer wearables.

Emergency department early mortality model for patients admitted after presenting to a tertiary medical center emergency department.

Identifying patients in the emergency department (ED) at higher risk for in-hospital mortality can inform shared decision making and goals-of-care discussions. Electronic health record systems allow for integrated multivariable logistic regression (LR) modeling, which can provide early predictions of mortality risk in time for crucial decision making during a patient's initial care. Many commonly used LR models require blood gas analysis values, which are not frequently obtained in the ED. The goal of this study was to develop an all-cause mortality prediction model, derived from commonly collected ED data, which can assess mortality risk early in ED care. Data were obtained for all patients, age 18 and older, admitted from the ED to Atrium Health Wake Forest Baptist from April 1, 2016, through March 31, 2020. Initial vital signs including heart rate, respiratory rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse oximetry, weight, body mass index, comprehensive metabolic panel, and a complete blood count were electronically retrieved for all patients. The prediction model was developed using LR. The ED early mortality (EDEM) model was compared with the rapid Emergency Medicine Score (REMS) for performance analysis. A total of 45,004 patients met inclusion criteria, comprising a total of 77,117 admissions. In this cohort, 52.8% of patients were male and 47.2% were female. The model used 35 variables and yielded an area under the receiver operating characteristic curve (AUC) of 0.889 (95% CI 0.874-0.905) with a sensitivity of 0.828 (95% CI 0.791-0.860), a specificity of 0.788 (95% CI 0.783-0.794), a negative predictive value of 0.995 (95% CI 0.994-0.996), and a positive predictive value of 0.084 (95% CI 0.076-0.092). This outperformed REMS in this data set, which yielded an AUC of 0.500 (95% CI 0.455-0.545). The EDEM model was predictive of in-hospital mortality and was superior to REMS.

Reference Ranges for Cerebral Oxygenation in Neonates During Immediate Transition After Birth: Differences Between Devices.

The aim was to define reference ranges for cerebral oxygen saturation (crSO2-ROOT) during immediate transition after birth in stable neonates. In a prospective observational study, the crSO2-ROOT was continuously measured in neonates during the first 15 min after birth. The neonatal sensor was placed on the head and fixed with a bandage. Median values and 10th and 90th centiles were calculated for each minute. Additionally, cerebral fractional tissue oxygen extraction (cFTOE-ROOT) was calculated using crSO2-ROOT and arterial oxygen saturation (SpO2) measured with pulse oximetry. These crSO-ROOT values were compared with already published reference ranges of cerebral oxygen saturation measured using different devices: crSO2-INVOS and cTOI-NIRO. The data of 122 neonates (14 preterm/108 term neonates) were analysed. The crSO2-ROOT values had a similar course when compared to cTOI-NIRO values, whereas crSO2-INVOS values were initially lower and exceeded during the first minutes after birth. The present observational study added reference ranges of crSO2-ROOT in stable neonates immediately after birth. As there are differences regarding reference ranges of various near-infrared spectroscopy (NIRS) devices, it is important to be aware of this information for future clinical use.