AJP - Gastrointestinal and Liver Physiology, Vol 248, Issue 2 251-G255, Copyright © 1985 by American Physiological Society
Sleeve device functions as a Starling resistor to record sphincter pressure
J. H. Linehan, J. Dent, W. J. Dodds and W. J. Hogan
In 1976 Dent (Gastroenterology 71: 263-267) introduced a sleeve-catheter
device for obtaining continuous recording of lower esophageal sphincter
pressure. The infused sleeve accommodates for axial sphincter movement by
providing a large surface of collapsible membrane that is capable of
sensing maximal sphincter pressure at any point along the sleeve. Although
sleeve performance was tested previously, the precise physical principal of
its function has not been delineated. This study tests the hypothesis that
the sleeve device functions as a Starling resistor. The term "Starling
resistor" is an eponym that designates the physics of fluid flow through
collapsible tubes. When pressure at any point along an infused collapsible
conduit is greater than the intraluminal pressure at the distal end of the
conduit, partial collapse occurs at some axial location along the conduit
where the transmural pressure equals zero. The location of zero transmural
pressure is termed the "equal pressure point" (EPP). The partial collapse
at the EPP causes a local change in luminal resistance that is directly
related to the magnitude of the external pressure at the EPP and
accompanied by a corresponding change in the pressure upstream from the
EPP. A correlate to the performance of Starling resistors is that the
pressure upstream to the EPP is not affected by the downstream pressure, so
long as the downstream pressure is less than the external pressure. To test
our hypothesis, we evaluated sleeve performance in vitro using a
two-chambered model that allowed application of static or oscillatory
pressures at one or two sites along the sleeve.(ABSTRACT TRUNCATED AT 250
WORDS)
