Search

We chose the "natural laboratory" provided by high-altitude native ethnic Tibetan women who had completed childbearing to examine the hypothesis that multiple oxygen delivery traits were associated with lifetime reproductive success and had genomic associations. Four hundred seventeen (417) women aged 46 to 86 y residing at ≥3,500 m in Upper Mustang, Nepal, provided information on reproductive histories, sociocultural factors, physiological measurements, and DNA samples for this observational cohort study. Simultaneously assessing multiple traits identified combinations associated with lifetime reproductive success measured as the number of livebirths. Women with the most livebirths had distinctive hematological and cardiovascular traits. A hemoglobin concentration near the sample mode and a high percent of oxygen saturation of hemoglobin raised arterial oxygen concentration without risking elevated blood viscosity. We propose ongoing stabilizing selection on hemoglobin concentration because extreme values predicted fewer livebirths and directional selection favoring higher oxygen saturation because higher values had more predicted livebirths. EPAS1, an oxygen homeostasis locus with strong signals of positive natural selection and a high frequency of variants occurring only among populations indigenous to the Tibetan Plateau, associated with hemoglobin concentration. High blood flow into the lungs, wide left ventricles, and low hypoxic heart rate responses aided effective convective oxygen transport to tissues. Women with physiologies closer to unstressed, low altitude values had the highest lifetime reproductive success. This example of ethnic Tibetan women residing at high altitudes in Nepal links reproductive fitness with trait combinations increasing oxygen delivery under severe hypoxic stress and demonstrates ongoing natural selection., Competing Interests: Competing interests statement:The authors declare no competing interest.

Background: In acute stroke, diffusion-weighted imaging (DWI) is used to assess the ischemic core. Dynamic-susceptibility contrast perfusion magnetic resonance imaging allows an estimation of the oxygen extraction fraction (OEF), but the outcome of DWI lesions with increased OEF postrecanalization is unclear. This study investigated the impact of OEF on the fate of DWI lesions in patients achieving recanalization after thrombectomy., Methods: This was a retrospective analysis of the HIBISCUS-STROKE cohort (Cohort of Patients to Identify Biological and Imaging Markers of Cardiovascular Outcomes in Stroke; NCT: 03149705), a single-center observational study that prospectively enrolled patients who underwent magnetic resonance imaging triage for thrombectomy and a day-6 T2-fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging. Automated postprocessing of admission dynamic-susceptibility contrast perfusion magnetic resonance imaging generated OEF maps. At visual analysis, the OEF status within DWI lesions was assessed in comparison to the contralateral side and correlated with volume changes (difference of ischemic lesion between admission DWI and registered day-6 T2-FLAIR). At voxel-based analysis, recovered DWI regions (lesions present on the admission DWI but absent on the registered day-6 T2-FLAIR) and nonrecovered regions were segmented to extract semiquantitative OEF values., Results: Of the participants enrolled from 2016 to 2022, 134 of 321 (41.7%) were included (median age, 71.0 years; 58.2% male; median baseline National Institutes of Health Scale score, 15.0). At visual analysis, 46 of 134 (34.3%) patients had increased OEF within DWI lesions. These patients were more likely to show a reduction in ischemic lesion volumes compared with those without increased OEF (median change, -4.0 versus 4.8 mL; P <0.0001). Multivariable analysis indicated that increased OEF within DWI lesions was associated with a reduction in ischemic lesion volumes from admission DWI to day-6 T2-FLAIR (odds ratio, 0.68 [95% CI, 0.49-0.87]; P =0.008). At voxel-based analysis, recovered DWI regions had increased OEF, while nonrecovered regions had decreased OEF (median, 126.9% versus -27.0%; P <0.0001)., Conclusions: Increased OEF within hyperacute DWI lesions was associated with ischemic lesion recovery between admission DWI and day-6 T2-FLAIR in patients achieving recanalization after thrombectomy., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03149705., Competing Interests: None.

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.)

Numerous studies report on the influence of temperature on blood gases in ectothermic vertebrates, but there is merely a cursory understanding of these effects in developing animals. Animals that develop in eggs are at the mercy of environmental temperature and are expected to lack the capacity to regulate gas exchange and may regulate blood gases by means of altered conductance for gas exchange. We, therefore, devised a series of studies to characterize the developmental changes in blood gases when embryonic alligators were exposed to 25, 30 and 35 °C. To determine how blood parameters were impacted by changes in embryonic temperature, blood was sampled from the chorioallantoic membrane artery. The blood in the chorioallantoic membrane artery is a mixture of oxygen-poor and oxygen-rich blood, which based on the embryonic vascular anatomy may reflect blood that perfuses the chemoreceptors of the developing animal. Our findings indicate that following a 48 h exposure to 25 °C or 35 °C, there was a positive relationship between CAM artery blood PO 2 , PCO 2 and glucose. However, blood pH suggests embryonic alligators lack an acute regulatory mechanism for adjusting blood pH., Competing Interests: Declaration of competing interest The authors declare to have no known competing financial interests or personal relationships that could have appeared to influence the data in this manuscript., (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.)

Objectives: We prospectively compared cerebral oxygen saturation (CrSO2) and pain score changes during procedures in late preterm (LPT) versus term infants., Methods: Near-infrared spectroscopy, pulse oximetry, Neonatal Infant Pain Scale (NIPS) and Premature Infant Pain Profile-Revised (PIPP-R) scores were assessed and CrSO2 data analyzed., Results: Thirty infants in each group were evaluated. LPT infants displayed a milder significant drop in Minimum post-procedural CrSO2 and smaller Maximum-Minimum post-procedural CrSO2 disparity. CrSO2 minute changes between the groups were non-significant. Moderate correlations were observed in both groups between NIPS and Minimum post-procedural CrSO2, and a moderate correlation was found in the Maximum-Minimum post-procedural CrSO2 difference in LPT infants. No correlation between PIPP-R and CrSO2 values was noted., Conclusion: LPT and term infants demonstrated decreased CrSO2 in response to painful procedures. Correlations between CrSO2 and PIPP-R or NIPS scores were poor to moderate, reflecting the complex nature of these associations relative to gestational age., (© 2024. The Author(s).)

