American Thoracic Society/European Respiratory Society. ATS/ERS Statement on respiratory muscle testing

Effects of Obesity and Sex on Ventilatory Constraints during a Cardiopulmonary Exercise Test in Children

PURPOSE

Ventilatory constraints are common during exercise in children, but the effects of obesity and sex are unclear. The purpose of this study was to investigate the effects of obesity and sex on ventilatory constraints (i.e., expiratory flow limitation (EFL) and dynamic hyperinflation) during a maximal exercise test in children.

METHODS

Thirty-four 8- to 12-yr-old children without obesity (18 females) and 54 with obesity (23 females) completed pulmonary function testing and maximal cardiopulmonary exercise tests. EFL was calculated as the overlap between tidal flow-volume loops during exercise and maximal expiratory flow-volume loops. Dynamic hyperinflation was calculated as the change in inspiratory capacity from rest to exercise.

RESULTS

Maximal minute ventilation was not different between children with and without obesity. Average end-inspiratory lung volumes (EILV) and end-expiratory lung volumes (EELV) were significantly lower during exercise in children with obesity (EILV: 68.8% ± 0.7% TLC; EELV: 41.2% ± 0.5% TLC) compared with children without obesity (EILV: 73.7% ± 0.8% TLC; EELV: 44.8% ± 0.6% TLC; P < 0.001). Throughout exercise, children with obesity experienced more EFL and dynamic hyperinflation compared with those without obesity ( P < 0.001). Also, males experienced more EFL and dynamic hyperinflation throughout exercise compared with females ( P < 0.001). At maximal exercise, the prevalence of EFL was similar in males with and without obesity; however, the prevalence of EFL in females was significantly different, with 57% of females with obesity experiencing EFL compared with 17% of females without obesity ( P < 0.05). At maximal exercise, 44% of children with obesity experienced dynamic hyperinflation compared with 12% of children without obesity ( P = 0.002).

CONCLUSIONS

Obesity in children increases the risk of developing mechanical ventilatory constraints such as dynamic hyperinflation and EFL. Sex differences were apparent with males experiencing more ventilatory constraints compared with females.

A cross-sectional study in 18 patients with typical and mild forms of nemaline myopathy in the Netherlands

Nemaline myopathy (NM) is a congenital myopathy with generalised muscle weakness, most pronounced in neck flexor, bulbar and respiratory muscles. The aim of this cross-sectional study was to assess the Dutch NM patient cohort. We assessed medical history, physical examination, quality of life (QoL), fatigue severity, motor function (MFM), and respiratory muscle function. We included 18 of the 28 identified patients (13 females (11-67 years old); five males (31-74 years old)) with typical or mild NM and eight different genotypes. Nine patients (50 %) used a wheelchair, eight patients (44 %) used mechanical ventilation, and four patients (22 %) were on tube feeding. Spinal deformities were found in 14 patients (78 %). The median Medical Research Council (MRC) sum score was 38/60 [interquartile range 32-51] in typical and 48/60 [44-50] in mild NM. The experienced QoL was lower and fatigue severity was higher than reference values of the healthy population. The total MFM score was 55 % [49-94] in typical and 88 % [72-93] in mild NM. Most of the patients who performed spirometry had a restrictive lung function pattern (11/15). This identification and characterisation of the Dutch NM patient cohort is important for international collaboration and can guide the design of future clinical trials.

Tongue pressure, respiratory muscle and limb strength and functional exercise capacity in oesophageal cancer

OBJECTIVES

Preoperative management of oesophageal cancer requires effective prehabilitation. This study investigates the relationship between tongue pressure, respiratory muscle, handgrip and lower limb muscle strengths, and functional exercise capacity in patients with oesophageal cancer to develop a novel prehabilitation strategy.

METHODS

This prospective, single-centre, observational study analysed data from 29 pretreatment patients with oesophageal cancer. We evaluated tongue pressure, maximal inspiratory and expiratory pressures, handgrip and lower limb muscle strengths, functional exercise capacity and dysphagia scores before treatment. The relationship between parameters was identified using Spearman's correlation analysis.

RESULTS

Maximal inspiratory and expiratory pressures were significantly associated with handgrip and lower extremity muscle strengths and functional exercise capacity. However, tongue pressure was not associated with maximal inspiratory and expiratory pressures, handgrip and lower extremity muscle strengths and functional exercise capacity. Rather, tongue pressure was significantly associated with clinical T, dysphagia and nutritional status scores.

CONCLUSIONS

Respiratory muscle strength was associated with conventional sarcopenia and functional exercise capacity. Tongue pressure was not associated with respiratory muscle strength, conventional sarcopenia and functional exercise capacity. Rather, tongue pressure was associated with clinical T, dysphagia and nutritional status scores. Preoperative management of oesophageal cancer requires prehabilitation consisting of exercise and nutritional therapy and an additional swallowing programme, such as tongue resistance training, for patients without progress in oral intake, based on tongue pressure evaluation.

Investigating the relationship of trunk and postural control with pulmonary functions in subacute stroke patients

Stroke is a disease with high mortality and morbidity that not only causes weakness in the extremities, loss of balance, and disturbances in trunk and postural control, but also affects respiratory function. The aim of this study was to investigate the relationship between trunk and postural control and pulmonary function in subacute stroke patients. Herein, 32 volunteer patients who were diagnosed with hemiplegia by a competent physician after unilateral hemorrhagic or ischemic stroke and who met the inclusion criteria participated in the study. Functional independence of the participants was evaluated using the Modified Rankin Scale (mRS) and their cognitive function was assessed with the Standardized Mini Mental State Examination. Respiratory function was evaluated with spirometric measurements, inspiratory muscle strength was evaluated with intraoral pressure measurements, trunk control was evaluated using the Trunk Impairment Scale (TIS), postural control was evaluated using the Postural Assessment Scale for Stroke Patients (PASS-T), computerized postural sway evaluation, and static posture analysis. A significant correlation was found between the TIS scores and inspiratory muscle strength (p < 0.05). A significant correlation was also found between the PASS-T scores and inspiratory muscle strength and pulmonary function (p < 0.05). All of the COP parameters measured were significantly correlated with the PEF(L/s) and FEF25-75 (L/s) (p < 0.05). In conclusion, this study showed that trunk and postural control are associated with inspiratory muscle strength and pulmonary function. It is recommended that evaluation of trunk and postural control and respiratory functions, as well as exercise training to improve these parameters, should be included in rehabilitation programs for individuals with stroke.

Longitudinal effects of obesity on pulmonary function in obese children and adolescents

BACKGROUND

To investigate the longitudinal effects of obesity on change in lung function after 1 year of follow-up in obese children and adolescents.

METHODS

Obese children/adolescents aged 8-15 years with pulmonary function test (PFT) results and recorded anthropometric obesity indices from 1 year earlier for comparison were recruited. Multiple linear regression of change in each lung function parameter was applied to determine the effect of sex, change in body mass index (ΔBMI), change in chest circumference (ΔCC), change in waist circumference (ΔWC), and change in waist circumference-to-height ratio (ΔWC/Ht).

RESULTS

Sixty-six children/adolescents (mean age: 12.5 ± 2.6 years) were recruited. Multiple linear regression analysis showed that ΔWC negatively affects the ratio of the forced expiratory volume in the first 1 s to the forced vital capacity of the lungs Δ(FEV1/FVC) (b = -0.3, p = 0.002), forced expiratory flow rate within 25-75% of vital capacity (ΔFEF25-75%) (b = -0.92, p = 0.006), and Δ(FEF25-75%/FVC) (b = -0.99, p = 0.003). When replacing ΔWC with Δ(WC/Ht) as the independent variable, Δ(WC/Ht) also negatively affects Δ(FEV1/FVC) (b = -33.71, p = 0.02), ΔFEF25-75% (b = -102.9, p = 0.03) and Δ(FEF25-75%/FVC) (b = -102.7, p = 0.03).

CONCLUSION

After 1 year of follow-up, change in abdominal adiposity determined by WC and WC/Ht exerted significant negative effect on lung function change specific to FEV1/FVC, FEF25-75% /FVC, and FEF25-75%.

IMPACT

Longitudinal effects of change in obesity on lung function in obese children and adolescents are evidenced. Change in waist circumference or waist-to-height ratio, which indicates abdominal adiposity, was inversely correlated with a change in FEV1/FVC, FEF25-75% /FVC, and FEF25-75% in children and adolescents with obesity after 1 year of follow-up. Our results suggest using waist circumference and/or waist-to-height ratio in addition to BW and/or BMI for monitoring obesity. Fat loss programs, especially those focused on reducing abdominal adiposity should be encouraged to prevent late lung function impairment.

Implications of Airway Resistance and Conductance on the Respiratory Rate in individuals With Various Nutritional States Exposed To Exercise

Purpose

To determine how airway resistance (RAW) and airway conductance (GAW) affect inspiratory time (iT) and expiratory time (eT) in subjects with different nutritional states using the step test.

Methods

Forty-eight participants were recruited and divided into three groups: 16 normal weight (NW), 16 overweight (OW), and 16 obese (OB). A lung function test and anthropometric evaluation were performed. iT and eT were measured using a sonographic device before and after the step test.

Results

Body Mass Index (BMI) and Body Fat Percentage (BF%) were significantly higher (P<0.0001; P<0.0001, respectively) in OB group. RAW was significantly higher in the OB group (P=0.004), and GAW (P=0.004) was significantly lower in the same group. At rest, the Respiratory Rate (RR) was significantly higher in OB group (P<0.05), while iT and eT showed no significant differences. On the other hand, after the step test, eT was significantly lower (P=0.016), with the multiple linear regression model being the best predictor of post-exercise eT, including BF%/GAW and BF%/sGAW (explained variability of 15.7% and 14.6%, respectively).

