Relationship Between Diaphragm Thickness, Thickening Fraction, Dome Excursion, and Respiratory Pressures in Healthy Subjects: An Ultrasound Study.

PURPOSE: Diaphragm ultrasonography is used to identify causes of diaphragm dysfunction. However, its correlation with pulmonary function tests, including maximal inspiratory (MIP) and expiratory pressures (MEP), remains unclear. This study investigated this relationship by measuring diaphragm thickness, thickening fraction (TF), and excursion (DE) using ultrasonography, and their relationship to MIP and MEP. It also examined the influence of age, sex, height, and BMI on these measures. METHODS: We recruited healthy Japanese volunteers and conducted pulmonary function tests and diaphragm ultrasonography in a seated position. Diaphragm ultrasonography was performed during quiet breathing (QB) and deep breathing (DB) to measure the diaphragm thickness, TF, and DE. A multivariate analysis was conducted, adjusting for age, sex, height, and BMI. RESULTS: Between March 2022 and January 2023, 109 individuals (56 males) were included from three facilities. The mean (standard deviation) MIP and MEP [cmH2O] were 72.2 (24.6) and 96.9 (35.8), respectively. Thickness [mm] at the end of expiration was 1.7 (0.4), TF [%] was 50.0 (25.9) during QB and 110.7 (44.3) during DB, and DE [cm] was 1.7 (0.6) during QB and 4.4 (1.4) during DB. Multivariate analysis revealed that only DE (DB) had a statistically significant relationship with MIP and MEP (p = 0.021, p = 0.008). Sex, age, and BMI had a statistically significant influence on relationships between DE (DB) and MIP (p = 0.008, 0.048, and < 0.001, respectively). CONCLUSION: In healthy adults, DE (DB) has a relationship with MIP and MEP. Sex, age, and BMI, but not height, are influencing factors on this relationship.

Association of Hoover's Sign with Maximal Expiratory-to-Inspiratory Pressure Ratio in Patients with COPD.

Purpose: In chronic obstructive pulmonary disease (COPD) some patients develop paradoxical inspiratory rib motion, which is termed Hoover's sign. Our objective was to determine whether Hoover's sign is associated with a difference in the maximal expiratory pressure (MEP), the maximal inspiratory pressure (MIP), the MEP/MIP ratio, and other features on pulmonary function tests (PFTs). Methods: This observational prospective single-center cohort study enrolled patients with an established diagnosis of COPD with Global initiative for chronic Obstructive Lung Disease (GOLD) stage 3 (severe) and 4 (very severe) based on PFTs. Respiratory pressure measurements were also collected. Patients were examined for the presence or absence of Hoover's sign on physical examination by 2 internal medicine resident physicians trained in examining for Hoover's sign by a pulmonologist. Results: A total of 71 patients were examined for the presence of Hoover's sign. Hoover's sign was present in 49.3% of patients. Observer agreement (k statistic) was 0.8 for Hoover's sign. Median MEP/MIP was significantly greater in patients with Hoover's sign than those without Hoover's sign (1.88 versus 1.16, p<0.001). Patients with Hoover's sign also had a significantly lower MIP (39.0 versus 58.0, p<0.001) and higher residual volume (RV) to total lung capacity (TLC) ratio indicating a higher degree of air trapping (65 versus 59.5, p<0.014). Conclusion: The presence of Hoover's sign in patients with COPD is associated with a higher MEP/MIP ratio. This suggests respiratory pressure measurements can predict diaphragm dysfunction in patients with GOLD stage 3 and 4 COPD. Patients with Hoover's sign were also found to have a lower MIP and more air trapping.

Comparison of international and Japanese predictive equations for maximal respiratory mouth pressures.

Respiratory muscle weakness has attracted attention because sarcopenia and respiratory muscle dysfunction may play a key role in the development of respiratory failure. To evaluate respiratory muscle strength appropriately, individual factors such as sex, age, body size, and ethnicity should be considered. This study aimed to compare equations available in Japan and other countries for predicting respiratory muscle strength. We tested 21 equations for maximal inspiratory pressure (MIP) and 17 for maximal expiratory pressure (MEP) for each sex (76 equations in total) in 159 normal, healthy subjects. We observed wide variations in the overall agreement among the MIP and MEP equations. Some equations showed a proper normal distribution, with median values of almost 100%, and the Japanese equations released in 1997 generally showed the best distributions of both %MIP and %MEP. We can conclude that it is better to use Japanese equations when evaluating respiratory muscle strength in Japanese subjects.

