The Effects of Heliox on the Output and Particle-Size Distribution of Salbutamol Using Jet and Vibrating Mesh Nebulizers

Abstract

There are theoretical benefits of delivering drug aerosols to patients with asthma and COPD using Heliox as a carrier gas. The objective of this study was to develop systems to allow bronchodilators nebulised by a breath enhanced jet nebuliser and a vibrating mesh nebuliser to be delivered to patients in Heliox. This was achieved by attaching a reservoir to the nebulisers to ensure inhaled Heliox was not diluted by entrained air. For the vibrating mesh nebuliser, the total output was significantly higher after 5min nebulisation when Heliox rather than air was used as the delivery gas (p<0.001). The proportion of drug in particles <5µm was 58.1% for Heliox and 50.1% when air was entrained. When the breath enhanced nebuliser was used a much higher driving flow of Heliox, compared to air, was required to deliver a similar dose of drug (p<0.05). The total amount of drug likely to be inhaled was significantly higher when the vibrating mesh nebuliser (Aerogen) was used compared to the breath enhanced jet nebuliser (Pari LC plus) (p<0.001). The amount of drug likely to be inhaled was also significantly greater for the adult as opposed to paediatric breathing pattern for all nebulisers and flows tested with the exception of the Aeroneb and Heliox entrainment.In this case, total amounts were similar for both patterns but for the paediatric pattern, the time taken to reach this output was longer. Such information is required to allow appropriate interpretation of clinical trials of drug delivery using Heliox.3

An In Vitro Assessment of Aerosol Delivery Through Patient Breathing Circuits Used with Medical Air or a Helium–Oxygen Mixture

“…This result is consistent with the data of O'Callaghan and colleagues, (16) wherein a similar difference was reported between air and He/O 2 for the Aeroneb Pro. In the present work, when the supplied gases were humidified differences in droplet sizes between air and He/O 2 were less pronounced, suggesting that these differences were related to droplet evaporation between nebulization and measurement.…”

“…As such, the influence of He/O 2 on aerosol delivery during NIV should be evaluated for a given combination of delivery device and breathing circuit prior to employing that combination for coadministration of He/O 2 and aerosol therapy. Further, as He/O 2 is known to affect droplet size distributions delivered from jet nebulizers, (14)(15)(16)(17) and, though less so, from vibrating mesh nebulizers, (16,18) these modalities of aerosol delivery may require particular attention.…”

Laser diffraction characterization of droplet size distributions produced by vibrating mesh nebulization in air and a helium–oxygen mixture

“…Fink and colleagues (Fink, 2006;Fink, Heramia, Bathe, & Watson, 2003) reported nearly identical droplet sizes, as measured by laser diffraction, in oxygen and He/O 2 for the Aeroneb Pro (Aerogen Ltd., Ireland) vibrating mesh nebulizer. Working with the same nebulizer, but using a cascade impactor for aerosol sizing, O'Callaghan et al (2007) measured a small reduction in median droplet size in He/O 2 compared to air; however, an explanation of this effect was not provided.…”

“…For jet nebulizers, atomization of a liquid medication is driven by a pressurized supply of gas accelerated through a nozzle, and brought into contact with a liquid surface. When these nebulizers are supplied with He/O 2 , the lower density of He/O 2 compared to air results in a smaller energy available for atomization at equivalent supplied volume flow rates, leading to the production of larger droplets (Corcoran, Dauber, Chigier, & Iacono, 2002;O'Callaghan et al, 2007;Piva, Menna Barreto, Zelmanovitz, Amanté a, & Cox, 2002), and to a lower aerosol output rate (Corcoran et al, 2002;Hess, Acosta, Ritz, Kacmarek, & Camargo, 1999;O'Callaghan et al, 2007). While these effects can be overcome by increasing the supplied flow rate of He/O 2 , the necessity to adjust operating conditions in order to achieve the same performance in He/O 2 as in air, and to perform adequate testing to confirm said performance, may be seen as obstacles in the clinical use of He/O 2 with medical aerosols.…”

Aerosolization Studies of Zn-DTPA Using Nebulizers for Decorporation of Internal Radioactive Contamination

“…They used the percentage of particles that are smaller than 5 microns as the criteria to evaluate the medication performance of a nebulizer. They found that by changing the carrier gas into a lighter gas, the percentage increased (O'Callaghan et al, 2007). However, most of the researchers concentrated on the mechanical factors of a nebulizer as well as focused on the medication properties in the nebulizer.…”