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Aim: To investigate if tachypneic response to hypoxia is decreased in older patients., Methods: We included all patients ≥65 years of age attending 52 Spanish emergency departments (EDs) for whom peripheral arterial oxygen saturation (SatO 2 ) measured by pulsioxymetry and respiratory rate (RR) were registered at ED arrival. We assessed the relationship between SatO2 and RR in different models, and with the best-fitting model, we independently analyzed this relationship in four subgroups according to patient age (65-69, 70-79, 80-89, and ≥90 years). Five sensitivity analyses using different subsets of patients were carried out to check for the consistency of the results., Results: We included 7126 patients, with medians for SatO 2 and RR of 97% (interquartile range [IQR]: 94-98) and 15 bpm (IQR: 15-16), respectively. We found significant associations (P < 0.001) between SatO 2 and RR in every model tested (P < 0.001 for all), with the quadratic model obtaining the best fit (R 2 : 0.098) over those obtained with linear (R 2 : 0.096) and logarithmic (R 2 : 0.092) models. The same was observed in sensitivity analyses, with R 2 for quadratic models ranging from 0.069 in patients with low comorbidity and 0.102 in patients breathing room air. The mean RR for 100% SatO 2 was 15 bpm and increased as SatO 2 decreased, although with a progressive slowing of the slope, with a mean RR of 27 at 50% SatO 2 . We detected a decreased RR response to increasing hypoxemia according to age and, while the RR curve was higher and with a progressively steepening slope in the 972 patients aged 65-69 (mean RR of 42 bpm with 50% SatO 2 ), a progressive slowing of slope was observed in the 2693 patients aged 70-79 (mean RR of 28 with 50% SatO2), the 2582 aged 80-89 (mean RR of 25) and the 879 aged ≥90 (mean RR of 23). Sensitivity analyses provided very similar results., Conclusion: Tachypneic response to hypoxemia in older patients decreases as age advances, regardless of the reason leading to hypoxemia. Geriatr Gerontol Int 2024; 24: 1120-1129., (© 2024 Japan Geriatrics Society.)

Objectives: The objectives of our systematic review and meta-analyses were to determine the diagnostic accuracy of central venous oxygen saturation (Scv o2 ) in estimating mixed venous oxygen saturation (Sv o2 ) and cardiac index in critically ill patients., Data Sources: A systematic search using MEDLINE, Cochrane Central Register of Controlled Trials, and Embase was completed on May 6, 2024., Study Selection: Studies of patients in the ICU for whom Scv o2 and at least one reference standard test was performed (thermodilution and/or Sv o2 ) were included., Data Extraction: Individual patient data were used to calculate the pooled intraclass correlation coefficient (ICC) for Sv o2 and Spearman correlation for cardiac index. The Quality Assessment of Diagnostic Accuracy Studies-2 and Grading Recommendations Assessment, Development, and Evaluation tools were used for the risk of bias and certainty of evidence assessments., Data Synthesis: Of 3427 studies, a total of 18 studies with 1971 patients were identified. We meta-analyzed 16 studies (1335 patients) that used Sv o2 as a reference and three studies (166 patients) that used thermodilution as reference. The ICC for reference Sv o2 was 0.83 (95% CI, 0.75-0.89) with a mean difference of 2.98% toward Scv o2 . The Spearman rank correlation for reference cardiac index is 0.47 (95% CI, 0.46-0.48; p < 0.0001)., Conclusions: There is moderate reliability for Scv o2 in predicting Sv o2 in critical care patients with variability based on sampling site and presence of sepsis. There is limited evidence on the independent use of Scv o2 in predicting cardiac index., Competing Interests: The authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.)

Introduction: The apnea-hypopnea index (AHI) is the current diagnostic parameter for diagnosing and estimating the severity of obstructive sleep apnea (OSA). It is, however, poorly associated with the main clinical symptom of OSA, excessive daytime sleepiness, and with the often-seen cognitive decline among OSA patients. To better evaluate OSA severity, novel hypoxic load parameters have been introduced that consider the duration and depth of oxygen saturation drops associated with apneas or hypopneas. The aim of this paper was to compare novel hypoxic load parameters and traditional OSA parameters to verbal memory and executive function in OSA patients., Method: A total of 207 adults completed a one-night polysomnography at sleep laboratory and two neuropsychological assessments, the Rey Auditory Verbal Learning Test and Stroop test., Results: Simple linear regression analyses were used to evaluate independent associations between each OSA parameter and cognitive performance. Associations were found between immediate recall and arousal index, hypoxia <90 %, average SpO 2 during sleep, and DesSev100+RevSev100. Total recall was associated with all OSA parameters, and no associations were found with the Stroop test. Subsequently, sex, age, and education were included as covariates in multiple linear regression analyses for each OSA parameter and cognitive performance. The main findings of the study were that average SpO 2 during sleep was a significant predictor of total recall (p < .007, β = -.188) with the regression model explaining 21.2 % of performance variation. Average SpO 2 during sleep was also a significant predictor of immediate recall (p < .022, β = -.171) with the regression model explaining 11.4 % of performance variation. Neither traditional OSA parameters nor novel hypoxic load parameters predicted cognitive performance after adjustment for sex, age, and education., Conclusion: The findings validate that the AHI is not an effective indicator of cognitive performance in OSA and suggest that average oxygen saturation during sleep may be the strongest PSG predictor of cognitive decline seen in OSA. The results also underline the importance of considering age when choosing neurocognitive tests, the importance of including more than one test for each cognitive domain as most tests are not pure measures of a single cognitive factor, and the importance of including tests that cover all cognitive domains as OSA is likely to have diffuse cognitive effects., Competing Interests: Declaration of competing interest KTH: no conflict of interest. HH: no conflict of interest. TK: no conflict of interest. SN: no conflict of interest. TD: no conflict of interest. IHN: no conflict of interest. TL: no conflict of interest. ESA: honoraria from Nox Medical, Philips, ResMed, Jazz Pharmaceuticals, Linde Healthcare, Alcoa – Fjardaral, WinkSleep, ApniMed and Vistor. She is also a member of the Philips Sleep Medicine & Innovation Medical Advisory Board. MKJ: no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Objectives: The objective of this systematic review was to clarify the status of near-infrared spectroscopy (NIRS) in monitoring perioperative renal regional tissue oxygen saturation (rSO 2 ) and determine whether there is evidence supporting its use in predicting postoperative acute kidney injury (AKI)., Design: A systematic search of electronic databases was conducted to identify all clinical studies that utilized NIRS to monitor renal rSO 2 during the perioperative period to observe postoperative AKI., Setting: Studies published online as of May 31, 2024, were included in the review., Participants: Studies involving human participants undergoing surgery with a predefined outcome of AKI were included., Interventions: Regional tissue oxygen saturation was measured using NIRS., Measurements and Main Results: A total of 144 records were identified in the primary search after removing duplicates. After screening, 18 studies were included in the analysis, consisting of 3 case-control studies and 15 prospective cohort studies. Thirteen reports focused on pediatric surgery, whereas five reports focused on adult surgery. Sixteen studies involved cardiovascular surgery with cardiopulmonary bypass, and two studies focused on liver surgery. All studies received a quality score of 7 or above. Significant heterogeneity and mostly short follow up periods were noted., Conclusion: Renal desaturation may indicate AKI in patients; however, further studies are required to substantiate this relationship. Additional clinical trials are necessary to evaluate normal values and establish the exact threshold of renal rSO 2 that signifies a meaningful decline in renal function., Competing Interests: Declaration of competing interest The authors declare that the research was conducted without any commercial or financial relationship that could be construed as a potential conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Background: High-flow nasal oxygenation is reported to prolong duration of apnea while maintaining adequate oxygen saturation with the mouth closed. Also, buccal oxygenation is known to have similar effects in obese adults. We compared the effect of these two methods on prolongation of acceptable apnea time in pediatric patients with their mouth open., Methods: Thirty-eight patients, aged 0-10 years were randomly allocated to either the high-flow nasal oxygenation group (n = 17) or the buccal oxygenation group (n = 21). After induction of anesthesia including neuromuscular blockade, manual ventilation was initiated until the expiratory oxygen concentration reached 90%. Subsequently, ventilation was paused, and the patient's head was extended, and mouth was opened. The HFNO group received 2 L·min -1 ·kg -1 of oxygen, and the BO group received 0.5 L·min -1 ·kg -1 of oxygen. We set a target apnea time according to previous literature. When the apnea time reached the target, we defined the case as "success" in prolongation of safe apnea time and resumed ventilation. When the pulse oximetry decreased to 92% before the target apnea time, it was recorded as "failure" and rescue ventilation was given., Results: The success rate of safe apnea prolongation was 100% in the high-flow nasal oxygenation group compared to 76% in the buccal oxygenation group (p = .04). Oxygen reserve index, end-tidal or transcutaneous carbon dioxide partial pressure, and pulse oximetry did not differ between groups., Conclusion: High-flow nasal oxygenation is effective in maintaining appropriate arterial oxygen saturation during apnea even in children with their mouth open and is superior to buccal oxygenation. Buccal oxygenation may be a good alternative when high-flow nasal oxygenation is not available., (© 2024 John Wiley & Sons Ltd.)

Background: Patients with respiratory disease often need oxygen supplements through a High-flow nasal cannula (HFNC), both hypoxia and hyperoxia can be harmful. Proper oxygen therapy requires careful monitoring of oxygen levels and adjustments to oxygen levels. A new automated system called Targeted SpO2 Feedback (TSF) improved the oxygen delivery system compared to manual adjustments. [Correction added on 25 October 2024, after first online publication: Background subsection in Abstract has been added on this version.] AIM: To test whether targeted SpO2 feedback (TSF), an automatic control system for fraction of inspired oxygen (FiO2), achieves more time in the optimal SpO2 range and/or reduces the frequency of manual adjustments to administered FiO2 compared with conventional manual titration in patients with hypoxia on high-flow nasal cannula (HFNC) therapy., Study Design: Twenty-two patients were recruited from two hospitals. For each, two sessions of manual mode and two sessions of TSF were applied in a random order, each session lasting 2 h. The target SpO2 on TSF was 95%. Oxygen monitoring levels were classified into four SpO2 ranges: hypoxia (≤ 89%), borderline (90%-93%), optimal (94%-96%) and hyperoxia (≥ 97%). The two modes were compared based on the proportion of time spent in each SpO2 range and the number of manual FiO2 adjustments., Results: The proportion of time in the optimal SpO2 range was 20.5% under manual titration mode and 65.4% under TSF (p < .01). The proportions of time in the hypoxia range were 1.1% and 0.4%, respectively (p = .31), in the borderline range 4.7% and 3.5%, respectively (p = .54), and in the hyperoxia range 73.7% and 30.7%, respectively (p < .01). There were statistical differences only in the optimal and hyperoxia SpO2 ranges. During the 8 h, the frequency of manual FiO2 adjustment was 0.7 times for the manual mode and 0.2 times for TSF, showing no statistically significant difference (p = 0.076)., Conclusion: Compared with manual titration, TSF achieved greater time of the optimal SpO2 and less time of hyperoxia during HFNC. The frequency of manual adjustments on TSF tended to be less than on manual titration mode., Relevance to Clinical Practice: Automatic closed-loop algorithm FiO2 monitoring systems can achieve better oxygen treatments than conventional monitoring and may reduce nurse workloads. In the era of pandemic respiratory diseases, this system can also facilitate contactless SpO2 monitoring during HFNC therapy., (© 2024 British Association of Critical Care Nurses.)

