Comparison of lung deposition of colomycin using the HaloLite and the Pari LC Plus nebulisers in patients with cystic fibrosis

Aim: To examine the effectiveness of delivery of nebulised colistin by the HaloLite nebuliser compared to the Pari LC Plus in patients with cystic fibrosis. Methods: Randomised crossover trial of 15 patients aged > 6 years. Inhalation of one mega unit of colistin in 3 ml diluent, labelled with technetium-99m DTPA, was used to assess lung deposition. The Pari was nebulised to dryness and one button press of the HaloLite was completed. Following a seven day washout period, patients inhaled colistin twice daily for seven days through the first device. Sputum specimens were analysed for colistin levels and pseudomonas load. This procedure was repeated with the alternative device. Results: Lung uptake of radiolabelled colistin was significantly higher with the Pari. However, lung uptake calculated as a percentage of the amount of drug used was significantly higher for the HaloLite. Time to nebulise was significantly shorter with the HaloLite. Sputum levels of colistin were higher following use of the Pari; this was close to significance. Conclusion: The manufacturer's recommended dosages for nebulising antibiotics with a HaloLite result in a lower delivery than patients receive when using a Pari nebuliser. The concept of adaptive aerosol delivery has several theoretical advantages but the recommended doses for the HaloLite need to be modified in order to improve effectiveness.