Dimitra Nikoletou

Proportional assist ventilation as an aid to exercise training in severe chronic obstructive pulmonary disease

Background: The effects of providing ventilatory assistance to patients with severe chronic obstructive pulmonary disease (COPD) during a high intensity outpatient cycle exercise programme were examined. Methods: Nineteen patients (17 men) with severe COPD (mean (SD) forced expiratory volume in 1 second (FEV1) 27 (7)% predicted) underwent a 6 week supervised outpatient cycle exercise programme. Ten patients were randomised to exercise with ventilatory assistance using proportional assist ventilation (PAV) and nine (two women) to exercise unaided. Before and after training patients performed a maximal symptom limited incremental cycle test to determine peak work rate (Wpeak) followed by a constant work rate (CWR) test at 70% of Wpeak achieved in the baseline incremental test. Minute ventilation (Ve), heart rate, and arterialised venous plasma lactate concentration [La+] were measured before and after each test. Results: Mean training intensity (Wt/Wpeak) at 6 weeks was 15.2% (95% CI 3.2 to 27.1) higher in the group that used ventilatory assistance (p=0.016). Peak work rate after training was 18.4% (95% CI 6.4 to 30.5) higher (p=0.005) in the assisted group (p=0.09). [La+] at an identical workload after training was reduced by 30% (95% CI 16 to 44) in the assisted group (p=0.002 compared with baseline) and by 11% (95% CI –7 to 31) (p=0.08 compared with baseline) in the unassisted group (mean difference 18.4% (95% CI 3.3 to 40), p=0.09). A significant inverse relationship was found between reduction in plasma lactate concentration (ΔL) at an equivalent workload after training during the CWR test and Wt/Wpeak achieved during the last week of training (r=–0.7, p=0.0006). Conclusions: PAV enables a higher intensity of training in patients with severe COPD, leading to greater improvements in maximum exercise capacity with evidence of true physiological adaptation.

Non-volitional assessment of skeletal muscle strength in patients with chronic obstructive pulmonary disease

Background: Although quadriceps weakness is well recognised in chronic obstructive pulmonary disease (COPD), the aetiology remains unknown. In disabled patients the quadriceps is a particularly underused muscle and may not reflect skeletal muscle function as a whole. Loss of muscle function is likely to be equally distributed if the underlying pathology is a systemic abnormality. Conversely, if deconditioning and disuse are the principal aetiological factors, weakness would be most marked in the lower limb muscles. Methods: The non-volitional technique of supramaximal magnetic stimulation was used to assess twitch tensions of the adductor pollicis, quadriceps, and diaphragm muscles (TwAP, TwQ, and TwPdi) in 22 stable non-weight losing COPD patients and 18 elderly controls. Results: Mean (SD) TwQ tension was reduced in the COPD patients (7.1 (2.2) kg v 10.0 (2.7) kg; 95% confidence intervals (CI) −4.4 to −1.4; p<0.001). Neither TwAP nor TwPdi (when corrected for lung volume) differed significantly between patients and controls (mean (SD) TwAP 6.52 (1.90) N for COPD patients and 6.80 (1.99) N for controls (95% CI −1.5 to 0.97, p=0.65; TwPdi 23.0 (5.6) cm H2O for COPD patients and 23.5 (5.2) cm H2O for controls (95% CI −4.5 to 3.5, p=0.81). Conclusions: The strength of the adductor pollicis muscle (and the diaphragm) is normal in patients with stable COPD whereas quadriceps strength is substantially reduced. Disuse may be the principal factor in the development of skeletal muscle weakness in COPD, but a systemic process preferentially affecting the proximal muscles cannot be excluded.

Effect of salmeterol on respiratory muscle activity during exercise in poorly reversible COPD

