CaMKIIδ-dependent dysregulation of atrial Na+ homeostasis promotes pro-arrhythmic activity in an obstructive sleep apnea mouse model.

Background: Obstructive sleep apnea (OSA) has been linked to various pathologies, including arrhythmias such as atrial fibrillation. Specific treatment options for OSA are mainly limited to symptomatic approaches. We previously showed that increased production of reactive oxygen species (ROS) stimulates late sodium current through the voltage-dependent Na+ channels via Ca2+/calmodulin-dependent protein kinase IIδ (CaMKIIδ), thereby increasing the propensity for arrhythmias. However, the impact on atrial intracellular Na+ homeostasis has never been demonstrated. Moreover, the patients often exhibit a broad range of comorbidities, making it difficult to ascertain the effects of OSA alone. Objective: We analyzed the effects of OSA on ROS production, cytosolic Na+ level, and rate of spontaneous arrhythmia in atrial cardiomyocytes isolated from an OSA mouse model free from comorbidities. Methods: OSA was induced in C57BL/6 wild-type and CaMKIIδ-knockout mice by polytetrafluorethylene (PTFE) injection into the tongue. After 8 weeks, their atrial cardiomyocytes were analyzed for cytosolic and mitochondrial ROS production via laser-scanning confocal microscopy. Quantifications of the cytosolic Na+ concentration and arrhythmia were performed by epifluorescence microscopy. Results: PTFE treatment resulted in increased cytosolic and mitochondrial ROS production. Importantly, the cytosolic Na+ concentration was dramatically increased at various stimulation frequencies in the PTFE-treated mice, while the CaMKIIδ-knockout mice were protected. Accordingly, the rate of spontaneous Ca2+ release events increased in the wild-type PTFE mice while being impeded in the CaMKIIδ-knockout mice. Conclusion: Atrial Na+ concentration and propensity for spontaneous Ca2+ release events were higher in an OSA mouse model in a CaMKIIδ-dependent manner, which could have therapeutic implications.

Obesity hypoventilation syndrome, literature review.

Obesity is a global health concern that has been increasing over the years, and it is associated with several pathophysiological changes affecting the respiratory system, including alveolar hypoventilation. Obesity hypoventilation syndrome (OHS) is one of the six subtypes of sleep-hypoventilation disorders. It is defined as the presence of obesity, chronic alveolar hypoventilation leading to daytime hypercapnia and hypoxia, and sleep-disordered breathing. The existence of a sleep disorder is one of the characteristics that patients with OHS present. Among them, 90% of patients have obstructive sleep apnea (OSA), and the remaining 10% of patients with OHS have non-obstructive sleep hypoventilation without OSA or with mild OSA. This review aims to provide a comprehensive understanding of the epidemiological and pathophysiological impact of OHS and to highlight its clinical features, prognosis, and severity, as well as the available treatment options.

TO-LAB model: Real time Touchless Lung Abnormality detection model using USRP based machine learning algorithm.

BACKGROUND: Due to the increasing prevalence of respiratory diseases and the importance of early diagnosis. The need for non-invasive and touchless medical diagnostic solutions has become increasingly crucial in modern healthcare to detect lung abnormalities. OBJECTIVE: Existing methods for lung abnormality detection often rely on invasive and time-consuming procedures limiting their effectiveness in real-time diagnosis. This work introduces a novel Touchless Lung Abnormality (TO-LAB) detection model utilizing universal software radio peripherals (USRP) and machine learning algorithms. METHODS: The TO-LAB model integrates a blood pressure meter and an RGB-D depth-sensing camera to gather individual data without physical contact. Heart rate (HR) is analyzed through image conversion to IPPG signals, while blood pressure (BP) is obtained via analog conversion from the blood pressure meter. This touchless imaging setup facilitates the extraction of essential signal features crucial for respiratory pattern analysis. Advanced computer vision algorithms like Mel-frequency cepstral coefficients (MFCC) and Principal Component Analysis (PCA) process the acquired data to focus on breathing abnormalities. These features are then combined and inputted into a machine learning-based Multi-class SVM for breathing activity analysis. The Multi-class SVM categorizes breathing abnormalities as normal, shallow, or elevated based on the fused features. The efficiency of this TO-LAB model is evaluated with the simulated and real-time data. RESULTS: According to the findings, the proposed TO-LAB model attains the maximum accuracy of 96.15% for real time data; however, the accuracy increases to 99.54% for simulated data for the efficient classification of breathing abnormalities. CONCLUSION: From this analysis, our model attains better results in simulated data but it declines the accuracy while processing with real-time data. Moreover, this work has a significant medical impact since it presents a solution to the problem of gathering enough data during the epidemic to create a realistic model with a large dataset.

