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Airflow and device effects on aerosol delivery for large animals
Author(s) -
Davis M. S.,
Foster Wm. F.
Publication year - 2001
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1046/j.1365-2885.2001.00308.x
Subject(s) - aerosol , nebulizer , airflow , delivery system , medicine , inhalation , biomedical engineering , anesthesia , chemistry , mechanical engineering , organic chemistry , engineering
Aerosol delivery of medications has recently gained acceptance in large animal veterinary medicine. However, delivery of therapeutic aerosols currently relies on equipment modified from human use and delivery of medical aerosols may be adversely affected by the equipment design. In this study, we demonstrate the effect of typical large animal inspiratory flow rates on aerosol delivery characteristics. A benchtop system was assembled to simulate aerosol delivery to large animals. Phasic airflow was generated using a large animal anesthesia machine set to deliver 6 bpm (7 L/breath) at 100, 150 and 180 L/min mean inspiratory airflow. Aerosol from a DeVilbis ultrasonic nebulizer was delivered to a simulated facemask using standard 22 mm tubing and fittings. Total mass, delivery efficiency and mass median aerosol diameter (MMAD) was measured with and without an inspiratory one‐way valve on the facemask. Delivered aerosol mass ranged from 0.26 to 0.08 g/min and delivery efficiency ranged from 30 to 6%. Both parameters were significantly reduced by both increasing flow rates and the presence of a one‐way valve between the nebulizer and the facemask. Average MMAD was 0.7 μm and was not affected by any experimental variable. These results demonstrate that current aerosol equipment used on large animals has a substantial adverse effect on aerosol delivery. Elimination of one‐way valves between the aerosol source and the patient is expected to improve delivery of the aerosol in these patients.