Purpose:  Peripheral responses might be important in handcycling, given the involvement of small muscles compared to other exercise modalities. Therefore, the goal of this study was to compare changes in muscle oxygen saturation (∆SmO 2 ) and deoxyhemoglobin level (∆[HHb]) between different efforts and muscles., Methods:  Handcyclists participated in a Wingate, a maximal incremental test and a 20-min time-trial (TT). Oxygen uptake (VO 2 ) as well as ∆SmO 2 , ∆[HHb], deoxygenation and reoxygenation rates in the triceps brachii (TB), biceps brachii (BB), anterior deltoid (AD) and extensor carpi radialis brevis (ER) were measured., Results:  ER ∆[HHb]max was 37% greater in the incremental test than in the Wingate (ES = 0.392, P = 0.031). TT mean power (W/kg) was associated with BB ∆SmO 2 min measured in the incremental test (r = -0.998 [-1.190, -0.806], P = 0.002) and in the Wingate (r = -0.994 [-1.327, -0.661], P = 0.006). MAP (W/kg) was associated with Wingate BB ∆SmO 2 min (r = -0.983 [-0.999, -0.839], P = 0.003), and Wingate peak (r = 0.649 [0.379, 0.895], P = 0.008) and mean power (W/kg) (r = 0.925 [0.752, 0.972], P = 0.003) was associated with right handgrip force. The strongest physiological predictor for TT performance was BB ∆SmO 2 min in the incremental test (P = 0.002, r 2  = 0.993, SEE 0.016 W/kg), Wingate BB ∆SmO 2 min for MAP (P = 0.003, r 2  = 0.956, SEE 0.058 W/kg) and right handgrip force for Wingate peak power (P = 0.005, r 2  = 0.856, SEE 0.551 W/kg)., Conclusion:  Peripheral aerobic responses (muscle oxygenation) were predictive of handcycling performance., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: To validate a method for continuously estimating the Pao 2 /Fio 2 (PF) ratio in all critically ill pediatric patients using only standard continuous data monitoring., Design: Retrospective study on a high temporal resolution database., Setting: PICU in Montreal, QC, Canada., Patients/subjects: We included any patients admitted from May 2015 to May 2023 who had an arterial blood gas (ABG) with concurrent continuous pulsed oximetry saturation (Spo 2 ) values. We used our previously validated mathematical model to determine the magnitude of hypoxemia by computing the estimated ePao 2 /Fio 2 (ePF) ratio and comparing it to the Spo 2 /Fio 2 (SF), using PF ratio as the reference standard., Interventions: None., Measurements and Main Results: We analyzed a total of 20,828 ABGs. When Spo 2 was below or equal to 97%, the ePF ratio showed a significantly better hypoxemia classification (none, light/moderate, or severe) than the SF ratio (0.80 vs. 0.72; p < 0.001), a lower fixed bias (16.26 vs. -35.24; p < 0.001), a lower mean absolute error (37.92 vs. 63.93; p < 0.001) and a lower proportional bias (slope of 1.01 vs. 0.81; p < 0.001). ePF ratio has also a better limits of agreement difference from Bland-Altman plot (248.10 vs. 292.45; p < 0.001) and coefficient of determination (0.68 vs. 0.59; p < 0.001). When Spo 2 was above 97%, the ePF ratio had better classification with Kappa (0.53 vs. 0.43; p < 0.001) and lower fixed bias (-0.63 vs. 65.68; p < 0.001)., Conclusions: The PF ratio based on ePF allows for a continuous estimation of hypoxemia severity with a better performance than the SF ratio., Competing Interests: The authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.)

Background: PEEP is a cornerstone treatment for children with pediatric ARDS. Unfortunately, its titration is often performed solely by evaluating oxygen saturation, which can lead to inadequate PEEP level settings and consequent adverse effects. This study aimed to assess the impact of increasing PEEP on hemodynamics, respiratory system mechanics, and oxygenation in children with ARDS., Methods: Children receiving mechanical ventilation and on pressure-controlled volume-guaranteed mode were prospectively assessed for inclusion. PEEP was sequentially changed to 5, 12, 10, 8 cm H 2 O, and again to 5 cm H 2 O. After 10 min at each PEEP level, hemodynamic, ventilatory, and oxygenation variables were collected., Results: A total of 31 subjects were included, with median age and weight of 6 months and 6.3 kg, respectively. The main reasons for pediatric ICU admission were respiratory failure caused by acute viral bronchiolitis (45%) and community-acquired pneumonia (32%). Most subjects had mild or moderate ARDS (45% and 42%, respectively), with a median (interquartile range) oxygenation index of 8.4 (5.8-12.7). Oxygen saturation improved significantly when PEEP was increased. However, although no significant changes in blood pressure were observed, the median cardiac index at PEEP of 12 cm H 2 O was significantly lower than that observed at any other PEEP level ( P = .001). Fourteen participants (45%) experienced a reduction in cardiac index of > 10% when PEEP was increased to 12 cm H 2 O. Also, the estimated oxygen delivery was significantly lower, at 12 cm H 2 O PEEP. Finally, respiratory system compliance significantly reduced when PEEP was increased. At a PEEP of 12 cm H 2 O, static compliance had a median reduction of 25% in relation to the initial assessment (PEEP of 5 cm H 2 O)., Conclusions: Although it may improve arterial oxygen saturation, inappropriately high PEEP levels may reduce cardiac output, oxygen delivery, and respiratory system compliance in pediatric subjects with ARDS with low potential for lung recruitability., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

Objectives: To evaluate whether kangaroo mother care (KMC) in preterm infants on non-invasive respiratory support improves indices of cardiorespiratory wellbeing., Study Design: Prospective quasi-experimental observational study., Setting: Tertiary perinatal neonatal unit., Patients: 50 very preterm infants being managed with nasal continuous positive airway pressure., Interventions: Continuous high-resolution preductal pulse-oximetry recordings using Masimo Radical-7 oximeter for 1 hour (incubator care) followed by 1 hour during KMC performed on the same day., Main Outcome Measures: Measures of cardiorespiratory stability (dips in oxygen saturations (SpO 2 )) of ≥5% less than baseline, % time spent with oxygen saturations <90%, SpO 2 variability and heart rate fluctuation and incidence of bradycardias., Results: The gestational age and birth weight of the cohort were 28.4±2.1 weeks and 1137±301 g, respectively. Dips in SpO 2 of ≥5% less than baseline were significantly fewer with KMC, median (IQR) 24 (12 to 42) vs 13 (3 to 25), p=0.001. SpO 2 variability (Delta 12 s and 2 s), (1.24±0.6 vs 0.9±0.4, p=0.005 and 4.1±1.7 vs 2.8±1.2, p<0.0001) and rapid resaturation and desaturation indices were significantly lower during KMC, compared with incubator care. Percentage time spent in oxygen saturations <90% was less with KMC (7.5% vs 2.7%, p=0.04). Mean heart rate was comparable although fluctuations in heart rate (rise by >8 bpm) were lower with KMC (43±22 vs 33±20, p=0.03). Seven (14%) infants had bradycardias during incubator care and none during KMC, p=0.012., Conclusions: KMC improves cardiorespiratory stability in ventilated preterm infants. Regular KMC has the potential to improve clinical outcomes in this vulnerable cohort., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Characterisation of oxygen saturation (SpO 2 )-related predictors that correspond with both bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) development and survival status in infants with BPD-PH may improve patient outcomes. This investigation assessed whether (1) infants with BPD-PH compared with infants with BPD alone, and (2) BPD-PH non-survivors compared with BPD-PH survivors would (a) achieve lower SpO 2 distributions, (b) have a higher fraction of inspired oxygen (FiO 2 ) exposure and (c) have a higher oxygen saturation index (OSI)., Design: Case-control study between infants with BPD-PH (cases) and BPD alone (controls) and by survival status within cases., Setting: Single-centre study in the USA., Patients: Infants born at <29 weeks' gestation and on respiratory support at 36 weeks' postmenstrual age., Exposures: FiO 2 exposure, SpO 2 distributions and OSI were analysed over the week preceding BPD-PH diagnosis., Main Outcomes and Measures: BPD-PH, BPD alone and survival status in infants with BPD-PH., Results: 40 infants with BPD-PH were compared with 40 infants with BPD alone. Infants who developed BPD-PH achieved lower SpO 2 compared with infants with BPD (p<0.001), were exposed to a higher FiO 2 (0.50 vs 0.34; p=0.02) and had a higher OSI (4.3 vs 2.6; p=0.03). Compared with survivors, infants with BPD-PH who died achieved a lower SpO 2 (p<0.001) and were exposed to a higher FiO 2 (0.70 vs 0.42; p=0.049)., Conclusions: SpO 2 -related predictors differed between infants with BPD-PH and BPD alone and among infants with BPD-PH by survival status. The OSI may provide a non-invasive predictor for BPD-PH in preterm infants., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Research examining the changes in muscle oxygen saturation across multiple sets of resistance exercise is limited. The purpose of this study was to describe the physiological response of muscle oxygenation parameters during upper-body resistance exercise and examine the differential effects of relevant participant characteristics on resistance training performance and muscle oxygen saturation dynamics. Sixty-one recreationally trained men (n = 44; 21.8 ± 2.6 years) and women (n = 17; 20.2 ± 1.8 years) completed five-repetition maximum sets of barbell bench presses at a load equal to 75% 1-RM with a 2 min rest interval. Muscle oxygen saturation (SmO 2 ) dynamics within the anterior deltoid were monitored using a portable near-infrared spectroscopy sensor. The percent change in SmO 2 (∆%SmO 2 ), the muscle oxygen re-saturation rate (SmO 2 RecSlope), and the highest measured SmO 2 value during recovery periods (SmO 2 Peak) were measured. Two-way (sex [men, women] x time [sets 1-5]) repeated measures analyses of variance (ANOVA) were performed on muscle saturation variables. To examine the effect of relevant controlling variables, separate analyses of covariance (ANCOVA) with repeated measures were also performed. No differences were seen with ∆%SmO 2 across sets. The main effects for sets occurred for SmO 2 RecSlope, whereby a decline was noted on sets 4 and 5 ( p = 0.001) compared to set 1. Additionally, SmO 2 Peak was the lowest on set 5 ( p < 0.001) compared to all other sets. Moreover, body mass ( p = 0.013), diastolic blood pressure ( p = 0.044), and mean arterial pressure ( p = 0.033) for ∆%SmO 2 were the only significant covariates noted amongst the muscle oxygenation variables. In conclusion, no sex differences and only a few set differences in muscle oxygen saturation dynamics were seen without employing any covariates. Body mass, diastolic blood pressure, and mean arterial pressure were identified as factors that could influence observed responses.