Oxygen saturation and work of breathing indices in preterm infants with bronchopulmonary dysplasia compared to healthy preterm infants at discharge.

BACKGROUND: Thoracoabdominal asynchrony (TAA) is commonly seen in preterm infants. Respiratory inductive plethysmography (RIP) is a noninvasive way to objectively assess work of breathing (WOB) indices. The impact of bronchopulmonary dysplasia (BPD) on TAA at discharge has not been established. The aim of this study is to compare WOB indices in premature infants with a diagnosis of BPD to premature infants without a diagnosis of BPD at discharge. METHODS: A prospective, observational study of premature infants (<32 weeks gestation) at discharge during quiet breathing in the supine position. RIP noninvasively measured WOB indices. A high-resolution pulse oximeter collected oxygen saturation and heart rate data. RESULTS: This study included thirty-one infants with BPD and thirty-four infants without BPD. Infants diagnosed with BPD had increased phase angle [BPD Φ = 73 . 90 (8.2) vs NoBPD Φ = 52.6 (8.2), p = 0.039]. Infants diagnosed with BPD had decreased saturations [BPD SpO2 = 96% (0.4) vs NoBPD Sp02 98% (0.3), p=<0.001], increased time with saturations less than 85% [BPD % =2.74 (0.7) vs NoBPD % =0.91 (0.4), p = .018], and increased time with saturations less than 80% [BPD % =1.57 (0.5) vs NoBPD % =0.52 (0.3), p = 0.045]. There was no difference in heart rate or breaths per minute for infants with BPD versus controls. CONCLUSION: Premature infants with BPD demonstrated increased TAA and had lower saturations compared to infants without BPD at discharge despite being chronologically older and being discharged at an older corrected gestational age. The impact of BPD on breathing patterns persists at discharge and suggests these patients may have residual lung and/or respiratory muscle dysfunction.

Reduction of ringing artifacts induced by diaphragm drifting in free-breathing dynamic pulmonary MRI using 3D koosh-ball acquisition.

PURPOSE: To reduce the ringing artifacts of the motion-resolved images in free-breathing dynamic pulmonary MRI. METHODS: A golden-step based interleaving (GSI) technique was proposed to reduce ringing artifacts induced by diaphragm drifting. The pulmonary MRI data were acquired using a superior-inferior navigated 3D radial UTE sequence in an interleaved manner during free breathing. Successive interleaves were acquired in an incoherent fashion along the polar direction. Four-dimensional images were reconstructed from the motion-resolved k-space data obtained by retrospectively binning. The reconstruction algorithms included standard nonuniform fast Fourier transform (NUFFT), Voronoi-density-compensated NUFFT, extra-dimensional UTE, and motion-state weighted motion-compensation reconstruction. The proposed interleaving technique was compared with a conventional sequential interleaving (SeqI) technique on a phantom and eight subjects. RESULTS: The quantified ringing artifacts level in the motion-resolved image is positively correlated with the quantified nonuniformity level of the corresponding k-space. The nonuniformity levels of the end-expiratory and end-inspiratory k-space binned from GSI data (0.34 ± 0.07, 0.33 ± 0.05) are significantly lower with statistical significance (p < 0.05) than that binned from SeqI data (0.44 ± 0.11, 0.42 ± 0.12). Ringing artifacts are substantially reduced in the dynamic images of eight subjects acquired using the proposed technique in comparison with that acquired using the conventional SeqI technique. CONCLUSION: Ringing artifacts in the motion-resolved images induced by diaphragm drifting can be reduced using the proposed GSI technique for free-breathing dynamic pulmonary MRI. This technique has the potential to reduce ringing artifacts in free-breathing liver and kidney MRI based on full-echo interleaved 3D radial acquisition.

Prevalence, Severity, and Treatment of Obstructive Sleep Apnea in Children with Down Syndrome in Qatar.

