Exploratory study of factors associated with probable respiratory sarcopenia in elderly subjects.

BACKGROUND: The diagnostic criteria for respiratory sarcopenia have been recently reported. However, no studies have clarified the characteristics of skeletal muscle impairment of the limbs in subjects with respiratory sarcopenia. This study aimed to explore the factors, including skeletal muscle, associated with probable respiratory sarcopenia in elderly subjects. METHODS: Subjects were classified into the probable respiratory sarcopenia group and nonrespiratory sarcopenia group. Probable respiratory sarcopenia was defined as the concurrent presence of respiratory muscle weakness (as less than the predicted value calculated from age, sex, and height) and low skeletal muscle mass (<7.0 kg/m2 in males and 5.7 kg/m2 in females). The following factors were measured: respiratory muscle strength, skeletal muscle mass index, muscle thickness and echo intensity of the rectus femoris, extracellular-to-intracellular water ratio, hand grip strength, 5 sit-to-stand, knee extension strength, bone mineral density, age, sex, body mass index, degree of frailty, presence or absence of medical history, presence or absence of habitual exercise, period of time since the start of exercise, and number of hours of exercise at a time. The association subjects with probable respiratory sarcopenia were analyzed using hierarchical logistic regression analysis. RESULTS: Twenty-six with probable respiratory sarcopenia and 54 with nonrespiratory sarcopenia were included. Hierarchical logistic regression analysis revealed that echo intensity was a significant predictor of probable respiratory sarcopenia. The odds ratio for echo intensity was 2.54 (95% confidence interval: 1.04-6.23). CONCLUSIONS: Our results suggest that a decrease in muscle quality in the lower extremity is associated with probable respiratory sarcopenia.

The Relationship between Inspiratory Muscle Strength and Cycling Performance: Insights from Hypoxia and Inspiratory Muscle Warm-Up.

Hypoxia increases inspiratory muscle work and consequently contributes to a reduction in exercise performance. We evaluate the effects of inspiratory muscle warm-up (IMW) on a 10 km cycling time trial in normoxia (NOR) and hypoxia (HYP). Eight cyclists performed four time trial sessions, two in HYP (FiO2: 0.145) and two in NOR (FiO2: 0.209), of which one was with IMW (set at 40% of maximal inspiratory pressure-MIP) and the other was with the placebo effect (PLA: set at 15% MIP). Time trials were unchanged by IMW (NORIMW: 893.8 ± 31.5 vs. NORPLA: 925.5 ± 51.0 s; HYPIMW: 976.8 ± 34.2 vs. HYPPLA: 1008.3 ± 56.0 s; p > 0.05), while ventilation was higher in HYPIMW (107.7 ± 18.3) than HYPPLA (100.1 ± 18.9 L.min-1; p ≤ 0.05), and SpO2 was lower (HYPIMW: 73 ± 6 vs. HYPPLA: 76 ± 6%; p ≤ 0.05). A post-exercise-induced reduction in inspiratory strength was correlated with exercise elapsed time during IMW sessions (HYPIMW: r = -0.79; p ≤ 0.05; NORIMW: r = -0.70; p ≤ 0.05). IMW did not improve the 10 km time trial performance under normoxia and hypoxia.

Improvements of the shape and strength of the diaphragm after endoscopic lung volume reduction.

RATIONALE: Endoscopic lung volume reduction improves lung function, quality of life and exercise capacity in severe emphysema patients. However, its effect on the diaphragm function is not well understood. We hypothesised that endoscopic lung volume reduction increases its strength by modifying its shape. OBJECTIVES: To investigate changes in both diaphragm shape and strength induced by the insertion of endobronchial valves. METHODS: In 19 patients, both the diaphragm shape and strength were investigated respectively by 3D Slicer software applied on CT scans acquired at functional residual capacity and by transdiaphragmatic pressure measurements by bilateral magnetic stimulation of the phrenic nerves before and 3 months after unilateral valves insertion. MEASUREMENTS AND MAIN RESULTS: After lung volume reduction (median (IQR), 434 mL (-597 to -156], p<0.0001), diaphragm strength increased (transdiaphragmatic pressure: 3 cmH2O (2.3 to 4.2), p<0.0001). On the treated side, this increase was associated with an increase in the coronal (16 mm (13 to 24), p<0.0001) and sagittal (26 mm (21 to 30), p<0.0001) lengths as well as in the area of the zone of apposition (62 cm2 (3 to 100), p<0.0001) with a decrease in the coronal (8 mm (-12 to -4), p<0.0001) and sagittal (9 mm (-18 to -2), p=0.0029) radii of curvature. CONCLUSIONS: Endoscopic lung volume reduction modifies the diaphragm shape by increasing its length and its zone of apposition and by decreasing its radius of curvature on the treated side, resulting in an increase in its strength. TRIAL REGISTRATION NUMBER: NCT05799352.