Sarcopenia is not associated with inspiratory muscle strength but with expiratory muscle strength among older adults requiring long-term care/support.

BACKGROUND: Recently, the concept of respiratory sarcopenia has been advocated, but evidence is lacking regarding which respiratory parameters are appropriate indicators. Therefore, we investigated the association between sarcopenia, respiratory function, and respiratory muscle strength to identify the most appropriate parameters for respiratory sarcopenia. METHODS: We included 124 older adults (67 men, 57 women; average age 77.2 ± 8.3 years) requiring long-term care/support who underwent Day Care for rehabilitation. Handgrip strength, usual gait speed, and skeletal muscle mass were measured using bioelectrical impedance analysis. Participants were then diagnosed with sarcopenia using the algorithm of the Asian Working Group for Sarcopenia 2019. Parameters of respiratory function (forced vital capacity, forced expiratory volume in one second [FEV1.0], FEV1.0%, and peak expiratory flow rate) and respiratory muscle strength (maximal expiratory pressure [MEP] and maximal inspiratory pressure) were also measured according to American Thoracic Society guidelines. Respiratory parameters significantly related to sarcopenia were identified using binomial logistic regression and receiver operating characteristic analyses. RESULTS: Seventy-seven participants were classified as having sarcopenia. Binomial logistic regression analysis showed that MEP was the only respiratory parameter significantly associated with sarcopenia. The cut-off MEP value for predicting sarcopenia was 47.0 cmH20 for men and 40.9 cmH20 for women. CONCLUSIONS: The most appropriate parameter for assessing respiratory sarcopenia may be MEP, which is an indicator of expiratory muscle strength, rather than FVC, MIP, or PEFR, as suggested in previous studies. Measuring MEP is simpler than measuring respiratory function parameters. Moreover, it is expected to have clinical applications such as respiratory sarcopenia screening.

Predictive equations for ventilatory muscle strength in the Brazilian population: a systematic review / Equações preditivas da força muscular ventilatória na população brasileira: uma revisão sistemática / Ecuaciones predictivas de la fuerza muscular respiratoria en la población brasileña: una revisión sistemática

ABSTRACT Maximal inspiratory and expiratory pressures (MIP and MEP) assess the strength index of the respiratory muscles. These measures are relevant to assess respiratory muscle strength and for clinical monitoring. This study evaluates papers that suggest predictive equations of MIP and MEP for the Brazilian population. We included studies that established prediction equations for MIP and MEP for the healthy Brazilian population, aged from 4 to 90 years old, both men and women and that had the maximum respiratory pressures measured in a sitting position. A search was carried out in March 2020 on MEDLINE, LILACS, Cochrane, SciELO, CINAHL, Web of Science, and SCOPUS databases, without date or language filters. The descriptors used were "muscle strength," "equations," "predictive respiratory muscles" and their respective synonyms. Out of the 3,920 studies found in databases, 963 were duplicates, 2,779 were excluded, 178 had their full texts analyzed, and only 9 met the inclusion criteria. The predictive equations of ventilatory muscle strength analyzed in this review used age, weight, and stature as variables. However, the studies showed methodological weaknesses, such as lack of cross-validation of the equation, exclusion of outliers, and lack of familiarization of MIP and MEP.

