Journal of Applied Physiology, Vol 73, Issue 2 410-419, Copyright © 1992 by American Physiological Society
Bronchial provocation tests in small animals: a quantified and automated procedure
M. Chauveau, M. Leroy, G. Le Gall and A. Lockhart
Laboratoire de Physiologie Respiratoire, Unite de Formation et de Recherche, Cochin Port Royal, Paris, France.
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.
