Evaluation of patients with chronic obstructive pulmonary disease by maximal inspiratory pressure and diaphragmatic excursion with ultrasound sonography

BACKGROUND

Decreased respiratory muscle strength and muscle mass is key in diagnosing respiratory sarcopenia. However, the role of reduced diaphragm activity, expressed as the maximal level of diaphragmatic excursion (DEmax), in diagnosing respiratory sarcopenia in patients with chronic obstructive pulmonary disease (COPD) remains unclear. This study aimed to characterize patients with COPD and low DEmax and maximal inspiratory pressure (MIP), a measure of inspiratory muscle strength, and assess the role of DEmax in respiratory sarcopenia.

METHODS

Patients with COPD underwent spirometry, exercise tolerance (VO2peak) test, and MIP measurement. DEmax and sternocleidomastoid thickness at the maximal inspiratory level (TscmMIL) were assessed using ultrasound sonography.

RESULTS

Overall, 58 patients with COPD (median age, 76 years; median %FEV1, 51.3 %) were included, 28 of whom showed a %MIP of ≥80 %, defined as having preserved MIP. Based on the %MIP of 80 % and median value of DEmax (48.0 mm) as thresholds, the patients were stratified into four groups: both-high (n = 18), %MIP-alone low (n = 11), DEmax-alone low (n = 10), and both-low (n = 19) groups. The both-low group exhibited the lowest %FEV1, Δinspiratory capacity, VO2peak, and TscmMIL, and these values were significantly lower than those of the both-high group. Except for %FEV1, these values were significantly lower in the both-low group than in the %MIP-alone low group despite adjusting DEmax level for body mass index.

CONCLUSION

Measuring DEmax along with MIP can characterize patients with COPD, reduced exercise capacity, and decreased accessory respiratory muscle mass and can help diagnose respiratory sarcopenia.

Respiratory sarcopenia screening in dialysis patients: cross-sectional and multicentre study protocol

BACKGROUND

Respiratory sarcopenia is characterized by the weakness of respiratory muscles associated with sarcopenia due to aging or systemic diseases such as chronic kidney disease (CKD). Patients with CKD undergoing dialysis are particularly susceptible to respiratory muscle weakness caused by factors such as fluid overload and electrolyte imbalance. This weakness not only affects ventilation but also impairs oxygen uptake and delivery to muscle tissue, potentially leading to severe sarcopenia. Thus, the objective of this study is to conduct a respiratory sarcopenia screening in patients with CKD undergoing haemodialysis (HD) and peritoneal dialysis (PD).

METHODS

This is an observational, cross-sectional and multicentre study conducted between March 2023 and March 2025. The study was approved by the Research Ethics Committee at two centres. Sarcopenia diagnosis is determined based on low handgrip strength and amount of appendicular skeletal muscle mass, assessed through bioelectrical impedance analysis. Respiratory sarcopenia is diagnosed in patients with sarcopenia who have low inspiratory muscle strength, evaluated through a manovacuometry test. The severity of sarcopenia and respiratory sarcopenia is defined, respectively, by low physical performance (measured using the Short Physical Performance Battery and Timed-Up and Go test) and pulmonary performance (measured through spirometry). Thus, this study will include 81 patients undergoing dialysis (41 on HD and 40 on PD) from three participating centres.

DISCUSSION

The literature has been focused on respiratory function in CKD; however, the relationship with sarcopenia remains understudied. We believe that, similar to appendicular skeleton muscles, the axial skeleton muscles are also likely to weaken with the presence of chronic disease, such as CKD.

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.

Diaphragmatic muscle thickness in older people with and without sarcopenia

BACKGROUND

Studies in mice have suggested that sarcopenic animals may have atrophic diaphragmatic muscles; however, to date, no clinical studies are available.

AIMS

To investigate whether the diaphragmatic thickness is affected in older patients with sarcopenia and if this is associated with impaired respiratory functions.

METHODS

Thirty sarcopenic and 30 non-sarcopenic elderly patients aged over 65 were included. All patients underwent comprehensive geriatric assessment. The diagnosis of sarcopenia was made according to the criteria of the European Working Group on Sarcopenia in Older People. Ultrasonographic evaluations of the patients were carried out by an experienced radiologist. Diaphragmatic thickness was measured in three positions: end of deep inspiration, quiet breathing, end of forced expiration. Peak expiratory flow (PEF) rate was evaluated by a peak flow meter.

RESULTS

The mean age of the patients was 77 ± 6 years, and 58% were females. Diaphragmatic thickness in three different positions (deep inspiration [2.3 mm (min-max: 1.3-4.1) vs. 2.5 mm (min-max: 1.9-4.9)], quiet breathing [1.8 mm (min-max: 1.0-2.8) vs. 2.00 mm (min-max: 1.3-3.9)] and end of forced expiration [1.1 mm (min-max: 0.7-2.5) vs. 1.5 mm (min-max: 0.5-3.4)]) were found to be thinner in sarcopenic patients compared to non-sarcopenics (p = 0.02, p = 0.02, p < 0.01, respectively). Also, PEF rate results were lower in patients with sarcopenia (245 L/min [min-max: 150-500] vs. 310 L/min [min-max: 220-610], p < 0.01). Diaphragmatic muscle thicknesses in all three positions were independently associated with sarcopenia status of the participants.

CONCLUSIONS

Our results suggest that sarcopenia in older people may be associated with reduced diaphragmatic muscle thickness and respiratory functions. Findings are needed to be confirmed in further multicenter studies with big sample sizes.