INTRODUCTION: Patients with Down syndrome (DS) are at risk for sleep disorder breathing (SDB) due to their abnormal craniofacial anatomy, hypotonia, and propensity for obesity. The prevalence and severity of SDB in this population vary between different cohorts due to the multifactorial nature of these patients and the different diagnostic criteria used. We aim to report the prevalence and severity of SDB in the DS population in Qatar. METHODS: This study is a retrospective review of all patients with genetically confirmed DS who completed a diagnostic polysomnography (PSG) study at Sidra Medicine in Doha, Qatar, which is the only pediatric sleep center in the country, between September 2019 and July 2022. Clinical and PSG data were collected from the patients' electronic medical records. Central and obstructive events were scored according to the American Academy of Sleep Medicine (AASM) criteria. Obstructive sleep apnea (OSA) diagnosis was made based on apnea-hypopnea index (AHI) and defined as AHI >1.5 events/hour. OSA was considered mild if AHI was ≥ 1.5 but < 5, moderate if AHI was ≥ 5 but < 10, and severe if AHI was ≥ 10 events/hour. Diagnosis with central apnea was considered if the central apnea index was > 5 events/hour. Hypoventilation was considered present if end-tidal/transcutaneous carbon dioxide gas was more than 50 mmHg for more than 25% of total sleep time. Multiple regression analysis was performed to evaluate predictors of high AHI and rapid eye movement (REM)-AHI. RESULTS: A total of 80 patients (49 males and 31 females) were included. Median (range) age was 7.3 years (0.9, 21). The mean (range) BMI z-score was 1.7 (-1.3, 4.3). Sixty-five patients were diagnosed with OSA, with a prevalence rate of 81%. OSA was mild in 25 (38.5%) patients, moderate in 15 (23.1%) patients, and severe in 25 (38.5%) patients. Only one patient was diagnosed with central apnea and five patients (6.9%) with alveolar hypoventilation. Multiple regression analysis showed BMI (P = 0.007) and snoring/apnea symptoms (P=0.023) to be predictive of high AHI. No correlation was found between the same variables and REM-AHI. Treatments used for OSA included anti-inflammatory medications in 37 (46%) patients, tonsillectomy/adenoidectomy in 13 (16.5%) patients, and positive airway pressure support in 10 (15%) patients. CONCLUSION: Our patient population with DS had a high prevalence of OSA comparable to other reported cohorts. High BMI and symptoms of snoring are predictive of OSA.

Effect of Short-term Deep Breathing Exercises on Perioperative Anxiety and Pain in Pediatric Orthopedic Patients: A Randomized Controlled Trial.

PURPOSE: There are currently no pediatric studies examining the effects of deep breathing on perioperative pain and anxiety. This study sought to determine the effect of short-term deep breathing exercises on perioperative anxiety and pain in pediatric patients and their parents. DESIGN: A randomized controlled trial was conducted in the Department of Orthopaedic Surgery where pediatric patients about to undergo surgery were allocated to a control group or a deep breathing group. In the intervention group, patients and their main guardian were guided to practice 10 minutes of deep breathing exercises twice a day for 3 to 4 days prior to surgery. Perioperative anxiety and pain were measured for both the children and parents as outcome indicators. METHODS: Perioperative anxiety was measured using the modified Yale Preoperative Anxiety Scale-Short Form (mYPAS-SF) and state anxiety was measured using the State-Trait Anxiety Inventory (STAI). Patients reported their pain levels daily using the Wong-Baker FACES Pain Rating Scale. The following cutoffs were determined as high levels of anxiety: STAI (adult) > 44, STAI (child) > 36, and mYPAS-SF ≥ 30. FINDINGS: No significant differences were found in the STAI, mYPAS-SF, and Wong-Baker FACES Pain Rating Scale scores of the patients between the intervention and control group. Overall statistics showed that parents had significantly higher postoperative state anxiety levels toward female children (44.93 ± 9.01) compared to male children (40.18 ± 9.89). Preoperative and postoperative parental state anxiety levels were correlated with the child's postoperative anxiety. Furthermore, children's postoperative state anxiety was slightly correlated with postoperative pain. CONCLUSIONS: Short-term use of our deep breathing exercises was ineffective in reducing incidences of perioperative pain and anxiety in pediatric orthopedic patients. A longer period of deep breathing administration may be required for the intervention to be effective. Parental anxiety may have an effect on anxiety levels in children, and postoperative parental anxiety may be affected by the gender of the child.

Study on the circadian rhythm and sleep state characteristics of patients with acute cerebral infarction accompanied by sleep-breathing disorders.