Background: Some patients with irreversible chronic obstructive pulmonary disease (COPD) experience subjective benefit from long acting bronchodilators without change in forced expiratory volume in 1 second (FEV1). Dynamic hyperinflation is an important determinant of exercise induced dyspnoea in COPD. We hypothesised that long acting bronchodilators improve symptoms by reducing dynamic hyperinflation and work of breathing, as measured by respiratory muscle pressure-time products. Methods: Sixteen patients with “irreversible” COPD (<10% improvement in FEV1 following a bronchodilator challenge; mean FEV1 31.1% predicted) were recruited into a randomised, double blind, placebo controlled, crossover study of salmeterol (50 μg twice a day). Treatment periods were of 2 weeks duration with a 2 week washout period. Primary outcome measures were end exercise isotime transdiaphragmatic pressure-time product and dynamic hyperinflation as measured by inspiratory capacity. Results: Salmeterol significantly reduced the transdiaphragmatic pressure-time product (294.5 v 348.6 cm H2O/s/min; p = 0.03), dynamic hyperinflation (0.22 v 0.33 litres; p = 0.002), and Borg scores during endurance treadmill walk (3.78 v 4.62; p = 0.02). There was no significant change in exercise endurance time. Improvements in isotime Borg score were significantly correlated to changes in tidal volume/oesophageal pressure swings, end expiratory lung volume, and inspiratory capacity, but not pressure-time products. Conclusions: Despite apparent “non-reversibility” in spirometric parameters, long acting bronchodilators can cause both symptomatic and physiological improvement during exercise in severe COPD.

Cough augmentation in amyotrophic lateral sclerosis

Cough flows and pressures were measured during cough augmentation in healthy subjects and patients with bulbar and nonbulbar amyotrophic lateral sclerosis. Manual assistance increased flow 11% in bulbar (p < 0.01) and 13% in nonbulbar (p < 0.001) patients. Mechanical insufflation-exsufflation increased flow 17% in healthy subjects (p < 0.05), 26% (p < 0.001) in bulbar, and 28% (p < 0.001) in nonbulbar patients. The greatest improvements were in patients with the weakest coughs. Patient group and level of weakness influenced the effect of augmentation.

Abdominal muscle and quadriceps strength in chronic obstructive pulmonary disease

Background: Quadriceps muscle weakness is common in chronic obstructive pulmonary disease (COPD) but is not observed in a small hand muscle (adductor pollicis). Although this could be explained by reduced activity in the quadriceps, the observation could also be explained by anatomical location of the muscle or fibre type composition. However, the abdominal muscles are of a similar anatomical and fibre type distribution to the quadriceps, although they remain active in COPD. Cough gastric pressure is a recently described technique that assesses abdominal muscle (and hence expiratory muscle) strength more accurately than traditional techniques. A study was undertaken to test the hypothesis that more severe weakness exists in the quadriceps than in the abdominal muscles of patients with COPD compared with healthy elderly controls. Methods: Maximum cough gastric pressure and quadriceps isometric strength were measured in 43 patients with stable COPD and 25 healthy elderly volunteers matched for anthropometric variables. Results: Despite a significant reduction in mean quadriceps strength (29.9 kg v 41.2 kg; 95% CI −17.9 to −4.6; p = 0.001), cough gastric pressure was preserved in patients with COPD (227.3 cm H2O v 204.8 cm H2O; 95% CI −5.4 to 50.6; p = 0.11). Conclusions: Abdominal muscle strength is preserved in stable COPD outpatients in the presence of quadriceps weakness. This suggests that anatomical location and fibre type cannot explain quadriceps weakness in COPD. By inference, we conclude that disuse and consequent deconditioning are important factors in the development of quadriceps muscle weakness in COPD patients, or that activity protects the abdominal muscles from possible systemic myopathic processes.

The Chelsea Critical Care Physical Assessment Tool (CPAx): validation of an innovative new tool to measure physical morbidity in the general adult critical care population; an observational proof-of-concept pilot study

OBJECTIVE To develop a scoring system to measure physical morbidity in critical care - the Chelsea Critical Care Physical Assessment Tool (CPAx). METHOD The development process was iterative involving content validity indices (CVI), a focus group and an observational study of 33 patients to test construct validity against the Medical Research Council score for muscle strength, peak cough flow, Australian Therapy Outcome Measures score, Glasgow Coma Scale score, Bloomsbury sedation score, Sequential Organ Failure Assessment score, Short Form 36 (SF-36) score, days of mechanical ventilation and inter-rater reliability. PARTICIPANTS Trauma and general critical care patients from two London teaching hospitals. RESULTS Users of the CPAx felt that it possessed content validity, giving a final CVI of 1.00 (P<0.05). Construct validation data showed moderate to strong significant correlations between the CPAx score and all secondary measures, apart from the mental component of the SF-36 which demonstrated weak correlation with the CPAx score (r=0.024, P=0.720). Reliability testing showed internal consistency of α=0.798 and inter-rater reliability of κ=0.988 (95% confidence interval 0.791 to 1.000) between five raters. CONCLUSION This pilot work supports proof of concept of the CPAx as a measure of physical morbidity in the critical care population, and is a cogent argument for further investigation of the scoring system.