Purpose: We studied the effect of O 2 supplementation on physiological response to exercise in patients with moderate to severe interstitial lung disease (ILD)., Methods: Thirteen patients (age 66 ± 10 yr, 7 males) with ILD (total lung capacity, 71% ± 22% predicted; carbon monoxide diffusion capacity, 44% ± 16% predicted) and 13 healthy individuals (age 50 ± 17 yr, 7 males) were tested. ILD patients performed symptom-limited cardiopulmonary exercise tests and constant work rate (WR) tests at 80% of the WR at the gas exchange threshold. Tests breathing room air (RA; 21% O 2 ) were compared with tests performed breathing 30% O 2 . Oxygen uptake (V̇O 2 ) kinetics were calculated from the constant WR test results., Results: In the ILD group, peak WR, peak V̇O 2 , and V̇O 2 at the gas exchange threshold improved significantly when breathing 30% O 2 compared with RA (mean ± SD, 75 ± 26 vs 66 ± 23 W, 17 ± 4 vs 15 ± 2 mL·kg -1 ·min -1 , and 932 ± 245 vs 854 ± 232 mL·min -1 ; P = 0.004, P = 0.001, and P = 0.01, respectively). O 2 saturation (SpO 2 %) at peak exercise was higher with 30% O 2 (97% ± 4% vs 88% ± 9%, P = 0.002). The time constant (tau) of V̇O 2 kinetics was faster in ILD patients while breathing 30% O 2 (41 ± 10 s) compared with RA (52 ± 14 s, P = 0.003). There was a negative linear relation between tau and SpO 2 % with RA ( r = -0.76, P = 0.006) and while breathing 30% O 2 ( r = -0.68, P = 0.02)., Conclusions: Using a clinically applicable level of O 2 supplementation (30%) improved maximal, aerobic exercise capacity and V̇O 2 kinetics in ILD patients, likely due to increased blood O 2 content subsequently increasing the O 2 delivery to the working muscles., (Copyright © 2024 by the American College of Sports Medicine.)

Background: Glucose oxidase (GOx)-based blood glucose monitors (BGMs) are influenced by the partial pressure of oxygen (Po 2 ) within the applied sample. Limited in-clinic data exists regarding the quantitative effect of Po 2 in unmanipulated capillary fingertip blood samples across physiologically representative glucose and Po 2 ranges., Method: Clinical accuracy data were collected as part of a BGM manufacturer's ongoing post-market surveillance program for a commercially available GOx-based BGM test-strip. The data set comprised 29 901 paired BGM-comparator readings and corresponding Po 2 values from 5 428 blood samples from a panel of 975 subjects., Results: A linear regression-calculated bias range of 5.22% (+0.72% [low Po 2 : 45 mm Hg] to -4.5% [high Po 2 : 105 mm Hg]); biases calculated as absolute at <100 mg/dL glucose was found. Below the nominal Po 2 of 75 mm Hg, a linear regression bias of +3.14% was calculated at low Po 2 , while negligible impact on bias (regression slope: +0.002%) was observed at higher than nominal levels (>75 mm Hg). When evaluating BGM performance under corner conditions of low (<70 mg/dL) and high (>180 mg/dL) glucose, combined with low and high Po 2 , linear regression biases ranged from +1.52% to -5.32% within this small group of subjects and with no readings recorded at <70 mg/dL glucose at low and high Po 2 ., Conclusions: Data from this large-scale clinical study, performed on unmanipulated fingertip capillary bloods from a diverse diabetes population, indicate Po 2 sensitivity of the BGM to be markedly lower than published studies, which are mainly laboratory-based, requiring artificial manipulation of oxygen levels in aliquots of venous blood., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: SS, SP, HC, and MG are employees of LifeScan Scotland, Ltd.

During acute hypoxic exposure, cerebral blood flow (CBF) increases to compensate for the reduced arterial oxygen content (CaO 2 ). Nevertheless, as exposure extends, both CaO 2 and CBF progressively normalize. Haemoconcentration is the primary mechanism underlying the CaO 2 restoration and may therefore explain, at least in part, the CBF normalization. Accordingly, we tested the hypothesis that reversing the haemoconcentration associated with extended hypoxic exposure returns CBF towards the values observed in acute hypoxia. Twenty-three healthy lowlanders (12 females) completed two identical 4-day sojourns in a hypobaric chamber, one in normoxia (NX) and one in hypobaric hypoxia (HH, 3500 m). CBF was measured by ultrasound after 1, 6, 12, 48 and 96 h and compared between sojourns to assess the time course of changes in CBF. In addition, CBF was measured at the end of the HH sojourn after hypervolaemic haemodilution. Compared with NX, CBF was increased in HH after 1 h (P = 0.001) but similar at all later time points (all P > 0.199). Haemoglobin concentration was higher in HH than NX from 12 h to 96 h (all P < 0.001). While haemodilution reduced haemoglobin concentration from 14.8 ± 1.0 to 13.9 ± 1.2 g·dl -1 (P < 0.001), it did not increase CBF (974 ± 282 to 872 ± 200 ml·min -1 ; P = 0.135). We thus conclude that, at least at this moderate altitude, haemoconcentration is not the primary mechanism underlying CBF normalization with acclimatization. These data ostensibly reflect the fact that CBF regulation at high altitude is a complex process that integrates physiological variables beyond CaO 2 . KEY POINTS: Acute hypoxia causes an increase in cerebral blood flow (CBF). However, as exposure extends, CBF progressively normalizes. We investigated whether hypoxia-induced haemoconcentration contributes to the normalization of CBF during extended hypoxia. Following 4 days of hypobaric hypoxic exposure (corresponding to 3500 m altitude), we measured CBF before and after abolishing hypoxia-induced haemoconcentration by hypervolaemic haemodilution. Contrary to our hypothesis, the haemodilution did not increase CBF in hypoxia. Our findings do not support haemoconcentration as a stimulus for the CBF normalization during extended hypoxia., (© 2024 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

The present investigation aimed to study the cardiovascular responses and the cerebral oxygenation (Cox) during exercise in acute hypoxia and with contemporary mental stress. Fifteen physically active, healthy males (age 29.0 ± 5.9 years) completed a cardiopulmonary test on a cycle ergometer to determine the workload at their gas exchange threshold (GET). On a separate day, participants performed two randomly assigned exercise tests pedaling for 6 min at a workload corresponding to 80% of the GET: (1) during normoxia (NORMO), and (2) during acute, normobaric hypoxia at 13.5% inspired oxygen (HYPO). During the last 3 min of the exercise, they also performed a mental task (MT). Hemodynamics were assessed with impedance cardiography, and peripheral arterial oxygen saturation and Cox were continuously measured by near-infrared spectroscopy. The main results were that both in NORMO and HYPO conditions, the MT caused a significant increase in the heart rate and ventricular filling rate. Moreover, MT significantly reduced (74.8 ± 5.5 vs. 62.0 ± 5.2 A.U.) Cox, while the reaction time (RT) increased (813.3 ± 110.2 vs. 868.2 ± 118.1 ms) during the HYPO test without affecting the correctness of the answers. We conclude that in young, healthy males, adding an MT during mild intensity exercise in both normoxia and acute moderate (normobaric) hypoxia induces a similar hemodynamic response. However, MT and exercise in HYPO cause a decrease in Cox and an impairment in RT., Competing Interests: The authors have no conflicts of interest that are directly relevant to the content of this manuscript.