RESUMO As pressões respiratórias máximas (PImáx e PEmáx) avaliam o índice de força dos músculos respiratórios. Essas medidas são relevantes para a avaliação da força muscular respiratória e para o monitoramento clínico. O objetivo deste estudo foi avaliar os artigos que sugerem equações preditivas de PImáx e PEmáx para a população brasileira. Foram incluídos estudos que estabeleceram equações de predição para PImáx e PEmáx da população brasileira saudável, com idades entre 4 e 90 anos e de ambos os sexos, que mediam as pressões respiratórias máximas na posição sentada. Uma pesquisa foi realizada, em março de 2020, nas bases de dados MEDLINE, LILACS, Cochrane, SciELO, CINAHL, Web of Science e SCOPUS, sem filtros de tempo ou idioma. Os descritores utilizados foram "força muscular", "equações" e "músculos respiratórios preditivos", com seus respectivos sinônimos. Dos 3.920 estudos encontrados nas bases de dados, 963 eram duplicados e 2.779 foram excluídos, 178 tiveram seus textos analisados integralmente e apenas 9 atendiam aos critérios de inclusão. As variáveis utilizadas nas equações preditivas de força muscular ventilatória analisadas nesta revisão foram: idade, peso e estatura. No entanto, os estudos mostraram fragilidades metodológicas, como falta de validação cruzada da equação, exclusão de outliers e familiarização do PImáx e PEmáx.

RESUMEN Las presiones inspiratoria y espiratoria máximas (PImáx y PEmáx) evalúan el índice de fuerza muscular respiratoria. Estas medidas son importantes en la evaluación de la fuerza muscular respiratoria y el seguimiento clínico. El objetivo de este estudio fue evaluar los artículos proponen ecuaciones predictivas para PImáx y PEmáx a la población brasileña. Se incluyeron estudios que establecieron ecuaciones predictivas para PImáx y PEmáx a la población brasileña sana de ambos sexos, de entre 4 y 90 años de edad, y que miden las presiones respiratorias máximas en posición sentada. Se realizó, en marzo de 2020, una búsqueda en las bases de datos MEDLINE, LILACS, Cochrane, SciELO, CINAHL, Web of Science y SCOPUS, sin año de publicación específico ni idioma. Los descriptores utilizados fueron "fuerza muscular", "ecuaciones" y "músculos respiratorios predictivos" y sus respectivos sinónimos. De los 3.920 estudios encontrados, 963 eran duplicados y se excluyeron 2.779, así se analizaron 178 textos en su totalidad y solo 9 cumplieron con los criterios de inclusión. Las variables edad, peso y talla fueron las que habían sido utilizadas en las ecuaciones predictivas de fuerza muscular respiratoria analizadas por esta revisión. Sin embargo, los estudios apuntaron limitaciones metodológicas, como falta de validación cruzada de la ecuación, exclusión de outliers y familiaridad de la PImáx y PEmáx.

Respiratory Muscle Strength in Healthy Indian Children of Age 7-17 Years: A Cross-Sectional Study.

PURPOSE: As the values of respiratory muscle strength vary according to race, ethnicity, and geographical area, there is a wide-ranging difference among different populations. Thus, the available reference values may not have an application for use in the Indian paediatric population, creating a need for generating values which will be appropriate for the Indian paediatric context. MATERIALS AND METHODS: Assessment of respiratory muscle strength was carried out by assessing maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) and synthesising predictive formulas using anthropometric variables like height, gender and age, which will be suitable for Indian children. RESULTS: We calculated MIP and MEP of 320 (boys=160 and girls= 160) children in the age range of 7 years to 17 years of Mangaluru city, India. Results stated that mean MIP and MEP for boys were 72.5±32.8 cm H2O and 73±33.2 cm H2O, while for the girls it was 67±30.2 cm H2O and 68±30.1 cm H2O, respectively. CONCLUSION: This study concluded that there is a difference in respiratory pressure values of Indian children with respect to those of other countries. Age, gender, height and BMI have a significant role in determining respiratory muscle strength. Boys demonstrated higher MIP and MEP. As age, height, weight and BMI increases, so does MIP and MEP.

The relationship between maximal expiratory pressure values and critical outcomes in mechanically ventilated patients: a post hoc analysis of an observational study.