The health effects of ultrafine particles (UFPs) are of growing global concern, but the epidemiological evidence remains limited. Sleep-disordered breathing (SDB) characterized by hypoxemia is a prevalent condition linked to many debilitating chronic diseases. However, the role of UFPs in the development of SDB is lacking. Therefore, this prospective panel study was performed to specifically investigate the association of short-term exposure to UFPs with SDB parameters in patients with chronic obstructive pulmonary disease (COPD). Ninety-one COPD patients completed 226 clinical visits in Beijing, China. Personal exposure to ambient UFPs of 0-7 days was estimated based on infiltration factor and time-activity pattern. Real-time monitoring of sleep oxygen saturation, spirometry, respiratory questionnaires and airway inflammation detection were performed at each clinical visit. Generalized estimating equation was used to estimate the effects of UFPs. Exposure to UFPs was significantly associated with increased oxygen desaturation index (ODI) and percent of the time with oxygen saturation below 90 % (T90), with estimates of 21.50 % (95%CI: 6.38 %, 38.76 %) and 18.75 % (95%CI: 2.83 %, 37.14 %), respectively, per 3442 particles/cm 3 increment of UFPs at lag 0-3 h. Particularly, UFPs' exposure within 0-7 days was positively associated with the concentration of alveolar nitric oxide (CaNO), and alveolar eosinophilic inflammation measured by CaNO exceeding 5 ppb was associated with 29.63 % and 33.48 % increases in ODI and T90, respectively. In addition, amplified effects on oxygen desaturation were observed in current smokers. Notably, individuals with better lung function and activity tolerance were more affected by ambient UFPs due to longer time spent outdoors. To our knowledge, this is the first study to link UFPs to hypoxemia during sleep and uncover the key role of alveolar eosinophilic inflammation. Our findings provide new insights into the effect spectrum of UFPs and potential environmental and behavioral intervention strategies to protect susceptible populations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Traditional heart failure research often uses daytime population parameter estimates to assess hypoxia and arrhythmias. This approach might not accurately represent heart failure patients as nighttime cardiac behaviors offer crucial insights into their health, especially regarding oxygen levels and heart rhythms. We conducted a prospective study on nocturnal oxygen saturation and heart rate in home-dwelling heart failure patients over 6 nights. Patients were recruited from the Walter Reed National Military Medical Center heart failure clinic. Criteria included a clinical diagnosis of heart failure, a New York Heart Association (NYHA) classification of I to III, ages between 21 to 90, cognitive intactness, capability to use the wearable device, and willingness to use the device for 6 consecutive nights. Average oxygen saturation was 92% with individual readings ranging from 40% to 100%. The mean heart rate was 72 beats per minute (bpm), but individual rates ranged from 18 bpm to a high of 296 bpm. A significant drop in oxygen levels and sleep arrhythmias were consistently observed among participants. Heart failure patients demonstrate notable and variable desaturations and arrhythmias across multiple nights. A single-night sleep study or a 24-hour heart rate monitor may not comprehensively depict patients' oxygenation and heart rate irregularities. Our research highlights wearable devices' potency in medical research for capturing essential nocturnal data. In only 6 nights, we gleaned invaluable clinical insights for optimizing patient care. This study is pioneering, being the first to intensively examine nighttime oxygen levels and heart rates in home-based heart failure patients., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Pulse oximetry is a standart of anesthesia for perioperative monitoring. Due to the principles of Hb oxygen dissociation curve, peripheral oxygen saturation has an approximate sensitivity and specificity of 90% for the detection of hypoxemia., Objectives: The primary outcome of the study was to evaluate ORi Ⓡ as an early parameter to determine hypoxia in morbidly obese patients. The secondary outcome was to compare the effectiveness of ORi Ⓡ with SpO 2 in non-obese patients., Design: Prospective, observational study., Setting: Department of elective operating room at tertiary hospital., Patients and Methods: Observational study included written informed consent from 51 patients with 19 < BMI < 25 kg/m 2 and 51 patients with BMI > 40 kg/m 2 undergoing an elective surgery requiring tracheal intubation. In addition to standard monitors, an ORi sensor was placed and baseline values were recorded. The patients were preoxygenated until end tidal expiratory oxygen concentration is reached to 90%. After anesthesia induction and tracheal intubation, the breathing circuit was not connected tracheal tube until the SpO 2 decreased to 95%. Shapiro-Wilk, Pearson Chi-square, t-test, and Mann Whitney U test were used for the study., Main Outcome Measures: Times of tolerable apnea, ORi Ⓡ and SpO 2 values at the end of preoxygenation, beginning of intubation, beginning of the ORi alarm, when SpO 2 reached 95%, and when ORi reaches a plateau., Sample Size: 102 patients., Results: The alert period: time to reach ORi Ⓡ from 0.24 to a value of 95% SpO 2 was observed as 32 s in morbidly obese patients and 94 s in patients with a normal body mass index. The SpO 2 alert period was determined as time difference between 97% and 95% SpO 2 . The data were recorded as 15 s and 36 s, respectively. It was observed that tolerable apnea, ORi Ⓡ , SpO 2 and added alert times were longer in patients with normal BMI compared to morbidly obese patients., Conclusions: As a result, ORi Ⓡ can provide an early warning to prevent unexpected hypoxia before saturation begins to decrease in morbidly obese patients., Limitations: Inability to perform arterial blood gas sampling in the time periods when we looked at the parameters to determine the relationship between ORi Ⓡ and PaO 2 ., Gov Identifier: NCT05480748 registered 2022-07-29., (© 2024. The Author(s).)

This paper presents the development of a vital sign monitoring system designed specifically for professional athletes, with a focus on runners. The system aims to enhance athletic performance and mitigate health risks associated with intense training regimens. It comprises a wearable glove that monitors key physiological parameters such as heart rate, blood oxygen saturation (SpO2), body temperature, and gyroscope data used to calculate linear speed, among other relevant metrics. Additionally, environmental variables, including ambient temperature, are tracked. To ensure accuracy, the system incorporates an onboard filtering algorithm to minimize false positives, allowing for timely intervention during instances of physiological abnormalities. The study demonstrates the system's potential to optimize performance and protect athlete well-being by facilitating real-time adjustments to training intensity and duration. The experimental results show that the system adheres to the classical "220-age" formula for calculating maximum heart rate, responds promptly to predefined thresholds, and outperforms a moving average filter in noise reduction, with the Gaussian filter delivering superior performance.

Background and Aims: Because bronchoscopy is an invasive procedure, sedatives and analgesics are commonly administered, which may suppress the patient's spontaneous breathing and can lead to hypoventilation and hypoxemia. Few reports exist on the dynamic monitoring of oxygenation and ventilation during bronchoscopy. This study aimed to prospectively monitor and evaluate oxygenation and ventilation during bronchoscopy using transcutaneous arterial blood oxygen saturation and carbon dioxide., Methods: We included patients who required pathological diagnosis using fluoroscopic bronchoscopy at our hospital between March 2021 and April 2022. Midazolam was intravenously administered to all patients as a sedative during bronchoscopy, and fentanyl was administered in addition to midazolam when necessary. A transcutaneous blood gas monitor was used to measure dynamic changes, including arterial blood partial pressure of carbon dioxide (tcPCO 2 ), transcutaneous arterial blood oxygen saturation (SpO 2 ), pulse rate, and perfusion index during bronchoscopy. Quantitative data of tcPCO 2 and SpO 2 were presented as mean ± standard deviation (SD) (min-max), while the quantitative data of midazolam plus fentanyl and midazolam alone were compared. Similarly, data on sex, smoking history, and body mass index were compared. Subgroup comparisons of the difference (Δ value) between baseline tcPCO 2 at the beginning of bronchoscopy and the maximum value of tcPCO 2 during the examination were performed., Results: Of the 117 included cases, consecutive measurements were performed in 113 cases, with a success rate of 96.6%. Transbronchial lung biopsy was performed in 100 cases, whereas transbronchial lung cryobiopsy was performed in 17 cases. Midazolam and fentanyl were used as anesthetics during bronchoscopy in 46 cases, whereas midazolam alone was used in 67 cases. The median Δ value in the midazolam plus fentanyl and midazolam alone groups was 8.10 and 4.00 mmHg, respectively, indicating a significant difference of p < 0.005. The mean ± standard deviation of tcPCO 2 in the midazolam plus fentanyl and midazolam alone groups was 44.8 ± 7.83 and 40.6 ± 4.10 mmHg, respectively. The SpO 2 in the midazolam plus fentanyl and midazolam alone groups was 94.4 ± 3.37 and 96.2 ± 2.61%, respectively, with a larger SD and greater variability in the midazolam plus fentanyl group., Conclusion: A transcutaneous blood gas monitor is non-invasive and can easily measure the dynamic transition of CO 2 . Furthermore, tcPCO 2 can be used to evaluate the ventilatory status during bronchoscopy easily. A transcutaneous blood gas monitor may be useful to observe regarding respiratory depression during bronchoscopy, particularly when analgesics are used., (© 2024. The Author(s).)