WHODAS 2.0 in community rehabilitation: a qualitative investigation into the validity of a generic patient-reported measure of disability

Abstract Purpose: The World Health Organization Disability Assessment Schedule (WHODAS 2.0) was considered as a potentially appropriate patient-reported outcome measure (PROM) for community rehabilitation services in the UK. The study explored qualitative aspects of the measure’s content and content and construct validity. Method: A convenience sample of 10 community rehabilitation service users participated in semi-structured interviews and completed the WHODAS 2.0. Content analysis and a constant comparative method of analysis were applied. Participants’ accounts were compared with the measure’s content and its underlying construct of disability. Results: Participants’ reports of current difficulties were rich with accounts of bodily impairments and activity and participation limitations. WHODAS 2.0 content largely covered those activities that interviewees found difficult. Participants tended to conceptualize disability according to the medical model. The wording of the questionnaire allowed for ambiguity with respect to social perspectives on disability, which resulted in variability of scores. Conclusions: While WHODAS 2.0 content coverage appears comprehensive, the questionnaire in its current form tends to favor a medical construct of disability. We recommend caution when applying WHODAS 2.0 in contexts such as community rehabilitation, where social aspects of disability may be considered important. Further investigation of the measure’s construct validity might be warranted. Implications for Rehabilitation WHODAS 2.0 implicitly favors a medical interpretation of disability. WHODAS 2.0 may not be appropriate in contexts where social perspectives on disability are considered important, such as in community rehabilitation.

Evaluation of the effectiveness of a home-based inspiratory muscle training programme in patients with chronic obstructive pulmonary disease using multiple inspiratory muscle tests

Abstract Purpose: To evaluate the effectiveness of a home-based inspiratory muscle training (IMT) programme using multiple inspiratory muscle tests. Method: Sixty-eight patients (37 M) with moderate to severe chronic obstructive pulmonary disease (COPD) (Mean [SD], FEV1 36.1 [13.6]% pred.; FEV1/FVC 35.7 [11.2]%) were randomised into an experimental or control group and trained with a threshold loading device at intensity >30% maximum inspiratory pressure (PImax) or <15% PImax, respectively, for 7 weeks. Thirty-nine patients (23 M) completed the study. The following measures were assessed pre- and post-IMT: PImax, sniff inspiratory nasal pressure (SNIP), diaphragm contractility (Pdi,tw), incremental shuttle walk test (ISWT), respiratory muscle endurance (RME), chronic respiratory disease questionnaire (CRDQ), the hospital anxiety and depression scale (HADS) and the SF-36. Between-group changes were assessed using one-way analysis of variance (ANOVA). Results: PImax and perception of well-being improved significantly post-IMT [p = 0.04 and <0.05 in four domains, respectively]. This was not reflected in SNIP [p = 0.7], Pdi,tw [p = 0.8], RME [p = 0.9] or ISWT [p = 0.5]. Conclusions: A seven-week, community-based IMT programme, with realistic use of health-care resources, improves PImax and perception of well-being but a different design may be required for improvement in other measures. Multiple tests provide a more comprehensive evaluation of changes in muscle function post-IMT. Implications for Rehabilitation A seven-week, home-based inspiratory muscle training programme improves maximal inspiratory pressure and perception of well-being in patients with moderate to severe COPD but not sniff nasal inspiratory pressure or diaphragm contractility, respiratory muscle endurance and exercise capacity. Multiple tests are recommended for a more comprehensive assessment of changes in muscle function following inspiratory muscle training programmes. Therapists need to explore different community-based inspiratory muscle training regimes for COPD patients and identify the optimal exercise protocol that is likely to lead to improvements in diaphragm contractility and exercise capacity.

