Journal of Applied Physiology, Vol 54, Issue 4 1141-1148, Copyright © 1983 by American Physiological Society
Liquid ventilation in dogs: an apparatus for normobaric and hyperbaric studies
D. J. Harris, R. R. Coggin, J. Roby, M. Feezor, G. Turner and P. B. Bennett
A liquid-breathing apparatus is described for remote surface studies and
for use in experiments of near-hydraulic compression in dogs. It consists
of a flexible tank sealed against chamber gas, containing a supply of clean
warmed (38 degrees C) fluorocarbon (FC-80) equilibrated with 1 bar O2 and
an electronically controlled means of delivering the liquid to the dog.
Each breath (tidal volume 290 ml) was "weighed" into the animal by the
signal from a force platform supporting the dog and a digital control unit
that automatically actuated inspired-and expired-line solenoid valves. The
apparatus was successfully used to remotely maintain liquid ventilation in
awake dogs for 2 h during surface studies (5 dogs) and in dives to 1,000 m
seawater (5 dogs). During liquid breathing, mean arterial O2 partial
pressure was always adequate (congruent to 300 Torr) and mean arterial CO2
partial pressure was normal (less than or equal to 40 Torr). An
uncompensated metabolic acidosis was indicated by low pH values and a
decrease in arterial base excess to--4.5 meq x 1(-1). O2 uptake and CO2
output appeared to be significantly lower (42 and 35%, respectively) during
liquid ventilation.