Introduction: The performance of an oxygenator, as found in literature, is evaluated according to protocols that define standard values of the gas content in the inlet blood. However, when dealing with simulations of lung insufficiency, a more extensive evaluation is needed. This work aims to investigate and assess the gas exchange performance of an oxygenator for different input values of gas content in blood., Methods: Three commercially available oxygenators with different membrane surfaces were investigated in a mock loop for three blood flow rates (0.5l/min, 1l/min, and 5l/min) and two gas-to-blood ratios (1:1, and 15:1). The initial CO2 and O2 partial pressures (pCO2 and pO2) in blood were set to ≥ 100 mmHg and ≤10 mmHg, respectively. For each ratio, the efficiency, defined as the ratio between the difference of pressure inlet and outlet and the inlet pCO2 (pCO2(i)), was calculated., Results: The CO2 elimination in an oxygenator was higher for higher pCO2(i). While for a pCO2(i) of 100 mmHg, an oxygenator eliminated 80 mmHg, the same oxygenator at the same conditions eliminated 5 mmHg CO2 when pCO2(i) was 10 mmHg. The efficiency of the oxygenator decreased from 76,9% to 49,5%. For simulation reasons, the relation between the pCO2(i) and outlet (pCO2(o)) for each oxygenator at different blood and gas flows, was described as an exponential formula., Conclusion: The performance of an oxygenator in terms of CO2 elimination depends not only on the blood and gas flow, but also on the initial pCO2 value. This dependence is crucial for simulation studies in the future., 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.

Background: Serum creatinine (Scr) may be not suited to timely and accurately reflect kidney injury related to chronic liver disease. Currently, the ability of arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) sequences to evaluate renal blood flow (RBF) and blood oxygen in chronic liver disease remains to be verified., Purpose: To investigate the value of ASL and BOLD imaging in evaluating hemodynamics and oxygenation changes during kidney injury in an animal model of chronic liver disease., Study Type: Prospective., Animal Model: Chronic liver disease model was established by subcutaneous injection of carbon tetrachloride. Forty-three male Sprague-Dawley rats (8 weeks) were divided into a pathological group (0, 2, 4, 6, 8, 12 weeks, each group: N = 6) and a continuous-scanning group (N = 7)., Field Strength/sequence: 3-T, ASL, BOLD, and T2W., Assessment: Regions of interest in the cortex (CO), outer stripe of the outer medulla (OSOM), and inner stripe of the outer medulla (ISOM) are manually delineated. The RBF and T2* values at each time point (0, 2, 4, 6, 8, 12 weeks) are measured and compared. Hematoxylin-eosin score (HE Score, damage area scoring method), alpha-smooth muscle actin (α-SMA), hypoxia-inducible factor-1alpha (HIF-1α), peritubular capillar (PTC) density, Scr, and neutrophil gelatinase-associated lipocalin were harvested., Statistical Tests: Analysis of variance, Spearman correlation analysis, Kruskal-Wallis tests, and receiver operating characteristic analysis with the area under the curve (AUC). A P-value <0.05 was considered statistically significant., Results: Renal RBF and T2* values of CO, OSOM, and ISOM were significantly different from baseline. Both RBF and T2* were significantly correlated with HE Score, α-SMA, HIF-1α, and PTC density (|r| = 0.406-0.853). RBF demonstrated superior diagnostic capability in identifying severe kidney injury in this model of chronic liver disease (AUC = 0.964)., Data Conclusion: Imaging by ASL and BOLD may detect renal hemodynamics and oxygenation changes related to chronic liver disease early., Evidence Level: 5 TECHNICAL EFFICACY: Stage 2., (© 2024 International Society for Magnetic Resonance in Medicine.)

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.)

Background: The use of prone position (PP) has been widespread during the COVID-19 pandemic. Whereas it has demonstrated benefits, including improved oxygenation and lung aeration, the factors influencing the response in terms of gas exchange to PP remain unclear. In particular, the association between baseline quantitative computed tomography (CT) scan results and gas exchange response to PP in invasively ventilated subjects with COVID-19 ARDS is unknown. The present study aimed to compare baseline quantitative CT results between subjects responding to PP in terms of oxygenation or CO 2 clearance and those who did not., Methods: This was a single-center, retrospective observational study including critically ill, invasively ventilated subjects with COVID-19-related ARDS admitted to the ICUs of Niguarda Hospital between March 2020-November 2021. Blood gas samples were collected before and after PP. Subjects in whom the P aO 2 /F IO 2 increase was ≥ 20 mm Hg after PP were defined as oxygen responders. CO 2 responders were defined when the ventilatory ratio (VR) decreased during PP. Automated quantitative CT analyses were performed to obtain tissue mass and density of the lungs., Results: One hundred twenty-five subjects were enrolled, of which 116 (93%) were O 2 responders and 51 (41%) CO 2 responders. No difference in quantitative CT characteristics and oxygen were observed between responders and non-responders (tissue mass 1,532 ± 396 g vs 1,654 ± 304 g, P = .28; density -544 ± 109 HU vs -562 ± 58 HU P = .42). Similar findings were observed when dividing the population according to CO 2 response (tissue mass 1,551 ± 412 g vs 1,534 ± 377 g, P = .89; density -545 ± 123 HU vs -546 ± 94 HU, P = .99)., Conclusions: Most subjects with COVID-19-related ARDS improved their oxygenation at the first pronation cycle. The study suggests that baseline quantitative CT scan data were not associated with the response to PP in oxygenation or CO 2 in mechanically ventilated subjects with COVID-19-related ARDS., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

Background: Beneficial effects of breathing at [Formula: see text] < 0.21 on disease outcomes have been reported in previous preclinical and clinical studies. However, the safety and intra-hospital feasibility of breathing hypoxic gas for 5 d have not been established. In this study, we examined the physiologic effects of breathing a gas mixture with [Formula: see text] as low as 0.11 in 5 healthy volunteers., Methods: All 5 subjects completed the study, spending 5 consecutive days in a hypoxic tent, where the ambient oxygen level was lowered in a stepwise manner over 5 d, from [Formula: see text] of 0.16 on the first day to [Formula: see text] of 0.11 on the fifth day of the study. All the subjects returned to an environment at room air on the sixth day. The subjects' [Formula: see text], heart rate, and breathing frequency were continuously recorded, along with daily blood sampling, neurologic evaluations, transthoracic echocardiography, and mental status assessments., Results: Breathing hypoxia concentration dependently caused profound physiologic changes, including decreased [Formula: see text] and increased heart rate. At [Formula: see text] of 0.14, the mean [Formula: see text] was 92%; at [Formula: see text] of 0.13, the mean [Formula: see text] was 93%; at [Formula: see text] of 0.12, the mean [Formula: see text] was 88%; at [Formula: see text] of 0.11, the mean [Formula: see text] was 85%; and, finally, at an [Formula: see text] of 0.21, the mean [Formula: see text] was 98%. These changes were accompanied by increased erythropoietin levels and reticulocyte counts in blood. All 5 subjects concluded the study with no adverse events. No subjects exhibited signs of mental status changes or pulmonary hypertension., Conclusions: Results of the current physiologic study suggests that, within a hospital setting, delivering [Formula: see text] as low as 0.11 is feasible and safe in healthy subjects, and provides the foundation for future studies in which therapeutic effects of hypoxia breathing are tested., Competing Interests: Dr Mootha is listed as an inventor on patent applications filed by Massachusetts General Hospital on the therapeutic uses of hypoxia. Dr Berra is listed as the inventor on patent applications filed by Massachusetts General Hospital on the therapeutic uses of inhaled nitric oxide., (Copyright © 2024 by Daedalus Enterprises.)