Conclusion

Nutritional status can significantly impact lung function; at rest, there was a decrease in lung volumes and an increase in RR in OB subjects. In addition, there was a significant decrease in eT of OB subjects post-exercise. Finally, a significant relationship of BF%/GAW and BF%/sGAW with post-exercise eT was noted.

A Likely Pathogenic variant in the KBTBD13 Gene: A Case Series of Three Patients with Nemaline Myopathy Type 6

Background

Nemaline myopathy type 6 (NEM6) or KBTBD13-related congenital myopathy is the most prevalent type of nemaline myopathy in the Netherlands and is characterised by mild childhood-onset axial, proximal and distal muscle weakness with prominent neck flexor weakness combined with slowness of movements. The most prevalent variant in the Netherlands is the c.1222C > T p.(Arg408Cys) variant in the KBTBD13 gene, also called the Dutch founder variant.

Objective

To provide a comprehensive clinical and functional characterisation of three patients to assess the pathogenicity of a newly identified variant in the KBTBD13 gene.

Results

We present three cases (Patient 1: female, 76 years old; Patient 2: male, 63 years old; and his brother Patient 3: male, 61 years old) with a c.1222C > A p.(Arg408Ser) variant in the KBTBD13 gene. Patient 1 was also included previously in a histopathological study on NEM6. Symptoms of muscle weakness started in childhood and progressed to impaired functional abilities in adulthood. All three patients reported slowness of movements. On examination, they have mild axial, proximal and distal muscle weakness. None of the patients exhibited cardiac abnormalities. Spirometry in two patients showed a restrictive lung pattern. Muscle ultrasound showed symmetrically increased echogenicity indicating fatty replacement and fibrosis in a subset of muscles and histopathological analyses revealed nemaline rods and cores. Slower muscle relaxation kinetics with in vivo functional tests was observed. This was confirmed by in vitro functional tests showing impaired relaxation kinetics in isolated muscle fibres. We found a genealogic link between patient 1, and patient 2 and 3 nine generations earlier.

Conclusions

The c.1222C > A p.(Arg408Ser) variant in the KBTBD13 gene is a likely pathogenic variant causing NEM6.

Functional performance of patients submitted to cardiac surgery with different levels of sleep quality: an observational study

OBJECTIVE

To describe pulmonary function, muscle strength and functional performance in the different qualities of sleep and the impact of this on the number of physiotherapeutic assistances.

METHODS

This is an observational study. In the pre and post operative period, sleep behavior was evaluated using the Pittsburgh questionnaire. Patients were divided into three groups: Good Sleep Quality (GSQ), Poor Sleep Quality (PSQ) and Sleep Disordered (SDB). At this time, other tests were also performed, such as: 6-Minute Walk Test (6MWT), Sit and Stand Test (SST), gait speed test and Timed Up to Go (TUG), Medical Research Council (MRC), maximal inspiratory pressure and maximal expiratory, vital capacity and peak expiratory flow. The functional performance and lung function of each group were compared.

RESULTS

A total of 105 people, undergoing cardiac surgery and admitted to hospital were evaluated, 33 with GSQ, 41 with PSQ and 31 with SD. Patients who were in the SDB group had a lower functional performance than the other groups. 6MWT (meters) in the GSQ was 499 ± 87, versus 487 ± 91 in the PSQ and 430 ± 78 in the SD (p = 0.02). In the SST (seconds) it was 10.4 ± 1.1 in the GQS, 11.1 ± 2.3 in the PSQ and 15.4 ± 2.1 in the SD (p = 0.04). Lung function and muscle strength did not differ between groups. Regarding the refusal to perform physical therapy, the SD group was more incident, the main reason being drowsiness.

CONCLUSION

Based on the results, we found that sleep quality interferes with functional performance and physical therapy assistance during the hospital stay in patients undergoing cardiac surgery.

Prediction of nocturnal ventilation by pulmonary function testing in patients with amyotrophic lateral sclerosis

BACKGROUND

In amyotrophic lateral sclerosis (ALS) prognosis is poor due to progressive weakening of the respiratory muscles. Survival and quality of life can be improved by noninvasive ventilation (NIV), which is initially applied while sleeping. The indication for NIV is based on pulmonary function testing (PFT) and polysomnography (PSG) with capnography (tCO2). While it is desirable to predict nocturnal ventilation by waking PFT in ALS, the parameters suited for reliable predictions remain elusive.

METHODS

We retrospectively analyzed parameters derived from PFT (spirometry, body plethysmography, diffusion capacity, respiratory muscle testing) and blood gas analysis, PSG and tCO2 in 42 patients with ALS (27 men, 15 women, age 69 ± 12.1 years) and performed Spearman's correlation analysis of daytime waking parameters and nighttime sleep parameters.

RESULTS

28 patients (66.7%) showed restrictive impairment of ventilation and 15 patients (48.3%) showed insufficiency of the respiratory musculature. There was no obstructive impairment of ventilation. We did not observe any significant correlations between any single daytime PFT parameter with nocturnal pCO2. However, there were significant correlations between the ratios PIF/PEF, MEF50/MIF50, DLCO/VA as well as FEV1/FVC and nocturnal pCO2. Highly normal FEV1/FVC and Krogh-Factor (DLCOc/VA) indicated nocturnal hypercapnia. Furthermore, waking hypercapnia, concentrations of bicarbonate and base excess were each positively correlated with nocturnal hypercapnia.

CONCLUSIONS

Waking PFT is not a good predictor of nocturnal ventilation. Inspiratory parameters as well as the ratios FEV1/FVC and DLCO/VA performed best and should be included in the interpretation. Our analyses confirm the relevance of inspiratory muscle weakness in ALS. PSG and tCO2 remain the gold standard for the assessment of nocturnal ventilation.

The role of serum chloride ion in the prognosis of COPD

BACKGROUND

As exacerbations of chronic obstructive pulmonary disease (COPD) are one of the leading causes of hospitalization and are associated with significant mortality, it is particularly important to accurately assess the risk of exacerbations in COPD. Most of the current clinical biomarkers are related to inflammation and few consider how ion levels affect COPD. Chloride ion, the second most abundant serum electrolyte, has been shown to be associated with poor prognoses in several diseases, but their relationship with COPD remains unclear.

METHODS

In total, 105 patients with acute exacerbations of COPD were recruited. Data on clinical characteristics, lung function, blood count, blood biochemistry, relevant scales including the Clinical COPD Questionnaire (CCQ), BODE (BMI, airflow obstruction, dyspnea, exercise capacity) index and the St. George's Respiratory Questionnaire (SGRQ) were collected from all patients for statistical analysis.

RESULT

There were significant differences in lung function indicators and disease severity in the low chloride ion subgroup compared with the high chloride ion subgroup. On multiple logistic regression analysis, chloride ion was an independent factor affecting lung function in COPD patients (OR=0.808, 95% CI: 0.708 - 0.922, p=0.002). The sensitivity of chloride ion in predicting COPD severity was 78%, the specificity was 63%, and the area under the curve was 0.734 (p<0.001). Subgroup analysis showed that chloride ion was a stronger predictor in male and smoking patients.

CONCLUSIONS

Chloride ion was a novel prognostic biomarker for COPD, and low levels of chloride ion were independently associated with exacerbations in COPD patients.

Inspiratory muscle training impact on respiratory muscle strength, pulmonary function, and quality of life in children with chest burn: A randomized controlled trial

PURPOSE

Respiratory muscle function is compromised in children recovering from chest wall burns, which potentially leads to more impact on exercise capacity and quality of life. This study investigates the effects of an inspiratory muscle training intervention accompanied with a pulmonary rehabilitation program on respiratory muscle strength, lung function, functional capacity, and quality of life in chest burned children.

METHODS

Forty children with burns, aged from 10 to 18 years old and total body surface area of 30% to 50%, were randomly allocated to the inspiratory muscle training group (IMT- G: n = 20) or control group (CG: n = 20). They received IMT plus pulmonary rehabilitation or pulmonary rehabilitation with sham IMT, respectively for eight weeks. The outcomes were the respiratory muscle strength measured by maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP); lung functions (FEV1, FVC and FEV1/FVC ratio); functional capacity as well as Pediatric Quality of Life to measure physical and psychosocial functioning. outcome measures were assessed at before and after intervention (after eight weeks).

RESULTS

Based on the pre-intervention assessments, we found no significant difference between both groups (p > 0.05). Significant post-intervention differences were reported between both groups in MIP (P = .003), MEP (P = .017), FVC (P = .001), FEV1 (P = .007), FEV1/FVC ratio (P = .028), functional capacity (P = .003), physical domain of QoL (P = .006) and psychological domain of QoL (P = .002) in favor of the IMT group.

CONCLUSIONS

Eight weeks of inspiratory muscle training combined with pulmonary rehabilitation program improved children with chest burns' respiratory muscles strength, lung functions, functional capacity, and quality of life. Inspiratory muscle training may be employed in burn rehabilitation programs. It is a safe and effective therapy in chest burned children.

Assessment of Chronic Hypercapnic Respiratory Failure

Undiagnosed chronic hypercapnic respiratory failure may be encountered during the evaluation of sleep-related breathing disorders at the sleep clinic. This article reviews the mechanism of chronic hypercapnic respiratory failure and the systematic approach to the assessment of specific sleep disorders associated with nocturnal hypoventilation encountered in clinical practice.

