Postprint version. Published in Medical and Biological Engineering and Computing, Volume 24, Issue 4, July 1, 1986, pages 379-385.
NOTE: At the time of publication, the author William Durgin was not yet affiliated with Cal Poly.
The definitive version is available at https://doi.org/10.1007/BF02442692.
Venous occlusion plethysmography (VOP) is a noninvasive technique widely employed for the detection of deep-vein thrombosis. Previous reports that VOP outflow curves are closely fit by a first-order exponential suggest that venous compliance and resistance are nearly constant. Typically, however, the venous compliance function has a sigmoid shape; in addition, the resistance in a collapsing tube must increase. This paradox was resolved by the surprising finding that for realistic nonlinear compliance and resistance these nonlinearities cancel, producing a quasilinear venous outflow that approximates a simple exponential.