Background: Hypoxia and hyperoxia can affect the acute psycho-physiological response to exercise. Recording various perceptual responses to exercise is of particular importance for investigating behavioral changes to physical activity, given that the perception of exercise-induced pain, discomfort or unpleasure, and a low level of exercise enjoyment are commonly associated with a low adherence to physical activity. Therefore, this study aimed to compare the acute perceptual and physiological responses to aerobic exercise under intermittent hypoxia-hyperoxia (IHHT), hypoxia-normoxia (IHT), and sustained normoxia (NOR) in young, recreational active, healthy males., Methods: Using a randomized, single-blinded, crossover design, 15 males (age: 24.5 ± 4.2 yrs) performed 40 min of submaximal constant-load cycling (at 60% peak oxygen uptake, 80 rpm) under IHHT (5 × 4 min hypoxia and hyperoxia), IHT (5 × 4 min hypoxia and normoxia), and NOR. Inspiratory fraction of oxygen during hypoxia and hyperoxia was set to 14% and 30%, respectively. Heart rate (HR), total hemoglobin (tHb) and muscle oxygen saturation (S m O 2 ) of the right vastus lateralis muscle were continuously recorded during cycling. Participants' peripheral oxygen saturation (S p O 2 ) and perceptual responses ( i.e ., perceived motor fatigue, effort perception, perceived physical strain, affective valence, arousal, motivation to exercise, and conflict to continue exercise) were surveyed prior, during (every 4 min), and after cycling. Prior to and after exercise, peripheral blood lactate concentration (BLC) was determined. Exercise enjoyment was ascertained after cycling. For statistical analysis, repeated measures analyses of variance were conducted., Results: No differences in the acute perceptual responses were found between conditions ( p ≥ 0.059, η p 2 ≤ 0.18), while the physiological responses differed. Accordingly, S p O 2 was higher during the hyperoxic periods during the IHHT compared to the normoxic periods during the IHT ( p < 0.001, η p 2 = 0.91). Moreover, HR ( p = 0.005, η p 2 = 0.33) and BLC ( p = 0.033, η p 2 = 0.28) were higher during IHT compared to NOR. No differences between conditions were found for changes in tHb ( p = 0.684, η p 2 = 0.03) and S m O 2 ( p = 0.093, η p 2 = 0.16)., Conclusion: IHT was associated with a higher physiological response and metabolic stress, while IHHT did not lead to an increase in HR and BLC compared to NOR. In addition, compared to IHT, IHHT seems to improve reoxygenation indicated by a higher S p O 2 during the hyperoxic periods. However, there were no differences in perceptual responses and ratings of exercise enjoyment between conditions. These results suggest that replacing normoxic by hyperoxic reoxygenation-periods during submaximal constant-load cycling under intermittent hypoxia reduced the exercise-related physiological stress but had no effect on perceptual responses and perceived exercise enjoyment in young recreational active healthy males., Competing Interests: The authors declare that they have no competing interests., (© 2024 Behrendt et al.)

(1) Background: Wearable sensors support healthcare professionals in clinical decision-making by measuring vital parameters such as heart rate (HR), respiration rate (RR), and blood oxygenation saturation (SpO 2 ). This study assessed the validity and reliability of two types of wearable sensors, based on electrocardiogram or photoplethysmography, compared with continuous monitoring of patients recovering from trauma surgery at the postanesthesia care unit. (2) Methods: In a prospective observational study, HR, RR, SpO 2 , and temperature of patients were simultaneously recorded with the VitalPatch and Radius PPG and compared with reference monitoring. Outcome measures were formulated as correlation coefficient for validity and mean difference with 95% limits of agreement for reliability for four random data pairs and 30-min pairs per vital sign per patient. (3) Results: Included were 60 patients. Correlation coefficients for VitalPatch were 0.57 to 0.85 for HR and 0.08 to 0.16 for RR, and for Radius PPG, correlation coefficients were 0.60 to 0.83 for HR, 0.20 to 0.12 for RR, and 0.57 to 0.61 for SpO 2 . Both sensors presented mean differences within the cutoff values of acceptable difference. (4) Conclusions: Moderate to strong correlations for HR and SpO 2 were demonstrated. Although mean differences were within acceptable cutoff values for all vital signs, only limits of agreement for HR measured by electrocardiography were considered clinically acceptable.

Study Objective: To evaluate the sensitivity and specificity of the combined Kushida morphometric model (KMM) and the oxygen desaturation index (ODI) for screening individuals with obstructive sleep apnea., Methods: Diagnostic test study with adults >18 years, both sexes, polysomnography, body mass index, neck circumference and intraoral measurements., Results: 144 patients were invited; of these, 75 met the exclusion criteria. 55 individuals presented AHI ≥5 ev/h and 14, an AHI <5 ev/h. Three AHI cut-off points were evaluated: AHI ≥5, ≥15, ≥30 ev/h. When adopting the cut-off point of AHI ≥5 ev/h, the KMM showed sensitivity (SE) = 60.0 %, specificity (SP) = 71.4 % and 95 % confidence interval of the area under the curve (95 % CI of AUC) = 0.655; the combination of KMM and ODI (KMM + ODI) revealed SE = 73.0 %, SP = 71.4 % (95 % CI of AUC = 0.779) and the ODI showed SE = 76.4 % and SP = 92.9 % (95 % CI of AUC = 0.815). At the cut-off point of AHI ≥15 ev/h, the KMM presented SE = 64.1 %, SP = 76.7 % (95 % CI of AUC = 0.735); the KMM + ODI showed SE = 82.1 %, SP = 83.3 % (95 % CI of AUC = 0.895); and the ODI presented SE = 76.9 %, SP = 100.0 % (95 % CI of AUC = 0.903). For the cut-off point of AHI ≥30 ev/h, the KMM showed SE = 56.0 %, SP = 77.2 % (95 % CI of AUC = 0.722); the KMM + ODI revealed SE = 92.0 %, SP = 79.5 % (95 % CI of AUC = 0.926); and the ODI showed SE = 92.0 %, SP = 90.9 % (95 % CI of AUC = 0.941)., Conclusion: The combination of oxygen desaturation index and Kushida morphometric model improved the sensitivity and specificity of this model regardless of obstructive sleep apnea severity suggesting greater effectiveness in risk prediction., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Adelmir Souza-Machado reports financial support was provided by National Council for Scientific and Technological Development, Research Support Foundation of the State of Bahia. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Prcis: Increased oxygen saturation (StO 2 ) was significantly associated with the severity of visual field (VF) damage in patients with glaucoma., Objective: To investigate the association between retinal StO 2 percentage and the severity of VF loss in glaucoma., Methods: A total of 198 eyes from 131 patients with glaucoma were included in this cross-sectional study. Participants underwent imaging using ocular oximetry (Zilia) and 24-2 Swedish Interactive Threshold Algorithm standard VF (Carl Zeiss-Meditec). StO 2 (%) was measured at 2 locations of the peripapillary optic nerve head (superotemporal, and inferotemporal). Measurements were reported as the mean of at least 5 measurements in each location. Associations between the severity of VF loss, reported as mean deviation, and StO 2 (%) were calculated., Results: A total of 198 eyes of 131 patients (mean (95% CI) age, 71.1 (68.9,73.3) years, 68 females (51.9%), and 63 males (48.1%) were analyzed. In univariable analysis, higher StO 2 -0.06 (-0.12, 0.00) was associated with severity in all hemifields ( P = 0.047). Multivariate regression analysis showed that each 1% increase in StO 2 was associated with -0.06 (-0.12, -0.00) dB loss in mean deviation in all hemifields ( P = 0.043). In multivariate regression analysis in the superior hemifields, higher StO 2 -0.07 (-0.16, 0.01) tended to be associated with superior hemifield severity ( P = 0.09)., Conclusions: Retinal oximetry enabled the continuous quantitative measurement of retinal StO 2. Increased StO 2 was significantly associated with the severity of VF damage in patients with glaucoma., Competing Interests: Disclosure: R.N.W.: C: Abbvie, Aerie Pharmaceuticals, Alcon, Allergan, Iantrek, Implandata, IOPtic, Nicox, Santen, Topcon Medical; F: Topcon Medical, Heidelberg Engineering, Carl Zeiss Meditec, Optovue, Centervue, Zilia; P: Toromedes, Carl Zeiss Meditec. The remaining authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Sleep-related bruxism (SB) is the habit of grinding or clenching the teeth during sleep, mediated by the non-peripheral central nervous system., Purpose: The objectives of this cross-sectional study were to evaluate associations between SB, microarousals and oxyhaemoglobin desaturations and to compare the frequency of SB and microarousals in sleep stages, in an apnoeic population., Methods: Two hundred and forty individuals composed the sample, who underwent a single full-night polysomnography. Self-reports and clinical inspections were not considered for assessing SB. The polysomnographic assessment of SB was performed using electrodes placed on masseter muscles and chin. SB was defined as more than two events of rhythmic masticatory muscle activity per hour of sleep. Microarousals were considered when there were abrupt changes in electroencephalogram frequencies, without complete awakening, lasting from 3 to 15 s. Oxyhaemoglobin desaturations were defined as significant drops (≥3%) in basal oxygen saturations. With these data, SB, microarousals and oxyhaemoglobin desaturations were evaluated and submitted to statistical analysis., Results: Statistically significant differences were observed between bruxers and non-bruxers when comparing the rates of microarousals (p < .001) and oxyhaemoglobin desaturations (p = .038). There was a higher number of SB and microarousals in NREM (non-rapid eye movement) two sleep stage (p < 0.001). Bruxers had a greater risk of higher numbers of microarousals (OR = 1.023; p = .003), which did not occur for oxyhaemoglobin desaturations (OR = 0.998; p = .741)., Conclusions: A higher number of microarousals presents relationship with SB; associations between SB and oxyhaemoglobin desaturations remained inconclusive; higher frequency of SB and microarousals was observed in NREM 2 sleep stage., (© 2024 John Wiley & Sons Ltd.)

In pulmonary disease patients since oxygen desaturation during 6-min walk test (6MWT) affects walk distance (6MWD), some novel indices such as desaturation/distance ratio [DDR, oxygen desaturation area (DAO 2 )/6MWD] and distance-saturation product [DSP, 6MWD × minimum peripheral oxygen saturation (SpO 2 )] are evaluated. However, there has been no study examining these indices that consider exercise-induced desaturation (EID) in patients with cardiovascular disease. In 94 cardiovascular disease patients without pulmonary complications, 6MWT and echocardiography were performed at the entry of cardiac rehabilitation. SpO 2 was measured during 6MWT using a continuously monitorable pulse oximeter, and DSP and DDR were calculated using minimum SpO 2 and DAO 2 [sum of (100-SpO 2 ) per second during 6MWT], respectively. EID was defined as SpO 2 decrease of ≥ 4% or minimum SpO 2 of < 90% during 6MWT. DSP was slightly lower and DDR was markedly higher in patients with EID than in those without. When examining correlations of DSP and DDR with their components, DSP was correlated with 6MWD much closely than minimum SpO 2 , while DDR was correlated as closely with DAO 2 as 6MWD. Furthermore, DAO 2 , but not minimum SpO 2 , had a direct correlation with 6MWD. As for associations with cardiac function, DSP was correlated with several cardiac parameters, but DDR was not correlated with any of these parameters. Our findings suggest that oxygen desaturation during 6MWT affects walking distance in cardiovascular disease patients even without pulmonary complications and that DDR is more appropriate than DSP as an index of walking performance that takes EID into consideration, independently of cardiac function., (© 2024. Springer Nature Japan KK, part of Springer Nature.)

