Acute thoracoabdominal and hemodynamic responses to tapered flow resistive loading in healthy adults

We investigated the acute physiological responses of tapered flow resistive loading (TFRL) at 30, 50 and 70% maximal inspiratory pressure (PImax) in 12 healthy adults to determine an optimal resistive load. Increased end-inspiratory rib cage and decreased end-expiratory abdominal volumes equally contributed to the expansion of thoracoabdominal tidal volume (captured by optoelectronic plethysmography). A significant decrease in end-expiratory thoracoabdominal volume was observed from 30 to 50% PImax, from 30 to 70% PImax, and from 50 to 70% PImax. Cardiac output (recorded by cardio-impedance) increased from rest by 30% across the three loading trials. Borg dyspnoea increased from 2.36 ± 0.20 at 30% PImax, to 3.45 ± 0.21 at 50% PImax, and 4.91 ± 0.25 at 70% PImax. End-tidal CO2 decreased from rest during 30, 50 and 70 %PImax (26.23 ± 0.59, 25.87 ± 1.02 and 24.30 ± 0.82 mmHg, respectively). Optimal intensity for TFRL is at 50% PImax to maximise global respiratory muscle and cardiovascular loading whilst minimising hyperventilation and breathlessness

Effect of portable noninvasive ventilation on thoracoabdominal volumes in recovery from intermittent exercise in patients with COPD

We previously showed that use of portable noninvasive ventilation (pNIV) during recovery periods within intermittent exercise improved breathlessness and exercise tolerance in patients with COPD compared with pursed-lip breathing (PLB). However, in a minority of patients recovery from dynamic hyperinflation (DH) was better with PLB, based on inspiratory capacity. We further explored this using Optoelectronic Plethysmography to assess total and compartmental thoracoabdominal volumes. Fourteen patients with COPD (means ± SD) (FEV1: 55% ± 22% predicted) underwent, in a balanced order sequence, two intermittent exercise protocols on the cycle ergometer consisting of five repeated 2-min exercise bouts at 80% peak capacity, separated by 2-min recovery periods, with application of pNIV or PLB in the 5 min of recovery. Our findings identified seven patients showing recovery in DH with pNIV (DH responders) whereas seven showed similar or better recovery in DH with PLB. When pNIV was applied, DH responders compared with DH nonresponders exhibited greater tidal volume (by 0.8 ± 0.3 L, P = 0.015), inspiratory flow rate (by 0.6 ± 0.5 L/s, P = 0.049), prolonged expiratory time (by 0.6 ± 0.5 s, P = 0.006), and duty cycle (by 0.7 ± 0.6 s, P = 0.007). DH responders showed a reduction in end-expiratory thoracoabdominal DH (by 265 ± 633 mL) predominantly driven by reduction in the abdominal compartment (by 210 ± 494 mL); this effectively offset end-inspiratory rib-cage DH. Compared with DH nonresponders, DH responders had significantly greater body mass index (BMI) by 8.4 ± 3.2 kg/m2, P = 0.022 and tended toward less severe resting hyperinflation by 0.3 ± 0.3 L. Patients with COPD who mitigate end-expiratory rib-cage DH by expiratory abdominal muscle recruitment benefit from pNIV application. NEW & NOTEWORTHY Compared with the pursed-lip breathing technique, acute application of portable noninvasive ventilation during recovery from intermittent exercise improved end-expiratory thoracoabdominal dynamic hyperinflation (DH) in 50% of patients with COPD (DH responders). DH responders, compared with DH nonresponders, exhibited a reduction in end-expiratory thoracoabdominal DH predominantly driven by the abdominal compartment that effectively offset end-expiratory rib cage DH. The essential difference between DH responders and DH nonresponders was, therefore, in the behavior of the abdomen

Gait differences between COPD and healthy controls: systematic review and meta-analysis

