Background: Treating severe respiratory disease in ruminants is often challenging, especially for judicious antimicrobial stewardship and appropriate treatment duration. Nebulized therapy in ruminants delivers intrapulmonary aerosolized drugs anecdotally with reported success, but safety and efficacy of commonly used therapeutic medications with commercially available veterinary nebulizers is unexplored. Hypothesis/
Objectives: To evaluate effects of the type of nebulization device and different drug formulations on drug flow rate and clinically relevant particle size distribution parameters correlated with extent of intrapulmonary drug delivery, including mass mean aerodynamic diameter (MMAD), fine particle fraction (FPF), and geometric standard deviation (GSD). Animals: No animals used.
Methods: Ampicillin, tulathromycin, dexamethasone, and albuterol sulfate solutions were prepared, viscosity measured, and then tested with 4 nebulizers through an inhalation cell with in-line particle size analysis via laser diffraction analysis. Flow rate was measured by changes in drug volume in reservoir cup over time of nebulization. Each drug x device pairing was tested in triplicate; MMAD, FPF, and GSD values calculated from serial 30-second measurement windows in triplicate within each data capture. Data were tested for normality using Shapiro-Wilks test and compared with ANOVA or Kruskal-Wallis test.
Results: Initial analysis demonstrates significant variation in particle size distribution factors among drugs when using the same nebulization device and among devices using the same drug formulation. Conclusions and Clinical Importance: Considerable and clinically relevant differences between nebulization devices and drugs used for treating respiratory disease in ruminants warrant further investigation to optimize treatment efficacy while enhancing patient safety and clinical outcomes.