Continuous measurements of respiratory muscle blood flow & oxygen consumption using non-invasive FD-NIRS & DCS.

Prior studies of muscle blood flow and muscle specific oxygen consumption have required invasive injection of dye and Magnetic Resonance Imaging, respectively. Such measures have limited utility for continuous monitoring of the respiratory muscles. Frequency domain near-infrared spectroscopy and diffuse correlation spectroscopy (FD-NIRS & DCS) can provide continuous surrogate measures of blood flow index (BFi) and metabolic rate of oxygen consumption (MRO2). This study aimed to validate sternocleidomastoid FD-NIRS & DCS outcomes against electromyography (EMG) and mouth pressure (Pm) during incremental inspiratory threshold loading (ITL). Six females and six male healthy adults (mean±SD; 30±7 years, maximum inspiratory pressure 118±61 cmH2O) performed incremental ITL starting at low loads (8±2 cmH2O) followed by 50g increments every two minutes until task failure. FD-NIRS & DCS continuously measured sternocleidomastoid oxygenated and deoxygenated hemoglobin+myoglobin (oxy/deoxy[Hb+Mb]), tissue saturation of oxygen (StO2), BFi, and MRO2. Ventilatory parameters including inspiratory Pm were also evaluated. Pm increased during incremental ITL (P<0.05), reaching -47[-74 - -34] cmH2O (median[25%-75%IQR] at task failure. Ventilatory parameters were constant throughout ITL (all P>0.05). Sternocleidomastoid BFi and MRO2 increased from the start of the ITL (both P<0.05). Deoxy[Hb+Mb] increased close to task failure, concomitantly with a constant increase in MRO2, and decreased StO2. Sternocleidomastoid deoxy[Hb+Mb], BFi, StO2 and MRO2 obtained during ITL via FD-NIRS & DCS correlated with sternocleidomastoid EMG (all P<0.05). In healthy adults, FD-NIRS & DCS can provide continuous surrogate measures of respiratory BFi and MRO-2. Increasing sternocleidomastoid oxygen consumption near task failure was associated with increased oxygen extraction and reduced tissue saturation.

Respiratory, cardiovascular and musculoskeletal mechanisms involved in the pathophysiology of pulmonary hypertension: An updated systematic review of preclinical and clinical studies.

BACKGROUND: Progressive exercise intolerance is a hallmark of pulmonary hypertension (pH), severely impacting patients' independence and quality of life (QoL). Accumulating evidence over the last decade shows that combined abnormalities in peripheral reflexes and target organs contribute to disease progression and exercise intolerance. OBJECTIVE: The aim of this study was to review the literature of the last decade on the contribution of the cardiovascular, respiratory, and musculoskeletal systems to pathophysiology and exercise intolerance in pH. METHODS: A systematic literature search was conducted using specific terms in PubMed, SciELO, and the Cochrane Library databases for original pre-clinical or clinical studies published between 2013 and 2023. Studies followed randomized controlled/non-randomized controlled and pre-post designs. RESULTS: The systematic review identified 25 articles reporting functional or structural changes in the respiratory, cardiovascular, and musculoskeletal systems in pH. Moreover, altered biomarkers in these systems, lower cardiac baroreflex, and heightened peripheral chemoreflex activity seemed to contribute to functional changes associated with poor prognosis and exercise intolerance in pH. Potential therapeutic strategies acutely explored involved manipulating the baroreflex and peripheral chemoreflex, improving cardiovascular autonomic control via cardiac vagal control, and targeting specific pathways such as GPER1, GDF-15, miR-126, and the JMJD1C gene. CONCLUSION: Information published in the last 10 years advances the notion that pH pathophysiology involves functional and structural changes in the respiratory, cardiovascular, and musculoskeletal systems and their integration with peripheral reflexes. These findings suggest potential therapeutic targets, yet unexplored in clinical trials, that could assist in improving exercise tolerance and QoL in patients with pH.

