Chronic Access System for Extracorporeal Treatment of Blood Including a Continuously Wearable Hemodialyzer

Abstract

A patient wearable, continuously operating extracorporeal pump apparatus which accesses the patient's arterial venous pressure differential by applying external pressure to a subcutaneous graft that has been cannualized to modulate blood flow through an extracorporeal circuit and to drive the pump for delivering a medicament, such as an anticoagulant, to the site of an intravenous cannula to prevent clogging thereof and also to move a dialysate through a circuit, including a dialyzer and a dialysate rejuvenating cartridge, whereby kidney failure can be treated without recourse to prior art hemodialysis machines found in most treatment facilities. With slight modification, the present invention can be used to remove excess fluids from CHF patients, to remove toxins from the blood in those suffering from liver failure and to facilitate administration of insulin to diabetics and/or glucose to those having hypoglycemia.

1 - 42 . (canceled) 
     
     
         43 . A medical device for delivering metered quantities of a medicament into a patient's vascular system comprising:
 (a) a reservoir containing a medicament, the reservoir being in fluid communication with at least one percutaneous cannula via a compressible tube segment; and   (b) an extracorporeal peristaltic pump having a roller coacting with the compressible tube segment and adapted to be powered by the patient's arteriovenous pressure differential for moving the medicament through the at least one cannula.   
     
     
         44 . The medical device of  claim 43  wherein the reservoir is in fluid communication with the cannula via a compressible tube segment and the pump is a peristaltic pump having a roller coacting with the compressible tube segment. 
     
     
         45 . The medical device of  claim 44  wherein said peristaltic pump comprises:
 (a) a frame having a central opening; 
 (b) a lever plate pivotally mounted to the frame and occupying the central opening; 
 (c) first and second expandable and compressible ventricles each having an inlet port and an outlet port and adapted to be selectively filled and emptied of the patient's blood disposed on opposed sides of the lever plate and arranged such that expanding the first bladder pivots the lever plate in a direction to compress the second ventricle and expanding the second bladder pivots the lever plate in a direction to compress the first ventricle; 
 (d) means for selectively opening and closing said inlet ports and outlet ports of the first and second bladders; and 
 (e) means coupling the pivotally mounted lever plate to the roller for rotating the roller in one of a clockwise or counter-clockwise direction. 
 
     
     
         46 . The medical device of  claim 45  wherein the first and second ventricles each have an inlet port and an outlet port and are adapted to be selectively filled and emptied of the patient's blood in expanding and compressing the first and second ventricles, respectively. 
     
     
         47 . The medical device of  claim 43  wherein the medicament is an anti-coagulant. 
     
     
         48 . The medical device of  claim 46  and further including means for selectively opening and closing said inlet ports and outlet ports of the first and second bladders. 
     
     
         49 . The medical device of  claim 48  wherein said means for selectively opening and closing said inlet ports and said outlet ports comprises:
 (a) permanent magnets slidably mounted in the frame and individually in alignment with the inlet ports and outlet ports of the first and second ventricles; and 
 (b) electromagnets disposed relative to the permanent magnets to selectively attract and repel the permanent magnets. 
 
     
     
         50 . The medical device of  claim 45  and further including:
 (a) a dialyzer having a plurality of semi-permeable membranous wall surfaces contained within a liquid impervious housing, said housing having a pair of inlet ports and a pair of outlet ports; 
 (b) means for connecting a first of the pair of inlet ports and a first of the pair of outlet ports into the vascular system of a lower animal; 
 (c) means for connecting a second of the pair of inlet ports and a second of the pair of outlet ports in the vascular system of a human patient; and 
 (d) the first and second inlet ports and the first and second outlet ports in the housing arranged such that blood of the lower animal flows on one side of the wall surfaces and blood of the human patient flows over a second side of the wall surfaces. 
 
     
     
         51 . The medical device of  claim 46  wherein the means for connecting the first and second inlet ports includes at least one cannula. 
     
     
         52 . A method for obtaining access to a patient's arteriovenous pressure differential comprising the steps of
 (a) selecting a venous segment in the patient's forearm and surgically debranching the selected venous segment and tying off the distal end thereof;   (b) surgically anastomosing the distal end portion of the debranched vein to a selected artery in the patient's forearm;   (c) inserting a needle cannula percutaneously into the debranched vein segment; and   (d) sequentially applying pressure to the forearm sufficient to substantially occlude blood flow through the debranched vein segment and releasing the pressure whereby when the pressure is being applied, the needle cannula is exposed to arterial pressure and when released, the cannula is exposed to venous pressure.   
     
     
         53 . A method for obtaining therapeutic anticoagulation of an extracorporeal circuit comprising the steps of: providing the medical device of  claim 43 , where the medicament is an anti-coagulant;
 (a) percutaneously inserting the cannula into a debranched vein segment or a VFG;   (b) periodically compressing and releasing the debranched vein segment or the VFG to expose the blood exiting and entering said cannula to arterial pressure and venous pressure; and   (c) actuating the pump being activated based on the difference between the arterial pressure and the venous pressure of the blood entering and exiting the cannula.   
     
     
         54 . The method of  claim 53  and further including the steps of:
 (a) providing a dialyzer having a plurality of semi-permeable membranes within an outer housing; 
 (b) connecting the dialyzer to the cannula such that blood flows through a ventricle to power the pump and thence over a first surface of the plurality of membranes; 
 (c) the pump circulating dialysate through the housing and over a second surface of the membranes in proportion to the flow rate of the blood through the dialyzer; and 
 (d) providing a dialysate rejuvenating cartridge using the pump to move dialysate through said cartridge. 
 
     
     
         55 . The method of  claim 54  and further including the step of:
 (a) providing a dialysate rejuvenating cartridge using the pump to move dialysate through said cartridge. 
 
     
     
         56 . The method of  claim 55  and further including the step of:
 (a) providing an amberoid for blocking dialysate flow through the cartridge after a predetermined period of use of the dialysate.