BACKGROUND: Little interest has been paid to expiratory muscle strength, and the impact of expiratory muscle weakness on critical outcomes is not known. Very few studies assessed the relationship between maximal expiratory pressure (MEP) and critical outcomes. The aim of this study was to investigate the relationship between MEP and critical outcomes. METHODS: This work was a secondary analysis of a prospective, observational study of adult patients who required mechanical ventilation for ≥ 24 h in an 18-bed ICU. MEP was assessed before extubation after a successful, spontaneous breathing trial. The relationships between MEP and extubation failure, and short-term (30 days) mortality, were investigated. Univariate logistic regressions were computed to investigate the relationship between MEP values and critical outcomes. Two multivariate analyses, with and without maximal inspiratory pressure (MIP), both adjusted using principal component analysis, were undertaken. Unadjusted and adjusted ROC curves were computed to compare the respective ability of MEP, MIP and the combination of both measures to discriminate patients with and without extubation failure or premature death. RESULTS: One hundred and twenty-four patients were included. Median age was 66 years (IQR 18) and median mechanical ventilation duration was 7 days (IQR 6). Extubation failure rate was 15% (18/124 patients) and the rate for 30-day mortality was 11% (14/124 patient). Higher MEP values were significantly associated with a lower risk of extubation failure in the univariate analysis [OR 0.96 95% CI (0.93-0.98)], but not with short-term mortality. MEP was independently linked with extubation failure when MIP was not included in the multivariate model, but not when it was included, despite limited collinearity between these variables. This study was not able to differentiate the respective abilities of MEP, MIP, and their combination to discriminate patients with extubation failure or premature death (adjusted AUC for the combination of MEP and MIP: 0.825 and 0.650 for extubation failure and premature death, respectively). CONCLUSIONS: MEP is related to extubation failure. But, the results did not support its use as a substitute for MIP, since the relationship between MEP and critical outcomes was no longer significant when MIP was included. The use of MIP and MEP measurements combined did not reach higher discriminative capacities for critical outcomes that MEP or MIP alone. Trial Registration This study was retrospectively registered at https://clinicaltrials.gov/ct2/show/NCT02363231?cond=NCT02363231&draw=2&rank=1 (NCT02363231) in 13 February 2015.

[Evaluation of the relationship between the parameters of peripheral skeletal and respiratory muscles in patients with chronic obstructive pulmonary disease].

Chronic obstructive pulmonary disease (COPD) is a group of diseases with high levels of comorbidity. Pathological changes of peripheral skeletal and respiratory muscles in COPD patients, which are often underestimated, occupy a special place. AIM: To study the relationship between functional and quantitative parameters of the peripheral (limb muscle) and respiratory muscles in COPD patients. MATERIALS AND METHODS: 127 patients (98 men/29 women, mean age 67.68.2 years) were under observation without acute COPD. All COPD patients were classified according to GOLD (2019) into groups A, B, C, D. The algorithm of the European Working Group on Sarcopenia in Older People (EWGSOP2) was used to diagnose sarcopenia. The muscle mass was measured using dual energy X-ray absorptiometry (DXA) and the appendicular lean mass index (ASM) was estimated. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured by body plethysmograph MasterScreen Body. Quantitative assessment of thoracic muscle cross-sectional areas were performed using the CT scan using Vidar Dicom Viewer software. RESULTS: Sarcopenia was diagnosed in 43.3% of COPD patients. Respiratory muscle dysfunction was determined in 66.1% of patients with COPD, its probability increased in groups C and D in comparison with groups A and B [chance ratio 6.6 (95% confidence interval 2.915.0); p0.0001]. Correlations between the functional parameters of sarcopenia and respiratory muscle strength as well as between the mass of peripheral skeletal muscles and respiratory muscle area have been established according to the data of computerized tomography (р0.01). Sarcopenia as well as respiratory muscle dysfunction was observed more frequently in persons with severe and extremely severe airway obstruction and in patients with predominantly emphysematic COPD phenotype (p0.01). CONCLUSION: Sarcopenia is a frequent comorbidity in COPD and its development is connected with the severity of the course of the main disease. Correlation between parameters of peripheral (limb muscle) and respiratory muscles in patients with COPD has been determined.

Effect of cardiac surgery on respiratory muscle strength.

