Journal of aerosol medicine : the official journal of the International Society for Aerosols in Medicine
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It has been shown in vitro that even a small air leak in the facemask can drastically reduce the efficiency of drug delivery. In addition, it has been shown that drug deposition on the face does significantly add to overall drug loss and has the potential of local side effects. The aim of this study is therefore to verify these findings in vivo. ⋯ Overall mask deposition was between 0.8% and 5.2%. Overall face deposition was between 2.6% and 8.4%. The results from this pilot study support the results found in in vitro studies, where a facemask leak greatly reduces drug delivery to the patient.
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Comparative Study
Comparative analysis of methods to measure aerosols generated by a vibrating mesh nebulizer.
Different approaches have been employed for in vitro assessment of the aerosol particle size generated by inhalation devices. In this study, aerosols from the Omron MicroAir vibrating mesh (VM) nebulizer were measured by cascade impaction (CI) using the MSP Next Generation Pharmaceutical Impactor (NGI), the ThermoAndersen Cascade Impactor (ACI), and by time-of-flight (TOF) analysis with the TSI 3321 Aerodynamic Particle Sizer Spectrometer (APS). The VM nebulizer was evaluated with sodium fluoride (NaF; 2.5%) and with generic albuterol (0.083%). ⋯ In summary, the results of VM nebulized NaF and albuterol were more consistent and generally equivalent when determined by NGI (at RT and 4 degrees C) and ACI analysis (at 4 degrees C). In contrast, aerosol particle sizes measured by TOF in the APS at both RT and 4 degrees C were larger than results obtained by CI. Differences in aerosol particle distribution obtained by different analysis methods should be considered while evaluating the in vitro performance of VM nebulizers.
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Comparative Study
The effects of Heliox on the output and particle-size distribution of salbutamol using jet and vibrating mesh nebulizers.
There are theoretical benefits of delivering drug aerosols to patients with asthma and chronic obstructive pulmonary disease (COPD) using Heliox as a carrier gas. The objective of this study was to develop systems to allow bronchodilators nebulized by a breath enhanced jet nebulizer and a vibrating mesh nebulizer to be delivered to patients in Heliox. This was achieved by attaching a reservoir to the nebulizers to ensure inhaled Heliox was not diluted by entrained air. ⋯ The amount of drug likely to be inhaled was also significantly greater for the adult as opposed to pediatric breathing pattern for all nebulizers 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 pediatric 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.
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Randomized Controlled Trial Comparative Study
The effect of a first-generation antihistamine on sputum viscoelasticity in cystic fibrosis.
Tenacious airway secretions are responsible for much of the lung damage in cystic fibrosis (CF). Label warnings on potential secondary effects of some antihistamines include possible drying or thickening of lower airway secretions, suggesting that they are detrimental to individuals with airway disease. We studied the effects of cyproheptadine hydrochloride (CH) on sputum weight, viscoelasticity, and transportability in CF patients participating in a pilot trial of CH as an appetite stimulant to assure no potential adverse secondary effects on mucus clearance. ⋯ Weight on all specimens was obtained prior to both analyses. There were no significant differences in sputum weight wet, measures of mucus viscoelasticity (rheology), or cough transportability of mucus between baseline and 4 weeks in patients on placebo or CH. From this limited study, CH, a first-generation antihistamine, appears to have no adverse effects in sputum viscoelasticity or cough transportability in CF patients.
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There has been much clinical and academic interest in the use of noninvasive positive-pressure ventilation (NPPV) in patients with acute and chronic respiratory failure. The use of NPPV in appropriately selected patients improves survival and decreases the need for endotracheal intubation. The most commonly used interfaces for NPPV are nasal masks or oronasal masks, but nasal pillows, mouthpieces, total face masks, and helmets can also be used. ⋯ However, in vitro and in vivo studies have demonstrated that a significant amount of bronchodilator can be administered by in-line nebulizer or MDI during NPPV. The evidence base for aerosol delivery during NPPV is not nearly as mature as the evidence for aerosol delivery during invasive mechanical ventilation. With NPVV, issues related to the optimal interface, ventilator settings, and aerosol generator (nebulizer versus MDI) are largely unexplored.