Constant pressure variable flow pump

摘要

A variable flow constant pressure implantable pump employs an in-line needle restrictor having a variable insertion distance in a capillary. The degree of insertion determines the effective restriction within the capillary. The restrictor may be repositioned following implantation to vary the drug delivery rate by changing the effective restriction in the capillary. Various couplings may be used such that an auxiliary or bolus port delivers infusate directly into the outlet catheter so that medication from the main chamber does not pass through the auxiliary chamber. A combination of double lumen catheters and T- connectors are employed to provide parallel infusion paths.