OBJECTIVES: Pulmonary complications, such as atelectasis, pulmonary oedema, pleural effusion, bronchospasm, and pneumonia, have been reported following cardiac surgery. Shallow breathing leading to impaired lung function is the major cause of respiratory complications. Decreases in respiratory muscle strength can be measured using the maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) produced in the oral cavity. This study aimed to determine the decrease in respiratory muscle strength 8 weeks following cardiac surgery. Moreover, the relationship between lung function and respiratory muscle strength was studied. METHODS: In this observational study, 42 adult cardiac surgery patients (10 women, 32 men; mean age 65 ± 7 years) were investigated. Lung function and respiratory muscle strength were measured preoperatively and at 2 months postoperatively. RESULTS: The pre- and postoperative respiratory muscle strengths were in accordance with the predicted values. The MIP was 81.75 ± 22.04 cmH2O preoperatively and 74.56 ± 18.86 cmH2O at the 2-month follow-up (p = 0.146). The MEP was 98.55 ± 22.24 cmH2O preoperatively and 88.86 ± 18.14 cmH2O at the 2-month follow-up (p = 0.19). The preoperative lung function was in accordance with the predicted values; however, lung function significantly decreased postoperatively. At the 2-month follow-up, there was a moderate correlation between the MIP and forced expiratory volume (r = 0.59, p = 0 .0078). CONCLUSIONS: The respiratory muscle strength was not impeded either before or 2 months after cardiac surgery. However, the exact mechanism for the alteration in lung function remains unclear. Measures to re-establish the ideal postoperative lung capacity should concentrate on different perioperative pulmonary exercises.

Respiratory muscle strength and state of consciousness values measured prior to the decannulation in different levels of complexity. A longitudinal prospective case series study. / Valores de fuerza muscular respiratoria y estado de conciencia medido previo a la decanulación en diferentes niveles de complejidad. Estudio de serie de casos longitudinal y prospectiva.

OBJECTIVE: To describe the variables related to effective cough capacity and the state of consciousness measured prior to decannulation and compare their measured values between the different areas of care such as the Intensive Care Unit (ICU), General ward and Mechanical Ventilation Weaning and Rehabilitation Centers (MVWRC). Secondarily analyze the evolution of patients once decannulated. DESIGN: Case series, longitudinal and prospective. SCOPE: Multicentric 31 ICUs (polyvalent) and 5 MVWRC. PATIENTS: Tracheostomized adults prior to decannulation. MEASUREMENTS: Maximum expiratory pressure, peak expiratory flow coughed (PEFC), Glasgow Coma Scale (GCS). RESULTS: Two hundred and seven decannulated patients, 124 (60%) in ICU, 59 (28%) General ward and 24 (12%) in MVWRC. The PEFC presented differences between the patients (ICU 110 - 190 l/min versus MVWRC 167.5 - 232.5 l/min, p <.01). The GCS was different between General ward (9 -15) versus ICU (10-15) and MVWRC (12-15); p <.01 and p <.01, respectively. There were differences in the days of hospitalization (p <.01), days with tracheostomy (<0.01) and the number of patients referred at home (p =.02) between the different scenarios. CONCLUSION: There are differences in the values of PEFC and GCS observed when decannulating between different areas. A considerable number of patients are decannulated with values of PEFC and maximum expiratory pressure below the suggested cut-off points as predictors of failure in the literature. No patient in our series was decanulated with an GCS <8, this reflects the importance that the treating team gives to the state of consciousness prior to decannulation.

Maximal Static Respiratory and Sniff Pressures in Healthy Children. A Systematic Review and Meta-Analysis.

RATIONALE: Respiratory muscle strength in children can be assessed by maximal inspiratory pressures (MIP), maximal expiratory pressures (MEP), and sniff nasal inspiratory pressures (SNIP). However, previous studies involved small cohorts of healthy children and reported wide reference ranges. OBJECTIVES: To perform a systematic review to summarize existing reference ranges for MIP, MEP, and SNIP tests in healthy children and to conduct a meta-analysis to develop comprehensive prediction equations. DATA SOURCES: Five databases were searched for relevant studies from database inception to May 29, 2017. DATA EXTRACTION: Study inclusion was limited to publications that evaluated MIP, MEP, and SNIP values in healthy children aged 18 years or younger. Studies were also excluded if testing methodology differed greatly from the 2002 American Thoracic Society Statement on Respiratory Muscle Testing. Requests for raw data were made to authors via e-mail. SYNTHESIS: A total of 18 studies including 3,509 children were systematically reviewed. Diagnostic accuracy of the included studies was assessed using the QUADAS-2 tool, which revealed a high risk of bias for flow and timing and for applicability that may influence the generalizability of our findings. All 18 studies evaluated respiratory pressures in children in seated position. MIP tests were conducted from residual volume, MEP tests from total lung capacity, and SNIP tests from functional residual capacity. The MIP and MEP values in three age groups for boys and girls were summarized using meta-analysis based on individual participant data from five studies containing 1,709 healthy children. Further analyses showed that MIP and MEP were significantly greater in boys than in girls (P < 0.0001). In both sexes, MEP values were always greater than MIP values (P < 0.05). Multivariable random effects models were then performed to establish sex-specific prediction equations. These equations found age, height, and weight to be significant predictor variables. Only two studies with SNIP values from healthy children were included in the review, but they were not part of the meta-analysis. CONCLUSIONS: We summarized the available reference ranges for MIP, MEP, and SNIP tests based on existing literature, especially for three age groups, and developed prediction equations that can be used in pulmonary function laboratories to aid clinicians. Existing literature on SNIP tests is limited, and future studies are encouraged to explore their use in children. Systematic review registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42017072004).

