Background: Although the pathophysiological mechanisms involved in the development of dyspnoea and poor exercise tolerance in patients with COPD are complex, dynamic lung hyperinflation (DLH) plays a central role. Diaphragmatic excursions can be measured by ultrasonography (US) with high intra- and interobserver reliability. The objective of this study was to evaluate the effect of diaphragmatic excursions as assessed by US on exercise tolerance and DLH in patients with COPD.Methods: Patients with COPD (n=20) and age-matched control subjects (n=20) underwent US, which was used to determine the maximum level of diaphragmatic excursion (DE_max). Ventilation parameters, including the change in inspiratory capacity (ΔIC), were measured in the subjects during cardiopulmonary exercise testing (CPET). We examined the correlations between DE_maxand the ventilation parameters.Results: The DE_maxof patients with COPD was significantly lower than that of the controls (45.0±12.8 mmversus64.6±6.3 mm, respectively; p<0.01). The perception of peak dyspnoea (Borg scale) was significantly negatively correlated with DE_maxin patients with COPD. During CPET, oxygen uptake/weight (V′O₂/W) and minute ventilation (V′_E) were significantly positively correlated with DE_max, whileV′_E/V′O₂andV′_E/carbon dioxide output (V′CO₂) were significantly negatively correlated with DE_maxin patients with COPD. DE_maxwas also significantly positively correlated with ΔIC, reflecting DLH, and withV′O₂/W, reflecting exercise capacity.Conclusion: Reduced mobility of the diaphragm was related to decreased exercise capacity and increased dyspnoea due to dynamic lung hyperinflation in COPD patients.

Objective: Inspiratory muscle training (IMT) is used to improve inspiratory muscle strength in patients with COPD. However, the effect of IMT on diaphragmatic function has not yet been thoroughly evaluated. This study aimed to evaluate the effect of IMT on maximum diaphragmatic excursion (DE_max) using ultrasonography in patients with COPD.Methods: This was a single-centre, randomised, prospective, parallel-group, unblinded controlled trial involving 38 participants with stable COPD. Participants underwent a standardised 12-week pulmonary rehabilitation (PR) programme followed by a 12-week IMT programme, consisting of home-based IMT and low-frequency outpatient PR sessions supervised by physiotherapists (once every 2 weeks),versuslow-frequency outpatient PR alone as a control. The DE_maxand exercise tolerance were measured.Results: Out of the 38 patients initially enrolled in the PR programme, 33 successfully completed it and were subsequently randomised to the IMT programme. Finally, 15 (94%) and 14 (88%) patients from the IMT and control groups, respectively, completed the study. Following the IMT programme, DE_maxincreased in the IMT group (mean±sd50.1±7.6 mm to 60.6±8.0 mm, p<0.001), but not in the control group (47.4±7.9 mm to 46.9±8.3 mm, p=0.10). Changes in DE_maxand exercise tolerance (peak oxygen uptake) were greater in the IMT group than in the control group (both p<0.01).Conclusions: IMT following the PR programme improved DE_maxand exercise tolerance. Therefore, DE_maxmay be an important outcome of IMT.

(1): The superficial and deep parts of the infrapatellar fat pat (IFP) have different morphological and functional characteristics. Knee pain often occurs during movement, and it is important to clarify the movement of the IFP during knee joint movement. The purpose of this study is to clarify that the movement of the superficial and deep parts of the IFP are different during knee extension in vivo using ultrasonography (US). (2): US was performed on 15 knees of 15 healthy adults. The probe was placed longitudinally at the center of the patellar tendon and the IFP was imaged. Measurements were taken during active extension of the knee from 90 degrees to 10 degrees of knee flexion at a rate of 30 times/min. The captured US videos were analyzed using Flow particle image velocimetry (Flow PIV) fluid measurement software. The region-of-interest (ROI) was set at the superficial part and the deep part of the IFP, and the flow velocity was calculated for each. (3): The flow velocity of the deep part (1.37 ± 0.13 cm/s) of the IFP was significantly faster than that of the superficial part (0.80 ± 0.23 cm/s). (4): Our results show that the flow velocity of the IFP is different between the superficial and deep parts and that US may be a better assessment tool for the movement of the IFP.

To elucidate the local microcirculation of the infrapatellar fat pad (IFP) in patients with knee osteoarthritis (KOA) by determining the changes in IFP hardness and hemoglobin concentration during isometric quadriceps exercise (IQE). In this observational cross-sectional study, patients diagnosed with bilateral KOA were included in the KOA group (30 knees), healthy older adults in the control group (20 knees), and younger adults in the young group (20 knees). Ultrasonography was performed at rest and during IQE to measure IFP hardness based on shear wave velocity. Near-infrared spectroscopy was performed to measure oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), and total hemoglobin (cHb) in the IFP before (Baseline), during (IQE task), and after IQE (Post). IFP hardness and O2Hb, HHb, and cHb concentration were analyzed using a linear mixed model for the groups and measurement points. During IQE, IFP hardness changes were significantly less in the KOA group than in the other groups (KOA: 95% confidence intervals (CIs) [-0.854, 0.028]; control: 95% CI [-0.941, -0.341]; and young: 95% CI [-2.305, -1.706]). In the KOA group, O2Hb concentration exhibited no significant changes at Post compared with Baseline; however, significant changes were observed in the other groups (KOA: 95% CI [-1.176, 0.423]; control: 95% CI [-1.452, -0.276]; and young: 95% CI [-4.062, -2.102]). During IQE, changes in hardness and hemoglobin concentration in the IFP were not significant in the KOA group, suggesting impaired local microcirculation of the IFP.