Benefits of inspiratory muscle training therapy in institutionalized adult people with cerebral palsy: A double-blind randomized controlled trial

BACKGROUND

Respiratory health problems are one of the main causes of morbidity and mortality in adult people with cerebral palsy (CP). The influence of respiratory muscle training has not yet been studied in this population group. The objective of the study was to evaluate and compare the efficacy of two protocols with inspiratory muscle training (IMT), low intensity and high intensity, to improve respiratory strength and pulmonary function in adults with CP.

METHODS

The study was a controlled, randomized, double-blind trial with allocation concealment. Twenty-seven institutionalized CP patients were recruited and randomly distributed in the high-intensity training group (HIT) or low-intensity training group (LIT). Over 8 weeks, an IMT protocol was followed 5 days/week, 10 series of 1 min with 1 min rest between them. HIT trained with a load of 40% of the maximum inspiratory pressure (MIP) and LIT with 20%. Respiratory strength and pulmonary function were evaluated.

RESULTS

After IMT intervention, MIP, maximum expiratory pressure, forced expiratory volume in 1 s (FEV1) and peak expiratory flow increased in both groups; in HIT 29%, 19%, 13%, and 8%, respectively (p = 0.000, p = 0.000, p = 0.002, p = 0.001) and in LIT 17%, 7%, 3%, and 4%, respectively (p = 0.000, p = 0.000, p = 0.049, p = 0.113). All the improvements were significantly higher in HIT than in LIT.

CONCLUSION

Inspiratory muscle training improved respiratory muscle strength and pulmonary function in adults with CP. Training with a 40% MIP load improved all the evaluated parameters and was the most effective treatment for adults with CP.

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.

[Effects of gender on pulmonary rehabilitation outcomes in patients with COPD]

INTRODUCTION

COPD has become more prevalent among women, revealing a specific feminine phenotype. Women experience greater dyspnea and a more impaired quality of life. The main objective of this study was to assess the effect of gender on dyspnea during a pulmonary rehabilitation program (PRP).

METHODS

Retrospective study including COPD patients having participated in PRPs. The following data were analyzed according to gender before and after a PRP: dyspnea, quality of life, anxiety and depression, exercise capacity, muscle function (quadriceps and inspiratory muscles).

RESULTS

More than 500 patients (252 men and 252 women) were included. We did not find a significant effect of gender on the evolution of dyspnea, anxiety or depressive disorders, exercise capacity, inspiratory muscle strength, or overall quality of life score. That said, we found a possible effect on the sub-scores of the quality of life questionnaire, and regarding quadriceps strength. All criteria improved during the program in both groups.

CONCLUSIONS

During a PRP, gender does not impact the evolution of dyspnea. While women may nonetheless benefit to a greater extent in terms of quality of life sub-scores (impact, activities, symptoms) and quadriceps strength, these results still require confirmation.

Potential Diaphragm Muscle Weakness-related Dyspnea Persists 2 Years after COVID-19 and Could Be Improved by Inspiratory Muscle Training: Results of an Observational and an Interventional Clinical Trial

Rationale: Diaphragm muscle weakness might underlie persistent exertional dyspnea, despite normal lung and cardiac function in individuals who were previously hospitalized for acute coronavirus disease (COVID-19) illness. Objectives: The authors sought, first, to determine the persistence and pathophysiological nature of diaphragm muscle weakness and its association with exertional dyspnea 2 years after hospitalization for COVID-19 and, second, to investigate the impact of inspiratory muscle training (IMT) on diaphragm and inspiratory muscle weakness and exertional dyspnea in individuals with long COVID. Methods: Approximately 2 years after hospitalization for COVID-19, 30 individuals (11 women, 19 men; median age, 58 years; interquartile range [IQR] = 51-63) underwent comprehensive (invasive) respiratory muscle assessment and evaluation of dyspnea. Eighteen with persistent diaphragm muscle weakness and exertional dyspnea were randomized to 6 weeks of IMT or sham training; assessments were repeated immediately after and 6 weeks after IMT completion. The primary endpoint was change in inspiratory muscle fatiguability immediately after IMT. Measurements and Main Results: At a median of 31 months (IQR = 23-32) after hospitalization, 21 of 30 individuals reported relevant persistent exertional dyspnea. Diaphragm muscle weakness on exertion and reduced diaphragm cortical activation were potentially related to exertional dyspnea. Compared with sham control, IMT improved diaphragm and inspiratory muscle function (sniff transdiaphragmatic pressure, 83 cm H2O [IQR = 75-91] vs. 100 cm H2O [IQR = 81-113], P = 0.02), inspiratory muscle fatiguability (time to task failure, 365 s [IQR = 284-701] vs. 983 s [IQR = 551-1,494], P = 0.05), diaphragm voluntary activation index (79% [IQR = 63-92] vs. 89% [IQR = 75-94], P = 0.03), and dyspnea (Borg score, 7 [IQR = 5.5-8] vs. 6 [IQR = 4-7], P = 0.03). Improvements persisted for 6 weeks after IMT completion. Conclusions: To the best of the authors' knowledge, this study is the first to identify a potential treatment for persisting exertional dyspnea in long COVID and provide a possible pathophysiological explanation for the treatment benefit. Clinical trial registered with www.clinicaltrials.gov (NCT04854863, NCT05582642).

Neuromuscular Disorders in Pediatric Respiratory Disease

Respiratory sequelae are a frequent cause of morbidity and mortality in children with NMD. Impaired cough strength and resulting airway clearance as well as sleep disordered breathing are the two main categories of respiratory sequelae. Routine clinical evaluation and diagnostic testing by pulmonologists is an important pillar of the multidisciplinary care required for children with NMD. Regular surveillance for respiratory disease and timely implementation of treatment including pulmonary clearance techniques as well as ventilation can prevent respiratory related morbidity including hospital admissions and improve survival. Additionally, novel disease modifying therapies for some NMDs are now available which has significantly improved the clinical trajectories of patients resulting in a paradigm shift in clinical care. Pulmonologists are 'learning' the new natural history for these diseases and adjusting clinical management accordingly.

Incidence and influencing factors for respiratory sarcopenia in older adults: The first longitudinal evidence from the CHARLS

AIM

Respiratory sarcopenia (RS) has been newly defined in a position paper by four professional organizations in Japan, and it is necessary to examine its incidence and influencing factors using this new definition. So far, little work has been undertaken; we therefore conducted a longitudinal study to fill this gap.

METHODS

Our data were extracted from the China Health and Retirement Longitudinal Study. A total of 4301 older adults with complete data and without RS were chosen in 2011, of whom 3065 were followed up until 2015. The presence of low respiratory muscle strength plus low appendicular skeletal muscles mass was defined as RS based on t. A logistic regression model was used to identify the influencing factors for incident RS.

RESULTS

After an average of 4 years of follow-up, the cumulative incidence of RS was 5.2%, and it was particularly high in participants aged >80 (20.9%). Logistic regression analysis showed that being unmarried/divorced/widowed (odds ratio [OR] = 1.85, 95% confidence interval [CI] = 1.28-2.66, P = 0.001), not having dyslipidemia (OR = 0.35, 95% CI = 0.19-0.65, P = 0.001), having digestive disease (OR = 1.56, 95% CI = 1.11-2.19, P = 0.010), asthma (OR = 2.77, 95% CI = 1.55-4.94, P = 0.001), edentulism (OR = 1.73, 95% CI = 1.24-2.42, P = 0.001), low handgrip strength (OR = 2.82, 95% CI = 1.99-3.99, P < 0.001), or low 5-m gait speed (OR = 1.92, 95% CI = 1.23-3.01, P = 0.004) were associated with a greater likelihood of developing RS. After further adjustment for age and body mass index, asthma, edentulism, and low handgrip strength remained significant.

CONCLUSIONS

The identification and management of older adults with the influencing factors described above could be important in preventing RS. Geriatr Gerontol Int 2024; ••: ••-••.

Respiratory muscle strength in stroke: a case-control study

AIM

The aim of the study was to determine the respiratory muscle strength of stroke patients and compare them with healthy individuals.

METHOD

The study was conducted with 171 patients who had a stroke between 2017 and 2021 and 32 healthy controls. Respiratory muscle strength and inspiratory and expiratory mouth pressure (MIP and MEP) were measured using the portable MicroRPM device (Micro Medical, Basingstoke, UK).

RESULTS

The stroke group exhibited significantly lower values in both MIP for men (p<0.001) and women (p=0.013) and maximal expiratory pressure for men (p<0.001) and women (p=0.042), compared with the healthy control group. Notably, there was a significant difference in the MIPmen (p=0.026) and MEPmen (p=0.026) values when comparing the reference values, which were calculated based on age and sex, with those of the healthy group. The baseline values calculated according to age for stroke patients were as follows: MIPmen 31.68%, MIPwomen 63.58%, MEPmen 22.54%, and MEPwomen 42.30%.

CONCLUSION

This study highlights the significant respiratory muscle weakness experienced by stroke patients, with gender-specific differences. It highlights the importance of incorporating respiratory assessments and interventions into stroke rehabilitation protocols to improve the overall health and well-being of stroke patients.

Effects of home-based telerehabilitation-assisted inspiratory muscle training in patients with idiopathic pulmonary fibrosis: A randomized controlled trial

BACKGROUND AND OBJECTIVE

There are few studies that have used inspiratory muscle training (IMT) as an intervention for patients with isolated idiopathic pulmonary fibrosis (IPF). This study aimed to investigate and interpret the effects of home-based telerehabilitation-assisted IMT in patients with IPF.

