Physiotherapy plays an important role in the management of cystic fibrosis (CF). The role of physiotherapy has evolved dramatically as people with CF are now living into their 5th decade . Practioners cannot only be concerned with treating the basic defect, but also must treat disorders which arise secondarily.
Although airway clearance has been the mainstay of treatment in CF for the past 60 years, it is only recently that the understanding of the physiological principles underpinning these techniques has greatly improved. In addition, in the past few years there has been an evolution in the quality and rigor of airway clearance studies with four long-term randomized controlled trials being published over the past 3 years.
The aim of this article is to review and discuss recent publications on physiotherapy in CF, and will include articles related to airway clearance techniques, exercise, musculoskeletal issues, and urinary continence. On the basis of these articles, recommendations for treatment will be provided.
AIRWAY CLEARANCE TECHNIQUES
Airway clearance is aimed at assisting the removal of tenacious secretions from the airways, and consequently improve ventilation and lung mechanics, and reduce the impact of airway infection. It is important to clarify that the term ‘airway clearance techniques’ (ACTs) historically was referred to as ‘chest physiotherapy’ (CPT) which predominately consisted of postural drainage and percussion (PD&P). With the introduction of independent techniques, such as active cycle of breathing techniques (ACBT), autogenic drainage, positive expiratory pressure (PEP), oscillating PEP, and high frequency chest wall oscillation (HFCWO) to treat CF patients, the name changed to reflect the variety of techniques being used for airway clearance.
The Cochrane collaboration, which provides a comprehensive framework for examining the CF literature by performing systematic reviews, has summarized the results of randomized controlled studies of each ACT. One of their recent reviews comparing chest CPT to no CPT, in eight cross-over studies, reported that there was some evidence from short-term studies that CPT increased mucus transport rate, but longer-term trials were needed [2▪]. This will be difficult to achieve as it may be considered unethical to ask CF patients to stop performing their ACT. The Cochrane collaboration has also performed reviews comparing postural drainage to other ACTs [3▪], ACBT to other ACTs , PEP to other ACTs , and oscillating devices to other ACTs . Each of these reviews concluded that there are not enough adequately-powered long-term randomized controlled trials to answer the question asked. In addition, there was insufficient evidence to suggest that any one technique was superior to another. Most CF studies have been short-term with few numbers and underpowered.
McIlwaine et al. published a long-term 2 year crossover design study comparing PD&P to autogenic drainage. Interestingly, in the second year of the study, 10 of the 17 patients who had performed autogenic drainage for the first year refused to crossover to performing PD&P, and patients who did crossover were found to incorporate the autogenic drainage breathing technique into their daily treatment. Consequently, results from the second year had to be discarded. During the first year both groups showed improvment in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) although there was no significant difference between them (Table 1). Interestingly, this study was powered for a decline in FEV1 of – 2.3% per year based on the annual rate of decline at that time. Patient reported adherence during the first year of the study was high and may account for the increase in FVC and FEV1) seen in both groups. The study indicated that patients had a strong preference for performing autogenic drainage over PD&P.
Another study by Pryor et al. compared five different independently performed ACTs in a United Kingdom 1-year randomized controlled trial. Seventy-five patients were randomly assigned to one of the following techniques: ACBT, autogenic drainage, PEP, and two oscillating ACTs, namely, Flutter and Cornet. There were no significant differences in any of the outcome parameters of pulmonary function, body mass index, exercise capacity, and health related quality of life. Of the 75 participants who entered the study, 22 did not complete the study. Thirteen did not complete the study as they did not like the regimen to which they had been randomized. This significant dropout emphasises the importance of patient preference and its effect on adherence.
