Recording Pressure Changes in the Human Alimentary Tract Using a Radio-Telemetering Capsule

The use of telemetering capsules in disorders of the alimentary tract: Part I A technique for recording pressure changes

“…This excursion which appears on the pressure tracing does not then truly record the hydrostatic pressure surrounding the capsule and is an artefact caused by the breakdown in the radio link. Unfortunately, it was found that the nature of the positional or orientational changes experienced by the capsule was such that on our original apparatus (Smith and Ridgway, 1961) many of these artefacts could not be distinguished from some normal phasic pressure waves (Fig. 2).…”

“…In order to foster the use of this useful and interesting technique of investigation we have sought to contribute to the solution of the two outstanding difficulties in its general application: first, by developing a method of radiological markers for the estimation of the capsular position within the intestinal tract (Smith and Ridgway, 1961); and secondly, by establishing a technique for the combined recording of pressure and movement or orientational changes. The modification in technique presented in this paper exploits the problem by sometimes allowing the orientational or movement changes to be recorded, as well as the associated pressure change, so enhancing the clinical significance of the results.…”

“…The results of determinations using the first method are not completely satisfactory because of the overlapping of various parts of the digestive organs. Concentrating on the second method, we have employed radioopaque marker meals of bismuth carbonate, one taken before the capsule and another after it, to differentiate certain parts of the alimentary tract (Smith and Ridgway, 1961). It is possible to obtain fairly precise information in this way, but should interpretation prove difficult the radiological technique may be improved by stereoscopy or by special positioning so that the risk of overlap is lessened.…”

The use of telemetering capsules in disorders of the alimentary tract: Part II The application to the study of human gastro-intestinal motility

“…The capsule is swallowed one hour after a marker meal of bismuth or dilute barium. Five hours after the first marker meal, a second meal is consumed; the pill is located by relating it to the shadow 'The capsule was manufactured by Solartron Ltd. of the second marker in the stomach or to the first, which should now be outlining the ileocaecal region (Smith and Ridgway, 1961). Two further radiographs are usually taken at about eight hours and 24 hours after the beginning of the test.…”