Bronchial provocation tests in small animals: a quantified and automated procedure.
Bronchial provocation tests using aerosols in laboratory animals are difficult to standardize and quantify, because the amount of drug actually reaching the airways is unknown. To improve the quantification of aerosolized inhaled stimuli, we designed an apparatus that allows, in anesthetized intubated ventilated animals, control of temperature and hygrometry of inspired air, computerized measurement of pulmonary resistance, and fully automated delivery of a known amount of aerosolized drug directly into the trachea. Calibration of the aerosol delivery involved direct measurement of liquid delivered at the tip of the tracheal cannula. Despite all our efforts at standardization and full automation of all steps, reproducibility of aerosol delivery was poor, with stroke-by-stroke differences of 26 or 42%, according to whether an air-jet or an ultrasonic nebulizer was used. Histamine dose-response curves performed in 15 guinea pigs with this device confirmed marked differences among animals and also disclosed large intraindividual changes in bronchial responsiveness.
Chauveau
M
M
Laboratoire de Physiologie Respiratoire, Unité de Formation et de Recherche, Cochin Port Royal, Paris, France.
Leroy
M
M
Le Gall
G
G
Lockhart
A
A
D000336:Aerosols; D000403:Airway Resistance / Q000502:physiology; D000818:Animals; D001985:Bronchial Provocation Tests / Q000295:instrumentation / Q000379:methods*; D006168:Guinea Pigs; D010991:Plethysmography; D051381:Rats; D012143:Respiratory Physiological Phenomena
D000336:Aerosols