Sleep Quality in Greek Adolescent Swimmers.

The aim of our study was to investigate the relationship between sleep quality and functional indices, swimming distance and gender in adolescent competitive swimmers. Forty-eight adolescent swimmers (boys, n = 22, 15.7 ± 1.0 years and girls, n = 26, 15.1 ± 0.8 years) were included in our study. They were assessed for handgrip strength, respiratory muscle strength and pulmonary function, answered a Pittsburg Sleep Quality Index questionnaire (PSQI), and recorded their anthropometric and morphological characteristics and training load for the last four weeks. The results showed differences between swimming distance and chest circumference difference, between maximal inhalation and exhalation (Δchest) (p = 0.033), PSQI score (p < 0.001), and sleep quality domains for "cannot breathe comfortably" (p = 0.037) and "have pain" (p = 0.003). Binary logistic regression (chi-square = 37.457, p = 0.001) showed that the variables Δchest (p = 0.038, 95% CI: 1.05-6.07) and PSQI score (p = 0.048, 95% CI: 0.1-1.07) remained independent predictors of the swim distance groups. Girls had a lower percentage of predicted values for the maximal inspiratory pressure (p < 0.001), maximal expiratory pressure (p = 0.027), forced expiratory volume within the first second (p = 0.026), forced vital capacity (p = 0.008) and sleep quality domains for "cough or snore loudly" (p = 0.032) compared to boys. A regression analysis showed that the sleep quality score was explained by the six independent variables: respiratory muscle strength (t = 2.177, ß = 0.164, p = 0.035), Δchest (t = -2.353, ß = -0.17, p = 0.023), distance (t = -5.962, ß = -0.475, p < 0.001), total body water (t = -7.466, ß = -0.687, p < 0.001), lean body mass (t = -3.120, ß = -0.434, p = 0.003), and handgrip (t = 7.752, ß = 1.136, p < 0.001). Our findings demonstrate that sleep quality in adolescent swimmers is a multifactorial result of morphometric characteristics, strength and respiratory function.

Effects of exercise and doxorubicin on acute diaphragm neuromuscular transmission failure.

Doxorubicin (DOX) is a highly effective anthracycline antibiotic used to treat a wide variety of cancers including breast cancer, leukemia and lymphoma. Unfortunately, clinical use of DOX is limited due to adverse off-target effects resulting in fatigue, respiratory muscle weakness and dyspnea. The diaphragm is the primary muscle of inspiration and respiratory insufficiency is likely the result of both muscle weakness and neural impairment. However, the contribution of neuropathology to DOX-induced respiratory muscle dysfunction is unclear. We hypothesized that diaphragm weakness following acute DOX exposure is associated with neurotoxicity and that exercise preconditioning is sufficient to improve diaphragm muscle contractility by maintaining neuromuscular integrity. Adult female Sprague-Dawley rats were randomized into four experimental groups: 1) sedentary-saline, 2) sedentary-DOX, 3) exercise-saline or 4) exercise-DOX. Endurance exercise preconditioning consisted of treadmill running for 1 h/day at 30 m/min for 10 days. Twenty-four hours after the last bout of exercise, animals were treated with DOX (20 mg/kg, I.P.) or saline (equal volume). Our results demonstrate that 48-h following DOX administration diaphragm muscle specific force is reduced in sedentary-DOX rats in response to both phrenic nerve and direct diaphragm stimulation. Importantly, endurance exercise preconditioning in DOX-treated rats attenuated the decrease in diaphragm contractile function, reduced neuromuscular transmission failure and altered phrenic nerve morphology. These changes were associated with an exercise-induced reduction in circulating biomarkers of inflammation, nerve injury and reformation. Therefore, the results are consistent with exercise preconditioning as an effective way of reducing respiratory impairment via preservation of phrenic-diaphragm neuromuscular conduction.

Singing for lung health in COPD: a multicentre randomised controlled trial of online delivery.

