Lorna Johnson

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.

EFFECT OF A HOME EXERCISE VIDEO PROGRAMME IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

OBJECTIVE This pilot study investigated whether a home exercise video programme could improve exercise tolerance and breathlessness in patients with moderate to severe chronic obstructive pulmonary disease. METHODS Twenty subjects completed the study after being randomized to intervention or control. The intervention group (n=10), watched a 19-min video on the benefits of exercise for patients with chronic obstructive pulmonary disease and were given a 30-min exercise video, an illustrated exercise diary and an educational booklet about chronic obstructive pulmonary disease, for use at home. They were advised to follow the exercise video programme 4 times a week for 6 weeks. The control group (n=10) received the chronic obstructive pulmonary disease educational booklet only. Exercise tolerance was measured using the Incremental Shuttle Walk Test and breathlessness by the self-reported Chronic Respiratory Questionnaire. RESULTS The median change in the Incremental Shuttle Walk Test and breathlessness score significantly improved in the intervention group compared with the control (+45 m vs -15 m, p=0.013 and +0.5 vs -0.1 Chronic Respiratory Questionnaire units, p=0.042). The other findings for the self-reported Chronic Respiratory Questionnaire showed significant improvements in the intervention group for emotion (p<0.001) and fatigue (p=0.012), but not mastery (p=0.253). CONCLUSION This pilot study suggests that participation in a home exercise video programme may benefit people with chronic obstructive pulmonary disease.

Inspiratory muscle maximum relaxation rate measured from submaximal sniff nasal pressure in patients with severe COPD

Background: Slowing of the inspiratory muscle maximum relaxation rate (MRR) is a useful index of severe inspiratory muscle loading and potential fatigue and has been measured from the oesophageal pressure during sniffs in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate whether it is possible to measure MRR and detect slowing using sniff nasal pressure in patients with COPD and to investigate the relationship between sniff oesophageal and sniff nasal MRR. Methods: Eight patients with severe COPD (mean FEV1 0.7 l; 26% predicted) were studied. Each subject performed submaximal sniff manoeuvres before and after walking to a state of severe dyspnoea on a treadmill. Oesophageal and gastric pressures were measured using balloon tipped catheters and nasal pressure was measured using an individually modelled nasal cast. MRR (% pressure fall/10 ms) was determined for each sniff and any change following exercise was reported as percentage of baseline to allow comparison of sniff nasal and oesophageal MRR. Results: At rest the mean (SE) sniff Poes MRR was 7.1 (0.3) and the mean Pnasal MRR was 8.6 (0.1). At 1 minute following exercise there was a mean decrease in sniff Poes MRR of 33.7% (range 20.7–53.4%) and a mean decrease in sniff Pnasal MRR of 28.2% (range 8.1–52.8%). The degree of slowing and time course of recovery was similar, with both returning to baseline values within 5–10 minutes. A separate analysis of the sniff pressures using only the nasal pressure traces demonstrated a similar pattern of slowing and recovery. Conclusions: It is possible to detect slowing of the inspiratory muscles non-invasively using sniff nasal pressures in patients with COPD. This could be a useful technique with which to measure severe and potentially fatiguing inspiratory muscle loading, both in clinical settings and during exercise studies.

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.

Interprofessional working in acute care

Background:  This paper describes the development and implementation of an interprofessional (IP) module for pre‐qualification medical, nursing and physiotherapy students. The module focuses on clinical care in the acute care setting, and is called Interprofessional Working in Acute Care (IWAC).

Sniff Nasal Inspiratory Pressure in Patients with Moderate-to-Severe Chronic Obstructive Pulmonary Disease: Learning Effect and Short-Term Between-Session Repeatability

Background: Sniff nasal inspiratory pressure (SNIP) is a non-invasive measure of inspiratory muscle function often used as an outcome measure in clinical studies. An initial period of familiarisation with the test is recommended to minimise the learning effect. The repeatability of SNIP in patients with chronic obstructive pulmonary disease (COPD) is currently unknown. Objectives: The aim of this study was to assess the between-session repeatability of SNIP over a 3-week period in moderate-to-severe COPD patients and compare it with that of maximal inspiratory (PImax) and expiratory pressure (PEmax). Methods: Twenty-one patients (13 males) with a mean forced expiratory volume in 1 s (FEV1) of 38% of predicted (SD: 15) and FEV1/forced vital capacity of 34.3% (SD: 10.4) performed SNIP and PImax and PEmax manoeuvres on 3 different sessions (S1, S2 and S3) 3-7 days apart. SNIP was performed at functional residual capacity (FRC), and PImax was performed at FRC and at residual volume (RV) to explore volume-dependent differences in the learning effect between sessions and PEmax from total lung capacity. Results: The intra-class correlation coefficient (ICC) for SNIP was the highest of the three measures: S1-S3 ICC (95% CI) SNIP: 0.96 (0.88-0.94); PImax at FRC 0.82 (0.63-0.92); PImax at RV: 0.89 (0.78-0.95), and PEmax: 0.96 (0.92-0.98), and had the lowest mean change between sessions [mean S2 - S1: 2.1(p = 0.4) and S3 - S2: -0.3 (p = 0.9)]. Conclusions: SNIP is repeatable over a period of 3 weeks in medically stable, moderate-to-severe COPD patients. In our study, 2 sessions were adequate to learn how to perform the test.

Serum cotinine and prognosis in breast cancer

Various studies have suggested that women who smoke have a worse prognosis if they develop breast cancer. Cotinine levels have been measured in sera from 511 patients with stage I and II breast cancer diagnosed between 1975 and 1980, all of whom had complete follow-up. Although the known prognostic factors, axillary nodal status, tumour size and grade were found to be significant, there was no relationship between serum cotinine and metastasis-free survival. A point estimate of serum cotinine was not found to be a determinant of survival in women with early breast cancer.