US 4,447,224 A · Variable flow implantable infusion apparatus

Abstract

Implantable variable flow infusion apparatus comprises a collapsible infusate chamber having an outlet conduit leading to the infusion site by way of series-connected fixed and variable fluid flow restrictors. The infusate in the chamber is maintained under substantially constant pressure by a nonelectric energy storage cell to establish flow from the chamber to the site. The variable restrictor is controlled by commands from a preprogrammed microprocessor and programmable memory powered by a small long-lived battery. The processor sets the variable restrictor to the proper setting to establish the correct infusate flow for the particular time of day. A pressure transducer connected across the fixed restrictor senses the pressure differential across the fixed restrictor which differential indicates actual infusate flow from the chamber. The processor samples the output from the transducer at infrequent sampling intervals and issues command signals to control the variable restrictor whenever the actual infusate flow rate differs from the preprogrammed rate so that the apparatus consumes a minimal amount of battery energy and can thus remain implanted in the body for a prolonged period. The processor can also be reprogrammed and monitored by telemetry.

Claims20

Dependent claims

Variable flow implantable infusion apparatus comprising

A. a housing;
B. a variable volume infusate chamber in the housing;
C. means for conducting infusate from said chamber to an infusion site outside the housing, said conducting means including series-connected fixed and electromechanically variable fluid flow restricting means;
D. means in the housing for maintaining the contents in the infusate chamber under a substantially constant pressure;
E. means for sensing the pressure differential across said fixed restricting means and producing indications in response thereto;
F. programmable processing means in the housing which
(1) sets the restriction of the variable flow restricting means at a selected programmed value,
(2) samples the indications from the sensing means at selected programmed intervals,
(3) compares each sample value with a reference value programmed into the processing means, and
(4) issues a command signal for controlling the variable restricting means so as to maintain this constant selected infusate flow rate;
and
G. a battery for powering the variable restricting means and processing means.

9 more elements

Variable flow implantable infusion apparatus comprising

A. a housing;
B. a variable volume infusate chamber in the housing;
C. means for conducting infusate from said chamber outside the housing;
D. a variable volume fluid pressure reservoir in the housing;
E. a variable volume fluid displacement reservoir in the housing;
F. a fluid path extending between the pressure reservoir and the displacement reservoir, said path including series-connected fixed and variable flow restricting means, said reservoirs and path arranged to be filled with a sustantially incompressible control fluid;
G. means in the housing for maintaining the contents of the pressure reservoir under substantially constant pressure;
H. means for sensing the fluid pressure differential across the fixed restricting means and producing indications in response thereto;
I. programmable processing means in the housing which
(1) sets the restriction of the variable flow restricting means at a selected programmed value,
(2) samples the indications from the sensing means at selected programmed intervals,
(3) compares each sample value with a reference value programmed into the processing means, and
(4) issues a command signal for controlling the variable restricting means so as to maintain this constant selected infusate flow rate;
and
J. a battery for powering the variable restricting means and processing means.

12 more elements

Dependencies are inferred from the claim text.

Variable flow implantable infusion apparatus

Life of this patent

Variable flow implantable infusion apparatus

Life of this patent

Abstract

Claims20