Changes in airflow obstruction and oxygen saturation in response to exercise and bronchodilators in cystic fibrosis

Physiotherapy for cystic fibrosis in Australia and New Zealand: A clinical practice guideline

Physiotherapy management is a key element of care for people with cystic fibrosis (CF) throughout the lifespan. Although considerable evidence exists to support physiotherapy management of CF, there is documented variation in practice. The aim of this guideline is to optimize the physiotherapy management of people with CF in Australia and New Zealand. A systematic review of the literature in key areas of physiotherapy practice for CF was undertaken. Recommendations were formulated based on National Health and Medical Research Council (Australia) guidelines and considered the quality, quantity and level of the evidence; the consistency of the body of evidence; the likely clinical impact; and applicability to physiotherapy practice in Australia and New Zealand. A total of 30 recommendations were made for airway clearance therapy, inhalation therapy, exercise assessment and training, musculoskeletal management, management of urinary incontinence, managing the newly diagnosed patient with CF, delivery of non-invasive ventilation, and physiotherapy management before and after lung transplantation. These recommendations can be used to underpin the provision of evidence-based physiotherapy care to people with CF in Australia and New Zealand.

Effects of inspiratory muscle training in cystic fibrosis: a systematic review

OBJECTIVE

We performed a systematic review to determine the effect of inspiratory muscle training (IMT) on inspiratory muscle strength and endurance, exercise capacity, dyspnoea and quality of life for adolescents and adults living with cystic fibrosis.

DATA SOURCES

MEDLINE, EMBASE and CINAHL electronic databases were searched up to January 2008.

REVIEW METHODS

We performed a systematic review using the methodology outlined in the Cochrane Collaboration protocol. Articles were included if: (1) participants were adolescents or adults with cystic fibrosis (> 13 years of age); (2) an IMT group was compared to a sham IMT, no intervention or other intervention group; (3) the study used a randomized controlled trial or cross-over design; and (4) it was published in English. Data were abstracted and methodological quality was assessed independently by two reviewers.

RESULTS

The search strategy yielded 36 articles, of which two met the inclusion criteria. Both studies used a targeted or threshold device for IMT. Meta-analyses were limited to forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), which showed no difference in effect between the IMT group and the sham and/or control group. Individual study results were inconclusive for improvement in inspiratory muscle strength. One study demonstrated improvement in inspiratory muscle endurance.

CONCLUSION

The benefit of IMT in adolescents and adults with cystic fibrosis for outcomes of inspiratory muscle function is supported by weak evidence. Its impact on exercise capacity, dyspnoea and quality of life is not clear. Future research should investigate the characteristics of the subgroup of people with cystic fibrosis that might benefit most from IMT.

Platelet-derived growth factor receptor-alpha-expressing cells localize to the alveolar entry ring and have characteristics of myofibroblasts during pulmonary alveolar septal formation

Platelet-derived growth factor-A and its receptor, platelet-derived growth factor receptor-alpha (PDGF-Ralpha), are required for formation of the secondary pulmonary alveolar septa in mice. However, it remains unclear how these molecules direct the secondary septation process. We have examined the abundance, location, and the accumulation of alpha-smooth muscle actin (alphaSMA), neutral lipid droplets, and elastin in the proximity of PDGF-Ralpha-expressing alveolar cells during postnatal days 4 through 12 in the mouse. PDGF-Ralpha-expressing cells preferentially have characteristics of myofibroblasts and were more likely to contain alphaSMA than are alveolar cells that do not express PDGF-Ralpha. PDGF-Ralpha expressing cells were preferentially located in the alveolar entry ring (AER) where alphaSMA and elastic fibers accumulate. In contrast, PDGF-Ralpha expression inversely correlated with neutral lipid accumulation, which was more prominent at the alveolar base, distant from the AER. PDGF-Ralpha-expressing alveolar cells accumulate in the AER where they may promote mechanical stability during respiration. In addition to defining how alveolar septa form, these findings may have implications for the treatment of diseases which involve alveolar effacement such as emphysema and pulmonary fibrosis.

Traitements inhales bronchodilatateurs et fluidifiants dans la mucoviscidose

Poor clearance of airway secretions contributes to the pulmonary disease in cystic fibrosis (CF). Bronchodilator therapy might benefit in CF, but the efficacy is controversial. Effects of mucolytic agents have not been demonstrated conclusively. Only, efficacy of recombinant human deoxyribonuclease (rhDNase) is established with a rapid onset of benefit.

"CF asthma": what is it and what do we do about it?

The diagnosis of "CF asthma" is problematic and it is difficult to determine which patients have a combination of CF and asthma and which have asthma like symptoms caused by inflammation of the CF lung. This may not matter, however; the relevance lies in the possible approaches to treatment.