BACKGROUND Despite the importance of gait as a determinant of falls, disability and mortality in older people, understanding of gait impairment in COPD is limited. This study aimed to identify differences in gait characteristics during supervised walking tests between people with COPD and healthy controls. METHODS We searched 11 electronic databases, supplemented by Google Scholar searches and manual collation of references, in November 2019 and updated the search in July 2021. Record screening and information extraction were performed independently by one reviewer and checked for accuracy by a second. Meta-analyses were performed in studies not considered at a high risk of bias. RESULTS Searches yielded 21 085 unique records, of which 25 were included in the systematic review (including 1015 people with COPD and 2229 healthy controls). Gait speed was assessed in 17 studies (usual speed: 12; fast speed: three; both speeds: two), step length in nine, step duration in seven, cadence in six, and step width in five. Five studies were considered at a high risk of bias. Low-quality evidence indicated that people with COPD walk more slowly than healthy controls at their usual speed (mean difference (MD) -19 cm·s$^{-1}$, 95% CI -28 to -11 cm·s$^{-1}$) and at a fast speed (MD -30 cm·s$^{-1}$, 95% CI -47 to -13 cm·s$^{-1}$). Alterations in other gait characteristics were not statistically significant. CONCLUSION Low-quality evidence shows that people with COPD walk more slowly than healthy controls, which could contribute to an increased falls risk. The evidence for alterations in spatial and temporal components of gait was inconclusive. Gait impairment appears to be an important but understudied area in COPD

Investigating the prognostic value of digital mobility outcomes in patients with chronic obstructive pulmonary disease: a systematic literature review and meta-analysis

BACKGROUND: Reduced mobility is a central feature of COPD. Assessment of mobility outcomes that can be measured digitally (digital mobility outcomes (DMOs)) in daily life such as gait speed and steps per day is increasingly possible using devices such as pedometers and accelerometers, but the predictive value of these measures remains unclear in relation to key outcomes such as hospital admission and survival. METHODS: We conducted a systematic review, nested within a larger scoping review by the MOBILISE-D consortium, addressing DMOs in a range of chronic conditions. Qualitative and quantitative analysis considering steps per day and gait speed and their association with clinical outcomes in COPD patients was performed. RESULTS: 21 studies (6076 participants) were included. Nine studies evaluated steps per day and 11 evaluated a measure reflecting gait speed in daily life. Negative associations were demonstrated between mortality risk and steps per day (per 1000 steps) (hazard ratio (HR) 0.81, 95% CI 0.75-0.88, p<0.001), gait speed (<0.80 m·s$^{-1}$) (HR 3.55, 95% CI 1.72-7.36, p<0.001) and gait speed (per 1.0 m·s$^{-1}$) (HR 7.55, 95% CI 1.11-51.3, p=0.04). Fewer steps per day (per 1000) and slow gait speed (<0.80 m·s$^{-1}$) were also associated with increased healthcare utilisation (HR 0.80, 95% CI 0.72-0.88, p<0.001; OR 3.36, 95% CI 1.42-7.94, p=0.01, respectively). Available evidence was of low-moderate quality with few studies eligible for meta-analysis. CONCLUSION: Daily step count and gait speed are negatively associated with mortality risk and other important outcomes in people with COPD and therefore may have value as prognostic indicators in clinical trials, but the quantity and quality of evidence is limited. Larger studies with consistent methodologies are called for

Personalised exercise-rehabilitation for people with multiple long-term conditions (PERFORM):A randomised feasibility study

Objective: Existing exercise-based rehabilitation services, such as cardiac and pulmonary rehabilitation, are traditionally commissioned around single long-term conditions (LTCs) and therefore may not meet the complex needs of adults with multiple long-term conditions (MLTCs) or multimorbidity. The aim of this study was to assess the feasibility and acceptability of the newly developed personalised exercise-rehabilitation programme for people with multiple long-term conditions (PERFORM) and the trial methods. Design: A parallel two-group mixed-methods feasibility randomised controlled trial (RCT) with embedded process and economic evaluation. Setting: Three UK sites (two acute hospital settings, one community-based healthcare setting). Participants: 60 adults with MLTCs (defined as the presence of ≥2 LTCs) with at least one known to benefit from exercise therapy were randomised 2:1 to PERFORM intervention plus usual care (PERFORM group) or usual care alone (control group). Intervention: The intervention consisted of 8 weeks of supervised group-based exercise rehabilitation and structured self-care symptom-based support. Primary and secondary outcome measures: Primary feasibility outcomes included: trial recruitment (percentage of a target of 60 participants recruited within 4.5 months), retention (percentage of participants with complete EuroQol data at 3 months) and intervention adherence (percentage of intervention group attending ≥60% sessions). Other feasibility measures included completion of outcome measures at baseline (pre-randomisation), 3 months post-randomisation (including patient-reported outcomes, exercise capacity and collection of health and social care resource use) and intervention fidelity. Results: Target recruitment (40 PERFORM group, 20 control group) was met within the timeframe. Participants were 57% women with a mean (SD) age of 62 (13) years, body mass index of 30.8 (8.0) kg/m2 and a median of 4 LTCs (most common: diabetes (41.7%), hypertension (38.3%), asthma (36.7%) and a painful condition (35.0%)). We achieved EuroQol outcome retention of 76.7% (95% CI: 65.9% to 87.1%; 46/60 participants) and intervention adherence of 72.5% (95% CI: 56.3% to 84.4%; 29/40 participants). Data completion for attendees was over 90% for 11/18 outcome measures. Conclusions: Our findings support the feasibility and rationale for delivering the PERFORM comprehensive self-management and exercise-based rehabilitation intervention for people living with MLTCs and progression to a full multicentre RCT to formally assess clinical effectiveness and cost-effectiveness. Trial registration number: ISRCTN68786622.</p

