ISSN:
1741-0444
Keywords:
Digital computer
;
Plethysmograph
;
Pulmonary volumes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract The actual gas contents of lungs can be measured by a total plethysmographic technique. A classical way of obtaining thoracic gas volume (t.g.v.) is by fitting a straight line to the thoracic volume (Vt) and mouth pressure (Pm) changes occurring during a panting manoeuvre with airway occlusion at the mouth. In our lung-function laboratory, a minicomputer has been connected to a pressure-compensated flow body plethysmograph. We describe here both the plethysmographic technique of measuring thoracic flow (V′t) and the computerised system developed to calculate on-line lung volumes in patients. By replacing Vt and Pm by their time derivatives, V′t and P′m, in the linear regression procedure, we significantly improve the correlation coefficient, namely the confidence which can be attributed to calculated t.g.v. The within-subject reproducibility of lung volumes is thus improved, and a closer comparison is found between the computer-derived and hand-calculated volumes, both in normal subjects and patients.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02443382
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