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.)

Neural activity cannot be directly observed using fMRI; rather it must be inferred from the hemodynamic responses that neural activity causes. Solving this inverse problem is made possible through the use of forward models, which generate predicted hemodynamic responses given hypothesised underlying neural activity. Commonly-used hemodynamic models were developed to explain data from healthy young participants; however, studies of ageing and dementia are increasingly shifting the focus toward elderly populations. We evaluated the validity of a range of hemodynamic models across the healthy adult lifespan: from basis sets for the linear convolution models commonly used to analyse fMRI studies, to more advanced models including nonlinear fitting of a parameterised hemodynamic response function (HRF) and nonlinear fitting of a biophysical generative model (hemodynamic modelling, HDM). Using an exceptionally large sample of participants, and a sensorimotor task optimized for detecting the shape of the BOLD response to brief stimulation, we first characterised the effects of age on descriptive features of the response (e.g., peak amplitude and latency). We then compared these to features from more complex nonlinear models, fit to four regions of interest engaged by the task, namely left auditory cortex, bilateral visual cortex, left (contralateral) motor cortex and right (ipsilateral) motor cortex. Finally, we validated the extent to which parameter estimates from these models have predictive validity, in terms of how well they predict age in cross-validated multiple regression. We conclude that age-related differences in the BOLD response can be captured effectively by models with three free parameters. Furthermore, we show that biophysical models like the HDM have predictive validity comparable to more common models, while additionally providing insights into underlying mechanisms, which go beyond descriptive features like peak amplitude or latency, and include estimation of nonlinear effects. Here, the HDM revealed that most of the effects of age on the BOLD response could be explained by an increased rate of vasoactive signal decay and decreased transit rate of blood, rather than changes in neural activity per se. However, in the absence of other types of neural/hemodynamic data, unique interpretation of HDM parameters is difficult from fMRI data alone, and some brain regions in some tasks (e.g., ipsilateral motor cortex) can show responses that are more difficult to capture using current models., (© 2024 The Author(s). Human Brain Mapping published by Wiley Periodicals LLC.)

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).)

Background: Photoplethysmography (PPG) is a technology routinely used in clinical practice to assess blood oxygenation (SpO 2 ) and pulse rate (PR). Skin pigmentation may influence accuracy, leading to health outcomes disparities., Objective: This systematic review and meta-analysis primarily aimed to evaluate the accuracy of PPG-derived SpO 2 and PR by skin pigmentation. Secondarily, we aimed to evaluate statistical biases and the clinical relevance of PPG-derived SpO 2 and PR according to skin pigmentation., Methods: We identified 23 pulse oximetry studies (n=59,684; 197,353 paired SpO 2 -arterial blood observations) and 4 wearable PR studies (n=176; 140,771 paired PPG-electrocardiography observations). We evaluated accuracy according to skin pigmentation group by comparing SpO 2 accuracy root-mean-square values to the regulatory threshold of 3% and PR 95% limits of agreement values to +5 or -5 beats per minute (bpm), according to the standards of the American National Standards Institute, Association for the Advancement of Medical Instrumentation, and the International Electrotechnical Commission. We evaluated biases and clinical relevance using mean bias and 95% CI., Results: For SpO 2 , accuracy root-mean-square values were 3.96%, 4.71%, and 4.15%, and pooled mean biases were 0.70% (95% CI 0.17%-1.22%), 0.27% (95% CI -0.64% to 1.19%), and 1.27% (95% CI 0.58%-1.95%) for light, medium, and dark pigmentation, respectively. For PR, 95% limits of agreement values were from -16.02 to 13.54, from -18.62 to 16.84, and from -33.69 to 32.54, and pooled mean biases were -1.24 (95% CI -5.31 to 2.83) bpm, -0.89 (95% CI -3.70 to 1.93) bpm, and -0.57 (95% CI -9.44 to 8.29) bpm for light, medium, and dark pigmentation, respectively., Conclusions: SpO 2 and PR measurements may be inaccurate across all skin pigmentation groups, breaching U.S. Food and Drug Administration guidance and industry standard thresholds. Pulse oximeters significantly overestimate SpO 2 for both light and dark skin pigmentation, but this overestimation may not be clinically relevant. PRs obtained from wearables exhibit no statistically or clinically significant bias based on skin pigmentation., (©Sanidhya Singh, Miles Romney Bennett, Chen Chen, Sooyoon Shin, Hamid Ghanbari, Benjamin W Nelson. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 10.10.2024.)

Background: High-level expertise in team-sports is associated with superior performance on executive functions (EFs) such as working memory (WM) and action inhibition, and with altered activation of brain areas related to these EFs. In most such studies, athletes were sampled from the domain of dynamic (i.e., open-skill) team-sports (e.g., soccer players). Whether static (i.e., closed-skill) team-sports athletes (e.g., rowers and synchronized swimmers) also show superior EFs performance and differential EF-related functional brain activation remains unknown., Methods: We recruited 14 elite closed-skill athletes, all national champions, and internationally competitive in various rowing disciplines, as well as 14 controls matched on gender, age, and education, and had them perform working memory and action inhibition (stop-signal) tasks during fMRI scanning., Results: Group differences in performance in either task failed to obtain statistical significance, although athletes showed a numerical trend toward higher WM capacity than controls. Importantly, task-related BOLD responses suggested that Olympic closed-skill team athletes show stronger recruitment of brain areas that emphasize relatively stable task demands and weaker engagement of brain areas that emphasize rapidly changing demands imposed by extraneous stimulation., Conclusion: Functional brain imaging data suggest elite closed-skill athletes may employ different cognitive strategies., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

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).)