There is limited research on the circadian rhythm and sleep state in patients with acute cerebral infarction (ACI) accompanied by sleep-breathing disorders (SDB). This study aims to provide a scientific basis for individualized diagnosis and treatment for stroke-related SDB patients. The SC-500 sleep monitor was used to continuously monitor 1367 ACI patients over 5 days. Based on the apnea-hypopnea index (AHI), patients were divided into non-SDB group (normal) and SDB group (mild, moderate, severe, fluctuating). Interdaily stability (IS) and intradaily variability (IV) were calculated through heart rate monitoring, and sleep states and their correlations were analyzed. Compared to the non-SDB group, patients with moderate-to-severe ACI accompanied by SDB showed decreased IS, increased IV, and sleep fragmentation. Significant statistical differences were observed in total sleep time (TST), rapid eye movement latency (REML), sleep efficiency (SE), non-rapid eye movement stages 1-2 (NREM stages1-2), non-rapid eye movement stages 3-4 (NREM stages 3-4), proportion of non-rapid eye movement (NREM%), wake after sleep onset (WASO), and number of awakenings (NOA) between the SDB group and the non-SDB group (P < 0.05). AHI showed a strong negative correlation with IS and a strong positive correlation with IV. AHI was positively correlated with sleep latency (SL), REML, NREM stages1-2, NREM%, proportion of rapid eye movement (REM%), WASO, time out of bed (TOB), and NOA, and negatively correlated with TST, SE, NREM stages 3-4, and rapid eye movement (REM), all with statistical significance (P < 0.05). There were significant statistical differences in the Mini-Mental State Examination (MMSE) between patients with and without SDB, and among mild, moderate, severe, and fluctuating groups (P < 0.05). Patients with moderate-to-severe ACI accompanied by SDB are more likely to experience changes in circadian rhythm and sleep states, which in turn affect cognitive functions. Supplementary Information: The online version contains supplementary material available at 10.1007/s41105-024-00516-1.

Association between spontaneous breathing trial methods and reintubation in adult critically ill patients: A systematic review and network meta-analysis of randomized controlled trials.

BACKGROUND: Reintubation is associated with higher risk of mortality. There is no clear evidence on the best spontaneous breathing trial (SBT) method to reduce the risk of reintubation. RESEARCH QUESTION: Are different methods of conducting SBT in critically ill patients associated with different risk of reintubation compared to T-tube? STUDY DESIGN AND METHODS: We conducted a systematic review and Bayesian network meta-analysis of randomized controlled trials (RCTs) investigating the effects of different SBT methods on reintubation. We surveyed PubMed, MEDLINE, CINAHL and CENTRAL databases from inception to 26th January 2024. The Surface Under the Cumulative Ranking curve (SUCRA) was used to determine the likelihood that an intervention was ranked as the best. Pairwise comparisons were also investigated by frequentist meta-analysis. Certainty of the evidence was assessed according to the GRADE approach. RESULTS: A total of 22 RCTs were included, for a total of 6196 patients. The network included nine nodes, with 13 direct pairwise comparisons. About 71% of the patients were allocated to T-tube and PSV-ZEEP, with 2135 and 2101 patients, respectively. The only intervention with a significantly lower risk of reintubation compared to T-tube was high flow oxygen (HFO) (RR 0.23, CrI 0.09 to 0.51, moderate quality evidence). HFO was associated with the highest probability of being the best intervention for reducing the risk of reintubation (81.86%, SUCRA 96.42), followed by continuous positive airway pressure (11.8%, SUCRA 76.75). INTERPRETATION: HFO SBT was associated with a lower risk of reintubation in comparison to other SBT methods. The results of our analysis should be considered with caution due to the low number of studies that investigated HFO SBT, and potential clinical heterogeneity related to co-interventions. Further trials should be performed to confirm the results on larger cohorts of patients and assess specific subgroups.

Effects of Naltrexone on Sleep Quality and Periodic Breathing at High Altitude.

Foster, Katharine, James D. Anholm, Gary Foster, Suman Thapamagar, and Prajan Subedi. Effects of naltrexone on sleep quality and periodic breathing at high altitude. High Alt Med Biol. 00:000-000, 2024. Objective: This study examined the effects of naltrexone on breathing and sleep at high altitude. Mu-opioid receptor (MOR) agonists have a depressive effect on respiration. Naltrexone is known to block the MOR. We hypothesized that MOR blockade with naltrexone would result in higher nocturnal oxygen saturations, fewer apneas, and improved sleep at high altitude. Methods: This double-blind, placebo-controlled, crossover study included nine healthy volunteers (four females, five males) aged 27.9 (4.6) (mean [standard deviation]) years. Two overnight trips spaced at least 2 weeks apart took participants from Loma Linda, CA (355 m) to the Barcroft Laboratory, CA (3,810 m) for each arm. Participants ingested either 50 mg naltrexone or matching placebo at bedtime. Sleep metrics were recorded using an ambulatory physiological sleep monitor (APSM). Subjective data were measured with the Groningen Sleep Quality Scale, Stanford Sleepiness Scale, and the 2018 Lake Louise Score (LLS) for acute mountain sickness (AMS). Results: Mean overnight SpO2 was lower after taking naltrexone, 81% (6) versus 83% (4) (mean difference 1.9% [2.1, 95% confidence interval or CI = 0.1-3.6, p = 0.040]). The lowest overnight SpO2 (nadir) was lower on naltrexone 70% (6) versus 74% (4) (dif. 4.6% [4.3], CI = 1.0-8.2, p = 0.020). Total sleep time and total apnea-hypopnea index were unchanged. Subjective sleep quality was significantly worse on naltrexone measured via the Groningen Sleep Quality Scale (p = 0.033) and Stanford Sleepiness Scale (p = 0.038). AMS measured via LLS was significantly worse while taking naltrexone (p = 0.025). Conclusion: Contrary to our hypothesis, this study demonstrated a significant decrease in nocturnal oxygen saturation, worse sleep quality, and AMS scores. Further characterization of the MOR's effects on sleep and AMS is needed to evaluate potential exacerbating mechanisms for AMS and poor sleep quality at altitude.