A third study by Sontag et al. had similar problems. The 3-year USA multicentre randomized controlled trial compared HFCWO with Flutter and PD&P in 166 CF patients. The study was discontinued after 1.4 years due to a 34% dropout rate. Fifty-one percent dropped out of the PD&P group, 26% dropped out of the Flutter group, and 9% dropped out of the HFCWO group. Despite this dropout rate, the only significant difference was that the annual FEF25–75% predicted rate of decline was greater in those using HFCWO (P = 0.02). However, this study again illustrates the importance of patient preference for an ACT in an airway clearance study. Lastly, McIlwaine et al.[10▪▪] published the results of a 1-year Canadian multicentre randomized controlled study comparing PEP with HFCWO in 107 CF patients. The authors only enrolled patients who were willing to perform either technique for the 1-year period. Thus, only three patients dropped out due to not being randomized to the technique they wanted. Adherence was high, being reported as 94% in each group. The study used pulmonary exacerbation as the primary outcome instead of FEV1 and demonstrated that HFCWO was not as effective as PEP in maintaining the health of CF patients. Pulmonary exacerbations requiring antibiotics were observed to be more frequent in HFCWO (n = 96) than PEP (n = 49) (P = 0.007). A subsequent economic cost analysis revealed that HFCWO cost 10 times the amount compared to PEP, to maintain health in CF patients over a 1-year period.
These studies highlight important points when considering which ACTs to use for CF patients:
- No ACT has been shown to be superior to another. Pryor et al. showed that ACBT, autogenic drainage, PEP, and oscillating PEP were equally effective in maintaining health. McIlwaine et al.[10▪▪] showed autogenic drainage was as least as effective as PD&P.
- HFCWO may have a negative effect on the well-being of the patient as measured by pulmonary function and number of pulmonary exacerbations.
- Patients demonstrated the least preference for postural drainage and percussion.
ROLE OF EXERCISE
The benefit of exercise in the treatment of CF is well known. The prognostic importance of exercise testing gained importance after Nixon et al. demonstrated that exercise capacity was an independent predictor of life expectancy in CF patients. Exercise is increasingly regarded as an essential component of the overall physiotherapy management of CF. This is highlighted by the European Cystic Fibrosis Society forming an exercise working group to develop guidelines for exercise testing, assessment of physical activity, and activity/exercise counseling for patients with CF. It is expected that these guidelines will be published within the next year.
Proponents have suggested that exercise alone can be used as an ACT, but evidence to support this was limited until recently. Two systematic reviews have summarized the effects of exercise for patients with CF [12,13] and concluded that exercise in addition to PD&P, had beneficial effects on FVC and FEV1. Exercise has the added advantage of improving general fitness, self-esteem, and measures of quality of life. Exercise is socially acceptable and helps to normalize the patient's life rather than adding a therapy that accentuates differences from peers.
More recently, as a better understanding of the physiology behind ACTs has developed, it is possible to hypothesize why exercise alone cannot act as an ACT. For ACTs to be effective, two components are required: firstly, a method to ventilate behind obstructed lung units and secondly, an expiratory airflow of more than 30–60 l/min with a peak expiratory flow rate/peak inspiratory flow rate (PEFR/PIFR) ratio of 1 to 1.1 . Aerobic exercise increases tidal volume breathing as patients breathe into the inspiratory reserve volume. This has been associated with air moving from unobstructed lung units to obstructed ones through the use of collateral ventilation channels and the principle of interdependence . This fulfills the first criteria for exercise to be an effective ACT, However, although, aerobic exercise does increase expiratory airflow to more than 60 l/min, the PEFR is less than the PIFR, thus, an expiratory bias does not exist to mobilize secretions proximally and fails to meet the second criteria.
Recently, Dwyer et al. examined the effect of exercise on mucociliary clearance. In that study exercise performed on a treadmill was compared with oscillating PEP using the Flutter device. The PEFR/PIFR with the Flutter was 1.13 which is sufficient to mobilize secretions proximally, whereas the PEFR/PIFR with exercise was 0.9 which is not sufficient to mobilize secretions. Despite this, both the treadmill and the Flutter device decreased the viscoelastic properties of the mucus . In another study, Dwyer et al. compared PEP with treadmill exercise and observed whole lung mucociliary clearance was greater with PEP compared to the treadmill. When peripheral lung clearance was compared with central lung clearance, treadmill exercise was as effective as PEP. The question then is, how can expiratory airflow be assisted to mobilize secretions from the proximal airways with exercise and could this be an effective substitute for an ACT? Some answers have been provided by Reix et al. who added huffing, also known as the forced expiration technique, to exercise. A crossover study was conducted in 34 patients with CF comparing exercise with forced expiration technique to ACBT. No difference was observed between exercise and ACBT in sputum production or FEV1. However, this small trial was only equivalent to a phase II study and needs to be followed by a long-term multicentre phase III study.