BACKGROUND: Singing for lung health (SLH) is an arts-based breathing control and movement intervention for people with long-term respiratory conditions, intended to improve symptoms and quality of life. Online, remotely delivered programmes might improve accessibility; however, no previous studies have assessed the effectiveness of this approach. METHODS: We conducted an assessor-blind randomised controlled trial comparing the impact of 12 weeks of once-weekly online SLH sessions against usual care on health-related quality of life, assessed using the RAND 36-Item Short Form Health Survey (SF-36) Mental Health Composite (MHC) and Physical Health Composite (PHC) scores. RESULTS: We enrolled 115 people with stable chronic obstructive pulmonary disease (COPD), median (IQR) age 69 (62-74), 56.5% females, 80% prior pulmonary rehabilitation, Medical Research Council dyspnoea scale 4 (3-4), forced expiratory volume in 1 s % predicted 49 (35-63). 50 participants in each arm completed the study. The intervention arm experienced improvements in physical but not mental health components of RAND SF-36; PHC (regression coefficient (95% CI): 1.77 (95% CI 0.11 to 3.44); p=0.037), but not MHC (0.86 (95% CI -1.68 to 3.40); p=0.504). A prespecified responder analysis based on achieving a 10% improvement from baseline demonstrated a response rate for PHC of 32% in the SLH arm and 12.7% for usual care (p=0.024). A between-group difference in responder rate was not found in relation to the MHC (19.3% vs 25.9%; p=0.403). DISCUSSION AND CONCLUSION: A 12-week online SLH programme can improve the physical component of quality of life for people with COPD, but the overall effect is relatively modest compared with the impact seen in research using face-to-face group sessions. Further work on the content, duration and dose of online interventions may be useful. TRIAL REGISTRATION NUMBER: NCT04034212.

High-intensity intermittent inspiratory and abdominal muscle combined training in respiratory, swallowing and systemic muscles of healthy adults.

BACKGROUND: Low-intensity continuous inspiratory muscle training improves its strength. The abdominal muscles are the main expiratory muscles, and their training may improve expiratory muscle strength. Respiratory muscle strength regulates coughing effectiveness, which is critical for pneumonia management. In older people, risk factors for the development of pneumonia were respiratory muscle weakness and swallowing impairment. Currently, the impact of high-intensity intermittent inspiratory and abdominal muscle combined training on the respiratory, swallowing, and systemic muscles is unclear. OBJECTIVE: We aimed to explore the effects of high-intensity inspiratory muscle training combined with or without abdominal muscle training on respiratory muscle strength as well as the strength, mass, and performance of swallowing and systemic muscles. METHODS: Twenty-eight healthy adults were divided into two groups. Participants performed high-intensity intermittent inspiratory muscle single or its combination with abdominal muscle training for 4 weeks. Respiratory muscle strength, swallowing muscle strength and mass, systemic muscle strength, mass and performance were measured at baseline, Week 2 and Week 4. RESULTS: Both groups showed greater maximal respiratory pressures at Week 2 and Week 4 than baseline. Both groups showed improved tongue pressure and geniohyoid muscle thickness at Week 4. In addition, the combined training group improved body trunk muscle mass, handgrip strength and five-time chair stand test, whereas the single training group did not. CONCLUSION: This study revealed that high-intensity inspiratory muscle training improved inspiratory muscle strength and swallowing muscle strength and mass. Moreover, inspiratory and abdominal muscle combined training showed an additional benefit of improving systemic muscle strength, mass and performance. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000046724; https://upload.umin.ac.jp/cgi-open-bin/ctr/index.cgi?ctrno=UMIN000046724.

Reliability and Validity of Maximal Respiratory Pressures.

BACKGROUND: Maximal respiratory pressure is used to assess the inspiratory and expiratory muscles strength by using maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax). This study aimed to summarize and evaluate the reliability and validity of maximal respiratory pressure measurements. METHODS: This systematic review followed the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) recommendations and was reported by using the PRISMA checklist. Studies published before March 2023 were searched in PubMed and EMBASE databases. RESULTS: A total of 642 studies were identified by using the online search strategy and manual search (602 and 40, respectively). Twenty-three studies were included. The level of evidence for test-retest reliability was moderate for PImax and PEmax (intraclass correlation coefficient > 0.70 for both), inter-rater reliability was low for PImax and very low for PEmax (intraclass correlation coefficient > 0.70 for both), and the measurement error was very low for PImax and PEmax. In addition, concurrent validity presented a high level of evidence for PImax and PEmax (r > 0.80). CONCLUSIONS: Only concurrent validity of maximal respiratory pressure measured with the manometers evaluated in this review presented a high level of evidence. The quality of clinical studies by using maximal respiratory pressure would be improved if more high-quality studies on measurement properties, by following well established guidelines and the COSMIN initiative, were available.

