Chest physiotherapy during an acute exacerbation of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a slowly progressive, irreversible constriction of the airways causing breathlessness, cough and respiratory distress. The primary cause is repeated exposure to cigarette smoke, although occupational exposures may contribute towards its development. ¹ The prevalence of COPD is estimated between 2% and 4%, representing approximately one to two million people in England. ² Acute exacerbations occur when there is rapid and prolonged worsening of symptoms, which may include increased secretions and cough, and one in eight unplanned hospital stays concern COPD, making it the second largest cause of emergency admissions in the United Kingdom. ² Across Europe, admission rates vary in Nordic countries; rates have been estimated to be between 360 and 460 per 100,000 per year, and in 1994, COPD admissions are numbered 125,508 in Germany, 45,624 in Spain and 40,190 in Italy. ³ This places a considerable financial burden on health care services, representing a condition for which economic evaluation of therapeutic interventions is particularly relevant. The National Institute for Health and Clinical Excellence (NICE) estimates the direct cost of COPD to the National Health Services (NHS), which exceeds £491m per year (expenditure based on 2001–2002 activity). ⁴ More than half of this relates to hospital care with more than one million inpatient ‘bed days’ per year attributable to the disease. ² The estimates of cost are US$88 to US$7757 per exacerbation in the United States, ⁵ and across Europe, inpatient costs account for approximately Eur2.9b annually. ³

COPD is a heterogeneous condition. Individuals commonly experience dyspnoea, but a smaller proportion may experience excessive secretions, particularly during an exacerbation. Removing these secretions may or may not be beneficial to these individuals, and this may be an individual preference. Manual chest physiotherapy (MCP) involves external manipulation of the thorax using the techniques of percussion and vibration, and recent systematic reviews have identified a limited role for MCP during an acute exacerbation of COPD. ^{6 –8} NICE guidelines recommend that all the patients are taught to use positive expiratory pressure and instructed in active cycle of breathing technique. ² These guidelines are based on the best evidence that is currently available. However, physiotherapy research is a growing discipline and much of the earlier evidence regarding chest physiotherapy is fundamentally flawed by small sample sizes and a lack of homogeneity within the sample studied. ⁹ These studies measure short-term outcomes and in essence, consider efficacy, that is to say the effects, both positive and negative, of these techniques.

In 2001, a comprehensive review of the literature regarding manual physiotherapy techniques was undertaken. ⁹ This focused on patients with compromised respiratory function and impaired mucociliary clearance, who were not being mechanically ventilated. It aimed to identify studies of acceptable quality, designed to evaluate the use and the mode of manual techniques, so as to compile clear and concise clinical practice guidelines. This proved impossible to achieve, owing to the lack of suitable evidence. Whilst eight articles report designs that evaluate a specific manual technique, using secretion clearance as the main outcome, when compared with either a ‘control’ or ‘standard’ treatment, four of them found no evidence where the manual techniques conferred greater efficacy. The remaining found that the manual percussion was associated with sputum mobilisation, ¹⁰ the vibrations and percussion were associated with an increased wet weight of sputum, ¹¹ there was a significant increase in the sputum clearance at 60 min posttreatment with mechanical vibration but no difference over 24 h ¹² and the fast manual percussion produced the greatest sputum volume, 60 min after the treatment. ¹³

An update of these earlier studies reveals small changes since 2001. ¹⁴ A systematic review conducted in 2004 to produce American College of Chest Physicians (ACCP) guidelines found that some airway clearance techniques improved sputum expectoration, but found no high quality evidence for long-term outcomes. ¹⁵ Moreover, whilst MCP was recommended for Cystic Fibrosis (CF), there was some evidence that manually assisted cough might be detrimental in COPD and, therefore, should not be used to treat acute exacerbations. The 2007 overview by Garrod and Lasserson ¹⁶ of systematic reviews of the role of physiotherapy in managing chronic lung diseases suggested that the randomised controlled trials of MCP were still required to evaluate effects on health-related quality of life, exacerbation frequency and hospital admission. Some of these have been addressed by the study, which has demonstrated that the use of MCP does not appear to affect longer term quality of life. ¹⁷ While the MATREX cost-effectiveness analysis provided some indication that the MCP was minimally cost-effective, it remains difficult to recommend that the MCP can be implemented solely on the basis of this cost-effectiveness analysis.

Other respiratory physiotherapy techniques are needed to be investigated, in relation to predetermined valid outcomes of effectiveness, consistent with the increasing contemporary emphasis on longer term patient-reported outcomes rather than being restricted to the short-term efficacy, if it is to be of any experienced benefit to the patients themselves. Effectiveness studies should also encompass additional measures of cost, as not only are outcomes driven to be patient-related but also benefits must be weighed against the cost of an intervention.