Effects of ventilation and pleural effusion on measurements of
pulmonary tissue volume and blood flow by airway gas temperature in
the dog.
Kano, Aki, Kenjiro Kambara, Michio Arakawa, Fumio Ando, Michiya Ohno,
Masago Tsuchiya, Kazuhiko Nishigaki, and Hisayoshi Fujiwara.
Second Department of Internal Medicine, Gifu University School of
Medicine, 40 Tsukasa-machi, Gifu City, Gifu 500, Japan
APStracts 2:0240A, 1995.
We studied the effects of ventilation and pleural effusion on
measurements of pulmonary tissue volume (so-called airway thermal
volume) and pulmonary blood flow using the airway gas thermometry
method of Serikov et al. in 39 anesthetized, closed-chest, ventilated
dogs with or without lung edema or pleural effusion. To examine the
differential effects of increased-pressure and increased-permeability
lung edema on accuracy and sensitivity of airway thermal volume and
pulmonary blood flow, two models of lung edema were induced by
intravenous infusion of a dextran-70 solution and alloxan
monohydrate, respectively. Dogs were hyperventilated for 3 min using
a wide range of minute ventilation to produce two steady-state
conditions of airway temperature. Higher levels of minute ventilation
increased an estimated amount of airway thermal volume. The airway
thermal volume produced by hyperventilation at minute ventilations of
559, 158 and 72 ml/min/kg was consistent with the gravimetric total
lung mass, the blood-free wet lung weight and the extravascular lung
water volume, respectively. The coefficient of lung thermal
conductivity (KT), a practical index of the rate of heat conduction
through tissue from lung vessels, was related to the ratio of the
decrease in expired air temperature to minute ventilation, and
estimated pulmonary blood flow was consistent with the thermodilution
cardiac output. Pleural effusion had little effect on measurements of
airway thermal volume and pulmonary blood flow. However, airway
thermal volume and pulmonary blood flow showed increased variation in
dogs with dextran-induced lung edema.
Received 17 August 1994; accepted in final form 17 May 1995.
APS Manuscript Number A871-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 June 1995.