Interrupter airway and tissue resistance: errors caused by valve
properties and respiratory system compliance.
Kessler, Volker, Georg Mols, Holger Bernhard, Christoph
Haberth[umlaut]ur and Josef Guttmann.
1Section of Experimental Anesthesiology, Department of
Anesthesiology and Critical Care Medicine, University of Freiburg,
Germany and 2Division of Clinical Physiology, Clinic of Cardiac and
Thoracic Surgery, University Hospital, Basel, Switzerland
APStracts 6:0268A, 1999.
The interrupter technique is used to determine airway and tissue
resistance. Their accuracy is influenced by the technical properties
of the interrupter device and the compliance of the respiratory
system. We investigated the influence of valve characteristics and
respiratory system compliance on the accuracy of determining airway
and tissue resistance by means of a computer simulation. With
decreasing compliance we found increasing errors both in airway and
tissue resistance determination of up to 34% and 71% respectively. On
this basis we developed a new occlusion valve, with special emphasis
on rapid closing time and tightness in the closed state in order to
improve the accuracy of resistance determination. The newly developed
occlusion device greatly improves the accuracy of airway and tissue
resistance determination. We conclude that respiratory system
compliance is a limiting factor for the accuracy of the interrupter
technique. To apply the interrupter technique in patients with
extremely low respiratory system compliances we need sophisticated
technical devices.
Received 26 October 1998; accepted in final form 8 June 1999.
APS Manuscript Number A970-8.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 25 June 1999