P/FP [PaO2/(FiO2*PEEP)] is associated with in-hospital mortality in patients with acute respiratory distress syndrome (ARDS). However, to the best of our knowledge, the association between P/FP after 24 hours of invasive mechanical ventilation (IMV) and in-hospital mortality in patients with ARDS due to Coronavirus Disease 2019 (COVID-19) remained unclear. This study aimed to evaluate the relationship between the P/FP after 24 hours of IMV and in-hospital mortality in patients with ARDS due to COVID-19. We reanalyzed previously published data from Peru. Hueda-Zavaleta et al conducted a retrospective cohort study between April 2020 and April 2021 in southern Peru. A total of 200 hospitalized COVID-19 patients requiring IMV were included in this analysis. We used Cox proportional hazard regression models and Kaplan-Meier survival analysis to investigate the effect of P/FP after 24 hours of IMV on in-hospital mortality. We used a restricted cubic spline regression and a two-piecewise Cox proportional hazards model to explore the relationship between P/FP after 24 hours of IMV and in-hospital mortality in patients with ARDS due to COVID-19. Of the 200 patients, 51 (25.50%) died in hospital. The median P/FP was 20.45 mm Hg/cmH2O [interquartile range 15.79-25.21 mm Hg/cmH2O], with a range of 5.67 mm Hg/cmH2O to 51.21 mm Hg/cmH2O. Based on the P/FP ratio, patients were equally divided into 2 groups (low group [P/FP < 20.50 mm Hg/cmH2O] and high group [P/FP ≥ 20.50 mm Hg/cmH2O]). In-hospital mortality was lower in the high P/FP group than in the low P/FP group (12 [12%] vs 39 [39%]; unadjusted hazard ratio [HR]: 0.33, 95% confidence interval [CI]: 0.17-0.63; adjusted HR: 0.10, 95% CI: 0.02-0.47). We also found a nonlinear relationship between P/FP and in-hospital mortality. After adjusting for potential confounders, the HR was 0.67 (95% CI: 0.56-0.79) for P/FP ≤ 22 mm Hg/cmH2O and 1.10 (95% CI: 0.83-1.47) for P/FP > 22 mm Hg/cmH2O. In addition, lymphocytes ≤ 1 × 109/L and acute kidney failure had a higher risk of death. After adjusting for potential confounders, the P/FP after 24 hours of IMV was nonlinearly associated with in-hospital mortality in patients with ARDS due to COVID-19., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: As a supportive treatment, the effectiveness of oxygen therapy in ischemic stroke (IS) patients remains unclear. This study aimed to evaluate the relationships between arterial partial pressure of oxygen (PaO 2 ) and both consciousness at discharge and all-cause mortality risk in ICU IS patients., Methods: Blood gas measurements for all patients diagnosed with IS were extracted from the MIMIC-IV database. Patients were classified into four groups based on their average PaO 2 during the first ICU day: hypoxemia (PaO 2  < 80 mmHg), normoxemia (PaO 2 80-120 mmHg), mild hyperoxemia (PaO 2 121-199 mmHg), and moderate/severe hyperoxemia (PaO 2  ≥ 200 mmHg). The primary endpoint was 90-day all-cause mortality. Secondary outcomes included the level of consciousness at discharge, assessed by the Glasgow Coma Scale (GCS), and 30-day all-cause mortality. Multivariate Cox regression and Restricted cubic spline (RCS) analysis were used to investigate the relationship between mean PaO 2 and mortality, and to assess the nonlinear association between exposure and outcomes., Results: This study included a total of 946 IS patients. The cumulative incidence of 30-day and 90-day all-cause mortality increased with decreasing PaO 2 levels. RCS analysis revealed a nonlinear relationship between PaO 2 and the risk of 30-day all-cause mortality (nonlinear P < 0.0001, overall P < 0.0001), as well as a nonlinear association between PaO 2 and 90-day all-cause mortality (nonlinear P < 0.0001, overall P < 0.0001). The results remained consistent after excluding the small subset of patients who received reperfusion therapy. Sensitivity analysis indicated that the favorable impact on survival tends to increase with the extended duration of elevated PaO 2 ., Conclusions: For IS patients who do not receive reperfusion therapy or whose recanalization status is unknown, a lower PaO 2 early during ICU admission is considered an independent risk factor for short-term and recent mortality. Adjusting respiratory parameters to maintain supraphysiological levels of PaO 2 appears to be beneficial for survival, although this finding requires further validation through additional studies., Trial Registration: Not applicable., (© 2024. The Author(s).)

Introduction: Hypoxia training is mandatory for military pilots, but variability in hypoxia symptoms challenges the training. In a previous study we showed that 64% of pilots recognized hypoxia faster in their second normobaric hypoxia session conducted 2.4 yr after the first. Our aim here was to evaluate whether a third session conducted 5.0 yr after the first would provide further benefit., Methods: This study was conducted under normobaric conditions in a tactical F/A-18C Hornet simulator in three sessions in which the pilots performed visual identification missions and breathed 21% oxygen in nitrogen. The breathing gas was changed to a hypoxic mixture containing either 8%, 7%, or 6% oxygen in nitrogen without the pilot's knowledge. Data were collected from 102 military pilots. The primary outcome was the time taken for initial identification of hypoxia symptoms., Results: Hypoxia symptoms were recognized on average in the first session in 8% oxygen in 100 s, 7% oxygen in 90 s, and 6% oxygen in 78 s; in the second in 87 s, 80 s, and 71 s, respectively; and in the third in 79 s, 67 s, and 64 s, respectively. In 2 sessions 20 pilots and in each 3 training sessions 3 pilots had slow recognition times., Discussion: Hypoxia symptom recognition improved the further the repeated normobaric hypoxia training went. More emphasis should be put on the 23% group of slow hypoxia symptom recognizers and more customized hypoxia training for them should be offered. Leinonen AM, Varis NO, Kokki HJ, Leino TK. Normobaric hypoxia symptom recognition in three training sessions. Aerosp Med Hum Perform. 2024; 95(10):758-764.

Background: In patients with chronic obstructive pulmonary disease (COPD), early detection of noninvasive ventilation (NIV) failure is a promising technique for decreasing mortality. The objective of this study was to evaluate the efficacy of heart rate, acidosis, consciousness, oxygenation, and respiratory rate (HACOR) score in predicting NIV outcome in COPD-associated respiratory failure., Methodology: A prospective observational study was conducted on 100 COPD patients with acute respiratory failure who were initiated on NIV. HACOR score was calculated at the start of NIV and after 1-2, 12, and 24 hours. NIV failure was defined as progression to invasive mechanical ventilation or death. NIV success was defined as liberation from NIV prior to hospital day seven and not meeting criteria for failure., Results: In this study, 100 patients with COPD and respiratory failure were enrolled. Their mean age was 65.34 years [standard deviation (SD) 8.19]. Male patients were predominant ( n = 81). Eighty-nine percent of patients were smokers, and the remaining had exposure to biomass fuel. At the initiation of NIV, the median HACOR score was 3 (interquartile: 2, 4). In 13% of patients, there was NIV failure. There were 17 (17%) patients whose HACOR score at initiation was ≥5. In patients with a HACOR score ≥5, the NIV failure rate was 76.4% and mortality was 41.1%. The area under the curve (AUC) for prediction of NIV failure by HACOR score at initiation was 0.980 ( p -value < 0.05)., Conclusion: The HACOR score had high sensitivity as well as specificity at initiation in the prediction of NIV failure. A higher HACOR score predicts a high chance of NIV failure. Obtaining the HACOR score at the bedside makes it convenient for assessing the efficacy of NIV in patients with COPD., (© Journal of the Association of Physicians of India 2024.)