Incorporating biofeedback into the Mindfulness in Motion Intervention for health care professionals: Impact on sleep and stress.

CONTEXT: Health care providers (HCP) experience high stress and burnout rates. Mindfulness Based Interventions (MBI) with biofeedback may help improve resiliency but require further research. DESIGN AND STUDY PARTICIPANTS: Aims were to evaluate changes in sleep patterns, nocturnal physiology, stress, mood disturbances, and perceived experience with biofeedback during the Mindfulness in Motion (MIM) intervention. Data from 66 HCP were included after removing those below 75 % compliance with wearable sensors and wellness surveys. Participants were enrolled in MIM, including eight weekly one-hour virtually delivered synchronous group meetings and ∼10 min of mindfulness home practice at least 3 times per week using a mobile application. Participants wore wearable sensors to monitor sleep and nocturnal physiology and completed short daily stress and mood disturbances. RESULTS: According to mixed effect models, no sleep nor physiological metrics changed across MIM (p > 0.05). More time was spent in bed after MIM sessions (8.33±1.03 h) compared to night before (8.05±0.93 h; p = 0.040). Heart rate variability was lower nights after MIM (33.00±15.59 ms) compared to nights before (34.50±17.04 ms; p = 0.004) but was not clinically meaningful (effect= 0.033). Significant reductions were noted in perceived stress at weeks 3 through 8 compared to Baseline and lower Total Mood Disturbance at weeks 3, 5, 6, and 8 compared to Baseline (p < 0.001). CONCLUSIONS: Participating in the MIM with mobile applications and wearable sensors reduced perceived stress and mood disturbances but did not induce physiological changes. Additional research is warranted to further evaluate objective physiological outcomes while controlling for confounding variables (e.g., alcohol, medications).

Evaluation of self-contained breathing apparatus (SCBA) weight on firefighter stamina, comfort, and postural stability.

Firefighters wear personal protective equipment to protect them from the thermal and chemical environment in which they operate. The self-contained breathing apparatus (SCBA) provides isolation of the airway from the hazardous fireground. National standards limit SCBA weight, however, integration of additional features could result in an SCBA exceeding the current limit. The purpose of this study was to examine the effects of increased SCBA weight on firefighters' physiological responses, work output, dynamic stability, and comfort. Completion of simulated firefighting activities induced a strong physiological response. Peak oxygen consumption was higher with the lightest SCBA than the heaviest SCBA. Few other physiological differences were noted as SCBA weight increased. Importantly, increased SCBA weight resulted in significantly more negative perceptions by the firefighters and a trend towards significance for the duration of work time prior to reaching volitional fatigue. These results should be considered when assessing changes to existing SCBA weight limits.

Increased SCBA weight above existing national standards resulted in negative perceptions by the firefighters, but not significant physiological changes after two simulated bouts of firefighting activity. SCBA weight had a nearly significant impact on the time firefighters worked before reaching volitional fatigue, with heavier SCBA trending towards decreased working time.

Prevalence of sleep-disordered breathing in children and adolescents with large horizontal maxillary overjet due to mandibular retrognathia: a case control study.

STUDY OBJECTIVES: The aim of the study was to examine the prevalence of sleep-disordered breathing (SDB) in children and adolescents with large overjet due to mandibular retrognathia compared to a control group. METHODS: In this case-control study children with large overjet ≥ 6 mm due to mandibular retrognathia (study group) were compared to a group with neutral occlusion (controls). All participants underwent respiratory polygraphy (PG) and questionnaires regarding sleepiness and snoring. Differences across groups were tested by: Chi-square, general linear model adjusted for age, sex, and body mass index (BMI), and Mann-Whitney test. Differences in results of PG were also tested by general linear model adjusted for age, sex, and BMI according to severity of mandibular retrognathia. RESULTS: Thirty-seven (19 male;18 female, median age 12.3 years) participants were included in the study group and 32 (16 male;16 female, median age 12.2 years) in the control group. No significant difference in SDB assessed by PG or questionnaires between the groups was found even though the snore index was higher in the study group (p=0.051). The snore index was higher than the parent-reported snoring. Respiration rate was significantly reduced in the study group (p=0.043), and estimated sleep time efficiency was significantly reduced in males compared to females (p<0.001). CONCLUSIONS: No significant differences in SDB were found between the groups even though the snore index was higher in the study group. The snore index of the PG was higher than the parent-reported snoring. Estimated sleep time efficiency was reduced in males. The study improves the understanding of risk of SDB in non-obese children with large overjet due to mandibular retrognathia and may contribute to an interdisciplinary approach of risk assessment of SDB in children with malocclusion. CLINICAL TRIAL REGISTRATION: NCT04964830.

