Discussion
All participants in this study encountered problems with their nebulisers. Teale et al13 estimated a 50% prevalence of problems with nebuliser use among elderly patients with COPD who were prescribed a nebuliser and recruited through a hospital, and who received comprehensive instruction on its use. However, the present study provides a more representative setting where most (80%) of the patients acquired their nebuliser through a route other than the hospital, and most had received no instruction on its use.
Problems were reported with all aspects of nebuliser use, many of which could impact on clinical outcomes. For example, incorrectly assembling components such as an inverted facemask or a loosely fitted nebuliser cap is likely to reduce the amount of drug reaching patients’ lungs. In instances where the vaporiser head was missing, no aerosol would be produced during nebulisation. Failure to fit the facemask, or use the mouthpiece correctly, results in aerosol escaping to the surrounding atmosphere rather than entering the airways. An ill-fitting mask may also result in drug deposition on the patient's face or in the eyes,19 potentially causing adverse effects such as glaucoma.20 ,21 Preference for facemasks or mouthpieces varied between participants. To promote effective therapy, patients should be given the choice of interface that they find most comfortable and easy to use. Ideally, all patients supplied with a mouthpiece should keep a facemask in case of an emergency. Problems with manual dexterity, having a poor grip, difficulty opening vials and poor eyesight were contributory factors to problems for many patients.
Confusion about the amount of saline required to dilute drug formulations or use of other diluents was identified. Substituting isotonic saline with water is hazardous, producing hypotonic solutions that may cause bronchoconstriction.22 Moreover, there was considerable confusion regarding whether dilution was necessary.
This study has shown that patients had poor understanding of correct inhalation technique. Breathing technique is considered less critical for nebulisers compared with pMDIs or DPIs. COPD is characterised by airway constriction, resulting in limited aerosol deposition in the lungs and in particular into the smaller airways.23 Body posture can affect the area of drug deposition and trying out certain body manoeuvres can help in targeting poorly ventilated airways. There was uncertainty among patients in regard to achieving optimal efficacy. The majority of patients in this study were found to be nose breathing. Heyder et al24 determined that a larger amount of aerosol is needed to compensate for loss in the nose. Inhaling slowly and deeply through the mouth and breath holding for a few seconds (when possible) before exhalation can increase the amount of drug deposited in the airways by at least two-fold compared with normal tidal breathing.25 Although slow, deep breathing with breath holding may not always be possible, especially for patients with severe disease, such inhalation technique is beneficial whenever possible.
Patients in this study undertook inadequate cleaning and maintenance procedures. Previous studies have found problems with cleaning to be frequent.13 ,18 Adherence to manufacturers’ cleaning and maintenance instructions is essential for correct operation of the equipment.26 Most recommend cleaning parts after each use with warm soapy water, with disinfection/boiling at least weekly. Some recommend the nebuliser be run empty, or with saline, after use. Inadequate cleaning and drying affect nebuliser performance and can lead to subtherapeutic outcomes as well as being an infection risk. Inadequately cleaned and maintained nebulisers have been identified as potential reservoirs for serious pathogens, such as Pseudomonas spp, which may be delivered to the lung.27–29 The potential for occurrence of an exacerbation, and the need for strategies to improve adherence to nebuliser cleaning and sanitisation regimes are clear.
With regard to maintaining the nebuliser and compressor, the infrequent replacement of the disposable parts of the nebuliser system and lack of servicing have been previously documented.15 ,17 ,18 Blockage of inlet filters and lack of servicing affect compressor performance.14 In this study, discoloured filters were observed and a lack of servicing of the compressor was especially prominent.
Strengths of this study are that it represents a comprehensive examination of the whole process of nebuliser use by using a structured observation to document practices combined with patients’ own explanations of their experiences, concerns and rationale. While the study included patients from across 38 medical practices and intermediate care, it is limited in that it was undertaken in only one part of Greater London and may not reflect provision and support elsewhere.
Nebulisers remain an important part of therapy for many patients with COPD, including those with severe disease. However, this study has identified that participants experienced difficulties with all aspects of nebuliser use and devised strategies to overcome these, many of which would be anticipated to have an impact on clinical outcomes and potentially contribute to treatment failures. They described a service which did not always meet their needs in terms of supply and maintenance of equipment and associated support. Ensuring appropriate systems, services and support for these patients should be a priority for healthcare providers if optimal outcomes from medication are to be achieved, reducing disease burden for patients and promoting cost-effective care.