METHODS

Twenty-eight participants with IPF took part in the study. Lung function tests, functional exercise capacity by 6-min walk distance (6MWD), dyspnoea perception by modified medical research council dyspnoea scale (mMRC), and inspiratory muscle strength by maximal inspiratory pressure (MIP) were assessed. IMT was performed twice a day, 7 days/week, for 8 weeks. The intervention group (n = 14) performed IMT at 50% of their baseline MIP while the control group (n = 14) performed IMT without applied resistance. Loading intensity was progressed by keeping the load at 4-6 on a modified Borg scale for the highest tolerable perceived respiratory effort for each patient.

RESULTS

Dyspnoea based on mMRC score (p < 0.001, η2 effect size = 0.48) significantly decreased within the intervention group compared with the control group. There were significant increases in the intervention group compared to the control group based on 6MWD (p < 0.001, η2 effect size = 0.43), MIP (p = 0.006, η2 effect size = 0.25) and MIP % predicted (p = 0.008, η2 effect size = 0.25).

CONCLUSION

The findings of this study suggest that an 8-week home-based telerehabilitation-assisted IMT intervention produced improvements in inspiratory muscle strength, leading to improvements in functional exercise capacity and dyspnoea.

Influence of an inspiratory muscle fatigue protocol on healthy youths on respiratory muscle strength, vertical jump performance and muscle oxygen saturation: a randomized controlled trial

BACKGROUND

Inspiratory muscle fatigue has been shown to have effects on limbs blood flow and physical performance. This study aimed to evaluate the influence of an inspiratory muscle fatigue protocol on respiratory muscle strength, vertical jump performance and muscle oxygen saturation in healthy youths.

METHODS

A randomized and double-blinded controlled clinical trial, was conducted. Twenty-four participants aged 18-45 years, non-smokers and engaged in sports activity at least three times a week for a minimum of one year were enrolled in this investigation. Participants were randomly assigned to three groups: Inspiratory Muscle Fatigue (IMFG), Activation, and Control. Measurements of vertical jump, diaphragmatic ultrasound, muscle oxygen saturation, and maximum inspiratory pressure were taken at two stages: before the intervention (T1) and immediately after treatment (T2).

RESULTS

The IMFG showed lower scores in muscle oxygen saturation and cardiorespiratory variables after undergoing the diaphragmatic fatigue intervention compared to the activation and control groups (p < 0.05). For the vertical jump variables, intragroup differences were found (p < 0.01), but no differences were shown between the three groups (p > 0.05).

CONCLUSIONS

Inspiratory muscle fatigue appears to negatively impact vertical jump performance, muscle oxygen saturation and inspiratory muscle strength in healthy youths.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT06271876. Date of registration 02/21/2024. https://clinicaltrials.gov/study/NCT06271876 .

Ultrasonographic Assessment of Diaphragm Function to Predict Need for Mechanical Ventilation and its Liberation in Patients with Neuromuscular Disorders: An Observational Cohort Pilot Study

BACKGROUND

Management of assisted ventilation and determining the optimal timing for discontinuation presents a significant clinical obstacle in patients affected by neuromuscular (NM) diseases. This study aimed to evaluate the efficacy of ultrasound in appraising diaphragmatic function for predicting the necessity of intubation and determining the opportune moment to discontinue mechanical ventilation (MV) in patients with NM disorders.

METHODS

The study was conducted in adult patients with NM diseases requiring inpatient care in the high-dependency neurology ward and the intensive care unit. Ultrasonographic assessment of diaphragmatic excursion (DE) and diaphragmatic thickness fraction (DTF) was conducted at the patient's bedside every 48 h for ventilated patients and every 72 h for nonventilated patients until they were weaned from the ventilator or discharged home. Qualitative data are expressed as percentages or numbers, and quantitative data are represented as mean ± standard deviation. Unpaired t-tests were employed to compare continuous variables, and χ2 tests were used for categorical variables. Contingency table analysis was used to compute relative risks in comparing the baseline DE and DTF with the sequential changes in these values.

RESULTS

In cases in which the baseline left DE measured less than 1 cm, the relative risk for the requirement of ventilation was 2.5 times higher, with a confidence interval of 0.62-0.99 (P = 0.19). Notably, a bilateral reduction in DE within the initial 48 h of admission was identified as predictive of need for intubation. When comparing ventilated and nonventilated patients, it was observed that the mean DE values for the left and right sides in ventilated patients (0.74 and 0.79) were significantly lower than those in nonventilated patients (1.3 and 1.66), with corresponding P values of 0.05 and 0.01, respectively. Furthermore, a decline in right DE by more than 50% within 72 h of admission presented a relative risk of 3.3 for the necessity of ventilation, with a confidence interval of 1.29-8.59 (P = 0.01). Duration of ventilation ranged from 2 to 45 days, with an average of 13.14 days, whereas the mean ventilator-free days recorded was 13.57. Notably, a sequential increase in bilateral DE correlated with an extended duration of ventilator-free days.

CONCLUSIONS

The presence of a baseline left DE of less than 1 cm, a consecutive decrease in DE measurements within 48 h, and a comparative reduction in right DE of more than 50% within the initial 3 days are indicators associated with the requirement for MV in patients with NM disease. Furthermore, the upward trajectory of DE in mechanically ventilated patients is linked to an increased number of days free from ventilator support, suggesting its potential to forecast earlier weaning.

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.

Cumulative Effects of Concurrent Inspiratory Muscle Training and Postural Correction Bands on Older Individuals Community Dwellers: A Randomized Study

PURPOSE

Posture correction bands (PCBs) have been proposed as aids to help chest expansion and to enhance respiratory function. However, the impact of PCBs on community-based older individuals engaged in inspiratory muscle training (IMT) at home remains unclear.

MATERIALS AND METHODS

Community-based individuals aged 65 years and older were divided into the PCB group, wearing PCBs, and the NPCB group, not wearing PCBs. The IMT regimen lasted 8 weeks, with sessions 5 times a week, including 4 sets per day and 15 repetitions per set. Training intensity was set at 50% of the maximum inspiratory pressure of each subject. To assess the effects of IMT, respiratory function, 6-minute walk test, and grip strength were measured before, during, and after the training period. Data were analyzed using repeated-measures analysis of variance, with post-hoc evaluation employing Bonferroni correction.

RESULTS

A total of 40 subjects were evenly divided into the PCB group and the NPCB group, with 20 subjects in each group. No significant difference was observed in respiratory muscle strength based on PCB use. However, during the initial 4 weeks, the PCB group exhibited a trend towards an increase in respiratory muscle strength compared to the NPCB group; this trend, however, did not prove to be statistically significant by the end of the 8-week period. Performance on the 6-minute walk test significantly improved in both groups.

CONCLUSION

The PCB group exhibited a tendency for increase in respiratory muscle strength in the first 4 weeks; however, ultimately there was no significant difference compared to the NPCB group.

CLINICAL TRIAL REGISTRATION

This study was registered with the Clinical Research Information Service, part of the World Health Organization's International Clinical Trials Registry Platform (Clinical Research Information Service No. KCT0008075).

Exercise Improves Respiratory Function, Body Fluid and Nitric Oxide in Hemodialysis Patients

Emerging evidence suggests that resistance training (RT) can mitigate respiratory muscle weakness in hemodialysis (HD) patients. However, the underlying mechanisms responsible for these beneficial effects remain unclear. The purpose of this study was to assess the impact of periodized RT on respiratory muscle strength and its relationship with handgrip strength (HGS), fat-free mass (FFM), nitric oxide (NO), and interdialytic weight gain (IWG) in HD patients. Thirty-three patients were randomly assigned to two groups: control (CTL; n=18) and RT (n=15). The RT group did not perform any additional exercise training specific to the respiratory tract. Maximal inspiratory (MIP) and expiratory (MEP) pressures, peak expiratory flow (PEF), HGS, FFM, NO, and IWG were measured before and after the intervention period. Participants in the RT group engaged in a 24-week RT program, three times per week. RT resulted in significant improvements in MIP, MEP, PEF, as well as enhancements in HGS, FFM, NO, and IWG (p<0.05). Notably, inverse correlations were observed between MIP (r=-0.37, p=0.03) and PEF (r=-0.4, p=0.02) with IWG. Thus, the amelioration of HGS and FFM coincided with a reduction in respiratory muscle weakness among HD patients. Decreased IWG and increased circulating NO are plausible mechanisms contributing to these improvements.

Deep learning-based respiratory muscle segmentation as a potential imaging biomarker for respiratory function assessment

Respiratory diseases significantly affect respiratory function, making them a considerable contributor to global mortality. The respiratory muscles play an important role in disease prognosis; as such, quantitative analysis of the respiratory muscles is crucial to assess the status of the respiratory system and the quality of life in patients. In this study, we aimed to develop an automated approach for the segmentation and classification of three types of respiratory muscles from computed tomography (CT) images using artificial intelligence. With a dataset of approximately 600,000 thoracic CT images from 3,200 individuals, we trained the model using the Attention U-Net architecture, optimized for detailed and focused segmentation. Subsequently, we calculated the volumes and densities from the muscle masks segmented by our model and performed correlation analysis with pulmonary function test (PFT) parameters. The segmentation models for muscle tissue and respiratory muscles obtained dice scores of 0.9823 and 0.9688, respectively. The classification model, achieving a generalized dice score of 0.9900, also demonstrated high accuracy in classifying thoracic region muscle types, as evidenced by its F1 scores: 0.9793 for the pectoralis muscle, 0.9975 for the erector spinae muscle, and 0.9839 for the intercostal muscle. In the correlation analysis, the volume of the respiratory muscles showed a strong correlation with PFT parameters, suggesting that respiratory muscle volume may serve as a potential novel biomarker for respiratory function. Although muscle density showed a weaker correlation with the PFT parameters, it has a potential significance in medical research.