Objective: To measure the effects kangaroo mother care (KMC) on the regional cerebral oxygen saturation (rSO 2 ) measured with near-infrared spectroscopy (NIRS) in premature infants and to study the physiological stability and comfort of the infants during such interventions., Design: This was a prospective, single-centered, single-blind, 2-arm, parallel-group randomized controlled trial conducted., Settings: The study was carried out in a tertiary neonatal intensive care unit in Medical Faculty Hospital in Konya/Turkey., Participants: Premature infants born between 24 and 36 +6 weeks. Participants were randomly assigned to one of two groups: kangaroo care (n = 20) and control groups (n = 20). The rSO 2 , oxygen saturation (%SpO 2 ), heart rate (HR), respiratory rate, body temperature, and comfort levels of the infants were evaluated in three stages., Findings: In the 60th min measurement of the intervention group, rSO 2 , body temperature, heart rate, respiratory rate, and, comfort level, the comfort level was found to be higher and significant in the 30th and 60th min measurements (p < 0.001). In the intervention group, the rSO 2 (p < 0.001), body temperature (p < 0.001), HR (p < 0.001), SpO 2 (p < 0.001), respiratory rate (p < 0.001), and comfort levels (p < 0.001) scores with the control group and the group × time interaction was significant., Key Conclusions: KMC moderately increased the rSO 2 levels and also created a moderate effect size on the physiological parameters and comfort levels of the newborns, which implicates its short-term benefits for premature infants., Practice Implications: KMC may be beneficial in stabilizing rSO 2 and physiological parameters and increasing comfort in premature infants. The trial was registered in ClinicalTrials.gov (identifier: NCT04725435)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Purpose: In the perioperative period, fractional-inspired oxygen is used at values up to 80% to stay within the safe range, even for a short time. A clear value for the safe range has not been specified, and therefore, clinicians prefer a high oxygen value. This study aims to reduce unnecessary oxygen exposure in pediatrice patients and to provide the optimum fractional inspired oxygen value., Design: The study was designed as a prospective randomized controlled study, including 139 patients aged 1 to 8 years without comorbidity., Methods: Three groups were formed by adjusting the fractional inspired oxygen to 30%, 50%, or 80% intraoperatively. In the intraoperative period, a strict inspired oxygen protocol (hypoxemia threshold was SpO 2 < 90) and oxygen reserve index, fractional expired oxygen value, and peripheral oxygen saturation were used to maintain the balance of hypoxemia and hyperoxemia., Findings: One hundred and nine children were included. The mean oxygen reserve index was significantly lower in the 30% group than in the other groups (0.09 ± 0.05, P < .0001). The mean arterial pressure in the 30% group was significantly lower than the 80% group but within the normal range (78 ± 6 mmHg, P < .003). There was no significant difference between the groups regarding delirium and pain in the recovery unit., Conclusions: Due to the known and unknown harmful effects of unnecessary oxygen exposure, it may be time to use optimal oxygen and to fear unnecessary oxygen, not less oxygen. As the next step, we think studies should be conducted with patient groups with lower oxygen concentrations (eg, %21 vs %24 vs %30), more patients, and arterial blood gas monitoring., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.)

Purpose: Portable near-infrared spectroscopy devices allow measurements of muscle oxygen saturation (SmO 2 ) in real time and non-invasively. To use NIRS for typical applications including intensity control and load monitoring, the day-to-day variability needs to be known to interpret changes confidently. This study investigates the absolute and relative test-retest reliability of the Moxy Monitor and investigates side differences of SmO 2 at the vastus lateralis muscle of both legs in cyclists., Methods: Twelve trained cyclists and triathletes completed 3 incremental step tests with 5 min step duration starting at 1.0 W/kg with an increase of 0.5 W/kg separated by 2-7 days. SmO 2 was averaged over the last minute of each stage. For all power outputs, the intra-class coefficient (ICC), the standard error of measurement (SEM) and the minimal detectable change (MDC) were calculated. Dominant and non-dominant leg SmO 2 were compared using a three-factor ANOVA and limits of agreement (LoA)., Results: ANOVA showed no significant systematic differences between trials and side. For both legs and all intensities, the ICC ranged from 0.79 to 0.92, the SEM from 5 to 9% SmO 2 and the MDC from 14 to 18% SmO 2 . The bias and LoA between both legs were -2.0% ± 19.9% SmO 2 ., Conclusion: Relative reliability of SmO 2 was numerically good to excellent according to current standards. However, it depends on the specific analytical goal whether the test-retest reliability is deemed sufficient. Wide LoA indicate side differences in muscle oxygenation during exercise unexplained by leg dominance., (© 2024. The Author(s).)

Near-infrared spectroscopy (NIRS) can be used to demonstrate muscle metabolism and oxygenation. NIRS-based oximeters enable the noninvasive measurement of static and dynamic muscle oxygenation. This study aimed to evaluate the relationship between NIRS readings and exercise capacity in group E COPD patients. The prospective study included 40 patients with group E COPD who presented to our outpatient clinic between May 2021 and June 2022. The patients were evaluated with pulmonary function testing, 6-Minute Walk Test (6MWT), echocardiography, and dyspnea and quality of life assessments. NIRS muscle oxygen saturation (SmO 2 ) levels at the start and end of the 6MWT were obtained. 6MWT distance was positively correlated with intercostal SmO 2 and fingertip SO 2 at the start (R = 0.679, p ≤ 0.001 and R = 0.321, p = 0.04, respectively) and end of the 6MWT (R = 0.693, p ≤ 0.001 and R = 0.635, p ≤ 0.001, respectively) and negatively correlated with the number of hospitalizations due to exacerbations in the last year and mean pulmonary arterial pressure (R =  - 0.648, p ≤ 0.001 and R =  - 0.676, p ≤ 0.001, respectively). SF-36 score was positively correlated with intercostal SmO 2 at the beginning of the 6MWT (R = 0.336, p = 0.03). Intercostal SmO 2 levels at the start of the 6MWT positively correlated with diffusing capacity of the lung for carbon dioxide (DLCO) (R = 0.388, p = 0.01) and ratio of DLCO to alveolar volume (DLCO/VA) levels (R = 0.379, p = 0.02), and these correlations persisted more strongly after the 6MWT (R = 0.524, p = 0.01; R = 0.500, p = 0.01, respectively). NIRS is a practical and noninvasive method for measuring muscle oxygenation and can be used as an alternative to 6MWT in the evaluation of exercise capacity in patients with group E COPD., (© 2024. The Author(s).)

Objective: To define percentile charts for arterial oxygen saturation (SpO 2 ), heart rate (HR), and cerebral oxygen saturation (crSO 2 ) during the first 15 minutes after birth in neonates born very or extremely preterm and with favorable outcome., Study Design: We conducted a secondary-outcome analysis of neonates born preterm included in the Cerebral regional tissue Oxygen Saturation to Guide Oxygen Delivery in preterm neonates during immediate transition after birth III (COSGOD III) trial with visible cerebral oximetry measurements and with favorable outcome, defined as survival without cerebral injuries until term age. We excluded infants with inflammatory morbidities within the first week after birth. SpO 2 was obtained by pulse oximetry, and electrocardiogram or pulse oximetry were used for measurement of HR. crSO 2 was assessed with near-infrared spectroscopy. Measurements were performed during the first 15 minutes after birth. Percentile charts (10th to 90th centile) were defined for each minute., Results: A total of 207 neonates born preterm with a gestational age of 29.7 (23.9-31.9) weeks and a birth weight of 1200 (378-2320) g were eligible for analyses. The 10th percentile of SpO 2 at minute 2, 5, 10, and 15 was 32%, 52%, 83%, and 85%, respectively. The 10th percentile of HR at minute 2, 5, 10, and 15 was 70, 109, 126, and 134 beats/min, respectively. The 10th percentile of crSO 2 at minute 2, 5, 20, and 15 was 15%, 27%, 59%, and 63%, respectively., Conclusions: This study provides new centile charts for SpO 2 , HR, and crSO 2 for neonates born extremely or very preterm with favorable outcome. Implementing these centiles in guiding interventions during the stabilization process after birth might help to more accurately target oxygenation during postnatal transition period., Competing Interests: Declaration of Competing Interest The COSGOD III trial received support from the Austrian Science Fund and the Health Research Board (HRB) Clinical Research Facility at the University of Cork for the submitted work and from the Stollery Children’s Hospital Foundation facilitated by the Women and Children’s Health Research Institute; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work. The COSGOD III trial was funded by the Austrian Science Fund (Fonds zur Förderung der wissenschaftlichen Forschung [FWF] Austria) through an unconditional and unrestricted grant (KLI 586-B31). Health Research Board (HRB) Clinical Research Facility at University College Cork supported the study at the Infant Centre, University College Cork, Cork University Maternity Hospital, Cork, Ireland. G.S. was a recipient of the Heart and Stroke Foundation/University of Alberta Professorship of Neonatal Resuscitation, a National New Investigator of the Heart and Stroke Foundation Canada, and an Alberta New Investigator of the Heart and Stroke Foundation Alberta. This research was facilitated by the Women and Children’s Health Research Institute through the support of the Stollery Children’s Hospital Foundation. No funding was received for the analysis of the data presented in the submitted manuscript, and funders had no influence on analysis, and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication. The authors have no conflicts of interest relevant to this article., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Background: Nocturnal hypoxemic burden has been shown to be a robust, independent predictor of all-cause mortality in patients with heart failure and reduced ejection fraction (HFrEF) and to occur in a severe form even in patients with low or negligible frequency of respiratory events (apneas/hypopneas). This suggests the existence of two components of hypoxemic burden: one unrelated to respiratory events and the other related. The aim of this study was to characterize these two components and to evaluate their prognostic value., Methods: Nocturnal hypoxemic burden was assessed in a cohort of 280 patients with HFrEF by measuring the percentage of sleep with an oxygen saturation (SpO 2 ) <90% (T90), and the area of the SpO 2 curve below 90% (Area90). Both indices were also recalculated within the sleep segments associated with respiratory events (event-related component: T90 Eve , Area90 Eve ) and outside these segments (nonspecific component: T90 Nspec , Area90 Nspec ). The outcome of the survival analysis (Cox regression) was all-cause mortality., Results: During a median follow-up of 60 months, 87 patients died. T90, Area90, and their components were significant in univariate analysis (P < .05 all). However, when these indices were adjusted for known risk factors, T90, T90 Nspec , Area90, and Area90 Nspec remained statistically significant (P = .018, hazard ratio (HR)=1.12, 95%CI=(1.02, 1.23); P = .007, HR=1.20, 95% CI = [1.05, 1.37]; P = .020, HR = 1.05, 95% CI = [1.01, 1.10]; P = .0006, HR = 1.15, 95% CI = [1.06, 1.25]), whereas T90 Eve and Area90 Eve did not (P = .27, P = .28). These results were internally validated using bootstrap resampling., Conclusions: By demonstrating a significant independent association of nonspecific hypoxemic burden with all-cause mortality, this study suggests that this component of total nocturnal hypoxemic burden may play an important prognostic role in patients with HFrEF., Competing Interests: Conflict of interest None reported., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Fidgety movements provide early information about a potential development of cerebral palsy in preterm neonates. The aim was to assess differences in the combined outcome of mortality and fidgety movements defined as normal or pathological in very preterm neonates according to the group allocation in the randomised-controlled multicentre COSGOD III trial. Preterm neonates of two centres participating in the COSGOD III trial, whose fidgety movements were assessed as normal or pathological at six to 20 weeks of corrected age, were analysed. In the COSGOD III trial cerebral oxygen saturation (crSO 2 ) was measured by near-infrared spectroscopy (NIRS) during postnatal transition and guided resuscitation in preterm neonates randomised to the NIRS-group, whereby medical support was according routine, as it was also in the control group. Fidgety movements were classified in normal or abnormal/absent at six to 20 weeks of corrected age. Mortality and fidgety movements of preterm neonates allocated to the NIRS-group were compared to the control-group. Normal outcome was defined as survival with normal fidgety movements. One-hundred-seventy-one preterm neonates were included (NIRS-group n = 82; control-group n = 89) with a median gestational age of 29.4 (27.4-30.4) and 28.7 (26.7-31.0) weeks in the NIRS-group and the control-group, respectively. There were no differences in the combined outcome between the two groups: 90.2% of the neonates in the NIRS-group and 89.9% in the control-group survived with normal outcome (relative risk [95% CI]; 0.96 [0.31-2.62]).Conclusions: In the present cohort of preterm neonates, monitoring of crSO 2 and dedicated interventions in addition to routine care during transition period after birth did not show an impact on mortality and fidgety movements defined as normal or pathological at six to 20 weeks corrected age. What is Known • Fidgety movements display early spontaneous motoric pattern and may provide early information about a potential development of cerebral palsy in preterm neonates.  What is New  • This retrospective observational study of the randomised-controlled multicentre COSGOD III trial is the first study investigating the potential influence of cerebral oxygenation guided resuscitation during postnatal transition period on combined outcome of mortality and fidgety movements up to 20 weeks of corrected age in very preterm neonates. • This study adds to the growing interest of assessing cerebral oxygenation, that monitoring of cerebral oxygen saturation and dedicated interventions during postnatal transition period according to the COSGOD III trial has no significant influence on mortality and fidgety movements defined as normal or pathological in very preterm neonates., (© 2024. The Author(s).)