Sequence comparison of spoiled gradient echo and balanced steady-state free precession for pulmonary free-breathing proton MRI in patients and healthy volunteers: Correspondence, repeatability, and validation with dynamic contrast-enhanced MRI.

Phase-resolved functional lung (PREFUL) MRI is a proton-based, contrast agent-free technique derived from the Fourier decomposition approach to measure regional ventilation and perfusion dynamics during free-breathing. Besides the necessity of extensive PREFUL postprocessing, the utilized MRI sequence must fulfill specific requirements. This study investigates the impact of sequence selection on PREFUL-MRI-derived functional parameters by comparing the standard spoiled gradient echo (SPGRE) sequence with a lung-optimized balanced steady-state free precession (bSSFP) sequence, thereby facilitating PREFULs clinical application in pulmonary disease assessment. This study comprised a prospective dataset of healthy volunteers and a retrospective dataset of patients with suspected chronic thromboembolic pulmonary hypertension. Both cohorts underwent PREFUL-MRI with both sequences to assess the correspondence of PREFUL ventilation and perfusion parameters (A). Additionally, healthy subjects were scanned a second time to evaluate repeatability (B), whereas patients received dynamic contrast-enhanced (DCE)-MRI, considered the perfusion gold standard for comparison with PREFUL-MRI (C). Signal-to-noise ratio (SNR), calculated from the unprocessed images, was compared alongside median differences of PREFUL-MRI-derived parameters using a paired Wilcoxon signed rank test. Further evaluations included calculation of the Pearson correlation, intraclass-correlation coefficient for repeatability assessment, and spatial overlap (SO) for regional comparison of PREFUL-MRI and DCE-MRI. bSSFP showed a clear SNR advantage over SPGRE (median: 23 vs. 9, p < 0.001). (A) Despite significant differences, parameter values were strongly correlated (r ≥ 0.75). After thresholding, binary maps showed high healthy overlap across both cohorts (SOHealthy > 86%) and high defect overlap in the patient cohort (SODefect ≥ 48%). (B) bSSFP demonstrated slightly higher repeatability across most parameters. (C) Both sequences demonstrated comparable correspondence to DCE-MRI, with SPGRE excelling in absolute quantification and bSSFP in spatial agreement. Although bSSFP showed superior SNR results, both sequences displayed spatial defect concordance and highly correlated PREFUL parameters with deviations regarding repeatability and alignment with DCE-MRI.

Respiratory performance in Duchenne muscular dystrophy: Clinical manifestations and lessons from animal models.

Duchenne muscular dystrophy (DMD) is a fatal genetic neuromuscular disease. Lack of dystrophin in skeletal muscles leads to intrinsic weakness, injury, subsequent degeneration and fibrosis, decreasing contractile function. Dystropathology eventually presents in all inspiratory and expiratory muscles of breathing, severely curtailing their critical function. In people with DMD, premature death is caused by respiratory or cardiac failure. There is an urgent need to develop therapies that improve quality of life and extend life expectancy in DMD. Surprisingly, there is a dearth of information on respiratory control in animal models of DMD, and respiratory outcome measures are often limited or absent in clinical trials. Characterization of respiratory performance in murine and canine models has revealed extensive remodelling of the diaphragm, the major muscle of inspiration. However, significant compensation by extradiaphragmatic muscles of breathing is evident in early disease, contributing to preservation of peak respiratory system performance. Loss of compensation afforded by accessory muscles in advanced disease is ultimately associated with compromised respiratory performance. A new and potentially more translatable murine model of DMD, the D2.mdx mouse, has recently been developed. Respiratory performance in D2.mdx mice is yet to be characterized fully. However, based on histopathological features, D2.mdx mice might serve as useful preclinical models, facilitating the testing of new therapeutics that rescue respiratory function. This review summarizes the pathophysiological mechanisms associated with DMD both in humans and in animal models, with a focus on breathing. We consider the translational value of each model to human DMD and highlight the urgent need for comprehensive characterization of breathing in representative preclinical models to better inform human trials.

Mechanical power density, spontaneous breathing indexes, and prolonged weaning failure: a prospective cohort study.