Influence of physical exercise on respiratory muscle function in older adults: A systematic review and meta-analysis.

Respiratory function decreases with aging. The literature showed that non-ventilatory specific exercise could have a positive impact on respiratory muscles. A systematic literature review was conducted to assess the effects of non-ventilatory specific exercise on maximal inspiratory (MIP) and expiratory pressure (MEP) and peak expiratory flow (PEF) in older adults. The included 9 trials investigated the effects of resistance training, yoga, Pilates, physical activity based on walking, and whole-body vibration training. The meta-analysis showed no statistically significant differences in MIP, MEP, and PEF after implementation of a non-ventilatory specific exercise program in older individuals. Between-study heterogeneity was substantial for MIP and MEP outcomes but it was not statistically significant for PEF. Further RCTs will be necessary to determine the effects of physical exercise interventions. PROSPERO registry CRD42023478262.

Effects of 12 weeks of inspiratory muscle training and whole body vibration on the inflammatory profile, BDNF and muscular system in pre-frail elderly women: A randomized controlled trial.

AIM: to investigate the effects of the whole body vibration (WBV) and inspiratory muscle training (IMT) on the inflammatory profile and in muscle mass and strength in pre-frail older women. METHODS: this study was a randomized double-blind trial. Forty two older women aged 60-80 years were randomly allocated to IMT + WBV (G1), IMTsham + WBV (G2) or Sham groups (G3). During 12 weeks G1 received both trainings, whereas G2 received WBV alone and G3 received IMT with a low fixed load and were positioned at the vibratory platform without therapeutic effect. Participants were evaluated before and after the intervention for the following outcomes: Brain-derived neurotrophic factor (BDNF) and inflammatory biomarkers (IB), respiratory (RT) and quadriceps thickness (QT) and diaphragmatic mobility (DM) using muscle ultrasound, body composition (BC) using a bioelectrical impedance scale and inspiratory muscle strength (IMS). RESULTS: after the training, G1 (114.93 ± 21.29) improved IMS (p<0.005) compared with G2 (91.29 ± 23.10) and G3 (85.21 ± 27.02). There was also a significant improve on time of the DM (p<0.001) and RT (p=0.006) for G1 (8.59 ± 3.55 and 11.11 ± 12.66) compared with G2 (1.05 ± 3.09 and 1.10 ± 10.60) and G3 (0.40 ± 2.29 and -1.85 ± 7.45). BDNF, IB, QT and BC were similar between groups. CONCLUSIONS: IMT associated with WBV is effective to improve in increasing IMS, RT and DM in pre-frail older women. However, these interventions do not modify BDNF, IB, QT or BC in this population.

Inspiratory Muscle Training in Patients Living with Chronic Kidney Disease and Receiving Hemodialysis: Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: People living with chronic kidney disease (CKD) and receiving hemodialysis (HD) have impaired respiratory muscle strength and endurance. The objective of this study was to systematically review the effects of inspiratory muscle training (IMT) on respiratory muscle strength, functional capacity, lung function, quality of life, endothelial function, and oxidative stress in people living with CKD and receiving HD. METHODS: An electronic search was conducted from inception to June 2023. Randomized controlled trials that evaluated the effects of IMT on respiratory muscle strength, functional capacity, lung function, endothelial function, quality of life, or oxidative stress in adults living with CKD and receiving HD, compared with control, placebo IMT, or conventional physical therapy, were included. RESULTS: Eight studies were included, totaling 246 people. The meta-analysis showed that IMT increased the maximum inspiratory pressure (MIP) by 22.53 cm H2O, the maximum expiratory pressure (MEP) by 19.54 cm H2O, and the distance covered in the 6-minute walk test by 77.63 m. Changes in lung function and quality of life were not observed. It was not possible to quantitatively analyze data on endothelial function and oxidative stress. CONCLUSIONS: IMT improves MIP, MEP, and functional capacity in people living with CKD and receiving HD. IMT did not demonstrate significant results for lung function and quality of life. Effects on endothelial function and oxidative capacity remain uncertain. IMPACT: Inspiratory muscle training improves MIP, MEP, and functional capacity in people living with CKD and receiving HD, compared with conventional physical therapy or controls or placebo intervention. Increases in functional capacity in this population are extremely important because of the relationship with the survival of these people.