P248 Measuring physical recovery in the critical care population: development of the Chelsea critical care physical assessment tool (CPAx)

Introduction The secondary physical effects of critical illness, for example, muscle atrophy, can be detrimental to functional outcome and quality of life in critical care survivors. To minimise these problems early physiotherapy in the Intensive Care Unit (ICU) is advocated. However, research to identify the optimal rehabilitation strategy is hindered by lack of an ICU specific objective measure of physical recovery. Current measures are either impairment specific, thus not capturing the full picture, or their validity is unproven in this population. Aim To develop a measurement tool to assess physical recovery in the heterogeneous general adult critical care population. Method Face/content validity The initial tool was developed in a clinical setting by specialist physiotherapists and is called the Chelsea Critical Care Physical Assessment tool (CPAx). It is a pictorial composite of 10 numerical evaluations of pertinent functions and impairments. It was tested for face and content validity with a content validity index questionnaire (CVIQ), a subsequent focus group and a repeat CVIQ. Inter-rater reliability Five physiotherapists using the CPAx regularly all assessed the same two patients. Data were analysed for intra-class correlation co-efficient (ICC) and internal consistency. Construct validity A dual centred cohort study of 32 ICU patients was completed. Treating physiotherapists assessed patients using the CPAx thrice weekly. Additionally, biceps and quadriceps strength, cough peak flow (CPF) and components of the AusTOMs scores (a physiotherapy outcome measure) were tested by a researcher blinded to the CPAx scores. Correlation co-efficients were then used to analyse the data. Results Face/content validity Pre and post focus group CVIs were 0.67 (p>0.05) and 0.83 (p<0.05), respectively. Reliability Reliability was strong with internal consistency of 0.98 and ICC 0.902 (95% CI 0.799 to 0.969; p=<0.001). Construct validity Pilot data showed strong positive correlations (0.744–0.922, p<0.01), between the CPAx, muscle strength and AusTOMs scores. Data were insufficient to analyse CPF results. Conclusion Preliminary data show that the CPAx is a reliable and valid measure of physical function in ICU patients. It can now be used as an outcome measure for physiotherapy research and has potential to act as a predictor of functional outcome in the ICU population.Abstract P248 Table 1 Construct validity data AusTOMs BPCA AusTOMs BPCI AusTOMs MSKA AusTOMs MSKI Left Quadriceps Right Quadriceps Left Biceps Right Biceps Correlation Coefficient with the CPAx score 0.922* 0.892* 0.888* 0.844* 0.756* 0.765* 0.744* 0.752* Number of patient measurements 42 40 42 41 42 42 42 42* Correlation is significant to the level p=0.01. AusTOMs BPCA, balance and postural control activity section of the AusTOMs tool; AusTOMsBPCI, balance and postural control impairment section of the AusTOMs tool; AusTOMs MSKA, musculoskeletal activity section of the AusTOMs; AusTOMs MSKI, musculoskeletal impairment section of the AusTOMs.

Giving hope, ticking boxes or securing services? A qualitative study of respiratory physiotherapists’ views on goal-setting with people with chronic obstructive pulmonary disease

Objective: To explore respiratory physiotherapists’ views and experiences of using goal-setting with people with chronic obstructive pulmonary disease in rehabilitation settings. Participants: A total of 17 respiratory physiotherapists with ⩾12 months current or previous experience of working with patients with chronic obstructive pulmonary disease in a non-acute setting. Participants were diverse in relation to age (25–49 years), sex (13 women), experience (Agenda for Change bands 6–8) and geographic location. Method: Data were collected via face-to-face qualitative in-depth interviews (40–70 minutes) using a semi-structured interview guide. Interview locations were selected by participants (included participants’ homes, public places and University). Interviews followed an interview guide, were audio-recorded and transcribed verbatim. Data Analysis: Data were analysed using thematic analysis; constant comparison was made within and between accounts, and negative case analysis was used. Results: Three themes emerged through the process of analysis: (1) ‘Explaining goal-setting’; (2) ‘Working with goals’; and (3) ‘Influences on collaborative goal-setting’. Goal-setting practices among respiratory physiotherapists varied considerably. Collaborative goal-setting was described as challenging and was sometimes driven by service need rather than patient values. Lack of training in collaborative goal-setting at both undergraduate and postgraduate level was also seen as an issue. Conclusion: Respiratory physiotherapists reflected uncertainties around the use of goal-setting in their practice, and conflict between patients’ goals and organisational demands. This work highlights a need for wider discussion to clarify the purpose and implementation of goal-setting in respiratory rehabilitation.