Exercise Capacity and Respiratory Profile in Patients after Orthopedic Liver Transplantation: a Follow-up Study.

INTRODUCTION: We sought to describe: 1) The influence of orthotopic liver transplantation (OLT) on exercise capacity, pulmonary function and respiratory muscle strength after surgery, 2) The relationship between exercise capacity and symptoms of anxiety and depression. MATERIAL AND METHODS: This is a prospective follow up study conducted with patients submitted to OLT. All patients were assessed before and 1 month after surgery through measurements: six minute walk test (6MWT), 6 min step test (6MST) and HADS (Hospital Anxiety and Depression Scale). FEV1% (forced expiratory volume), maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured in the pre-operative and on 1st, 3rd, 5th day and 1 month after surgery. RESULTS: In 77 patients , 6MWD improved 20.2 m (95%CI 8.1-32.3) and 6MST improved 7.8 steps after surgery (95%CI 3.9-11.6). Change in 6 MWD and 6 MST did not correlated with change HADS. The FEV1% at each time point were 88.8 ± 21.3 before surgery, 32.9 ± 9.9 on 1st day, 39.6 ± 11.5 on 3rd day, 46 ± 12.1 on 5th day and 86.6 ± 21.1 one month after surgery. MIP and MEP values at each time point were -67.4 ± 23.2 and 79.7 ± 26 before surgery, -30.8 ± 12.3 and 36.4 ± 15.4 on 1st day, -38.6 ± 14.1 and 43.8 ± 17 on 3rd day, -45.8 ± 15.9 and 49.7 ± 18.7 on 5th day and -67.1 ± 29.4 and 80.9 ± 23.9 one month after surgery. CONCLUSION: Exercise capacity was modestly increased after OLT without any correlation with symptoms of anxiety and depression. Pulmonary function and respiratory muscle strength decreased immediately after liver transplantation, and progressively recovered, returning to baseline values after 1 month.

Long-Term Pulmonary Function in Duchenne Muscular Dystrophy: Comparison of Eteplirsen-Treated Patients to Natural History.

BACKGROUND: Duchenne muscular dystrophy (DMD) is a rare, degenerative, X-linked genetic disease that results in progressive muscle loss and premature death, most commonly from respiratory or cardiac failure. DMD is primarily caused by whole exon deletions, resulting in a shift of the dystrophin mRNA reading frame that prevents production of functional dystrophin protein. Eteplirsen, a phosphorodiamidate morpholino oligomer (PMO), is designed to skip exon 51, restore the reading frame, and induce production of internally shortened dystrophin in patients with mutations amenable to such treatment. OBJECTIVE: Describe lung function assessed throughout eteplirsen studies 201/202. METHODS: Studies 201/202 included 12 patients treated with eteplirsen over 5 years. Pulmonary function tests included forced vital capacity (FVC), maximum expiratory pressure (MEP), and maximum inspiratory pressure (MIP). With no long-term placebo control, FVC results were compared with data from the United Dystrophinopathy Project (UDP). MIP and MEP were compared to published natural history. RESULTS: Age-adjusted mixed-model repeated-measures analysis showed decreases of 2.3% and 2.6% annually for FVC% p and MEP% p, and an annual increase of 0.6% for MIP% p for the eteplirsen-treated cohort. Data from the UDP demonstrated a 4.1% decline in FVC% p. The published natural history reports annual declines of at least 2.7% and 3.8% for MEP% p and MIP% p, respectively, in patients with DMD. CONCLUSIONS: With eteplirsen treatment, deterioration of respiratory muscle function based on FVC% p was half of that seen in the UDP; MEP% p and MIP% p compared favorably with natural history.