Effects of respiratory muscle training on post-stroke rehabilitation: A systematic review and meta-analysis

BACKGROUND

Stroke often results in significant respiratory dysfunction in patients. Respiratory muscle training (RMT) has been proposed as a rehabilitative intervention to address these challenges, but its effectiveness compared to routine training remains debated. This systematic review and meta-analysis aim to evaluate the effects of RMT on exercise tolerance, muscle strength, and pulmonary function in post-stroke patients.

AIM

To systematically assess the efficacy of RMT in improving exercise tolerance, respiratory muscle strength, and pulmonary function in patients recovering from a stroke, and to evaluate whether RMT offers a significant advantage over routine training modalities in enhancing these critical health outcomes in the post-stroke population.

METHODS

Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, a comprehensive search across PubMed, Embase, Web of Science, and the Cochrane Library was conducted on October 19, 2023, without temporal restrictions. Studies were selected based on the predefined inclusion and exclusion criteria focusing on various forms of RMT, control groups, and outcome measures [including forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), maximal voluntary ventilation (MVV), peak expiratory flow (PEF), maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and 6-min walking test (6MWT)]. Only randomized controlled trials (RCTs) were included. Data extraction and quality assessment were conducted independently by two reviewers using the Cochrane Collaboration's risk of bias tool. Statistical analyses, including those using the fixed-effect and random-effects models, sensitivity analysis, and publication bias assessment, were performed using Review Manager software.

RESULTS

A total of 15 RCTs were included. Results indicated significant improvements in MIP (12.51 cmH2O increase), MEP (6.24 cmH2O increase), and various pulmonary function parameters (including FEV1, FVC, MVV, and PEF). A substantial increase in 6MWT distance (22.26 meters) was also noted. However, the heterogeneity among studies was variable, and no significant publication bias was detected.

CONCLUSION

RMT significantly enhances walking ability, respiratory muscle strength (MIP and MEP), and key pulmonary function parameters (FEV1, FVC, MVV, and PEF) in post-stroke patients. These findings support the incorporation of RMT into post-stroke rehabilitative protocols.

Exploring Balance Impairment and Determinants in Chronic Obstructive Pulmonary Disease: A Comparative Study with Healthy Subjects

Background: Many pulmonary and extrapulmonary factors may impair balance in patients with chronic obstructive pulmonary disease (COPD), but the determinants of this impairment are still debated. The primary aim was to compare both balance-related and independent variables that may affect balance with healthy subjects. The secondary aim was to investigate the potential determinants of balance in patients with COPD. Methods: This comparative study recruited 23 patients with COPD and 23 age- and comorbidity-matched healthy subjects. Participants were assessed regarding demographic and clinical data, "Postural Stability Test" (PST), "Limits of Stability Test" (LOST), "Clinical Test of Sensory Integration of Balance" (CTSIB), pulmonary function, respiratory and peripheral muscle strength, functional capacity, and cognitive function. Results: There were significant differences in all outcome measures assessing balance, pulmonary function, respiratory muscle strength, peripheral muscle strength, and functional capacity, but not cognitive function, in the COPD group compared to the healthy group (p < 0.05). The PST had a significant and strong correlation with maximal inspiratory pressure (MIP) (r = -0.630, p = 0.001) and a significant and moderate correlation with m. quadriceps strength and 6 min walk test (6MWT) distance (r = -0.472, p = 0.023; r = -0.496, p = 0.016; respectively). MIP, m. quadriceps strength, and 6MWT distance were independent predictors to explain the PST with an R2 = 0.336 (p = 0.004). Conclusions: The present study revealed that balance is impaired in adults with COPD, even if compared with age- and comorbidity-matched healthy subjects. Assessing and improving balance and its determinants, inspiratory and peripheral muscle strength, and functional capacity may be important for fall prevention and disease management in patients with COPD.

Polysomnography findings and respiratory muscle function in infants with early onset spinal muscular atrophy after gene replacement as monotherapy: A prospective study

BACKGROUND

Gene replacement therapy (onasemnogene abeparvovec) is associated with an improvement of the prognosis of children with spinal muscular atrophy, but information on long-term respiratory outcome is scarce. The aim of this study was to report the polysomnography findings and respiratory muscle function of infants with treatment-naive spinal muscular atrophy type 1 and 2 up to 24 months after onasemnogene abeparvovec monotherapy.

METHODS

A clinical and motor evaluation, respiratory muscle function testing, and polysomnography were performed repeatedly.

RESULTS

Fifteen spinal muscular atrophy patients (1 presymptomatic, 7 type 1b, 6 type 1c, and 1 type 2) were included at a median age of 8.6 months (range 3.8-12.6) and followed for 24 months. The thoracic over head circumference ratio was close to normal at baseline (median 1.00 (range 0.90-1.05)) and increased significantly over time. All polysomnography and nocturnal gas exchange parameters were within normal ranges at baseline (median apnea-hypopnea index 2.5 events/hour (range 0.4-5.3)) and follow-up. The inspiratory muscle strength was normal at baseline but tended to slightly decrease over time and the expiratory muscle strength was low at any time especially for patients with recurrent respiratory infections (median (range) at baseline in cmH2O: crying esophageal pressure 54 (30-110), crying transdiaphragmatic pressure 65 (35-107), gastric pressure during maximal cough 26 (10-130), esophageal pressure during maximal cough 61 (38-150)). Only 3 patients required noninvasive ventilation.

CONCLUSION

A continuous respiratory monitoring of spinal muscular atrophy patients during the first years of life following onasemnogene abeparvovec monotherapy seems recommended despite the normality of polysomnography parameters.

Office-based respiratory assessment in patients with generalized myasthenia gravis

Patients with myasthenia gravis (MG) can present with respiratory dysfunction, ranging from exercise intolerance to overt respiratory failure, increased fatigue, or sleep-disordered breathing. To investigate the value of multiple respiratory tests in MG, we performed clinical and respiratory assessments in patients with mild to moderate generalized disease. One-hundred and thirty-six patients completed the myasthenia gravis quality-of-life score(MG-QOL-15), myasthenia gravis impairment index(MGII), Epworth sleepiness scale(ESS), University of California-San Diego Shortness of Breath Questionnaire(UCSD-SOB), Modified Medical Research Council Dyspnea Scales(MRC-DS), supine and upright forced vital capacity(FVC), maximal inspiratory pressures(MIPs) and sniff nasal inspiratory pressures(SNIP). Seventy-three (54 %) had respiratory and/or bulbar symptoms and 45 (33 %) had baseline abnormal FVC, with no significant postural changes (p = 0.89); 55 (40.4 %) had abnormal MIPs and 50 (37 %) had abnormal SNIPs. Overall, there were low scores on respiratory and disability scales. Females had increased odds of presenting with abnormal FVC (OR 2.89, p = 0.01) and MIPs (OR 2.48, p = 0.022). There were significant correlations between MIPs, FVC and SNIPs; between MGII/MG-QOL15 and UCSD-SOB/MRC-DS and between ESS and respiratory scales in the whole group. Our data suggests that office-based respiratory measurements are a useful screening method for stable MG patients, even when presenting with minimal respiratory symptoms and no significant disability.

Acute cardiac autonomic and hemodynamic responses to resistive breathing: Effect of loading type and intensity

OBJECTIVES

This study aimed to assess the acute impact of distinct loading breathing types and intensities on cardiac autonomic function and hemodynamic responses in healthy young adults.

METHODS

A randomized, crossover trial involved 28 participants who underwent inspiratory resistive breathing, expiratory resistive breathing (ERB) and combined resistive breathing, each at 30% and 60% of maximal respiratory pressures. Data on heart rate variability (HRV) and hemodynamic parameters were collected during each trial.

RESULTS

The study revealed significant main and interaction effects for both the performed task and the intensity across all measured variables (all p < 0.001). ERB at 60% load demonstrated significantly higher HRV values in the standard deviation of normal-to-normal RR intervals, the square root of the mean squared difference of successive normal-to-normal RR intervals and high-frequency power, as well as significantly lower values in heart rate, stroke volume, stroke volume index, cardiac output, cardiac index, end-diastolic volume and end-diastolic volume index, compared to other loaded protocols (all p < 0.001).

CONCLUSION

These findings highlight the acute effect of type-specific and load-dependent resistive breathing on cardiac autonomic and hemodynamic functions, where ERB at 60% intensity showed the most significant cardiovagal modulation while causing the least hemodynamic alterations.

Association between expiratory mouth pressure and abdominal muscle activity in healthy young males

PURPOSE

To clarify the association between forced expiration and the abdominal muscles by assessing the relationship between expiratory mouth pressure and abdominal muscle activity in healthy young males.

METHODS

Twenty-five males underwent forced expiration at 20, 30, 50, 75, and 100% of the maximal expiratory mouth pressure. Mouth pressure was measured using a bridge-type transducer connected to a mouth pressure meter. Abdominal crunch, twist crunch, and abdominal hollowing at maximal voluntary contraction were also performed. During forced expiration and abdominal exercises, the activity of the rectus abdominis (RA), oblique externus abdominis/oblique internus abdominis (OE/OI), and OI/transversus abdominis (OI/TrA) was measured using surface electromyography.

