The recording temperature of an unheated fleisch
pneumotachograph.
Miller, Martin R, Ole Find Pedersen, and Torben Sigsgaard.
The Department of Medicine, University of Birmingham, University
Hospital NHS Trust, Birmingham B29 6JD, UK and The Department of
Environmental and Occupational Medicine, Bygning 180, University of
Aarhus, Aarhus, Denmark
APStracts 3:0563A, 1996.
For an unheated Fleisch pneumotachograph (PT) the exact temperature of
the PT head during recording is not known. We measured PT head
temperature during blows from five normal subjects recorded using a
PT with and without an upstream assembly to condition the air to the
ambient which was set in a climate chamber. Group mean (SD)
temperature of a thermocouple (TC) placed inside the PT head was 11.8
(1.9) degrees C with 7 degrees C ambient, 25.4 (1.3) degrees C at 23
degrees C, and was 37.2 (0.3) degrees C at 37 degrees C. The between
subject range of temperature for this thermocouple was 7.5 degrees C
at 7 degrees C, 5.5 degrees C at 23 degrees C and 1.1 degrees C at 37
degrees C. The mean within subject within blow variation of
temperature for this TC was 10.0 degrees C and 3.3 degrees C for
ambient of 7 degrees C and 23 degrees C respectively. With the use of
an upstream metal heat exchanger the group mean (SD) temperature was
8.7 (0.4) degrees C, 23.2 (0.2) degrees C and 37.1 (0.2) degrees C
respectively, and within subject within blow variation was reduced to
<1 degrees C. A metal heat exchanger placed upstream of the PT
satisfactorily preconditioned expired air to the ambient temperature.
Received 13 May 1996; accepted in final form 21 November 1996.
APS Manuscript Number A451-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996