Background: In patients with interstitial lung disease (ILD), exercise-induced desaturation during the 6-min walk test (6MWT), specifically nadir oxygen saturation (nSpO2) of ≤88 % is a negative prognostic marker. As the 6MWT is often impractical for ILD patients, the aim of this study is to compare the 1-min sit-to-stand test (1minSTS) with the 6MWT to detect exercise-induced desaturation., Methods: Participants were recruited from a tertiary referral clinic with both tests performed on the same day. Utilising Bland-Altman analysis, the relationship between nSpO2 on 1minSTS and 6MWT was determined. An area under the receiver operating characteristic curve (AUC) determined the ability of nSpO2 on 1minSTS test to predict SpO2 ≤88 % on 6MWT., Results: Fifty participants completed the study (idiopathic pulmonary fibrosis n = 24, 48 %; connective tissue disease associated ILD n = 20, 40 %; other ILD n = 6, 12 %). Mean (SD) FVC%pred was 73 ± 16 %, mean DLCO%pred 57 ± 16 % and resting SpO2 99 ± 1 %. The 1minSTS resulted in less exercise-induced oxygen desaturation, with a median IQR nSpO2 of 95 % (89-98) and 93 % (85-96) respectively (p < 0.001). Moderate agreement was determined between the nSpO2 on both tests, with a mean difference of 3.2 % [-14 to +3.0 %]. The 1minSTS test accurately identified participants with nSpO2 ≤88 % on 6MWT (AUC 0.96). Oxygen desaturation ≤94 % during the 1minSTS test provided 100 % sensitivity and 87 % specificity for oxygen desaturation ≤88 % at 6MWT., Conclusion: This study demonstrates that exercise-induced oxygen desaturation during the 1minSTS test correlates with oxygen desaturation on 6MWT. The 1minSTS may be a practical screening tool for ILD patients who would benefit from further exercise testing., Competing Interests: Declaration of competing interest There are no conflicts of interest to declare that directly relate to this manuscript. Unrelated to the current work LT reports speaker's fees from Boehringer Ingelheim and Erbe Elektromedezin GbH, and prior in-kind research support from Air Liquide Healthcare. TJC reports grants or contracts from Boehringer Ingleheim, Pharmaxis, Bristol Myers Squibb, 4D, Roche, Pliant, Bridge Biotherapeutics and Avalyn Therapeutics; consulting fees with Boehringer Ingleheim, Pharmaxis, Bristol Myers Squibb, 4D, Roche, Pliant Bridge Biotherapeutics, Avalyn Therapeutics, DevPro, Endeavour, BioMedicine and Cincera; honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Bristol Myers Squibb, Roche and Boehringer Ingleheim; support for attending meetings and/or travel with Bristol Myers Squibb and Boehringer Ingelheim; participation on a data safety monitoring board or advisory Board with Boehringer Ingleheim, Bristol Myers Squibb, Roche, Pliant, Bridge Biotherapeutics, Avalyn Therapeutics, DevPro and Endeavour BioMedicine. SW has received an educational grant from Boehringer Ingleheim., (Copyright © 2024. Published by Elsevier Ltd.)

Oximeters have significantly evolved since their invention and are essential for monitoring chronic diseases in home care. However, commercial models can present an economic barrier. Therefore, we conducted a review of the use of low-cost pulse oximeters in the home care of patients with respiratory diseases. Our review included studies addressing oxygen saturation and heart rate monitoring in adults, focusing on the use of portable devices. Our search identified advances in vital signs monitoring that could provide accessible solutions for non-clinical settings. Although there are challenges related to clinical validation and accuracy, these oximeters may improve medical care, particularly in resource-limited areas. As a result, the accessibility of these devices opens up new possibilities for patients with chronic respiratory diseases in home care, enabling regular self-monitoring and increasing control over their health.

Background: Cerebral blood flow dynamics can be explored through analysis of endothelial frequencies. Our hypothesis posits a disparity in endothelial activity among neonates with perinatal asphyxia, stratified by the presence or absence of neuronal lesions., Methods: We conducted a retrospective longitudinal study involving newborns treated with hypothermia for moderate to severe asphyxia. Participants were grouped based on the presence or absence of neuronal damage to investigate temporal endothelial involvement in cerebral blood flow regulation. Regional cerebral oxygen saturation (rScO2) was measured using near-infrared spectroscopy (NIRS), and temporal series were analyzed in the frequency domain, utilizing the original frequency of the INVOS™ device., Results: The study included 88 patients, with 53% (47/88) being male and 33% (29/88) demonstrating brain lesions on magnetic resonance imaging. Among them, 86% (76/88) had a gestational age exceeding 37 weeks according to the Ballard scale, and 81% (71/88) had a birth weight exceeding 2500 g. Cohen's d effect size was calculated to assess differences in endothelial frequency between groups, indicating a small effect size based on cerebral MRI findings (Cohen's d values for Day 2 = 0.2351 and Day 3 = 0.2325)., Conclusion: NIRS represents a valuable tool for monitoring cerebral autoregulation in neonates affected by perinatal asphyxia, underscoring the utility of assessing endothelial frequency or energy on rScO2 measured by NIRS using the original INVOS™ device frequency., (© 2024. The Author(s).)

Background: Continuous monitoring of pulse oximetry (S pO 2 ) is recommended during the 6-min walk test (6MWT) to ensure that the lowest S pO 2 is recorded. In this case, severe exercise-induced desaturation (EID; S pO 2 < 80%) triggers walking interruption by the examiner. Our main objective was to assess the impact of this approach on 6MWT distance in patients with chronic respiratory diseases and, second, to evaluate the safety of the test without interruption due to severe EID., Methods: 6MWTs with continuous monitoring of S pO 2 were prospectively performed in subjects with chronic respiratory disease. The participants were randomly allocated to walk with or without S pO 2 real-time assessment. S pO 2 visualization during the test execution was available only in the first group, and walking interruption was requested by the examiner if S pO 2 < 80%., Results: One hundred forty-five participants were included in each group (68.6% females, 62 [52-69] y old) without differences in demographic and resting lung function parameters between them. The main respiratory conditions were COPD ( n = 101), asthma ( n = 73), pulmonary hypertension ( n = 47), and interstitial lung disease ( n = 39). The walked distance was similar comparing groups (349.5 ± 117.5 m vs 351.2 ± 105.4 m). Twenty-five subjects presented with severe EID in the group with real-time S pO 2 assessment, and 20 subjects had severe EID in the group without real-time assessment respectively (overall prevalence of 15.5%). The 23 participants who had their test interrupted by the examiner due to severe EID in the first group (2 subjects stopped by themselves due to excessive symptoms) walked a shorter distance compared to the 11 subjects with severe EID without test interruption in the second group (9 subjects stopped by themselves due to excessive symptoms): 240.6 ± 100.2 m versus 345.9 ± 73.4 m. No exercise-related serious adverse events were observed., Conclusions: Interruption driven by severe EID reduced the walked distance during the 6MWT. No serious adverse event, in turn, was observed in subjects with severe desaturation without real-time S pO 2 assessment., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