RESULTS

The determination coefficient (r2) for the linear relationship between mouth pressure and abdominal muscle activity was 0.86 ± 0.15 for the RA, 0.93 ± 0.06 for the OE/OI, and 0.90 ± 0.14 for the OE/OI. The slope of the linear relationship with r2 ≥ 0.50 showed no significant difference between the RA (0.22 ± 0.27) and the OE/OI (0.27 ± 0.21). However, it was significantly greater in the OI/TrA (1.78 ± 1.41) than in the RA and OE/OI. The OE/OI activity was significantly lower in the maximal forced expiration than in twist crunch, and the OI/TrA activity was not significantly greater in the maximal forced expiration than in twist crunch.

CONCLUSION

All abdominal muscles contribute to forced expiration with a greater contribution of the OI and TrA than the RA and OE. Furthermore, the contribution of the TrA would be greater than that of the OI.

Relationship between pulmonary, cough, and swallowing functions in individuals with amyotrophic lateral sclerosis

INTRODUCTION/AIMS

Evaluations of pulmonary, cough, and swallow function are frequently performed to assess disease progression in amyotrophic lateral sclerosis (ALS), yet the relationship between these functions remains unknown. We therefore aimed to determine relationships between these measures in individuals with ALS.

METHODS

One hundred individuals with ALS underwent standardized tests: forced vital capacity (FVC), maximum expiratory/inspiratory pressure (MEP, MIP), voluntary cough peak expiratory flow (PEF), and videofluoroscopic swallow evaluation (VF). Duplicate raters completed independent, blinded ratings using the Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) scale. Descriptives, Spearman's Rho correlations, Kruskal-Wallis analyses, and Pearson's chi-squared tests were completed.

RESULTS

Mean and standard deviation across pulmonary and cough measures were FVC: 74.2% predicted (± 22.6), MEP: 91.6 cmH2O (± 46.4), MIP cmH2O: 61.1 (± 28.9), voluntary PEF: 352.7 L/min (± 141.6). DIGEST grades included: 0 (normal swallowing): 31%, 1 (mild dysphagia): 48%, 2 (moderate dysphagia): 10%, 3 (severe dysphagia): 10%, and 4 (life-threatening dysphagia): 1%. Positive correlations were observed: MEP-MIP: r = .76, MIP-PEF: r = .68, MEP-PEF: r = .61, MIP-FVC: r = .60, PEF-FVC: r = .49, and MEP-FVC: r = .46, p < .0001. MEP (p = .009) and PEF (p = .04) differed across DIGEST safety grades. Post hoc analyses revealed significant between group differences in MEP and PEF across DIGEST safety grades 0 versus 1 and grades 0 versus 3, (p < .05).

DISCUSSION

In this cohort of individuals with ALS, pulmonary function, and voluntary cough were associated. Expiratory metrics (MEP, PEF) were diminished in individuals with unsafe swallowing, increasing their risk for effectively defending the airway.

Expiratory Threshold Loading and Attentional Performance

INTRODUCTION: While there are numerous factors that may affect pilot attentional performance, we hypothesize that an increased expiratory work of breathing experienced by fighter pilots may impose a "distraction stimulus" by creating an increased expiratory effort sensation. Therefore, the purpose of this study was to determine the extent to which increasing expiratory pressure time product or expiratory effort sensation impacts attentional performance.METHODS: Data was collected on 10 healthy participants (age: 29 ± 6 yr). Participants completed six repetitions of a modified Masked Conjunctive Continuous Performance Task protocol while breathing against four different expiratory threshold loads. Repeated measures analysis of variances and generalized additive mixed effects models were used to investigate the effects of expiratory threshold load conditions on expiratory pressure time product, expiratory effort sensation, and the influence of altered end tidal gases on Masked Conjunctive Continuous Performance Task scores.RESULTS: The overall median hit reaction times were significantly longer as the expiratory threshold loads increased. Specific shape-conjunctive and non-conjunctive median hit reaction times were longer with increased expiratory effort sensation. Additionally, increased expiratory effort sensation did not significantly change commission error rates, but did significantly increase omission error rates.DISCUSSION: The findings of our work suggest that both progressively greater expiratory threshold loads during spontaneous breathing and expiratory effort sensation may impair subjects' attentional performance due to longer reaction times and increased stimuli recognition error rates.Kelley EF, Cross TJ, Johnson BD. Expiratory threshold loading and attentional performance. Aerosp Med Hum Perform. 2024; 95(7):367-374.

Hypercapnia is not excluded by normoxia in neuromuscular disease patients: implications for oximetry

Background

Pulse oximetry is widely used in the assessment of chronic respiratory failure in neuromuscular disease (NMD) patients. Chronic respiratory failure is the major cause of morbidity and mortality, necessitating early diagnosis and intervention. Guidelines suggest that an arterial blood gas (ABG) measurement is indicated if oxygen saturation (S pO2 ) is ≤94% in the absence of lung disease. However, hypercapnia with normoxia (S pO2 ≥95%) has been observed on ABGs of patients with NMD, in particular those with motor neurone disease.

Methods

A single-centre retrospective audit of room-air ABGs in stable hypercapnic chronic respiratory failure patients from 1990 to 2020 was performed. Patients with parenchymal lung disease were excluded. Patients were grouped into three main categories: non-NMD, other NMD and motor neurone disease.

Findings

297 ABGs with hypercapnia from 180 patients with extrinsic restrictive lung disease were analysed. No patients with non-NMD, 54% of patients with other NMD and 36% of motor neurone disease patients demonstrated hypercapnia with normoxia (Chi-squared 61.33; p<0.001). The potential mechanism is proposed to be a difference in calculated respiratory quotient. If the alveolar-arterial gradient is assumed to be normal, the calculated respiratory quotient was significantly higher in motor neurone disease patients and other NMD patients compared with non-NMD patients (estimated marginal mean 0.99, 95% CI 0.94-1.03; 0.86 0.76-0.96; 0.73, 0.63-0.83, respectively; p<0.001) by mixed-model analysis.

Interpretation

Hypercapnia is not excluded with normal oximetry in NMD patients and may be due to an elevated respiratory quotient. This has implications in the diagnosis and monitoring of respiratory insufficiency in NMD patients with oximetry alone.

Is There a Direct Effect Between the Plication of the Myoaponeurotic Layer and the Force of Inspiratory and Expiratory Muscles After Abdominoplasty?

OBJECTIVE

Abdominoplasty may generate an increase in the intra-abdominal pressure (IAP) and consequently an alteration in the pulmonary ventilation. The purpose of this study was to evaluate the potential alterations in the maximal static inspiratory pressure (MIP) and maximal static expiratory pressure (MEP) after abdominoplasty.

METHODS

Thirty-three female patients, aged between 18 and 60, with type III/B Nahas abdominal deformity that underwent abdominoplasty with plication of the anterior rectus and external oblique aponeurosis were selected. The MIP and MEP were measured using a mouthpiece. This is a simple way to indirectly gauge inspiratory and expiratory muscle strength. Measurements were performed before surgery and on the 2nd, 7th, 15th, and 180th postoperative day. In addition, IAP was measured before abdominoplasty and after the placement of compression garment. The MIP and MEP were compared using analysis of variance, followed by the Bonferroni multiple comparison test pairing the different points in time. Paired Student's t test was used for comparing IAP measurements. Pearson's correlation test was used to compare MIP and MEP variations with IAP variation. Results were considered statistically significant when P ≤ 0.05.

RESULTS

A decrease was observed in MEP on the 2nd day, with a return close to normal values on the 15th day. In opposition MIP had a surprisingly increase on the 15th postoperative day (129 cmH2O), normalizing 180 days after the operation. A leap in IAP values was revealed at the end of the surgical procedure. It was not possible to establish a positive correlation between the increase of IAP and the alterations of MIP and MEP.

CONCLUSIONS

There is a decrease in maximum expiratory pressure on the very early postoperative day (2nd postoperative day) and an increase in maximum inspiratory pressure on the 15th postoperative day in patients who underwent abdominoplasty. There was no correlation between the IAP and maximum respiratory pressure variations, both inspiratory and expiratory.

Differences of ventilatory muscle recruitment and work of breathing in COPD and interstitial lung disease during exercise: a comprehensive evaluation

Introduction

COPD and interstitial lung disease (ILD) are significant chronic respiratory disorders, impacting quality of life. Respiratory muscle roles and differences remain not entirely clear. The objective of the present study was to evaluate the degree of recruitment of the respiratory muscles and the work of breathing in COPD and ILD during exercise.

Methods

We compared the sensory-mechanical relationships in COPD, ILD and healthy controls (n=20 each). They performed pulmonary function, noninvasive and invasive respiratory muscle strength, surface electromyography and work-of-breathing assessments.

Results

COPD and ILD did not show lower static muscle strength compared to controls, but did show poor performance in the exercise test with increased transdiaphragmatic pressure (P di). In ILD, there was a higher increase in oesophageal pressure and a lower gastric pressure (P ga) on inspiration; in COPD, there was a significant increase in P ga on inspiration. In ILD, there is greater recruitment of accessory inspiratory muscles, whereas in COPD, there is marked use of both inspiratory and expiratory muscles. The neuromechanical inefficiency (increased neural respiratory drive without the corresponding tidal volume) was found in both diseases. In COPD, there is a considerable increase in elastic work to overcome intrinsic positive end-expiratory pressure (PEEPi) and expiratory work of breathing, whereas in ILD, non-PEEPi elastic work of breathing is the highest part of the total work of breathing.

Conclusions

Early and increased activity of the respiratory muscles and work-of-breathing components significantly contribute to dyspnoea, exercise intolerance and neuromechanical inefficiency of ventilation in COPD and ILD. The mechanisms of P di generation were different between diseases.

