Association of Diaphragm Thickness and Respiratory Muscle Strength With Indices of Sarcopenia

Diaphragm thickness and ICU admission risk in elderly COVID-19 patients: a CT-based analysis

BACKGROUND

The objective of this study was to examine the impact of diaphragm thickness (DT) on the prognosis of elderly patients infected with COVID-19, particularly with regard to the necessity of intensive care unit (ICU) admission.

METHODS

Between August 2020 and January 2021, 188 patients aged ≥ 65 years who were admitted to the internal medicine department of our hospital with a diagnosis of COVID-19 infection, were included in this study. The patients' DTs of the patients were measured by a radiologist using computed tomography (CT) scans from the right and left diaphragm dome level. DT was compared with the progression of respiratory distress and the necessity of intensive care. In statistical analysis, p < 0.05 was considered significant.

RESULTS

Right DT was higher in the group of patients with admission to the ICU (p = 0.11). According to multivariate logistic regression analysis, ferritin level (OR = 1; 95% CI = 1-1; p = 0.014), IL-6 level (OR = 1.004; 95% CI = 1-1.007; p = 0.045) and higher right DT (OR = 11.015; 95% CI = 3.739-32.447; p = 0.035) were found to be independent risk factors predicting the ICU admission in COVID-19 patients. There was no significant association with left DT. The predictive value of right DT for ICU requirement in COVID-19 patients was evaluated by ROC analysis. The ROC analysis showed a cut-off value > 1.8, AUC = 0.632, p = 0.009, 95% Cl (0.558-0.701). In correlation analysis, a positive correlation was found between right DT and ICU admission (r = 0.331, p < 0.001).

CONCLUSION

Our study is the first to evaluate dome-level DT with CT in elderly patients with COVID-19. In the elderly population, higher right DT levels have been observed to enhance the probability of ICU admission. This may be due to the fact that our sample group consists only of elderly people and the effects of COVID-19. We believe that further validation with more comprehensive studies is needed for DT assessment for clinical treatment decisions, particularly in COVID-19 patients. In addition, we think that the proposal for a standardized measurement site and method for DT measurement will be a guide for future studies.

CLINICAL TRIAL

Not applicable.

Descriptive Epidemiology and Prognostic Significance of Diaphragm Thickness in the General Population: The Nagahama Study

BACKGROUND

Diaphragm thickness is a potential marker of sarcopenia in addition to muscle mass and strength at extremities. We aimed to clarify the descriptive epidemiology and prognostic significance of diaphragm thickness in the general population.

METHODS

The study participants were 3324 community residents (mean age: 61.4 ± 12.8 years) who participated in a longitudinal cohort study. Clinical parameters were obtained during the follow-up survey of the study population. Diaphragm thickness was measured from B-mode ultrasound images obtained in a supine position. Clinical and physical factors independently associated with diaphragm thickness were assessed by a linear regression model and a causal mediation analysis. All-cause mortality was determined by reviewing residential registry records. Prognostic significance of diaphragm thickness for all-cause mortality was examined using a Cox proportional hazard model analysis.

RESULTS

Diaphragm thickness was greater in men than women (end-expiration, β = 0.161, p < 0.001; end-inspiration, β = 0.156, p < 0.001) and associated with waist circumference (end-expiration, β = 0.259, p < 0.001; end-inspiration, β = 0.128, p < 0.001). Handgrip strength, smoking habit, insulin resistance and exercise habit were not associated with diaphragm thickness. Skeletal muscle mass index showed apparent association with diaphragm thickness, though this association was not observed after adjusting for waist circumference. Over a mean follow-up of 1686 days (15 358 person-years), there were 56 cases of all-cause mortality. Weak handgrip strength (hazard ratio = 0.95, p = 0.044) and low forced vital capacity (hazard ratio = 0.57, p = 0.045) were associated with all-cause mortality, though none of the diaphragm thickness parameters showed a significant association (thickness at end-expiration, p = 0.722; thickness at end-inspiration, p = 0.277; thickening fraction, p = 0.219).

CONCLUSIONS

Waist circumference but not parameters of sarcopenia was independently associated with diaphragm thickness. Diaphragm thickness was not associated with all-cause mortality. Diaphragm thickness may not be a marker of systemic sarcopenia.