Laboratory and free-living gait performance in adults with COPD and healthy controls

BACKGROUND Gait characteristics are important risk factors for falls, hospitalisations and mortality in older adults, but the impact of COPD on gait performance remains unclear. We aimed to identify differences in gait characteristics between adults with COPD and healthy age-matched controls during 1) laboratory tests that included complex movements and obstacles, 2) simulated daily-life activities (supervised) and 3) free-living daily-life activities (unsupervised). METHODS This case-control study used a multi-sensor wearable system (INDIP) to obtain seven gait characteristics for each walking bout performed by adults with mild-to-severe COPD (n=17; forced expiratory volume in 1 s 57±19% predicted) and controls (n=20) during laboratory tests, and during simulated and free-living daily-life activities. Gait characteristics were compared between adults with COPD and healthy controls for all walking bouts combined, and for shorter (≤30 s) and longer (>30 s) walking bouts separately. RESULTS Slower walking speed (-11 cm·s$^{-1}$, 95% CI: -20 to -3) and lower cadence (-6.6 steps·min$^{-1}$, 95% CI: -12.3 to -0.9) were recorded in adults with COPD compared to healthy controls during longer (>30 s) free-living walking bouts, but not during shorter (≤30 s) walking bouts in either laboratory or free-living settings. Double support duration and gait variability measures were generally comparable between the two groups. CONCLUSION Gait impairment of adults with mild-to-severe COPD mainly manifests during relatively long walking bouts (>30 s) in free-living conditions. Future research should determine the underlying mechanism(s) of this impairment to facilitate the development of interventions that can improve free-living gait performance in adults with COPD

Mobilise-D Insights To Estimate Real-World Walking Speed in Multiple Conditions With a Wearable Device

This study aimed to validate a wearable device\u27s walking speed estimation pipeline, considering complexity, speed, and walking bout duration. The goal was to provide recommendations on the use of wearable devices for real-world mobility analysis. Participants with Parkinson\u27s Disease, Multiple Sclerosis, Proximal Femoral Fracture, Chronic Obstructive Pulmonary Disease, Congestive Heart Failure, and healthy older adults (n = 97) were monitored in the laboratory and the real-world (2.5 h), using a lower back wearable device. Two walking speed estimation pipelines were validated across 4408/1298 (2.5 h/laboratory) detected walking bouts, compared to 4620/1365 bouts detected by a multi-sensor reference system. In the laboratory, the mean absolute error (MAE) and mean relative error (MRE) for walking speed estimation ranged from 0.06 to 0.12 m/s and - 2.1 to 14.4%, with ICCs (Intraclass correlation coefficients) between good (0.79) and excellent (0.91). Real-world MAE ranged from 0.09 to 0.13, MARE from 1.3 to 22.7%, with ICCs indicating moderate (0.57) to good (0.88) agreement. Lower errors were observed for cohorts without major gait impairments, less complex tasks, and longer walking bouts. The analytical pipelines demonstrated moderate to good accuracy in estimating walking speed. Accuracy depended on confounding factors, emphasizing the need for robust technical validation before clinical application.Trial registration: ISRCTN - 12246987