Diaphragm and Lung Transplantation

Mutual interactions between the diaphragm and lung transplantation (LTx) are known to exist. Before LTx, many factors can exert notable impact on the diaphragmatic function, such as the underlying respiratory disease, the comorbidities, and the chronic treatments of the patient. In the post-LTx setting, even the surgical procedure itself can cause a stressful trauma to the diaphragm, potentially leading to morphological and functional alterations. Conversely, the diaphragm can significantly influence various aspects of the LTx process, ranging from graft-to-chest cavity size matching to the long-term postoperative respiratory performance of the recipient. Despite this, there are still no standard criteria for evaluating, defining, and managing diaphragmatic dysfunction in the context of LTx to date. This deficiency hampers the accurate assessment of those factors which affect the diaphragm and its reciprocal influence on LTx outcomes. The objective of this narrative review is to delve into the complex role the diaphragm plays in the different stages of LTx and into the modifications of this muscle following surgery.

Investigation of Inspiratory Muscle Training Efficiency Before Bronchoscopic Lung Volume Reduction: A Randomized Controlled Trial

INTRODUCTION

Pulmonary rehabilitation (PR) is recommended prior to bronchoscopic lung volume reduction (BLVR) procedures to optimize patient outcomes. However, there's a lack of clear guidance on PR content. The aim of our study is to examine the effect of adding inspiratory muscle training (IMT) to standard PR before BLVR on exercise capacity, dyspnea, fatigue level and quality of life.

METHODS

Sixty-four patients were randomly assigned to either the PR Group (PRGr) or the PR with IMT group (IMTGr). Both groups underwent an 8-week standard PR program, including breathing exercises, muscle strengthening, and walking. Additionally, IMTGr received IMT sessions. Outcome measures comprised six-minute walking distance (6MWD), maximal inspiratory and expiratory pressures (MIP, MEP), peripheral muscle strength, modified Medical Research Council dyspnea score, fatigue symptom scale, spirometric parameters, Saint George Quality of Life Questionnaire (SGRQ), International Physical Activity Questionnaire Short Form (IPAQ-SF), and Hospital Anxiety and Depression Scale.

RESULTS

Our study found no significant difference in exercise capacity improvement between IMTGr and PRGr. However, IMTGr showed significant improvement in MIP compared to PRGr. Both groups experienced improvements in dyspnea, fatigue, and depression scores, as well as enhancements in 6MWD, MEP, peripheral muscle strength, IPAQ-SF and SGRQ scores.

CONCLUSION

Adding IMT to PR did not show a significant difference between groups among BLVR-eligible patients. However, improved respiratory muscle strength may have positive clinical implications. Further research is needed to explore short and long-term effects.

Breathing Motion Pattern in Cyclists: Role of Inferior against Superior Thorax Compartment

The thoracoabdominal breathing motion pattern is being considered in sports training because of its contribution, along with other physiological adaptations, to overall performance. We examined whether and how experience with cycling training modifies the thoracoabdominal motion patterns. We utilized optoelectronic plethysmography to monitor ten trained male cyclists and compared them to ten physically active male participants performing breathing maneuvers. Cyclists then participated in a self-paced time trial to explore the similarity between that observed during resting breathing. From the 3D coordinates of 32 markers positioned on each participant's trunk, we calculated the percentage of contribution of the superior thorax, inferior thorax, and abdomen and the correlation coefficient among these compartments. During the rest maneuvers, the cyclists showed a thoracoabdominal motion pattern characterized by an increased role of the inferior thorax relative to the superior thorax (26.69±5.88%, 34.93±5.03%; p=0.002, respectively), in contrast to the control group (26.69±5.88%; 25.71±6.04%, p=0.4, respectively). In addition, the inferior thorax showed higher coordination in phase with the abdomen. Furthermore, the results of the time trial test underscored the same pattern found in cyclists breathing at rest, suggesting that the development of a permanent modification in respiratory mechanics may be associated with cycling practice.

Cardiorespiratory Performance, Physical Activity, and Depression in Thai Older Adults with Sarcopenia and No Sarcopenia: A Matched Case-Control Study

BACKGROUND

Older adults have a high risk for musculoskeletal, cardiorespiratory, and mental health problems. We compared respiratory muscle strength, cardiovascular endurance, physical activity (PA), and depression between older adults with and without sarcopenia.

METHODS

This matched case-control study included 200 Thai older adults (100 participants with and without sarcopenia). According to the Asian Working Group for Sarcopenia 2019, participants completed a handgrip dynamometer, a 6 m walk test, and bioimpedance analysis for sarcopenia screening. Individuals were required to evaluate their cardiovascular endurance and respiratory muscle strength and complete a set of questionnaires (i.e., depression and PA). Participants with and without sarcopenia were compared using a t-test, and ANOVA was used for subgroup analysis.

RESULTS

Participants with sarcopenia had significantly lower inspiratory muscle strength (p < 0.001), functional capacity (p = 0.032), PA (p < 0.001), and higher depression scores (p < 0.001) than those without sarcopenia. Respiratory muscle strength and PA were significantly reduced in those with severe sarcopenia, followed by those with sarcopenia, possible sarcopenia, and no sarcopenia. Older adults with severe sarcopenia had higher depression scores than those with sarcopenia, possible sarcopenia, or no sarcopenia.

CONCLUSIONS

Older adults with sarcopenia may exhibit lower cardiorespiratory performance, less PA, and higher depression than those without sarcopenia.

Analyzing key elements of breathing patterns, deriving remaining variables, and identifying cutoff values in individuals with chronic respiratory disease and healthy subjects

BACKGROUND

Pulmonary physiology encompasses intricate breathing patterns (BPs), characterized by breathing frequency (Bf), volumes, and flows. The complexities intensify in the presence of interstitial lung disease (ILD) and chronic obstructive pulmonary disease (COPD), especially during exercise. This study seeks to identify pivotal factors driving changes among these variables and establish cutoff values, comparing their efficacy in differentiating BPs to traditional methods, specifically a breathing reserve (BR) of 30% and a Bf of 50 bpm.

METHODS

Screening 267 subjects revealed 23 with ILD, 126 with COPD, 33 healthy individuals, and the exclusion of 85 subjects. Lung function tests and ramp-pattern cardiopulmonary exercise testing (CPET) were conducted, identifying crucial BP elements. Changes were compared between groups at peak exercise. The area under the receiver operating characteristic curve (AUC) analysis determined cutoff values.

RESULTS

Inspiratory time (TI) remained constant at peak exercise for all subjects (two-group comparisons, all p=NS). Given known differences in expiratory time (TE) and tidal volume (VT) among ILD, COPD, and healthy states, constant TI could infer patterns for Bf, total breathing cycle time (TTOT=60/Bf), I:E ratio, inspiratory duty cycle (IDC, TI/TTOT), rapid shallow breathing index (Bf/VT), tidal inspiratory and expiratory flows (VT/TI and VT/TE), and minute ventilation (V̇E=Bf×VT) across conditions. These inferences aligned with measurements, with potential type II errors causing inconsistencies. RSBI of 23 bpm/L and VT/TI of 104 L/min may differentiate ILD from control, while V̇E of 54 L/min, BR of 30%, and VT/TE of 108 may differentiate COPD from control. BR of 21%, TE of 0.99 s, and IDC of .45 may differentiate ILD from COPD. The algorithm outperformed traditional methods (AUC 0.84-0.91 versus 0.59-0.90).

CONCLUSION

The quasi-fixed TI, in conjunction with TE and VT, proves effective in inferring time-related variables of BPs. The findings have the potential to significantly enhance medical education in interpreting cardiopulmonary exercise testing. Moreover, the study introduces a novel algorithm for distinguishing BPs among individuals with ILD, COPD, and those who are healthy.

Neuromuscular Emergencies

OBJECTIVE

This article aims to familiarize the reader with the clinical approach, diagnostic considerations, and treatment strategies for patients presenting with abrupt-onset or acutely worsening weakness due to neuromuscular disorders.

LATEST DEVELOPMENTS

Neuromuscular weakness is often the result of an inflammatory process. In recent years, there has been growing recognition of pathologic antibodies that cause neuromuscular injury. This has allowed clinicians to make a more accurate diagnosis. Additionally, neuromuscular junction disorders and myopathies are increasingly identified as the adverse effects of novel anticancer therapies, namely immune checkpoint inhibitors. More data are being incorporated into frameworks for neuroprognostication after neuromuscular emergencies, especially for commonly encountered disorders such as Guillain-Barré syndrome.

ESSENTIAL POINTS

Care of patients with neuromuscular emergencies requires prompt attention to respiratory status. Once supportive measures are in place to protect the airway and facilitate effective ventilation, diagnostic considerations should hinge on appropriate neurologic localization. Aggressive immunosuppression is often required for immune-mediated neuromuscular disorders, and clinicians must be thoughtful in selecting a strategy that best aligns with each patient's risk factors and comorbidities.

Acute and Late Pulmonary Effects After Radiation Therapy in Childhood Cancer Survivors: A PENTEC Comprehensive Review

OBJECTIVES

The Pediatric Normal Tissue Effects in the Clinic (PENTEC) pulmonary task force reviewed dosimetric and clinical factors associated with radiation therapy (RT)-associated pulmonary toxicity in children.

METHODS

Comprehensive search of PubMed (1965-2020) was conducted to assess available evidence and predictive models of RT-induced lung injury in pediatric cancer patients (<21 years old). Lung dose for radiation pneumonitis (RP) was obtained from dose-volume histogram (DVH) data. RP grade was obtained from standard criteria. Clinical pulmonary outcomes were evaluated using pulmonary function tests (PFTs), clinical assessment, and questionnaires.