A prospective observational study comparing mechanical power density (MP normalized to dynamic compliance) with traditional spontaneous breathing indexes (e.g., predicted body weight normalized tidal volume [VT/PBW], rapid shallow breathing index [RSBI], or the integrative weaning index [IWI]) for predicting prolonged weaning failure in 140 tracheotomized patients. We assessed the diagnostic accuracy of these indexes at the start and end of the weaning procedure using ROC curve analysis, expressed as the area under the receiver operating characteristic curve (AUROC). Weaning failure occurred in 41 out of 140 patients (29%), demonstrating significantly higher MP density (6156 cmH2O2/min [4402-7910] vs. 3004 cmH2O2/min [2153-3917], P < 0.01), lower spontaneous VT/PBW (5.8 mL*kg-1 [4.8-6.8] vs. 6.6 mL*kg-1 [5.7-7.9], P < 0.01) higher RSBI (68 min-1*L-1 [44-91] vs. 55 min-1*L-1 [41-76], P < 0.01) and lower IWI (41 L2/cmH2O*%*min*10-3 [25-72] vs. 71 L2/cmH2O*%*min*10-3 [50-106], P < 0.01) and at the end of weaning. MP density was more accurate at predicting weaning failures (AUROC 0.91 [95%CI 0.84-0.95]) than VT/PBW (0.67 [0.58-0.74]), RSBI (0.62 [0.53-0.70]), or IWI (0.73 [0.65-0.80]), and may help clinicians in identifying patients at high risk for long-term ventilator dependency.

Sleep-disordered breathing in children with Chiari type I malformation.

OBJECTIVE: The objective was to identify clinical and radiological factors associated with sleep-disordered breathing (SDB) in children with Chiari type I malformation (CIM) and to evaluate the efficacy of foramen magnum decompression (FMD) in resolving SDB. METHODS: A retrospective chart review was conducted for all children evaluated for CIM at a single institution from 2002 to 2022, identifying all children who had undergone nocturnal polysomnography (PSG). Apnea-hypopnea index (AHI) score, sleep apnea type (obstructive, central, mixed, and unspecified), clinical manifestations, and radiological measurements were recorded. SDB was considered present when officially diagnosed in the PSG report. Logistic regression was performed to identify factors correlating with the presence of SDB. For children with SDB who underwent FMD, the Wilcoxon signed-rank test was used to assess AHI improvement. RESULTS: Of the 997 children referred for CIM, 310 completed PSG. SDB was diagnosed in 147 patients (overall prevalence 14.7%, 95% CI 12.7%-17.1%; prevalence among children with PSG 47.4%, 95% CI 41.9%-53%). Specific SDB diagnosis consisted of 33% of patients with central sleep apnea, 27% with obstructive sleep apnea, 9% mixed, and 31% unspecified. Lower cranial nerve (CN) dysfunction (OR 3.891, p = 0.009), tonsillar position (OR 1.049, p = 0.017), Chiari type 1.5 malformation (OR 1.862, p = 0.044), and BMI (OR 1.039, p = 0.036) were significantly associated with presence of SDB. Of the 310 patients who underwent PSG, 47 were originally categorized as asymptomatic: 27 (57%) of these asymptomatic patients were diagnosed with SDB on PSG. Of children diagnosed with SDB, 34 completed PSG before and after FMD. Median AHI score decreased from 6.5 preoperatively to 1.8 postoperatively, with a median (IQR) difference of -2.3 (-11.9 to 0.1) (p = 0.001). Twelve (35%) had resolution of SDB. CONCLUSIONS: The authors' findings suggest that the prevalence of SDB in children with CIM is high (15%-47%). Furthermore, lower CN dysfunction, Chiari type 1.5, lower tonsillar position, and higher BMI may be risk factors. Notably, SDB can be present even in the absence of clinical symptoms. This study also demonstrates that surgical intervention has the potential to reduce the severity of SDB. These results could help clinicians identify CIM patients at risk for SDB and those who may benefit from surgical decompression.

The effect of acute respiratory demand on postural control: A systematic review.