Background: The incidence of hyperlactatemia due to hypoperfusion during cardiopulmonary bypass (CPB) increases morbidity. Carbon dioxide production during CPB is one of the lactate production markers, in addition to other markers such as delivery oxygen (DO2), oxygen consumption (VO2), mixed vein oxygen saturation (SvO2), and oxygen extraction ratio (O2ER)., Method: This observational analytic study was conducted on 40 adult cardiac surgery patients using a CPB machine. Initial lactate is taken when entering CPB and final lactate is examined 15 min after coming off bypass. The values of DO2, VO2, SvO2, VCO2, respiratory quotient (RQ), DO2/VCO2, PvCO2 × Ve/Q were calculated from the results of blood and venous gas analysis 1 h after entering CPB in the nadir of core temperature and lowest pump flow., Result: The multivariate test showed that the value of PvCO2 × Ve/Q was more effective than other oxygenation and carbon dioxide parameters in predicting an increase in the percentage of lactate. Each increase of 1 mmHg PvCO2 ×× Ve/Q can predict a final lactate increase of 29% from the initial lactate. The high PvCO2 × Ve/Q value is also the strongest correlation factor for the incidence of hyperlactatemia after CPB (final lactate >3 mmol/L). The cutoff value of this marker is >19.3 mmHg, which has a sensitivity of 100% and a specificity of 55.6% with a strong correlation value., Conclusion: The PvCO2 × Ve/Q value proved to be one of the significant markers in predicting hyperlactatemia during cardiac surgery using CPB., (Copyright © 2024 Copyright: © 2024 Annals of Cardiac Anaesthesia.)

Functional magnetic resonance imaging (fMRI) is currently one of the most popular technologies for measuring brain activity in both research and clinical contexts. However, clinical constraints often result in short fMRI scan durations, limiting the diagnostic performance for brain disorders. To address this limitation, we developed an end-to-end frequency-specific dual-attention-based adversarial network (FDAA-Net) to extend the time series of existing blood oxygen level-dependent (BOLD) data, enhancing their diagnostic utility. Our approach leverages the frequency-dependent nature of fMRI signals using variational mode decomposition (VMD), which adaptively tracks brain activity across different frequency bands. We integrated the generative adversarial network (GAN) with a spatial-temporal attention mechanism to fully capture relationships among spatially distributed brain regions and temporally continuous time windows. We also introduced a novel loss function to estimate the upward and downward trends of each frequency component. We validated FDAA-Net on the Human Connectome Project (HCP) database by comparing the original and predicted time series of brain regions in the default mode network (DMN), a key network activated during rest. FDAA-Net effectively overcame linear frequency-specific challenges and outperformed other popular prediction models. Test-retest reliability experiments demonstrated high consistency between the functional connectivity of predicted outcomes and targets. Furthermore, we examined the clinical applicability of FDAA-Net using short-term fMRI data from individuals with autism spectrum disorder (ASD) and major depressive disorder (MDD). The model achieved a maximum predicted sequence length of 40% of the original scan durations. The prolonged time series improved diagnostic performance by 8.0% for ASD and 11.3% for MDD compared with the original sequences. These findings highlight the potential of fMRI time series prediction to enhance diagnostic power of brain disorders in short fMRI scans., (© 2024 The Author(s). Human Brain Mapping published by Wiley Periodicals LLC.)

Purpose: The aim of this study was to evaluate one-year outcomes of lower versus higher oxygenation targets in intensive care unit (ICU) patients with coronavirus disease 2019 (COVID-19) and severe hypoxaemia., Methods: We conducted pre-planned analyses of one-year mortality and health-related quality of life (HRQoL) in the Handling Oxygenation Targets in COVID-19 trial. The trial randomised 726 ICU patients with COVID-19 and hypoxaemia to partial pressure of arterial oxygen targets of 8 kPa (60 mmHg) versus 12 kPa (90 mmHg) during ICU stay up to 90 days, including readmissions. HRQoL was assessed using EuroQol visual analogue scale (EQ-VAS) and 5-level 5-dimension questionnaire (EQ-5D-5L). Outcomes were analysed in the intention-to-treat population. Non-survivors were assigned the worst possible score (zero), and multiple imputation was applied for missing EQ-VAS values., Results: We obtained one-year vital status for 691/726 (95.2%) of patients and HRQoL data for 642/726 (88.4%). At one year, 117/348 (33.6%) of patients in the lower-oxygenation group had died compared to 134/343 (39.1%) in the higher-oxygenation group (adjusted risk ratio: 0.85; 98.6% confidence interval (CI) 0.66-1.09; p = 0.11). Median EQ-VAS was 50 (interquartile range, 0-80) versus 40 (0-75) (adjusted mean difference: 4.8; 98.6% CI  - 2.2 to 11.9; p = 0.09) and EQ-5D-5L index values were 0.61 (0-0.81) in the lower-oxygenation group versus 0.43 (0-0.79) (p = 0.20) in the higher-oxygenation group, respectively., Conclusion: Among adult ICU patients with COVID-19 and severe hypoxaemia, one-year mortality results were most compatible with benefit of the lower oxygenation target, which did not appear to result in more survivors with poor quality of life., (© 2024. The Author(s).)

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.)

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.)

The changes in brain function in response to mild head injury are usually subtle and go undetected. Physiological biomarkers would aid in the early diagnosis of mild head injury. In this study we used hypercapnia to follow changes in cerebral vascular reactivity after repetitive mild head injury. We hypothesized head injury would reduce vascular reactivity. Rats were maintained on a reverse light-dark cycle and head impacted daily at 24 h intervals over three days. All head impacts were delivered while rats were fully awake under red light illumination. There was no neuroradiological evidence of brain damage. After the 3rd impact rats were exposed to 5% CO 2 and imaged for changes in BOLD signal. All imaging was done while rats were awake without the confound of anesthesia. The data were registered to a 3D MRI rat atlas with 171 segmented brain areas providing site specific information on vascular reactivity. The changes in vascular reactivity were not uniform across the brain. The prefrontal cortex, somatosensory cortex and basal ganglia showed the hypothesized decrease in vascular reactivity while the cerebellum, thalamus, brainstem, and olfactory system showed an increase in BOLD signal to hypercapnia., (© 2024. The Author(s).)