RESULTS

More than 2,400 abstracts were identified; 460 articles had detailed treatment and toxicity data; and 11 articles with both detailed DVH and toxicity data were formally reviewed. Pooled cohorts treated during 1999 to 2016 included 277 and 507 patients age 0.04 to 22.7 years who were evaluable for acute and late RP analysis, respectively. After partial lung RT, there were 0.4% acute and 2.8% late grade 2, 0.4% acute and 0.8% late grade 3, and no grade 4 to 5 RP. RP risk after partial thoracic RT with mean lung dose (MLD) <14 Gy and total lung V20Gy <30% is low. Clinical and self-reported pulmonary outcomes data included 8,628 patients treated during 1970 to 2013, age 0 to 21.9 years. At a median 2.9- to 21.9-year follow-up, patients were often asymptomatic; abnormal PFTs were common and severity correlated with lung dose. At ≥10-year follow-up, multi-institutional studies suggested associations between total or ipsilateral lung doses >10 Gy and pulmonary complications and deaths. After whole lung irradiation (WLI), pulmonary toxicity is higher; no dose response relationship was identified. Bleomycin and other chemotherapeutics at current dose regimens do not contribute substantially to adverse pulmonary outcomes after partial lung irradiation but increase risk with WLI.

CONCLUSIONS

After partial lung RT, acute pulmonary toxicity is uncommon; grade 2 to 3 RP incidences are <1%. Late toxicities, including subclinical/asymptomatic impaired pulmonary function, are more common (<4%). Incidence and severity appear to increase over time. Upon review of available literature, there appears to be low risk of pulmonary complications in children with MLD < 14 Gy and V20Gy <30% using standard fractionated RT to partial lung volumes. A lack of robust data limit guidance on lung dose/volume constraints, highlighting the need for additional work to define factors associated with RT-induced lung injury.

Review of Pulmonary Manifestations in Antisynthetase Syndrome

Antisynthetase syndrome (ASyS) is now a widely recognized entity within the spectrum of idiopathic inflammatory myopathies. Initially described in patients with a triad of myositis, arthritis, and interstitial lung disease (ILD), its presentation can be diverse. Additional common symptoms experienced by patients with ASyS include Raynaud's phenomenon, mechanic's hand, and fever. Although there is a significant overlap with polymyositis and dermatomyositis, the key distinction lies in the presence of antisynthetase antibodies (ASAs). Up to 10 ASAs have been identified to correlate with a presentation of ASyS, each having manifestations that may slightly differ from others. Despite the proposal of three classification criteria to aid diagnosis, the heterogeneous nature of patient presentations poses challenges. ILD confers a significant burden in patients with ASyS, sometimes manifesting in isolation. Notably, ILD is also often the initial presentation of ASyS, requiring pulmonologists to remain vigilant for an accurate diagnosis. This article will comprehensively review the various aspects of ASyS, including disease presentation, diagnosis, management, and clinical course, with a primary focus on its pulmonary manifestations.

Lung Diseases and Rare Disorders: Is It a Lysosomal Storage Disease? Differential Diagnosis, Pathogenetic Mechanisms and Management

Pulmonologists may be involved in managing pulmonary diseases in children with complex clinical pictures without a diagnosis. Moreover, they are routinely involved in the multidisciplinary care of children with rare diseases, at baseline and during follow-up, for lung function monitoring. Lysosomal storage diseases (LSDs) are a group of genetic diseases characterised by a specific lysosomal enzyme deficiency. Despite varying pathogen and organ involvement, they are linked by the pathological accumulation of exceeding substrates, leading to cellular toxicity and subsequent organ damage. Less severe forms of LSDs can manifest during childhood or later in life, sometimes being underdiagnosed. Respiratory impairment may stem from different pathogenetic mechanisms, depending on substrate storage in bones, with skeletal deformity and restrictive pattern, in bronchi, with obstructive pattern, in lung interstitium, with altered alveolar gas exchange, and in muscles, with hypotonia. This narrative review aims to outline different pulmonary clinical findings and a diagnostic approach based on key elements for differential diagnosis in some treatable LSDs like Gaucher disease, Acid Sphingomyelinase deficiency, Pompe disease and Mucopolysaccharidosis. Alongside their respiratory clinical aspects, which might overlap, we will describe radiological findings, lung functional patterns and associated symptoms to guide pediatric pulmonologists in differential diagnosis. The second part of the paper will address follow-up and management specifics. Recent evidence suggests that new therapeutic strategies play a substantial role in preventing lung involvement in early-treated patients and enhancing lung function and radiological signs in others. Timely diagnosis, driven by clinical suspicion and diagnostic workup, can help in treating LSDs effectively.

Respiratory muscle strength can improve the prognostic assessment in COPD

Impaired lung function, respiratory muscle weakness and exercise intolerance are present in COPD and contribute to poor prognosis. However, the contribution of the combination of these manifestations to define prognosis in COPD is still unknown. This study aimed to define cut-off points for both inspiratory and expiratory muscle strength (MIP and MEP, respectively) for mortality prediction over 42-months in patients with COPD, and to investigate its combination with other noninvasive established prognostic measures (FEV1, V̇O2peak and 6MWD) to improve risk identification. Patients with COPD performed pulmonary function, respiratory muscle strength, six-minute walk and cardiopulmonary exercise tests, and were followed over 42 months to analyze all-cause mortality. A total of 79 patients were included. The sample was mostly (91.1%) comprised of severe (n = 37) and very severe (n = 34) COPD, and 43 (54%) patients died during the follow-up period. Cut-points of ≤ 55 and ≤ 80 cmH2O for MIP and MEP, respectively, were associated with increased risk of death (log-rank p = 0.0001 for both MIP and MEP) in 42 months. Furthermore, MIP and MEP substantially improved the mortality risk assessment when combined with FEV1 (log-ranks p = 0.006 for MIP and p < 0.001 for MEP), V̇O2peak (log-rank: p < 0.001 for both MIP and MEP) and 6MWD (log-ranks: p = 0.005 for MIP; p = 0.015 for MEP). Thus, patients severely affected by COPD presenting MIP ≤ 55 and/or MEP ≤ 80 cmH2O are at increased risk of mortality. Furthermore, MIP and MEP substantially improve the mortality risk assessment when combined with FEV1, V̇O2peak and 6MWD in patients with COPD.

Chest Dynamic MRI as Early Biomarker of Respiratory Impairment in Amyotrophic Lateral Sclerosis Patients: A Pilot Study

Background: Amyotrophic lateral sclerosis (ALS) is a neuromuscular progressive disorder characterized by limb and bulbar muscle wasting and weakness. A total of 30% of patients present a bulbar onset, while 70% have a spinal outbreak. Respiratory involvement represents one of the worst prognostic factors, and its early identification is fundamental for the early starting of non-invasive ventilation and for the stratification of patients. Due to the lack of biomarkers of early respiratory impairment, we aimed to evaluate the role of chest dynamic MRI in ALS patients. Methods: We enrolled 15 ALS patients and 11 healthy controls. We assessed the revised ALS functional rating scale, spirometry, and chest dynamic MRI. Data were analyzed by using the Mann-Whitney U test and Cox regression analysis. Results: We observed a statistically significant difference in both respiratory parameters and pulmonary measurements at MRI between ALS patients and healthy controls. Moreover, we found a close relationship between pulmonary measurements at MRI and respiratory parameters, which was statistically significant after multivariate analysis. A sub-group analysis including ALS patients without respiratory symptoms and with normal spirometry values revealed the superiority of chest dynamic MRI measurements in detecting signs of early respiratory impairment. Conclusions: Our data suggest the usefulness of chest dynamic MRI, a fast and economically affordable examination, in the evaluation of early respiratory impairment in ALS patients.

Diaphragm thickness and mobility elicited by two different modalities of inspiratory muscle loading in heart failure participants: A randomized crossover study

OBJECTIVES

To analyze diaphragmatic thickness, at end-inspiration and end-expiration, diaphragmatic thickening index and mobility via US under two different modalities of inspiratory muscle loading, in two different modalities of inspiratory muscle loading and different load intensities at full-vital capacity maneuvers and the relationship between diaphragmatic thickness with pulmonary function tests in participants with HF.

METHODS

This randomized crossover trial, enrolled with 17 HF subjects, evaluated diaphragm thickness (Tdi, mm), fractional thickness (TFdi, %), and mobility (mm) US during low and high intensities (30% and 60% of maximal inspiratory pressure-MIP) with two modalities of inspiratory muscle loading mechanical threshold loading (MTL) and tapered flow-resistive loading (TFRL).

RESULTS

Both MTL and TFRL produced a increase in Tdi, but only with high intensity loading compared to baseline-2.21 (0.26) vs. 2.68 (0.33) and 2.73 (0.44) mm; p = .01. TFdi was greater than baseline under all conditions, except during low intensity of TFRL. Diaphragm mobility was greater than baseline under all conditions, and high intensity of TFRL elicited greater mobility compared to all other conditions. Additionally, baseline Tdi was moderately correlated with pulmonary function tests.

CONCLUSIONS

MTL and TFRL modalities elicit similar increases in diaphragm thickness at loads, but only during high intensity loading it was greater than baseline. Diaphragm mobility was significantly greater than baseline under both loads and devices, and at high intensity compared to low intensity, although TFRL produced greater mobility compared to modalities of inspiratory muscle loading. There is an association between diaphragm thickness and pulmonary function tests.