Effects of fast expiration exercises without pressure on the respiratory muscle strength of healthy subjects.

[Purpose] The aim of this investigation was to determine the effects of 4 weeks of fast expiration exercises performed without pressure on respiratory muscle strength. [Subjects and Methods] Respiratory muscle strength of the training group that performed fast expiration exercises (n=12) was compared with that of a control group that performed no exercises (n=12). The fast expiration exercises were performed using a peak expiratory flow meter device and consisted of 20 fast expiration exercises performed 3 times per week for 4 weeks. Maximal expiratory and inspiratory pressures were evaluated as respiratory muscle strength using a spirometer pre- and post- intervention. [Results] There were significant increases in maximal expiratory pressure from 76.9 ± 29.1 to 96.1 ± 37.5 cmH2O and maximal inspiratory pressure from 80.8 ± 36.6 to 95.3 ± 37.6 cmH2O in the training group, but there was no significant difference in respiratory muscle strength between pre- and post-intervention in the control group. [Conclusion] Fast expiration exercises may be beneficial for increasing respiratory muscle strength. The findings of this study should be considered when prescribing a variation of the expiratory muscle strength training, as part of a pulmonary rehabilitation program.

Reference Range of Respiratory Muscle Strength and Its Clinical Application in Amyotrophic Lateral Sclerosis: A Single-Center Study.

BACKGROUND AND PURPOSE: Evaluating respiratory function is important in neuromuscular diseases. This study explored the reference ranges of the maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP) in healthy adults, and applied them to amyotrophic lateral sclerosis (ALS) patients. METHODS: MIP, MEP, and SNIP were measured in 67 healthy volunteers aged from 21 to 82 years. Reference ranges were evaluated by multivariate regression analysis using the generalized additive modeling of location, scale, and shape method. Thirty-six ALS patients were reviewed retrospectively, and abnormal values of MIP, MEP, and SNIP were determined according to the reference ranges. RESULTS: MIP, MEP, and SNIP were abnormal in 57.1%, 51.4%, and 25.7% of the ALS patients, respectively. MIP and SNIP were significantly correlated with the degree of restrictive pattern and respiratory symptoms. The ALS Functional Rating Scale-Revised score was correlated with SNIP. CONCLUSIONS: This study has provided the reference range of respiratory muscle strength in healthy adults. This range is suitable for evaluating respiratory function in ALS patients.

The Effects of Expiratory Muscle Strength Training on Voice and Associated Factors in Medical Professionals With Voice Disorders.

OBJECTIVES: This research used expiratory muscle strength training to explore the factors relevant to medical professionals with voice disorders. The maximal expiratory pressure (MEP) improved, which is measured by the maximal contracting force of expiratory muscles. The expiratory muscle strength increased, which can affect the positive pressure of pulmonary volume, thereby influencing subglottal pressure for speech to change the voice performance and vocal-fold vibration. METHODS: Twenty-nine participants with voice disorders who are working in a hospital and who are using their voice for more than 4 hours per day were recruited. The participants were randomly assigned to either the study group (STU) or the control group (CON). All participants underwent aerodynamics analysis, pulmonary function, MEP, and completed a vocal symptoms questionnaire before and after STU was provided. The interventions in the STU were conducted 3 days per week and involved performing 25 expiratory exercises (five cycles, each comprising five breaths) for 5 weeks. The CON did not receive any intervention. RESULTS: The voiceless /S/ expiratory time, symptom questionnaire scores, and MEP were greater in the STU than in the CON (P < 0.05). However, no statistically significant difference in the results of the pulmonary function was observed between the groups. The STU exhibited a greater percentage change in maximal voiced /Z/ phonation and voiceless /S/ expiratory compared with the CON (P < 0.05). CONCLUSIONS: The participants' voiceless /S/ expiratory time, symptom questionnaire scores, and MEP significantly improved after the intervention. Future studies can increase the number of participants, increase the number of study groups, and examine the effectiveness of long-term treatment.