The Effects of Various Approaches to Lobectomies on Respiratory Muscle Strength, Diaphragm Thickness, and Exercise Capacity in Lung Cancer.

BACKGROUND: The most common surgery for non-small cell lung cancer is lobectomy, which can be performed through either thoracotomy or video-assisted thoracic surgery (VATS). Insufficient research has examined respiratory muscle function and exercise capacity in lobectomy performed using conventional thoracotomy (CT), muscle-sparing thoracotomy (MST), or VATS. This study aimed to assess and compare respiratory muscle strength, diaphragm thickness, and exercise capacity in lobectomy using CT, MST, and VATS. METHODS: The primary outcomes were changes in respiratory muscle strength, diaphragm thickness, and exercise capacity. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were recorded for respiratory muscle strength. The 6-min walk test (6MWT) was used to assess functional exercise capacity. Diaphragm thickness was measured using B-mode ultrasound. RESULTS: The study included 42 individuals with lung cancer who underwent lobectomy via CT (n = 14), MST (n = 14), or VATS (n = 14). Assessments were performed on the day before surgery and on postoperative day 20 (range 17-25 days). The decrease in MIP (p < 0.001), MEP (p = 0.003), 6MWT (p < 0.001) values were lower in the VATS group than in the CT group. The decrease in 6MWT distance was lower in the MST group than in the CT group (p = 0.012). No significant differences were found among the groups in terms of diaphragmatic muscle thickness (p > 0.05). CONCLUSION: The VATS technique appears superior to the CT technique in terms of preserving respiratory muscle strength and functional exercise capacity. Thoracic surgeons should refer patients to physiotherapists before lobectomy, especially patients undergoing CT. If lobectomy with VATS will be technically difficult, MST may be an option preferable to CT because of its impact on exercise capacity.

Incremental Ramp Load Protocol to Assess Inspiratory Muscle Endurance in Healthy Individuals: Comparison with Incremental Step Loading Protocol.

INTRODUCTION: Protocols for obtaíníng the maxímum threshold pressure have been applied wíth límited precision to evaluate ínspiratory muscle endurance. In thís sense, new protocols are needed to allow more relíable measurements. The purpose of the present study was to compare a new incremental ramp load protocol for the evaluation of ínspíratory muscle endurance wíth the most used protocol in healthy indíviduals. METHODS: This was a prospective cross-sectional study carried out ín a síngle center. Nínety-two healthy indíviduals (43 men [22 ± 3 years] and 49 women [22 ± 3 years]) were randomly allocated to perform: (i) íncremental ramp load protocol and (íí) íncremental step loadíng protocol. The sustained pressure threshold (or maximum threshold pressure), maximum threshold pressure/dynamic strength índex ratío, time untíl task faílure, as well as dífference between the mean heart rate of the last five mínutes of baselíne and the peak heart rate of the last 30 seconds of each protocol were measured. RESULTS: Incremental ramp load protocol wíth small íncreases in the load and starting from mínímum values of strength index was able to evaluate the inspiratory muscle endurance through the maxímum threshold pressure of healthy indívíduals. CONCLUSION: The present study suggests that the íncremental ramp load protocol is able to measure maximum threshold pressure in a more thorough way, wíth less progression and greater accuracy in the load stratification compared to the límited incremental step loading protocol and with a safe and expected cardiovascular response in healthy individuals.

Association between computed tomography-quantified respiratory muscles and chronic obstructive pulmonary disease: a retrospective study.

