Nebulisers for giving medication in cystic fibrosis

Nebulisers change a liquid medication into a mist so it can be breathed in. There are different types of nebuliser systems and no review has yet considered whether any nebuliser is better than another.

1. Conventional nebuliser systems - a machine sucks air in and pushes it out at high speed; a tube attaches the machine to a chamber holding the medication where the air breaks it up into a mist. The mist of medication is delivered constantly.

2. Adaptive aerosol delivery nebuliser systems - use conventional technology as described above, but also monitor breathing and deliver the mist of medication only while the person is breathing in.

3. Adaptive aerosol delivery nebuliser systems with vibrating mesh technology - monitor breathing and deliver the mist of medication only while the person is breathing in and use vibrating mesh technology, as described below, to change the liquid medication into a mist.

4. Vibrating mesh technology nebuliser systems - move the liquid medication through a metal mesh to break up the liquid into a mist where each drop is a similar size; they deliver the mist of medication constantly.

5. Ultrasonic nebuliser systems - use a crystal to vibrate the liquid medication at a high-frequency to break up the liquid medication into a mist; they deliver the mist of medication constantly.

We included 20 studies (1936 participants) in this review which compared the delivery of tobramycin, colistin, dornase alfa, hypertonic sodium chloride and other nebulised medications through the different types of nebuliser. Some conventional nebuliser systems have faster air flows and smaller medication droplets. These systems decrease treatment time and deliver more medication into the lung than other conventional nebulisers which have slower air flows and larger medication droplets. Nebulisers using newer technologies, e.g. adaptive aerosol delivery or vibrating mesh technology, deliver the medication faster and may deliver more of the medication into the lung. These systems appear safe when used with the correct amount of medication, which may be different to that used in a conventional nebuliser system. Some studies suggest that people with cystic fibrosis may prefer these newer systems and may take more of their medication when using them. More research is needed into what dose of medication is needed and how these newer nebuliser technologies affect quality of life, burden of treatment, additional treatment needed and treatment costs.

Authors' conclusions: 

Clinicians should be aware of the variability in the performance of different nebuliser systems. Technologies such as adaptive aerosol delivery and vibrating mesh technology have advantages over conventional systems in terms of treatment time, deposition as a percentage of priming dose, patient preference and adherence. There is a need for long-term randomised controlled trials of these technologies to determine patient-focused outcomes (such as quality of life and burden of care), safe and effective dosing levels of medications and clinical outcomes (such as hospitalisations and need for antibiotics) and an economic evaluation of their use.

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Background: 

Nebuliser systems are used to deliver medications to control the symptoms and the progression of lung disease in people with cystic fibrosis. Many types of nebuliser systems are available for use with various medications; however, there has been no previous systematic review which has evaluated these systems.

Objectives: 

To evaluate effectiveness, safety, burden of treatment and adherence to nebulised therapy using different nebuliser systems for people with cystic fibrosis.

Search strategy: 

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches, handsearching of relevant journals and abstract books of conference proceedings. We searched the reference lists of each study for additional publications and approached the manufacturers of both nebuliser systems and nebulised medications for published and unpublished data.

Date of the most recent search: 15 Oct 2012.

Selection criteria: 

Randomised controlled trials or quasi-randomised controlled trials comparing nebuliser systems including conventional nebulisers, vibrating mesh technology systems, adaptive aerosol delivery systems and ultrasonic nebuliser systems.

Data collection and analysis: 

Two authors independently assessed studies for inclusion. They also independently extracted data and assessed the risk of bias. A third author assessed studies where agreement could not be reached.

Main results: 

The search identified 40 studies with 20 of these (1936 participants) included in the review. These studies compared the delivery of tobramycin, colistin, dornase alfa, hypertonic sodium chloride and other solutions through the different nebuliser systems. This review demonstrates variability in the delivery of medication depending on the nebuliser system used. Conventional nebuliser systems providing higher flows, higher respirable fractions and smaller particles decrease treatment time, increase deposition and may be preferred by people with CF, as compared to conventional nebuliser systems providing lower flows, lower respirable fractions and larger particles. Nebulisers using adaptive aerosol delivery or vibrating mesh technology reduce treatment time to a far greater extent. Deposition (as a percentage of priming dose) is greater than conventional with adaptive aerosol delivery. Vibrating mesh technology systems may give greater deposition than conventional when measuring sputum levels, but lower deposition when measuring serum levels or using gamma scintigraphy. The available data indicate that these newer systems are safe when used with an appropriate priming dose, which may be different to the priming dose used for conventional systems. There is an indication that adherence is maintained or improved with systems which use these newer technologies, but also that some nebuliser systems using vibrating mesh technology may be subject to increased failures.

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