Relationship Between Diaphragm Function and Sarcopenia Assessed by Ultrasound: A Cross-Sectional Study

Background/Objectives: The diaphragm is important for respiration, but the effects of age-related muscle loss and sarcopenia on diaphragm function are unclear. We evaluated the associations of sarcopenia and skeletal muscle mass (SMM) with diaphragm function. Methods: This study was conducted at three Japanese hospitals from May 2023 to September 2024. The participants underwent bioelectrical impedance for SMM assessment, as well as pulmonary function tests. Diaphragm ultrasound was used to measure the thickness at functional residual capacity (FRC), thickening fraction (TF), and diaphragm excursion (DE) during deep breathing (DB), and their associations with sarcopenia and low skeletal muscle index (SMI) were analyzed. Results: Overall, 148 patients (mean age 78.1 years; sarcopenia, n = 35; non-sarcopenia, n = 103) were included. No statistically significant differences in thickness(FRC), TF and DE were observed between the sarcopenia group and the non-sarcopenia group. The low SMI group had significantly lower thickness (difference -0.22, 95% CI; -0.41, -0.29) and DE (difference -9.2, 95%CI; -14.0, -4.49) than the normal SMI group. Multivariable linear regression analyses adjusted for age, sex, and stature revealed no association between thickness (FRC) and sarcopenia (p = 0.98), but thickness (FRC) was negatively associated with low SMI (p = 0.034). DE during DB was negatively associated with sarcopenia (p = 0.024) and low SMI (p = 0.001). TF showed no associations. Conclusions: DE during DB was reduced in patients with sarcopenia and low SMI, and thickness (FRC) was reduced in those with low SMI without sarcopenia.

The Role of Diaphragmatic Ultrasound in Identifying Sarcopenia in COPD Patients: A Cross-Sectional Study

Background/Aim

Chronic obstructive pulmonary disease (COPD) is often complicated by sarcopenia, a condition of reduced muscle mass and function that adversely affects quality of life, lung function, and exacerbation rates. Ultrasonography could be an effective tool for detecting sarcopenia, notably by assessing diaphragmatic function, which may indicate muscle health in COPD patients. This study aims to evaluate the effectiveness of diaphragmatic ultrasound in detecting sarcopenia among COPD patients.

Materials and Methods

Thirty-five patients with COPD, with a forced expiratory volume in one second (FEV1) between 30% and 80%, were consecutively enrolled in this cross-sectional and double-blind study. Sarcopenia was defined using the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. Muscle mass was assessed with bioelectrical impedance analysis (BIA), muscle strength was assessed using the handgrip test and physical performance was assessed using a 4-meter gait speed test. Pulmonary function tests (PFT) (including maximum inspiratory pressure-MIP and maximum expiratory pressure-MEP) were performed. Diaphragm excursion and thickness at residual volume, functional residual capacity, and total lung capacity were measured using ultrasound. The diaphragm thickening fraction was calculated during normal (TF) and deep breathing (TLC-TF).

Results

Seventeen of 35 patients (48.6%) were found to be sarcopenic. Diaphragm thickness did not show significant variation between the groups. Both TF (27.43%) and TLC-TF (39.7%) were found to be lower in the sarcopenic group (p<0.05). The diaphragmatic excursion in the sarcopenic group was found to be 1.38 cm (p=0.078). There was no difference in median MIP and MEP values between the groups.

Conclusion

Diaphragmatic TF may be a valuable tool for detecting sarcopenia in COPD patients, which may vary independently of PFTs. This study highlights TF as a potential auxiliary measure, but further research with larger sample sizes and additional parameters is needed to confirm its clinical utility.

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.

Evaluating Respiratory Muscle Strength in Sarcopenia Screening among Older Men in South Korea: A Retrospective Analysis

PURPOSE

To evaluate the potential of incorporating respiratory muscle strength, specifically maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP), along with traditional sarcopenia screening measures such as hand grip strength (HGS) and skeletal muscle mass index (SMI), to identify sarcopenia in older men.

MATERIALS AND METHODS

A retrospective analysis was conducted involving male patients aged 65 years and older who underwent measurements of respiratory muscle strength, HGS, and muscle mass at a general hospital in Korea from July 2016 to May 2022. Statistical analysis utilized independent t-tests and receiver operating characteristic (ROC) curves to assess the sensitivity and specificity of MIP, MEP, HGS, and SMI in sarcopenia screening. The cut-off values for sarcopenia screening were determined based on the area under the ROC curve (AUC).

RESULTS

The analysis of 282 study participants revealed the following cut-off values for sarcopenia based on the AUC: for MIP, the cut-off value was 65.50 cmH2O (AUC=0.70, sensitivity: 0.63, specificity: 0.61), while for MEP, it was 84.50 cmH2O (AUC=0.74, sensitivity: 0.66, specificity: 0.68).

CONCLUSIONS

This study showed the utility of respiratory muscle strength in screening for sarcopenia among older men. We suggest the screening cut-off values as 65.50 cmH2O for MIP and 84.50 cmH2O for MEP. Even when HGS and SMI measurements are not feasible, sarcopenia can be reasonably predicted based on respiratory muscle strength.

Validating respiratory sarcopenia diagnostic criteria by mortality based on a position paper by four professional organizations: Insights from the Otassha study

AIM

The Japanese Society for Respiratory Care and Rehabilitation, Japanese Association on Sarcopenia and Frailty, Japanese Society of Respiratory Physical Therapy, and Japanese Association of Rehabilitation Nutrition proposed the definition and diagnosis of respiratory sarcopenia using low respiratory muscle strength and appendicular skeletal muscle mass (ASM; ASM/height2) instead of respiratory muscle mass; however, these parameters have not been validated. This study aimed to confirm the validity of the respiratory sarcopenia definition proposed by these four professional organizations.