Background: Passengers on long-haul flights frequently consume alcohol. Inflight sleep exacerbates the fall in blood oxygen saturation (SpO 2 ) caused by the decreased oxygen partial pressure in the cabin. We investigated the combined influence of alcohol and hypobaric hypoxia on sleep, SpO 2 and heart rate., Methods: Two groups of healthy individuals spent either two nights with a 4-hour sleep opportunity (00:00-04:00 hours) in the sleep laboratory (n=23; 53 m above sea level) or in the altitude chamber (n=17; 753 hPa corresponding to 2438 m above sea level, hypobaric condition). Participants consumed alcohol before one of the nights (mean±SE blood alcohol concentration 0.043±0.003%). The order of the nights was counterbalanced. Two 8-hour recovery nights (23:00-07:00 hours) were scheduled between conditions. Polysomnography, SpO 2 and heart rate were recorded., Results: The combined exposure to alcohol and hypobaric condition decreased SpO 2 to a median (25th/75th percentile) of 85.32% (82.86/85.93) and increased heart rate to a median (25th/75th percentile) of 87.73 bpm (85.89/93.86) during sleep compared with 88.07% (86.50/88.49) and 72.90 bpm (70.90/78.17), respectively, in the non-alcohol hypobaric condition, 94.97% (94.59/95.33) and 76.97 bpm (65.17/79.52), respectively, in the alcohol condition and 95.88% (95.72/96.36) and 63.74 bpm (55.55/70.98), respectively, in the non-alcohol condition of the sleep laboratory group (all p<0.0001). Under the combined exposure SpO 2 was 201.18 min (188.08/214.42) below the clinical hypoxia threshold of 90% SpO 2 compared with 173.28 min (133.25/199.03) in the hypobaric condition and 0 min (0/0) in both sleep laboratory conditions. Deep sleep (N3) was reduced to 46.50 min (39.00/57.00) under the combined exposure compared with both sleep laboratory conditions (alcohol: 84.00 min (62.25/92.75); non-alcohol: 67.50 min (58.50/87.75); both p<0.003)., Conclusions: The combination of alcohol and inflight hypobaric hypoxia reduced sleep quality, challenged the cardiovascular system and led to extended duration of hypoxaemia (SpO 2 <90%)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: Women with hypertensive disorders of pregnancy (HDP) are at increased risk of developing premature cardiovascular disease (CVD). The mechanisms behind this are not fully understood, but microvascular alterations have been documented in retinal arterioles and venules. The aim of this study was to use non-invasive retinal imaging to investigate the structural and functional properties of arterioles, venules and capillaries in this patient group., Methods: We examined 27 women with previous HDP and 23 controls at 3 years postpartum. The retinal microvasculature was assessed by vessel calibre measurements, retinal oximetry and optical coherence tomography angiography. Differences were analysed using non-parametric tests and multiple regression analyses, adjusted for age and body mass index., Results: Median arteriolar oxygen saturation (SaO 2 ; 94.2% vs. 93.0%), venular oxygen saturation (SvO 2 ; 60.1% vs. 62.4%) and arteriovenous saturation difference (AV-difference; 32.8% vs. 32.3%) were similar across groups. Capillary vessel density (VD; 46.2% vs. 46.3%), skeletonised VD (VSD; 21.3 vs. 21.1 mm/mm 2 ) and vessel diameter index (21.65 vs. 21.86) were also comparable. In the HDP group, mean arterial pressure (MAP) was positively correlated with AV-difference (R 2  = 0.209) and negatively correlated with arteriolar diameter (CRAE; r 2  = 0.382)., Conclusions: Structural microvascular alterations appear not to be key biomarkers for CVD risk after HDP as early as 3 years postpartum in otherwise healthy women. Further studies are needed to evaluate whether such changes occur later in life. MAP was associated with AV-difference only in the HDP group, suggesting specific mechanisms affecting functional microvascular properties in these women., (© 2024 The Authors. Acta Ophthalmologica published by John Wiley & Sons Ltd on behalf of Acta Ophthalmologica Scandinavica Foundation.)

Hermand, Eric, Léo Lesaint, Laura Denis, Jean-Paul Richalet, and François J. Lhuissier. A step test to evaluate the susceptibility to severe high-altitude illness in field conditions. High Alt Med Biol. 25:158-163, 2024.-A laboratory-based hypoxic exercise test, performed on a cycle ergometer, can be used to predict susceptibility to severe high-altitude illness (SHAI) through the calculation of a clinicophysiological SHAI score. Our objective was to design a field-condition test and compare its derived SHAI score and various physiological parameters, such as peripheral oxygen saturation (SpO 2 ), and cardiac and ventilatory responses to hypoxia during exercise (HCRe and HVRe, respectively), to the laboratory test. A group of 43 healthy subjects (15 females and 28 males), with no prior experience at high altitude, performed a hypoxic cycle ergometer test (simulated altitude of 4,800 m) and step tests (20 cm high step) at 3,000, 4,000, and 4,800 m simulated altitudes. According to tested altitudes, differences were observed in O 2 desaturation, heart rate, and minute ventilation ( p < 0.001), whereas the computed HCRe and HVRe were not different ( p = 0.075 and p = 0.203, respectively). From the linear relationships between the step test and SHAI scores, we defined a risk zone, allowing us to evaluate the risk of developing SHAI and take adequate preventive measures in field conditions, from the calculated step test score for the given altitude. The predictive value of this new field test remains to be validated in real high-altitude conditions.

Purpose: To investigate the association between pretreatment blood flow velocity in the choroid and optic nerve head (ONH) and retinal oxygen metabolism in the acute uveitic phase and the development of 'sunset glow fundus' in Vogt-Koyanagi-Harada (VKH) disease., Methods: Retrospective analysis of 41 patients (82 eyes). Laser speckle flowgraphy and retinal oximetry measurements were performed at the presentation. The main outcome measure was the development of 'sunset glow fundus'., Results: Twenty patients (40 eyes) presented in the phase preceding anterior segment inflammation (early presentation), and 21 patients (42 eyes) presented with anterior segment inflammation (late presentation). In ONH, mean blur rate (MBR)-vessel, representing blood flow velocity in retinal vessels, was significantly lower in the late presentation group, while choroidal MBR was not significantly different. The late presentation group had significantly lower oxygen saturation in retinal venules, a higher arteriovenous oxygen saturation difference and a smaller calibre of retinal arterioles compared with the early presentation group. Eyes that subsequently developed 'sunset glow fundus' had significantly lower ONH MBR-vessels, lower oxygen saturation in retinal venules, a higher arteriovenous oxygen saturation difference and a smaller calibre of retinal arterioles compared with eyes without 'sunset glow fundus'. ONH MBR-vessel had a significant negative correlation with arteriovenous oxygen saturation difference and a significant positive correlation with calibre of retinal arterioles., Conclusions: In the acute uveitic phase of VKH disease, the development of 'sunset glow fundus' is associated with pretreatment reduced retinal blood flow velocity, calibre of retinal arterioles and oxygen saturation in retinal venules, as well as an increased arteriovenous oxygen saturation difference., (© 2024 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: Patients receiving venoarterial extracorporeal membrane oxygenation (VA-ECMO) frequently develop arterial hyperoxaemia, which may be harmful. However, lower oxygen saturation targets may also lead to harmful episodes of hypoxaemia., Methods: In this registry-embedded, multicentre trial, we randomly assigned adult patients receiving VA-ECMO in an intensive care unit (ICU) to either a conservative (target SaO 2 92-96%) or to a liberal oxygen strategy (target SaO 2 97-100%) through controlled oxygen administration via the ventilator and ECMO gas blender. The primary outcome was the number of ICU-free days to day 28. Secondary outcomes included ICU-free days to day 60, mortality, ECMO and ventilation duration, ICU and hospital lengths of stay, and functional outcomes at 6 months., Results: From September 2019 through June 2023, 934 patients who received VA-ECMO were reported to the EXCEL registry, of whom 300 (192 cardiogenic shock, 108 refractory cardiac arrest) were recruited. We randomised 149 to a conservative and 151 to a liberal oxygen strategy. The median number of ICU-free days to day 28 was similar in both groups (conservative: 0 days [interquartile range (IQR) 0-13.7] versus liberal: 0 days [IQR 0-13.7], median treatment effect: 0 days [95% confidence interval (CI) - 3.1 to 3.1]). Mortality at day 28 (59/159 [39.6%] vs 59/151 [39.1%]) and at day 60 (64/149 [43%] vs 62/151 [41.1%] were similar in conservative and liberal groups, as were all other secondary outcomes and adverse events. The conservative group experienced 44 (29.5%) major protocol deviations compared to 2 (1.3%) in the liberal oxygen group (P < 0.001)., Conclusions: In adults receiving VA-ECMO in ICU, a conservative compared to a liberal oxygen strategy, did not affect the number of ICU-free days to day 28., (© 2024. The Author(s).)

Patients with surgical, pulmonary, and cardiac problems, continual monitoring of Oxygen Saturation of a Person (SpO2) and Respiratory Rate (RR) is essential. Similarly, the persons with cardiopulmonary health issues, RR estimation is crucial. The performance of the ventilator assistance and lung medicines are evaluated using SpO2 and RR. For the persons, those who are living alone with respiratory illnesses need a compulsory estimation of RR. In case of serious illness, the RR might face abrupt changes. The immobility of the disturbance and RR makes the RR evaluation from the PhotoPlethysmoGraphic (PPG) signals is a difficult challenge. So, an efficient RR and SpO2 estimation framework from the PPG signal using the deep learning method is developed in this paper. At first, the PPG signal is collected from standard data sources. The collected PPG signals undergo signal pre-processing. The pre-processing procedures include Motion Artifacts (MA) removal and filtering techniques. The pre-processed signals are split into distinct windows. From the split windows of the signals, the spectral features, RR, and Respiratory Peak Variance (RPV) features are extracted. The retrieved features are selected optimally with the help of Advanced Golden Tortoise Beetle Optimizer (AGTBO). The weights are chosen optimally with the same AGTBO. The optimally selected features are fused with the optimal features to get the weighted optimal features. These weighted optimal features are fed into the Ensemble Learning-based RR and SpO2 Estimation Network (ELRR-SpO2EN). The ensemble learning model is developed by combining Multilayer Perceptron (MLP), AdaBoost, and Attention-based Long Short Term Memory (A-LSTM). The performance of the developed RR and SpO2 estimation model is compared with other existing techniques. The experimental analysis results revealed that the proposed AGTBO-ELRR-SpO2EN model attained 96 % accuracy for the second dataset, which is higher than the conventional models such as MLP (90 %), Adaboost (92 %), A-LSTM (92 %), and MLP-ADA-ALSTM (94 %). Thus, it has been confirmed that the designed RR and SpO2 estimation framework from PPG signals is more efficient than the other conventional models., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Alterations caused by face masks on physiological responses vary among different population groups. This study aimed to investigate whether physically active and sedentary individuals respond differently to face mask use during exercise., Methods: Sixteen healthy college students were divided into two groups: Physically active group (N.=10; 26.50±2.80 years) and Sedentary group (N.=6; 26.33±2.81 years). They performed three maximal cardiopulmonary exercise test (CPET)s following the Bruce protocol: one without a face mask (NON), one with a surgical mask (SUR) and one with a cloth mask (CLO). Cardiorespiratory parameters and heart rate were monitored continuously during the test. Blood pressure, oxygen saturation and lactate level were measured immediately before and after exertion., Results: Significant differences were found between the Physically active and the Sedentary group in peak VO2 (VO2peak) in NON (P=0.030). However, this difference disappeared when the face masks were used. Furthermore, VO2/kg (P=0.002) and METs (P=0.002) decreased significantly at the respiratory compensation point (RCP) only in the Physically active group with face masks. No significant differences were found between the two groups for exercise time, lactate level and dyspnea (P>0.05)., Conclusions: The decrease in exercise tolerance and cardiorespiratory responses, particularly VO2peak, due to face mask use was greater in physically active individuals compared to sedentary individuals. Population group characteristics should be considered when adapting face masks to daily life.