Effectiveness of bronchodilators in cystic fibrosis

Bronchodilators (xanthines, adrenergics, and parasympatholytics) have been used for years in the treatment of airway obstruction associated with cystic fibrosis. Their effectiveness in bringing about consistent and significant reversal of airway obstruction remains a topic for debate. A review of the literature suggests that the majority of patients with cystic fibrosis have hyperresponsive and hyperactive airways and will respond favorably to bronchodilators, at least some of the time. Bronchial hyperresponsiveness tends to be greater in patients with advanced disease than in mildly affected ones. Responses to bronchodilators appear to be greatest when airway disease is mild-to-moderate, when there is a documented excessive bronchial hyperresponsiveness to nonspecific bronchoconstrictors (methacholine, histamine), and when the patients are young. The response to intravenous xanthine and terbutaline is best when patients experience an acute pulmonary exacerbation and when aerosolized bronchodilators are relatively ineffective. Patients with advanced airway destruction and obstruction have a high degree of airway wall instability, which may be worsened by inhaled bronchodilators. Adrenergic and parasympatholytic aerosols are equally effective; combining them in optimal doses may be more beneficial than using either alone. Atropine and ipratropium bromide may be more effective in adults than children, but this remains to be further evaluated. Some of the apparently poor responses to inhaled bronchodilators are likely due to inadequate dosing. In conclusion, most patients with cystic fibrosis are likely to benefit from bronchodilator therapy when given in adequate doses, appropriate combinations, and by the appropriate route.

Short-term and long-term effects of albuterol aerosol therapy in cystic fibrosis: a preliminary report

The effectiveness of maintenance albuterol aerosol therapy in cystic fibrosis (CF) was assessed by comparing spirometric measurements at the beginning and end of 1 year. Peak expiratory flow rates (PEFR) were measured twice daily to determine bronchodilator responsiveness and spontaneous diurnal variation (SDV), and results were compared with groups of normal and asthmatic children. CF patients not receiving regular albuterol therapy served as a control group. In the treatment group, forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) were significantly increased (12.2% and 18.4%, respectively) over the course of the treatment year, as contrasted with a significant decrease during the preceding year. During the study year the CF control group had a significant decrease in FEV1 and FEF25-75%, and the difference between treatment and control groups was significant for FVC, FEV1, and FEF25-75%. PEFR increased from the first to the last week of the year-long observation period (from 71.8% to 78.7% of predicted values, P < 0.01). Spontaneous diurnal variations were significantly greater in the CF study group than a group of normal children; SDV decreased significantly in the treatment group during the year of study. A bronchodilator response of > 15% was present in 25.8% of CF patient days, but there was considerable interpatient variability. Frequent bronchodilator responders were accurately predicted by their baseline bronchodilator responsiveness, but not by age or personal or family history of asthma or atopy. No difference in long-term pulmonary function improvements were noted between frequent and infrequent responders. The results suggest that maintenance albuterol aerosol treatments reversed the progressive downward course in lung function in the CF treatment group. A double-blind placebo-controlled study is required to confirm these preliminary findings.

Evolution of pulmonary function during an acute exacerbation in hospitalized patients with cystic fibrosis

Few objective criteria have been validated for serial clinical monitoring in patients with cystic fibrosis (CF) during pulmonary exacerbations. While pulmonary function tests (PFT) are often used to monitor clinical improvement, it is not known which test correlates most closely with clinical improvement. To answer this, we measured routine PFT in 58 patients with CF before, during, and at discharge after 2-3 week hospital admission in 71 episodes of pulmonary exacerbation. Patients with CF were discharged based on clinical, radiological, and laboratory criteria. In general, all PFTs improved at midadmission and improved further by discharge, at which time forced expiratory volume in 1 second (FEV1), forced expiratory flow between 25% and 75% of forced vital capacity (FEF25-75), vital capacity (VC), maximal voluntary ventilation (MVV), and oxygen saturation by pulse oximetry (SPO2) increased. The residual volume to total capacity ratio (RV/TLC) and the slope of phase 3 in the single breath N2 washout curve (SP3 N2) decreased. The change in SP3 N2 was significantly greater than in any other PFT (P < 0.01 vs. VC and FEV1; P < 0.02 vs. RV and P < 0.001 vs. SPO2). A calculated optimal cut-off value for SP3 N2 improvement was significantly more sensitive in identifying patient improvement at discharge than any other pulmonary function test (P = 0.005). We speculate that clinical improvement in patients with CF is closely linked to improved distribution of ventilation.

Increased physiological dead space during exercise after bronchodilation in cystic fibrosis

Bicycle ergospirometry was performed on 14 patients with cystic fibrosis (CF), for evaluating the effects of salbutamol and theophylline on the ventilatory response to exercise. After 1 week without bronchodilator therapy the patients cycled at 1/3 and 2/3 of their individual maximal working capacity (Wmax). The test was repeated three times after treatment with salbutamol, theophylline, or both drugs, respectively. After the combined therapy, physiological deadspace, ventilation, ventilatory equivalent of oxygen, and end-expiratory oxygen pressure increased significantly during steady state exercise at 1/3 Wmax. Similar, although not statistically significant changes, were observed after monotherapy with salbutamol or theophylline and during exercise at 2/3 Wmax. These effects could not be predicted by any lung function tests at rest or by the Shwachman-Kulczycki score. The results indicate that in some patients with CF bronchodilators can impair lung function during exercise. In conclusion, the effects of medication on exercise performance of patients with CF have to be considered. Especially, the use of bronchodilators requires a careful evaluation of their real benefit in each individual patient.