METHODS

Participants of our cohort study in 2015 of 468 community-dwelling older people who were evaluated for sarcopenia and underwent spirometry were included in this analysis. We determined two respiratory sarcopenia models based on low skeletal muscle mass and respiratory muscle strength. Low skeletal muscle mass was defined by low ASM/height2, and low respiratory muscle strength was defined by peak expiratory flow rate (PEFR) or percentage of predicted PEFR (%PEFR). Survival status was assessed 5 years after baseline assessment (in 2020). To evaluate the validity of the cut-off values for PEFR and %PEFR, we determined different respiratory sarcopenia models by sequentially varying the cut-off values for each parameter, including ASM/height2, from high to low. We subsequently calculated the hazard ratio (HR) for mortality for each respiratory sarcopenia model using the Cox proportional hazards model. Additionally, we plotted the HR for each combination of cut-off values for ASM/height2 and PEFR or %PEFR on a three-dimensional chart to observe the relationship between the different cut-off values and HR.

RESULTS

A total of 31 people died during the 5-year observation period. With ASM/height2 cut-off values of approximately 7.0 kg/m2 for men and 5.7 kg/m2 for women and %PEFR cut-off values of 66-75%, respiratory sarcopenia was associated with mortality risk (HR, 2.36-3.27, point estimation range).

CONCLUSIONS

The definition of respiratory sarcopenia by the four professional organizations is related to future health outcomes, and this definition is valid. Geriatr Gerontol Int 2024; 24: 948-953.

[Evaluation of the Functional Reserve and Exercise Tolerance in Patients with CHF in Clinical Trials (Consent Document of the Editorial board of the Journal of Cardiology, the Board of the Society of Specialists in Heart Failure (SSHF) and Working Group "Non-drug treatment methods" of SSHF)]

Assessing the functional capacity and exercise tolerance is an important and widely used research tool in patients with heart failure. It is used not only in cardiac rehabilitation and physical therapy, but also for inclusion criteria and outcome measures in studies of drug interventions. This document outlines the scope, guidelines for the implementation and interpretation, and limitations of the methods for assessing the functional capacity and exercise tolerance in clinical trials in patients with heart failure.

Diaphragm Ultrasound in Different Clinical Scenarios: A Review with a Focus on Older Patients

Diaphragm muscle dysfunction is increasingly recognized as a fundamental marker of several age-related diseases and conditions including chronic obstructive pulmonary disease, heart failure and critical illness with respiratory failure. In older individuals with physical frailty and sarcopenia, the loss of muscle mass and function may also involve the diaphragm, contributing to respiratory dysfunction. Ultrasound has recently emerged as a feasible and reliable strategy to visualize diaphragm structure and function. In particular, it can help to predict the timing of extubation in patients undergoing mechanical ventilation in intensive care units (ICUs). Ultrasonographic evaluation of diaphragmatic function is relatively cheap, safe and quick and can provide useful information for real-time monitoring of respiratory function. In this review, we aim to present the current state of scientific evidence on the usefulness of ultrasound in the assessment of diaphragm dysfunction in different clinical settings, with a particular focus on older patients. We highlight the importance of the qualitative information gathered by ultrasound to assess the integrity, excursion, thickness and thickening of the diaphragm. The implementation of bedside diaphragm ultrasound could be useful for improving the quality and appropriateness of care, especially in older subjects with sarcopenia who experience acute respiratory failure, not only in the ICU setting.

Definition, diagnosis, and treatment of respiratory sarcopenia

PURPOSE OF REVIEW

Skeletal muscle weakness and wasting also occurs in the respiratory muscles, called respiratory sarcopenia. Respiratory sarcopenia may lead to worse clinical indicators and outcomes. We present a novel definition and diagnostic criteria for respiratory sarcopenia, summarize recent reports on the association between respiratory sarcopenia, physical and nutritional status, and clinical outcomes, and provide suggestions for the prevention and treatment of respiratory sarcopenia.

RECENT FINDINGS

Recently, a novel definition and diagnostic criteria for respiratory sarcopenia have been prepared. Respiratory sarcopenia is defined as a condition in which there is both low respiratory muscle strength and low respiratory muscle mass. Respiratory muscle strength, respiratory muscle mass, and appendicular skeletal muscle mass are used to diagnose respiratory sarcopenia. Currently, it is challenging to definitively diagnose respiratory sarcopenia due to the difficulty in accurately determining low respiratory muscle mass. Decreased respiratory muscle strength and respiratory muscle mass are associated with lower physical and nutritional status and poorer clinical outcomes. Exercise interventions, especially respiratory muscle training, nutritional interventions, and their combinations may effectively treat respiratory sarcopenia. Preventive interventions for respiratory sarcopenia are unclear.

SUMMARY

The novel definition and diagnostic criteria will contribute to promoting the assessment and intervention of respiratory sarcopenia.