Endotracheal intubation influences respiratory water loss during
heat stress in young lambs.
Hammarlund, Karen, Torgny Norsted, Tomas Riesenfeld, Gunnar Sedin.
Department of Paediatrics and the Department of Physiology and
Medical Biophysics, Uppsala University, Uppsala, Sweden.
APStracts 2:0209A, 1995.
To study the effect of intubation on respiratory water loss (RWL)
during heat stress, ten young non-sedated lambs were exposed to
radiative heat stress both when intubated and when not. RWL, oxygen
consumption (VO2) and carbon dioxide production (VCO2) were monitored
continuously using a flow-through system with a mass spectrometer for
gas analysis. When the lambs were not intubated, heat stress caused
RWL to increase by 218%, while VO2 and body temperature (Tbody)
remained unchanged. When the lambs were intubated, heat stress caused
RWL to increase by 131% and VO2 by 36%. On extubation during heat
stress, RWL increased by 117 +/- 48% (SEE) of the pre-extubation
value and body temperature started to fall. This study shows that
intubation reduces the ability of the lamb to increase RWL and heat
loss during heat stress in a warm environment, possibly as an effect
of exclusion of the nose and a reduction in dead space. After
extubation RWL increases markedly, a finding which might also be
valid for intubated infants.
Received 14 December 1993; accepted in final form 11 April 1995.
APS Manuscript Number A1198-3.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 May 1995.