Reference Range of Respiratory Muscle Strength and Its Clinical Application in Amyotrophic Lateral Sclerosis: A Single-Center Study

BACKGROUND AND PURPOSE: Evaluating respiratory function is important in neuromuscular diseases. This study explored the reference ranges of the maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP) in healthy adults, and applied them to amyotrophic lateral sclerosis (ALS) patients. METHODS: MIP, MEP, and SNIP were measured in 67 healthy volunteers aged from 21 to 82 years. Reference ranges were evaluated by multivariate regression analysis using the generalized additive modeling of location, scale, and shape method. Thirty-six ALS patients were reviewed retrospectively, and abnormal values of MIP, MEP, and SNIP were determined according to the reference ranges. RESULTS: MIP, MEP, and SNIP were abnormal in 57.1%, 51.4%, and 25.7% of the ALS patients, respectively. MIP and SNIP were significantly correlated with the degree of restrictive pattern and respiratory symptoms. The ALS Functional Rating Scale-Revised score was correlated with SNIP. CONCLUSIONS: This study has provided the reference range of respiratory muscle strength in healthy adults. This range is suitable for evaluating respiratory function in ALS patients.

Pattern of Respiratory Deterioration in Sporadic Amyotrophic Lateral Sclerosis According to Onset Lesion by Using Respiratory Function Tests.

Most amyotrophic lateral sclerosis (ALS) patients show focal onset of upper and lower motor neuron signs and spread of symptoms to other regions or the other side clinically. Progression patterns of sporadic ALS are unclear. The aim of this study was to evaluate the pattern of respiratory deterioration in sporadic ALS according to the onset site by using respiratory function tests. Study participants included 63 (42 cervical-onset [C-ALS] and 21 lumbosacral-onset [L-ALS]) ALS patients and 31 healthy controls. We compared respiratory function test parameters among the 3 groups. Age was 57.4±9.6 (mean±SD), 60.8±9, and 60.5±7 years, and there were 28, 15, and 20 male participants, in the C-ALS, L-ALS, and control groups, respectively. Disease duration did not differ between C-ALS and L-ALS patients. Sniff nasal inspiratory pressure (SNIP) was significantly low in C-ALS patients compared with controls. Maximal expiratory pressure (MEP) and forced vital capacity percent predicted (FVC% predicted) were significantly low in C-ALS and L-ALS patients compared with controls. Maximal inspiratory pressure to maximal expiratory pressure (MIP:MEP) ratio did not differ among the 3 groups. Eighteen C-ALS and 5 L-ALS patients were followed up. ΔMIP, ΔMEP, ΔSNIP, ΔPEF, and ΔFVC% predicted were higher in C-ALS than L-ALS patients without statistical significance. Fourteen C-ALS (77.8%) and 3 L-ALS (60%) patients showed a constant MIP:MEP ratio above or below 1 from the first to the last evaluation. Our results suggest that vulnerability of motor neurons in sporadic ALS might follow a topographic gradient.

Impact of backpack type on respiratory muscle strength and lung function in children.

We examine the influence of backpack type on lung function and respiratory muscle strength in children. Thirty-seven children were assessed for lung function and inspiratory and expiratory muscle strength under four randomly determined conditions: unloaded erect standing and three conditions carrying 15% of the child's body weight. In these three conditions, children carried the weight on a backpack with bilateral shoulder straps carried over both shoulders, on a backpack with bilateral shoulder straps carried over one shoulder and on a backpack with a mono shoulder strap. Significantly lower forced vital capacity, forced expiratory volume in one second and maximal expiratory pressure were observed when children carried a backpack with a mono shoulder strap compared to the unloaded standing position. In conclusion, the restrictive effect and the decrease in expiratory muscle strength were more pronounced for the backpack with a mono shoulder strap, suggesting that a double strap backpack is preferable to a mono shoulder strap backpack. Practitioner summary: There is little known about the effect of schoolbags on respiratory muscle function. We investigated the influence of backpack type on lung function and respiratory muscle strength. A backpack with a mono shoulder strap created a restrictive effect and a decrease in strength, suggesting that a double strap backpack is preferable to a mono shoulder strap backpack.