Objectives: A conservative oxygenation strategy, targeting peripheral oxygen saturations (Sp o2 ) between 88% and 92% in mechanically ventilated children in PICU, was associated with a shorter duration of organ support and greater survival compared with Sp o2 greater than 94% in our recent Oxy-PICU trial. Sp o2 monitors may overestimate arterial oxygen saturation (Sa o2 ) in patients with higher levels of skin pigmentation compared with those with less skin pigmentation. We investigated if ethnicity was associated with changes in distributions of Sp o2 and F io2 and outcome., Design: Post-hoc analysis of a pragmatic, open-label, multicenter randomized controlled trial., Setting: Fifteen PICUs across the United Kingdom and Scotland., Patients: Children aged 38 weeks corrected gestational age to 15 years accepted to a participating PICU as an unplanned admission and receiving invasive mechanical ventilation with supplemental oxygen for abnormal gas exchange., Methods: Hierarchical regression models for Sp o2 and F io2 , and ordinal models for the primary trial outcome of a composite of the duration of organ support at 30 days and death, were used to examine the effects of ethnicity, accounting for baseline Sp o2 , F io2 , and mean airway pressure and trial allocation., Measurements and Main Results: Ethnicity data were available for 1577 of 1986 eligible children, 1408 (89.3%) of which were White, Asian, or Black. Sp o2 and F io2 distributions did not vary according to Black or Asian ethnicity compared with White children. The trial primary outcome measure also did not vary significantly with ethnicity. The point estimate for the treatment effect of conservative oxygenation in Black children was 0.64 (95% CI, 0.33-1.25) compared with 0.84 (0.68-1.04) in the overall trial population., Conclusions: These data do not suggest that the association between improved outcomes and conservative oxygenation strategy in mechanically ventilated children in PICU is modified by ethnicity., Competing Interests: Drs. Jones’, Orzol’s, Lampro’s, Agbeko’s, and Harrison’s institutions received funding from the National Institute for Health and Care Research (NIHR). Dr. Ray’s institution received funding from the U.K. National Institute for Health Research (U.K. NIHR), the U.K. Engineering and Physical Science Research Council and consulting fees, honoraria, and travel fees from La Roche Limited and the Malaysian Society of Intensive Care during the study period. Dr. Gould’s, Mr. Mouncey’s, and Prof. Peters’ institutions received funding from the U.K. NIHR Health Technology Assessment Program (HTA). Dr. Giallongo received support for article research from the U.K. NIHR HTA program (project number 12/75/47). Drs. Wiegand, Ray, and Peters received funding from the European Physical Sciences Research Council: UCL Collaborative Healthcare Innovation through Mathematics, Engineering and AI that is based at University College London, the hub for Mathematics in Health Care (grant number EP/T017791/1). Dr. Wiegand was also supported through funding by the NIHR Biomedical Research Center (grant number NIHR203328). Dr. Charles is funded by an NIHR Predoctoral Fellowship in Epidemiology (grant number NIHR302788). The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 by the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.)

Background: The hemodynamics of prefrontal cortex (PFC) oxygenation are regulated by numerous processes operating over multiple temporal scales, producing complex patterns in its output fluctuations. Age may alter this multiscale regulation of PFC oxygenation, leading to diminished physiologic complexity of this important regulatory process. We aimed to characterize the effects of age on such complexity and its relationship to performance of an executive n-back task., Methods: Twenty-four younger (aged 28 ± 3 years) and 27 older (aged 78 ± 6 years) adults completed this study. Continuous oxygenation (HbO2) and deoxygenation (HHb) signals of PFC were recorded using functional near-infrared spectroscopy (fNIRS) while participants stood and watched a blank screen (blank), clicked a mouse when an X appeared (IdX), or when a letter was repeated from "2-back" in a sequence shown on a screen (2-back). We used multiscale entropy to quantify the HbO2 and HHb complexity of fNIRS signals., Results: Older adults exhibited lower HbO2 and HHb complexity compared to younger adults, regardless of task (p = .0005-.002). Both groups exhibited greater complexity during the IdX and 2-back than blank task (p = .02-.04). Across all participants, those with greater HbO2 and/or HHb complexity during the blank task exhibited faster IdX and 2-back reaction time (β = -0.56 to -0.6, p = .009-.02). Those demonstrating greater increase in HbO2 and/or HHb complexity from IdX to 2-back task had lower percent increase in reaction time from IdX to 2-back task (β = -0.41 to -0.37, p = .005-.01)., Conclusions: The complexity of fNIRS-measured PFC oxygenation fluctuations may capture the influence of aging on the regulation of prefrontal hemodynamics involved in executive-function-based task performance., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

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.)

Intracranial pressure (ICP) monitoring and monitoring of brain tissue oxygen (Pbto2) in addition to ICP have been used in the management of traumatic brain injury (TBI). However, the optimal monitoring method is inconclusive. We searched 4 databases with no language restrictions through January 2024 for peer-reviewed randomized controlled trials (RCTs) comparing ICP monitoring with combined Pbto2 and ICP monitoring in patients with traumatic brain injury. A favorable neurologic outcome was the primary outcome, and the secondary outcome was survival. Two reviewers screened manuscripts, extracted data, and assessed the risk of bias. We then performed a meta-analysis to assess efficacy using the Grading of Recommendations, Assessment, Development, and Evaluation working group approach. We included 5 trials comprising 512 patients. There was no difference in favorable neurologic outcome (risk ratio: 1.21; 95% confidence interval: 0.93, 1.58; I2: 45%; 5 RCTs: 512 patients; moderate certainty) and survival (risk ratio: 1.10; 95% confidence interval: 0.99, 1.21; I2: 13%; 5 RCTs: 512 patients; moderate certainty). We found no evidence that the combination of Pbto2 and ICP is more useful than ICP. The included RCTs are few and small, and further study is needed to draw conclusions., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: This study aims to analyze the risk factors for early postoperative brain injury in patients undergoing cardiovascular surgery and explore the predictive value of transcranial color Doppler (TCCD) and regional cerebral oxygen saturation (rSO 2 ) for detecting early postoperative brain injury in cardiovascular surgery patients., Methods: A total of 55 patients undergoing cardiovascular surgery with cardiopulmonary bypass in Changzhou No.2 The People's Hospital of Nanjing Medical University were included in this study. Neuron-specific enolase (NSE) concentration was measured 24 h after operation. Patients were divided into brain injury (NSE ≥ 16.3 ng/mL) and normal (0 < NSE < 16.3 ng/mL) groups according to the measured NSE concentration. The clinical outcomes between the two groups were compared, including decreased rSO 2 and cerebral blood flow (as measured by TCCD) levels. The risk factors of early postoperative brain injury were analyzed by multivariate logistic regression analysis, and the significant variables were analyzed by receiver operating characteristic (ROC) analysis., Results: A total of 50 patients were included in this study, with 20 patients in the brain injury group and 30 patients in the normal group. Cardiopulmonary bypass time (min) (107 ± 29 vs. 90 ± 28, P = 0.047) and aortic occlusion time (min) (111 (IQR 81-127) vs. 87 (IQR 72-116), P = 0.010) were significantly longer in the brain injury group than in the normal group. Patients in the brain injury group had greater decreased rSO 2 (%) (27.0 ± 7.3 vs. 17.5 ± 6.1, P < 0.001) and cerebral blood flow (%) (44.9 (IQR 37.8-69.2) vs. 29.1 (IQR 12.0-48.2), P = 0.004) levels. Multivariate logistic regression analysis suggested that decreased rSO 2 and cerebral blood flow levels, aortic occlusion time, and history of atrial fibrillation were independent risk factors for early postoperative brain injury (P < 0.05). ROC analysis reported that the best cutoff values for predicting early postoperative brain injury were 21.4% and 37.4% for decreased rSO 2 and cerebral blood flow levels, respectively (P < 0.05)., Conclusion: The decreased rSO 2 and cerebral blood flow levels, aorta occlusion time, and history of atrial fibrillation were independent risk factors for early postoperative brain injury. TCCD and rSO 2 could effectively monitor brain metabolism and cerebral blood flow and predict early postoperative brain injury., (© 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: The effects of oxygenation targets (partial pressure of arterial oxygen [Pa o2 ], arterial oxygen saturation [Sa o2 ]/peripheral oxygen saturation [Sp o2 ], or inspiratory oxygen concentration [Fi o2 ] on clinical outcomes in critically ill patients remains controversial. We reviewed the existing literature to assess the effects of lower and higher oxygenation targets on the mortality rates of critically ill intensive care unit (ICU) patients., Methods: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science databases were searched from their dates of inception to December 31, 2022, for randomized controlled trials (RCTs) comparing lower and higher oxygenation targets for critically ill patients ≥18 years of age undergoing mechanical ventilation, nasal cannula, oxygen mask, or high-flow oxygen therapy in the ICU. Data extraction was conducted independently, and RoB 2.0 software was used to evaluate the quality of each RCT. A random-effects model was used for the meta-analysis to calculate the relative risk (RR). We used the I 2 statistic as a measure of statistical heterogeneity. Certainty of evidence was assessed according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines., Results: We included 12 studies with a total of 7416 patients participating in RCTs. Oxygenation targets were extremely heterogeneous between studies. The meta-analysis found no differences in mortality between lower and higher oxygenation targets for critically ill ICU patients (relative risk [RR], 1.00; 95% confidence interval [CI], 0.93-1.09; moderate certainty). The incidence of serious adverse events (RR, 0.93; 95% CI, 0.85-1.00; high certainty), mechanical ventilation-free days through day 28 (mean difference [MD], -0.05; 95%CI, -1.23 to 1.13; low certainty), the number of patients requiring renal replacement therapy (RRT) (RR, 0.96; 95% CI, 0.84-1.10; low certainty), and ICU length of stay (MD, 1.05; 95% CI, -0.04 to 2.13; very low certainty) also did not differ among patients with lower or higher oxygenation targets., Conclusions: Critically ill ICU patients ≥18 years of age managed with lower and higher oxygenation targets did not differ in terms of mortality, RRT need, mechanical ventilation-free days through day 28, or ICU length of stay. However, due to considerable heterogeneity between specific targets in individual studies, no conclusion can be drawn regarding the effect of oxygenation targets on ICU outcomes., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 International Anesthesia Research Society.)

