The Evidence Regarding Exercise Training in the Management of Cystic Fibrosis: A Systematic Review

Purpose: To conduct a systematic review of the evidence regarding the efficacy of exercise training in the management of cystic fibrosis (CF).Methods: Articles were found by searching PEDRO, MEDLINE, and CINAHL databases. Included articles involved exercise-related interventions for long-term adaptations (ie, not acute effects of exercise). Articles were excluded if the language was other than English or if other non-exercise interventions were used. Date of publication was not a factor for exclusion. Two independent reviewers evaluated the included articles using Sackett''s levels of evidence and select scoring criteria.Results: Twelve articles were eligible for inclusion. Interventions studied included various aspects of exercise training: anaerobic, aerobic, or resistance training. Study end-points included pulmonary function, aerobic capacity, strength, and health-related quality of life (HRQL).Conclusions: Exercise training in individuals with CF is beneficial, with aerobic and resistance training having the greatest support in the literature for improved aerobic capacity and strength, respectively. Exercise training does not appear to have an effect of improving pulmonary function, but may have a preservation effect. Strong conclusions about improvement in HQRL from exercise training cannot be made. However, greater consistency in measuring this outcome is needed in future trials. There is a paucity of evidence regarding the role of exercise training in reducing hospitalization and health care utilization, and questions raised by this review should be considered in the design of future trials.Key Words: cystic fibrosis, aerobic exercise, review     

Triangulating Clinically Meaningful Change in the Six-minute Walk Test in Individuals with Chronic Heart Failure: A Systematic Review

Purpose

The purpose of the present review was to use existing, published data to provide an estimate of the amount of change in six-minute walk test distance (Δ6MWT) that represents a clinically meaningful change in individuals with chronic heart failure (CHF).

Methods

The present review included two separate literature searches of the CINAHL and Medline databases for articles that: (1) reported the intraclass correlation coefficient (ICC) of the 6MWT in individuals with CHF, and (2) used the 6MWT along with either aerobic capacity or health-related quality of life (HRQL) as study endpoints in randomized controlled trials (RCTs) of exercise-based intervention for individuals with CHF. The ICCs were used to calculate the minimum detectable difference (MDD) at the 95% confidence interval for each included study. The Δ6MWT associated with aerobic capacity and HRQL within-group effect sizes for the intervention and control groups in each included RCT was analyzed using receiver operating characteristic (ROC) curves.

Results

Thirteen articles reported the ICC for the 6MWT. The mean (standard deviation) MDD calculated based on these data was 43.1(16.8) m. Eighteen RCTs measured the 6MWT and either aerobic capacity and/or HRQL. A Δ6MWT of 40–45 m was associated with at least moderate aerobic capacity and HRQL effect sizes in the intervention groups. The Δ6MWT thresholds that discriminated between intervention and control groups using ROC curves revealed the following sensitivity/specificity for the respective thresholds: 19 m, 94.4/83.3%, 32 m, 83.3/94.4%, and 48 m 44.4/100% (AUC = .935, p = .009, CI_95% .855, 1.015).

Conclusions

A Δ6MWT of approximately 45 m appears to exceed measurement error and be associated with significant changes in either aerobic capacity and/or HRQL.Key Words: heart failure, six-minute walk test, clinically meaningful change, minimum detectable difference     

Discrepancies in the values of standard atmospheric pressure: the riddle resolved

Over half a century ago, when I took Beginning Physics at university, I was bothered by the anomaly that normal air pressure (which is arbitrary anyhow) was taken to be 1.013250 bar instead of a sensible 1.000000 bar. My professor could not explain why, nor could any of the many other scientists whom I have asked since then. Now in retirement, I have made a laborious search in utterly uncharted territory and discovered the answer.     

Inspiratory Muscle Training in Patients with Chronic Obstructive Pulmonary Disease: The State of the Evidence

Purpose: The purpose of the present review was to assess the quality of evidence in the literature regarding the specific benefits of inspiratory muscle training (IMT) with an emphasis on training intensity and the relationships between changes in inspiratory muscle function and other clinical outcome measures. Methods: Articles were found by searching CINAHL, PubMed, Medline via First Search, and ProQuest databases. Articles used in the review were randomized trials of IMT vs. sham IMT or no intervention, published in English in a peer-reviewed journal, included patients with chronic obstructive pulmonary disease (COPD), and specified the intensity of training. The quality of the studies was evaluated by 2 independent reviewers using the methodological rigor scale described by Medlicott and Harris as well as Sackett''s levels of evidence. Fifteen articles met the inclusion criteria and were used in this review. Results: Consistent improvements in maximal inspiratory pressures (ranging from −11 to −30 cm H₂O) and inspiratory muscle endurance were found. Improvements in dyspnea and health-related quality of life were also observed. Inspiratory muscle training may result in improved exercise tolerance as measured using walking tests. High-intensity IMT resulted in improved training efficiency with respect to inspiratory muscle strength, but evidence of the effect of high-intensity IMT on other clinical outcomes is lacking. Conclusion: Despite research spanning decades, there are numerous limitations in the literature regarding IMT. IMT appears to improve dyspnea, waking test distance, and health-related quality of life in individuals with COPD, but it is not clear whether this improvement is mediated through improved inspiratory muscle strength and endurance. This review discussed several considerations critical to the design of future trials.Key Words: inspiratory muscle training, COPD     

Exercise Training in Patients with Pulmonary Arterial Hypertension: A Case Report

Purpose: To describe the benefits of a feasible, outpatient exercise training program on exercise tolerance and health-related quality of life (HRQL) in individuals with pulmonary arterial hypertension (PAH). Methods: Case report on two subjects recruited from a tertiary care pulmonary hypertension clinic. Subject 1 was a 50-year-old male with idiopathic PAH. Subject 2 was a 54-year-old female with a 20+ year history of scleroderma and 6-year history of PAH. Both subjects underwent exercise training 3 times per week for 6 weeks using a cycle ergometer at workloads progressing from 50% to 80% of peak workload. Outcomes were assessed using cardiopulmonary exercise testing, six-minute walk test (6MWT), and HRQL using the Chronic Respiratory Disease Questionnaire (CRQ) and the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR). Results: Both subjects made substantial improvements in oxygen consumption and workload at anaerobic threshold (improvements of 3.8 and 4.2 mL·kg⁻¹·min,⁻¹ 26 and 18 W, respectively) and 6MWT distance (from 496 to 586m and 416 to 517m, respectively). Only Subject 1 made substantial improvements in peak oxygen consumption (from 16.0 to 18.3 mL·kg⁻¹·min⁻¹and from 15.0 to 15.6 mL·kg⁻¹·min,⁻¹ respectively) and peak work rate (from 112 to 130W and 66 to 69W, respectively). Both subjects demonstrated improved HRQL. No adverse events were noted. CONCLUSIONS: A short and practical exercise training program can improve measures of workload, aerobic capacity, and HRQL in individuals with PAH with no adverse effects shown in these two case studies.Key Words: pulmonary arterial hypertension, exercise training