Distal effects of tracheal gas insufflation: changes with catheter
position and oleic acid lung injury.
Nahum, Avi, Sue A. Ravenscraft, Alexander B. Adams, John J. Marini.
University of Minnesota, St. Paul-Ramsey Medical Center, Pulmonary
and Critical Care Department
APStracts 3:0188A, 1996.
We separated distal (turbulence related) and proximal (dead space
washout related) effects of tracheal gas insufflation (TGI) by
comparing the effects of straight and inverted catheters. We reasoned
that the inverted catheter was unlikely to remove CO2 from conducting
airways distal to its orifice. In six normal dogs during TGI at 10
L/min advancing the catheters from 10 to 1 cm above the main carina
decreased VD by 29 +/- 12 and 12 +/- 6 ml (p < 0.04) with the
straight and inverted catheters, respectively. By comparison, the
tracheal volume between 10 and 1 cm above the carina was 15 +/- 2 ml.
In another set of dogs (n=5) we examined the distal effects of TGI
before and after oleic acid-induced lung injury. During TGI at 10
L/min before and after OAI, the differences in PaCO2 between the
straight and inverted catheters were 5 +/- 1 and 9 +/- 6 mmHg (p
< 0.18), respectively. Our data suggest that distal effects of
TGI become more pronounced as the catheter tip is positioned closer
to the main carina. The distal effects of TGI were not diminished
after OAI when minute ventilation was maintained constant.
Received 20 March 1995; accepted in final form 2 April 1996.
APS Manuscript Number A298-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 16 April 96