Imed Corporation

Fisher Scientific Company

David E Kaplan

David H Burkett

Laurence Warden

Ronald D Irvin

Ronald J Harvey

A method for testing for patency at a venous access site during intravenous infusion of a medical solution includes the steps of occluding an intravenous injection tube upstream from the venous access site and monitoring the time and fluid pressure within the tube while the fluid pressure within the tube is varied by external contact with the tube. An apparatus for practicing the method of the invention includes a housing formed with a tube receiving portion for holding a portion of the tube in contact with an occluder finger, a fluid moving finger and a pressure transducer. The fluid moving finger is adapted to contact the tube so as to achieve a testing base pressure in the fluid, after occlusion by the occluder finger. A sequence of pressure drops are then effected by moving the fluid moving finger in stepped increments. An excessive time interval between a pressure drop and a recovery of fluid pressure back to the testing base pressure is an indication of an infiltration condition or some other obstruction.

Method and apparatus for infiltration detection during administration of

A linear peristaltic pump includes a mechanism for maintaining linear flow of fluid through an I.V. tube. The mechanism comprises a casing carrying a rotatable camshaft having a plurality of cams spaced therealong in helical arrangement and a plurality of fingers coupled to the camshaft. A housing for establishing linear reciprocal movement of the fingers in response to rotation of the shaft establishes a moving zone of occlusion along a tube held against the fingers. Aligning means are included for establishing an axis of rotation of the camshaft which is slightly tilted with respect to the tube. This is accomplished by raising or lowering the upstream or the downstream end of the camshaft to prevent unwanted pressure from building up in the tube to reduce pulsatile flow and maintain linear flow. The aligning mechanism comprises a generally cylindrical bushing having an eccentric hole therethrough for carrying the hinged connection between the casing and the housing. The bushing has a slot therethrough for adjustably rotating the bushing for adjusting the amount of tilt. The adjustment can take place during operation of the pump, having a pressure sensor against the tube, to achieve the optimal positioning of the camshaft depending on the tolerances of the pump mechanism to establish linear flow of fluid through the tube.

Peristaltic pump with mechanism for maintaining linear flow

A linear peristaltic pump equipped with a pressure relief mechanism for pumping I.V. fluids to a patient comprises a platen for supporting the tube, and a plurality of fingers which sequentially urge against the tube resting against the platen for creating a moving zone of occlusion. Cam lobes are formed to lift a penultimate and ultimate finger off of the tube at a rate faster than the other fingers to prevent pressure increases inside the tube which would otherwise be caused by other fingers urging against the tube. Additionally, the ultimate finger may be shortened with respect to the other fingers to reduce the total occlusion time of the ultimate finger to provide a more linearized flow of fluid to the patient.

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Moraga, CA, United States of America

David E Kaplan