BACKGROUND: Postural control can be challenged by breathing. RESEARCH QUESTION: What is the effect of an acute increase in respiratory demand on postural control compared to quiet breathing? METHODS: A systematic review was conducted. Electronic databases were systematically searched until October 18, 2022 on studies reporting changes in center of pressure (CoP) motion related to an acute manipulation of respiratory demand compared to quiet breathing during upright standing in healthy participants and/or participants with a clinical condition. RESULTS: Twenty-one studies in healthy participants showed that voluntary (not metabolic-induced) hyperventilation or inspiratory resistive loading significantly increased CoP motion, while breath-holding decreased CoP motion, compared to quiet breathing (p< 0.05). Manipulating respiratory rate or breathing patterns did not reveal consistent results. Four studies showed that people with low back pain showed similar CoP responses to increasing respiratory demand (p> 0.05), except for breathing at different rates, whereas they showed greater CoP motion during quiet breathing. SIGNIFICANCE: The extent of postural disturbance depended on the breathing mode and how it was quantified (i.e., CoP coupled with breathing movement or overall CoP measures). Voluntary hyperventilation and inspiratory resistive loading increased postural sway. For voluntary hyperventilation, this could be explained by CoP motion being directly coupled to chest wall movements whereas metabolic-induced hyperventilation did not increase CoP motion or CoP coupling with breathing. Breath-holding decreased postural sway. Patients with low back pain show greater postural sways than pain-free individuals during quiet breathing, although they exhibit similar postural adaptations to respiratory-related challenges as controls.

Variability in sleep architecture and alterations in circadian rhythms in patients with acute cerebral infarction accompanied by sleep-disordered breathing.

PURPOSE: To continuously and dynamically monitor the sleep status of patients in the acute phase of cerebral infarction, and to investigate the characteristics of acute cerebral infarction(ACI)associated with sleep-disordered breathing (SDB), variations in sleep structure, and changes in sleep circadian rhythms. METHODS: Patients with ACI within 48 h of onset who were admitted to the Department of Neurology at Kailuan General Hospital from November 2020 to December 2022 were selected. Detailed baseline information such as age, gender, smoking history, drinking history, were recorded for the selected participants. From the beginning of their hospitalization, the selected participants were monitored for their sleep status continuously for 5 days using the Intelligent Mattress-based Sleep Monitoring Platform System(IMSMPS). Based on the heart rate data obtained from the monitoring, the interdaily stability (IS) and intradaily variability (IV) of the sleep circadian rhythm were calculated. RESULTS: 1,367 patients with ACI were selected. Monitoring results over 5 days indicated 147 cases (10.75%) without SDB, and 1,220 cases (89.25%) with SDB. Among the group with SDB, there were 248 cases (18.14%) with continuous mild SDB, 395 cases (28.90%) with moderate SDB, 295 cases (21.58%) with severe SDB, and 282 cases (20.63%) that fluctuated between different severity levels. Within this fluctuating group, 152 cases (53.90%) fluctuated between two severity levels, 120 cases (42.55%) between three levels, and 10 cases (3.55%) among all four levels. There were statistically significant differences (P < 0.05) in the sleep latency, sleep efficiency, non-rapid eye movement stages 1-2, rapid eye movement, proportion of non-rapid eye movement, proportion of rapid eye movement, wake after sleep onset, time out of bed, number of awakenings, respiratory variability index, and heart rate variability index among patients with ACI monitored from day 1 to 5. However, other monitored sleep structure parameters did not show statistically significant differences (P > 0.05). The coefficient of variation for all sleep monitoring parameters ranged between 14.54 and 36.57%. The IV in the SDB group was higher than in the group without SDB (P < 0.05), and the IS was lower than in the group without SDB (P < 0.05). CONCLUSION: Patients in the acute phase of cerebral infarction have a high probability of accompanying SDB. The sleep structure of these patients shows significant variability based on the onset time of the stroke, and some patients experience fluctuations among different severity levels of SDB. ACI accompanied by SDB can further reduce the IS of a patient's sleep circadian rhythm and increase its IV.

Ultralow-Frequency Tip-Enhanced Raman Scattering Discovers Nanoscale Radial Breathing Mode on Strained 2D Semiconductors.

Collective excitations including plasmons, magnons, and layer-breathing vibration modes emerge at an ultralow frequency (<1 THz) and are crucial for understanding van der Waals materials. Strain at the nanoscale can drastically change the property of van der Waals materials and create localized states like quantum emitters. However, it remains unclear how nanoscale strain changes collective excitations. Herein, ultralow-frequency tip-enhanced Raman spectroscopy (TERS) with sub-10 nm resolution under ambient conditions is developed to explore the localized collective excitation on monolayer semiconductors with nanoscale strains. A new vibrational mode is discovered at around 12 cm-1 (0.36 THz) on monolayer MoSe2 nanobubbles and it is identified as the radial breathing mode (RBM) of the curved monolayer. The correlation is determined between the RBM frequency and the strain by simultaneously performing deterministic nanoindentation and TERS measurement on monolayer MoSe2. The generality of the RBM in nanoscale curved monolayer WSe2 and bilayer MoSe2 is demonstrated. Using the RBM frequency, the strain of the monolayer MoSe2 on the nanoscale can be mapped. Such an ultralow-frequency vibration from curved van der Waals materials provides a new approach to study nanoscale strains and points to more localized collective excitations to be discovered at the nanoscale.