BACKGROUND: This study examined the association between chest muscles and chronic obstructive pulmonary disease (COPD) and the relationship between chest muscle areas and acute exacerbations of COPD (AECOPD). METHODS: There were 168 subjects in the non-COPD group and 101 patients in the COPD group. The respiratory and accessory respiratory muscle areas were obtained using 3D Slicer software to analysis the imaging of  computed tomography (CT). Univariate and multivariate Poisson regressions were used to analyze the number of AECOPD cases during the preceding year. The cutoff value was obtained using a receiver operating characteristic (ROC) curve. RESULTS: We scanned 6342 subjects records, 269 of which were included in this study. We then measured the following muscle areas (non-COPD group vs. COPD group): pectoralis major (19.06 ± 5.36 cm2 vs. 13.25 ± 3.71 cm2, P < 0.001), pectoralis minor (6.81 ± 2.03 cm2 vs. 5.95 ± 1.81 cm2, P = 0.001), diaphragmatic dome (1.39 ± 0.97 cm2 vs. 0.85 ± 0.72 cm2, P = 0.011), musculus serratus anterior (28.03 ± 14.95 cm2 vs.16.76 ± 12.69 cm2, P < 0.001), intercostal muscle (12.36 ± 6.64 cm2 vs. 7.15 ± 5.6 cm2, P < 0.001), pectoralis subcutaneous fat (25.91 ± 13.23 cm2 vs. 18.79 ± 10.81 cm2, P < 0.001), paravertebral muscle (14.8 ± 4.35 cm2 vs. 13.33 ± 4.27 cm2, P = 0.007), and paravertebral subcutaneous fat (12.57 ± 5.09 cm2 vs. 10.14 ± 6.94 cm2, P = 0.001). The areas under the ROC curve for the pectoralis major, intercostal, and the musculus serratus anterior muscle areas were 81.56%, 73.28%, and 71.56%, respectively. Pectoralis major area was negatively associated with the number of AECOPD during the preceding year after adjustment (relative risk, 0.936; 95% confidence interval, 0.879-0.996; P = 0.037). CONCLUSION: The pectoralis major muscle area was negative associated with COPD. Moreover, there was a negative correlation between the number of AECOPD during the preceding year and the pectoralis major area.

Combined frequency domain near-infrared spectroscopy and diffuse correlation spectroscopy system for comprehensive metabolic monitoring of inspiratory muscles during loading.

Significance: Mechanical ventilation (MV) is a cornerstone technology in the intensive care unit as it assists with the delivery of oxygen in critically ill patients. The process of weaning patients from MV can be long and arduous and can lead to serious complications for many patients. Despite the known importance of inspiratory muscle function in the success of weaning, current clinical standards do not include direct monitoring of these muscles. Aim: The goal of this project was to develop and validate a combined frequency domain near-infrared spectroscopy (FD-NIRS) and diffuse correlation spectroscopy (DCS) system for the noninvasive characterization of inspiratory muscle response to a load. Approach: The system was fabricated by combining a custom digital FD-NIRS and DCS system. It was validated via liquid phantom titrations and a healthy volunteer study. The sternocleidomastoid (SCM), an accessory muscle of inspiration, was monitored during a short loading period in fourteen young, healthy volunteers. Volunteers performed two different respiratory exercises, a moderate load and a high load, which consisted of a one-minute baseline, a one-minute load, and a six-minute recovery period. Results: The system has low crosstalk between absorption, reduced scattering, and flow when tested in a set of liquid titrations. Faster dynamics were observed for changes in blood flow index (BFi), and metabolic rate of oxygen (MRO2) compared with hemoglobin + myoglobin (Hb+Mb) based parameters after the onset of loads in males. Additionally, larger percent changes in BFi, and MRO2 were observed compared with Hb+Mb parameters in both males and females. There were also sex differences in baseline values of oxygenated Hb+Mb, total Hb+Mb, and tissue saturation. Conclusions: The dynamic characteristics of Hb+Mb concentration and blood flow were distinct during loading of the SCM, suggesting that the combination of FD-NIRS and DCS may provide a more complete picture of inspiratory muscle dynamics.

Effect of diaphragmatic breathing training with visual biofeedback on respiratory function in patients with multiple rib fractures: A randomized-controlled study.