- We now have a better understanding of exercise as an ACT.
- Further clinical trials are required to understand the role of exercise as an ACT.
With increasing life expectancy of individuals with CF, musculoskeletal problems have become more prominent. Although these concerns may be considered secondary to the classical symptoms of CF, addressing these issues early may prevent or delay complications associated with musculoskeletal changes.
Individuals with CF may present with an altered posture. The prevalence of an increased thoracic kyphosis in the CF population is higher when compared with the non-CF population. Okuro et al. reported a prevalence of 61.9% in children and adolescents with CF, whereas Garcia et al. reported a 46% prevalence in the adult CF population. The trunk has two primary functions; postural control and ventilation .
The postural change seen in CF patients is the result of multiple factors. One major cause is lung obstruction leading to air trapping and hyperinflation. When ventilation is compromised, changes in posture may occur to allow the muscles of the chest and trunk to assist with breathing. With hyperinflation, the diaphragm is flattened and at a mechanical disadvantage. The breathing pattern is then altered, with reliance more on the accessory muscles of respiration which have become shortened [22▪]. Consequently, the bucket handle movement of the rib cage is impaired, with the ribs being held in a more horizontal position. With an increase in rib cage diameter, structural changes may occur to accommodate for hyperinflation . The result is thoracic kyphosis (Fig. 1). These changes within the truncal region of the body lead to decreased mobility which can continue to affect respiratory function as well as gross motor movement and general activity. Bone disease may also play a role in posture and although complicated, bone mineral density has been shown to be lower in the CF population . Vertebral fractures, osteoporosis, and osteopenia , all may contribute to the kyphotic posture [20,25].
Although there is predominant focus on the trunk and proximal muscle systems, the pelvic floor muscles are also compromised in the CF population. Urinary incontinence has a higher prevalence when compared with the non-CF population. In the CF adult female population the estimated rate of prevalence varies from 30 to 74%  and in the CF adolescent population it is 18.8–47% . The pelvic floor muscles are activated in high-pressure situations, such as coughing, laughing, and sneezing. The combination of an increased frequency of cough and alteration in core muscle function often leads to compromised pelvic floor muscles.
Although urinary incontinence can lead to social isolation, pain can contribute to altered activities of daily living. Festini et al. reports that there is a high prevalence of pain in the adult CF population and 60% reported changes in activity due to pain. Sermet-Gaudelus et al. also reported a high prevalence of pain amongst the CF adult and child population. Interestingly, the location of pain differed between the two groups; predominately chest pain, backache and headache for adults, and abdominal pain for children [28,29].
The role of physiotherapy in the treatment of the musculoskeletal sequalae of CF is to prevent as well as address problems once they arise. Prevention such as postural awareness, education, and targeted strengthening exercises may slow the onset of musculoskeletal issues. For example, the ‘knack’ can be taught to assist with pelvic floor muscle dysfunction . The knack is especially useful to use during a cough which causes an increase in abdominal pressure. Weight-bearing exercises can be used to improve bone health.
However, in addition to prevention, as the disease progresses, physiotherapy can assist with specific problems. As the thoracic region and rib cage are often affected, manual mobilization techniques can be used on tight joints and tightened muscle groups [21,30]. Once these areas are mobilized, it is important to retrain/stretch the supporting musculature.
Physiotherapy is an important component of care in the CF population. Long-term ACT studies have become more rigorous and have shown that no ACT is superior to another. Patient's preference will greatly influence how adherent they are in performing their ACT. Patients should be provided with choice in deciding which technique they want to use. The role of exercise and activity continues to be researched as an independent ACT as well as an adjunct to exisiting ACTs. The prevention and treatment of musculoskeletal problems must also be addressed. Physiotherapy will continue to contribute to the health of individuals with CF.
Figure 1 drawing by J. De Guzman.
Conflicts of interest
There are no conflicts of interest.
REFERENCES AND RECOMMENDED READING
Papers of particular interest, published within the annual period of review, have been highlighted as:
- ▪ of special interest
- ▪▪ of outstanding interest
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