Lung function has never been assessed during kangaroo mother care (KMC) in preterm infants. We measured lung (rSO 2 L) and cerebral (rSO 2 C) oxygenation by near-infrared spectroscopy (NIRS) in infants born at less than 32 weeks of gestation or weighing ≤ 1500 g during KMC. rSO 2 L, rSO 2 C, and pulmonary (FOEL) and cerebral (FOEC) tissue oxygen extraction fraction were measured in 20 preterm infants before, during, and after a 2-h period of KMC at a mean postnatal age of 36 ± 21 days of life. We found that rSO 2 L, rSO 2 C, FOEL, and FOEC did not change in our patients. After 120 min of KMC, rSO 2 L was lower (71.3 ± 1.4 vs. 76.7 ± 4.6%; P = 0.012) in infants with BPD (n = 6; 30%) than in infants without BPD (n = 14 = 60%), while FOEL was higher (0.26 ± 0.02 vs. 0.20 ± 0.05; P = 0.012).Conclusion: Cerebral and lung oxygenation did not change in preterm infants during KMC. A transient decrease in lung oxygenation was offset by the increase in oxygen extraction, but these changes were clinically insignificant. These results confirm the safety of KMC in preterm infants who are in stable clinical conditions. What is Known • Kangaroo mother care (KMC) is widely used to improve the care of preterm newborns since it improves their outcome. • KMC is safe as patients' vital parameters, are not negatively affected, but lung function has never been directly assessed. What is New • Cerebral and lung oxygenation measured by near-infrared spectroscopy did not change during KMC. • A transient decrease in lung oxygenation compensated for by the increase in oxygen extraction occurred only in infants with BPD, but these changes were clinically insignificant., (© 2024. The Author(s).)

Purpose: The purpose of this work is to apply multi-echo spin- and gradient-echo (SAGE) echo-planar imaging (EPI) combined with a navigator-based (NAV) prospective motion compensation method for a quantitative liver blood oxygen level dependent (BOLD) measurement with a breath-hold (BH) task., Methods: A five-echo SAGE sequence was developed to quantitatively measure T 2 and T 2 * to depict function with sufficient signal-to-noise ratio, spatial resolution and sensitivity to BOLD changes induced by the BH task. To account for respiratory motion, a navigator was employed in the form of a single gradient-echo projection readout, located at the diaphragm along the inferior-superior direction. Prior to each transverse imaging slice of the spin-echo EPI-based readouts, navigator acquisition and fat suppression were incorporated. Motion data was obtained from the navigator and transmitted back to the sequence, allowing real-time adjustments to slice positioning. Six healthy volunteers and three patients with liver carcinoma were included in this study. Quantitative T 2 and T 2 * were calculated at each time point of the BH task. Parameters of t value from first-level analysis using a general linear model and hepatovascular reactivity (HVR) of Echo1, T 2 and T 2 * were calculated., Results: The motion caused by respiratory activity was successfully compensated using the navigator signal. The average changes of T 2 and T 2 * during breath-hold were about 1% and 0.7%, respectively. With the help of NAV prospective motion compensation whole liver t values could be obtained without motion artifacts. The quantified liver T 2 (34.7 ± 0.7 ms) and T 2 * (29 ± 1.2 ms) values agreed with values from literature. In healthy volunteers, the distribution of statistical t value and HVR was homogeneous throughout the whole liver. In patients with liver carcinoma, the distribution of t value and HVR was inhomogeneous due to metastases or therapy., Conclusions: This study demonstrates the feasibility of using a NAV prospective motion compensation technique in conjunction with five-echo SAGE EPI for the quantitative measurement of liver BOLD with a BH task., (© 2024 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.)

BOLD signal variability (SDBOLD) has emerged as a unique measure of the adaptive properties of neural systems that facilitate fast, stable responding, based on claims that SDBOLD is independent of mean BOLD signal (meanBOLD) and is a powerful predictor of behavioral performance. We challenge these two claims. First, the apparent independence of SDBOLD and meanBOLD may reflect the presence of deactivations; we hypothesize that although SDBOLD may not be related to raw meanBOLD, it will be linearly related to "absolute" meanBOLD. Second, the observed relationship between SDBOLD and performance may be an artifact of using fixed-length trials longer than RTs. Such designs provide opportunities to toggle between on- and off-task states, and fast responders likely engage in more frequent state-switching, thereby artificially elevating SDBOLD. We hypothesize that SDBOLD will be higher and more strongly related to performance when using such fixed-length trials relative to self-paced trials that terminate upon a response. We test these two hypotheses in an fMRI study using blocks of fixed-length or self-paced trials. Results confirmed both hypotheses: (1) SDBOLD was robustly related with absolute meanBOLD, and (2) toggling between on- and off-task states during fixed-length trials reliably contributed to SDBOLD. Together, these findings suggest that a reappraisal of the functional significance of SDBOLD as a unique marker of cognitive performance is warranted., (© 2024 Massachusetts Institute of Technology.)

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.)