Objectives: The aim of this study was to investigate the effect of diaphragmatic breathing training with visual biofeedback on respiratory function in patients with multiple rib fractures. Patients and methods: Between June 2021 and October 2021, a total of 16 patients (15 males, 1 female; mean age: 49.50±11.85 years; range, 25 to 66 years) who were diagnosed with multiple rib fractures were randomly assigned into two groups as the control group (CG, n=8) and the visual biofeedback group (VBG, n=8). The effect of each diaphragmatic breathing training on respiratory function was evaluated before and after eight interventions. For respiratory function, pulmonary function test was used to measure pulmonary function and respiratory muscle strength, and the Pain, Inspiratory capacity, Cough (PIC) score was used to evaluated pain, inspiratory capacity, and cough ability. Results: In both groups, the pulmonary function representing the ratio of measurements to predicted values of both forced vital capacity (CG mean difference=25.37±4.58, p=0.002, VBG mean difference=24.25±3.96, p=0.007) and forced expiratory volume in 1 sec (CG mean difference=32.38±5.7, p=0.002, VBG mean difference=26.15±5.73, p <0.001) increased significantly. The maximal inspiratory (CG mean difference=14.00±0.35, p=0.002, VBG mean difference=20.5±6.26, p=0.009) and expiratory pressure (CG mean difference=43.72±29.44, p=0.034, VBG mean difference=25.76±6.78, p=0.015), the indicators of respiratory muscle strength, increased significantly in both groups. The PIC score, which evaluated pain, inspiratory capacity, and cough ability, also increased significantly in both groups (CG mean difference=1.63±0.26, p≤0.001, VBG mean difference=3.13±0.19, p <0.001). The change of PIC score after intervention did not significantly differ between the groups (F=1.439, p=0.250); however, there was a significant difference over time (F=38.476, p <0.001). The change of PIC scores differed over time between the groups (F=2.806 p=0.011). Conclusion: Diaphragmatic breathing training and diaphragmatic breathing training with visual biofeedback can improve pulmonary function, respiratory muscle strength, pain, inspiratory capacity, and cough ability in patients with multiple rib fractures.

Invasive versus non-invasive paediatric home mechanical ventilation: review of the international evolution over the past 24 years.

BACKGROUND: Home mechanical ventilation (HMV) is the treatment for chronic hypercapnic alveolar hypoventilation. The proportion and evolution of paediatric invasive (IMV) and non-invasive (NIV) HMV across the world is unknown, as well as the disorders and age of children using HMV. METHODS: Search of Medline/PubMed for publications of paediatric surveys on HMV from 2000 to 2023. RESULTS: Data from 32 international reports, representing 8815 children (59% boys) using HMV, were analysed. A substantial number of children had neuromuscular disorders (NMD; 37%), followed by cardiorespiratory (Cardio-Resp; 16%), central nervous system (CNS; 16%), upper airway (UA; 13%), other disorders (Others; 10%), central hypoventilation (4%), thoracic (3%) and genetic/congenital disorders (Gen/Cong; 1%). Mean age±SD (range) at HMV initiation was 6.7±3.7 (0.5-14.7) years. Age distribution was bimodal, with two peaks around 1-2 and 14-15 years. The number and proportion of children using NIV was significantly greater than that of children using IMV (n=6362 vs 2453, p=0.03; 72% vs 28%, p=0.048), with wide variations among countries, studies and disorders. NIV was used preferentially in the preponderance of children affected by UA, Gen/Cong, Thoracic, NMD and Cardio-Resp disorders. Children with NMD still receiving primary invasive HMV were mainly type I spinal muscular atrophy (SMA). Mean age±SD at initiation of IMV and NIV was 3.3±3.3 and 8.2±4.4 years (p<0.01), respectively. The rate of children receiving additional daytime HMV was higher with IMV as compared with NIV (69% vs 10%, p<0.001). The evolution of paediatric HMV over the last two decades consists of a growing number of children using HMV, in parallel to an increasing use of NIV in recent years (2020-2023). There is no clear trend in the profile of children over time (age at HMV). However, an increasing number of patients requiring HMV were observed in the Gen/Cong, CNS and Others groups. Finally, the estimated prevalence of paediatric HMV was calculated at 7.4/100 000 children. CONCLUSIONS: Patients with NMD represent the largest group of children using HMV. NIV is increasingly favoured in recent years, but IMV is still a prevalent intervention in young children, particularly in countries indicating less experience with NIV.