Background and Objective: The apnoea-hypopnoea index (AHI) and oxygen desaturation index (ODI) encounter challenges in capturing the intricate relationship between obstructive sleep apnoea (OSA) and cardiovascular disease (CVD) risks. Although novel hypoxic indices have been proposed to tackle these limitations, there remains a gap in comprehensive validation and comparisons across a unified dataset., Methods: Samples were derived from the Sleep Heart Health Study (SHHS), involving 4485 participants aged over 40 years after data quality screening. The study compared several key indices, including AHI, ODI, the reconstructed hypoxic burden (rHB), the percentage of sleep time with the duration of respiratory events causing desaturation (pRED&#95;3p) and the sleep breathing impairment index (SBII), in relation to CVD mortality and morbidity risks. Adjusted Cox proportional models were employed to calculate hazard ratios (HRs) for each index, and comparisons were performed., Results: SBII and pRED&#95;3p exhibited significant correlations with both CVD mortality and morbidity, with SBII showing the highest adjusted HR (95% confidence interval) for mortality (2.04 [1.25, 3.34]) and pRED&#95;3p for morbidity (1.43 [1.09-1.88]). In contrast, rHB was only significant in predicting CVD mortality (1.63 [1.05-2.53]), while AHI and ODI did not show significant correlations with CVD outcomes. The adjusted models based on SBII and pRED&#95;3p exhibited optimal performance in the CVD mortality and morbidity datasets, respectively., Conclusion: This study identified the optimal indices for OSA-related CVD risks prediction, SBII for mortality and pRED&#95;3p for morbidity. The open-source online platform provides the computation of the indices., (© 2024 Asian Pacific Society of Respirology.)

Purpose: The purpose of this study was to evaluate the accuracy of peripheral oxygen saturation (SpO 2 ) measurements from Polar Elixir™ pulse oximetry technology compared with arterial oxygen saturation (SaO 2 ) measurements during acute stepwise steady-state inspired hypoxia at rest. A post hoc objective was to determine if SpO 2 measurements could be improved by recalibrating the Polar Elixir™ algorithm with SaO 2 values from a random subset of participants., Methods: The International Organization for Standardization (ISO) protocol (ISO 80601-2-61:2017) for evaluating the SpO 2 accuracy of pulse oximeter equipment was followed whereby five plateaus of SaO 2 between 70% and 100% were achieved using stepwise reductions in inspired O 2 during supine rest. Blood samples drawn through a radial arterial catheter from 25 participants were first used to compare SaO 2 with SpO 2 measurements from Polar Elixir™. Then the Polar Elixir™ algorithm was recalibrated using SaO 2 data from 13 random participants, and SpO 2 estimates were recalculated for the other 12 participants. For SaO 2 values between 70% and 100%, root mean square error, intraclass correlation coefficients (ICC), Pearson correlations, and Bland-Altman plots were used to assess the accuracy, agreement, and strength of relationship between SaO 2 values and SpO 2 values from Polar Elixir™., Results: The initial root mean square error for Polar Elixir™ was 4.13%. After recalibrating the algorithm, the RMSE was improved to 2.67%. The ICC revealed excellent levels of agreement between SaO 2 and Polar Elixir™ SpO 2 values both before (ICC(1,3) = 0.837, df = 574, P < 0.001) and after (ICC(1,3) = 0.942, df = 287, P < 0.001) recalibration., Conclusions: Relative to ISO standards, Polar Elixir™ yielded accurate SpO 2 measurements during stepwise inspired hypoxia at rest when compared with SaO 2 values, which were improved by recalibrating the algorithm using a subset of the SaO 2 data., (Copyright © 2024 by the American College of Sports Medicine.)

Background: Peripherally measured oxygen saturation (SpO 2 ) may often differ from arterial oxygen saturation (SaO 2 ), measured by co-oximetry, especially within the lower range of oxygen saturations. This can potentially impact clinical decisions and therapy in children with congenital heart disease, as critical hypoxemia might remain unnoticed., Aims: Our aim was to investigate the accuracy of two different pulse oximeters compared to SaO 2 in infants with congenital heart diseases., Methods: Simultaneous recordings of SpO 2 , measured by two different pulse oximeters (Philips IntelliVue X3 Monitor and Nellcor™ OxiMax™), were compared to SaO 2 obtained by arterial blood gas analysis., Results: A total of 153 measurements were performed in 44 infants with arterial oxygen saturation between 70 and 100%. We divided the measurements into 3 subgroups: group 1-SaO 2 70.0%-85.0%, group 2-SaO 2 85.1%-94.0%, group 3-SaO 2 >94.1%. For Philipps, the median bias was 5.3 (IQR: 2.6-8.7) %, 2.3 (IQR: 0.9-6.0) % and 1.1 (IQR: -0.8-2.4) % in group 1, 2 and 3, respectively. For OxiMax™, the median bias was 2.7 (IQR: 0.5-5.1) %, 0.2 (IQR: -0.9-2.6) % and -0.5 (IQR: -1.3-0.6) % in group 1, 2 and 3, respectively. Regarding the accuracy of these oximeters, as evaluated with the Accuracy root mean squared index (Arms), it was 9.8 versus 4.5% in group 1, 4.5 versus 2.9% in group 2 and 2.4 versus 1.9% in group 3 for Philipps and OxiMax™, respectively., Conclusions: In lower range saturations between 70% and 85% the accuracy of both pulse oximeters exceeded the threshold of ≤3% recommended by the Food and Drug Administration (FDA). Therefore, peripheral pulse oximetry within the lower range of oxygen saturations should be interpreted with caution in infants with congenital heart diseases, taking into consideration its limitations. Direct co-oximetry should be the preferred method to support clinical decisions in children with cyanotic congenital heart diseases., (© 2024 The Author(s). Pediatric Anesthesia published by John Wiley & Sons Ltd.)

Background: Assessment of gastric conduit perfusion during esophagectomy is crucial to determine its viability and identify the optimal site for anastomosis. Indocyanine green (ICG) fluorescence imaging is commonly used for this purpose, but it is contraindicated in patients with hypersensitivity to ICG, iodine, or shellfish. Oxygen saturation endoscopic imaging (OXEI) is a newer, non-pharmacologic technique for assessing perfusion. We report our experience with OXEI in 3 esophagectomy patients who had contraindications to ICG., Methods: All 3 patients underwent robot-assisted esophagectomies. None of the conduits had ischemic areas identified by white light. Using a 5 mm laparoscopic specialized camera (ELUXEO Vision, FUJIFILM Healthcare Americas Corp., USA), OXEI was deployed for intracorporeal assessment of gastric conduit perfusion after pull-up into the chest. Postoperative outcomes including anastomotic leaks and complications were recorded., Results: In two patients, OXEI revealed ischemic zones, which were resected to ensure optimal conduit viability. In the remaining patient, OXEI indicated robust vascularity throughout the conduit. All three patients experienced uneventful postoperative courses and were discharged within 10 days. There were no instances of anastomotic leaks or other major complications., Conclusion: In our experience, OXEI is a viable method for intraoperative assessment of gastric conduit perfusion in patients with contraindications to ICG. Prospective studies are needed to validate its efficacy in preventing anastomotic complications and to compare it with other methods of perfusion assessment including gross visual and ICG dye in a larger patient population., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

When treating patients with orthognathic surgery, there might be a risk of obstructive sleep apnoea (OSA) due to soft tissue changes in the upper airways, especially in patients treated with isolated mandibular setback or mandibular setback in combination with maxillary advancement. In the present study, we assessed respiratory function during sleep with home cardiorespiratory polygraphy in 62 patients who had not been previously been diagnosed with OSA at three times: prior to orthognathic surgery for aesthetic and functional indications, and then 3 months and 1 year after surgery. We evaluated surgical displacement based on measurements in three dimensions using pre- and post-operative computed tomography. There were only minor changes in the respiratory parameters such as the apnoea-hypopnoea index (AHI), the apnoea-hypopnoea index in the supine position (AHI sup ), the oxygen saturation index (ODI) and the snore index. There was no significant correlation between surgical displacement and the AHI, AHI sup and ODI. There was a weak but significant correlation between vertical displacement of the anterior mandible and the snore index. Within the limitations of the present study, the risk for iatrogenic obstruction of the upper airways seems to be low in patients without OSA treated with orthognathic surgery., (© 2024 The Author(s). Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

Background/aims: We assessed the associations between retinopathy of prematurity (ROP) and continuous measurements of oxygen saturation (SpO 2 ), and developed a risk prediction model for severe ROP using birth data and SpO 2 data., Methods: This retrospective study included infants who were born before 30 weeks of gestation between August 2009 and January 2019 and who were screened for ROP at a single hospital in Japan. We extracted data on birth weight (BW), birth length, gestational age (GA) and minute-by-minute SpO 2 during the first 20 days from the medical records. We defined four SpO 2 variables using sequential measurements. Multivariate logistic regression was used to develop a model that combined birth data and SpO 2 data to predict treatment-requiring ROP (TR-ROP). The model's performance was evaluated using the area under the receiver operating characteristic curve (AUC)., Results: Among 350 infants, 83 (23.7%) required ROP treatment. The SpO 2 variables in infants with TR-ROP differed significantly from those with non-TR-ROP. The average SpO 2 and high SpO 2 showed strong associations with GA (r=0.73 and r=0.70, respectively). The model incorporating birth data and the four SpO 2 variables demonstrated good discriminative ability (AUC=0.83), but it did not outperform the model incorporating BW and GA (AUC=0.82)., Conclusion: Data obtained by continuous SpO 2 monitoring demonstrated valuable associations with severe ROP, as well as with GA. Differences in the distribution of average SpO 2 and high SpO 2 between infants with TR-ROP and non-TR-ROP could be used to establish efficient cut-off values for risk determination., Competing Interests: Competing interests: None declared. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)