Infusion apparatus

• US 5,425,716 A
• Filed: 05/20/1993
• Issued: 06/20/1995
• Est. Priority Date: 08/09/1991
• Status: Expired due to Term

• Current Assignee: Atom Kabushiki Kaisha
• Original Assignee: Atom Kabushiki Kaisha
• Inventors: Yamashita, Yoshishige, Kawasaki, Tatsuro, Matsubara, Kazuo
• Primary Examiner(s): Rosenbaum, C. Fred
• Assistant Examiner(s): VANOVER, PERRY
• Application Number:
  US08/039,031
• Time in Patent Office: 761 Days
• Field of Search: 128/DIG. 1, 128/DIG. 12, 128/DIG. 13, 604/65, 604/66, 604/67, 604/151, 604/154
• US Class Current: 604/152
• CPC Class Codes: A61M 2205/6018 providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 5/1456 with a replaceable reservoir comprising a piston rod to be moved into the reservoir, e.g. the piston rod is part of the removable reservoir
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: Y10S 128/12 Pressure infusion

Abstract

Infusion apparatus is provided for discriminating the specifications of syringes of any manufacturer, setting alarm levels corresponding to contained liquid solutions having various viscosities, and obtaining a net pressure for infusion from the force to a plunger by considering pressure loss dependent on a friction factor between the barrel and the plunger of the syringe. Syringe diameter is detected digitally to determine a capacity signal. The plunger force is detected by a pressure sensor and then A/D converted to a digital pressure signal. Specifications of syringes of manufacturers based on the syringe capacity signal are compared with the signals of the mounted syringe to select one among operation programs corresponding to their syringe specifications. A Dip switch selects a group of the operation programs for manufacturers. The digital pressure signal from the pressure converter is input to a comparator through a subtracter cooperating with a pressure loss constant table to compare outputs from a supremum constant table indicating the needle for the infusion solution is correctly injected into the blood vessel or muscle of the patient. A pressure loss is subtracted from the force detected based on the friction factor and the output from the pressure converter produces a value corresponding to the net pressure.

Claims

1. An infusion apparatus comprising:

a syringe for storing a medicinal liquid solution between a barrel and a movable plunger;

means for mounting said barrel on said infusion apparatus;

driving means for pushing said plunger in said barrel at a predetermined speed;

a pressure sensor for detecting the force on said plunger to provide an analogue signal;

a pressure converter for receiving and A/D converting said analogue signal to a digital pressure signal;

a comparator having inputs capable of receiving said digital pressure signal from said pressure converter;

a supremum limit constant table having data outputs connected to other inputs of said comparator; and

a selection switch for selecting a supremum limit value output from said supremum limit constant table.

2. An infusion apparatus according to claim 1, further comprising a learning function of updating the supremum value corresponding to an alarm produced within a predetermined period after infusion is started.

3. An infusion apparatus comprising:

a disposable syringe for storing a medicinal liquid solution between a barrel and a movable plunger;

means for mounting said barrel on said infusion apparatus;

driving means for pushing said plunger in said barrel at a predetermined speed;

a pressure sensor for detecting a force to said plunger to provide an analogue signal;

a pressure converter for receiving and A/D converting said analogue signal to a digital pressure signal;

a pressure loss constant table for outputting a pressure loss based on a friction factor between said barrel and said plunger; and

a subtracter for subtracting the pressure loss from said digital pressure signal, thereby obtaining a net pressure to said plunger.

4. An infusion apparatus according to claim 3, further comprising a learning function of storing, as the pressure loss, a pressure obtained when said plunger in said empty syringe is pushed at the predetermined speed, in said pressure loss constant table.

5. An infusion apparatus according to claim 3, wherein the friction factor is determined based on standards and specifications of said syringe.

6. An infusion apparatus in which a movable slider is brought into contact with a plunger of a syringe having a barrel, said barrel mounted on a base, and said plunger is pushed by moving said slider relative to said base, comprising:

driving means for pushing said slider at a predetermined speed;

a pressure sensor for detecting a force to said plunger to provide an analogue signal;

a pressure converter for receiving and A/D converting said analogue signal to a digital pressure information;

syringe diameter means for detecting the capacity of said plunger to provide digital diameter information;

data storage means for storing specification data for various syringes;

program storage means for storing operation programs for said various syringes;

comparing means for comparing said information from said pressure sensor and said syringe diameter means, with the respective specification data of said syringes stored in said data storage means to determine a specific syringe to be mounted; and

switching means for selecting a predetermined operation program for said specific syringe among said operation programs stored in the program storage means, according to a comparison result of said comparing means.

7. An infusion apparatus comprising:

a base;

a disposable syringe having barrel and plunger between which a medicinal solution is contained;

means for mounting said barrel on said base;

a movable slider abutted to said plunger to push said plunger;

a screw rod rotatably and axially-movably supported by said base and meshed with said movable slider;

a motor for rotating said screw rod; and

a pressure sensor disposed between an end of said screw rod and said base to provide an analogue signal corresponding to a force to said plunger.

8. An infusion apparatus comprising:

a base;

a syringe having a movable plunger and a barrel detachably mounted on said base for storing a medicinal liquid solution;

driving means fixed to said base for pushing said plunger at a predetermined speed;

a pressure sensor associated with said drive means for detecting a force to said plunger to provide an analogue signal;

an analogue to digital converter receiving and A/D converting said analogue signal to an n-bits wide digital pressure signal, where n is a positive integer;

a comparator having n inputs capable of receiving said digital pressure signal;

a supremum limit constant table having n outputs connected to other n inputs of said comparator; and

a selector for selecting an address of said supremum limit constant table to provide a predetermined supremum limit constant value.

9. An infusion apparatus in which a movable slider is brought into contact with a plunger of a syringe having a barrel, said barrel is mounted on a base, and said plunger is pushed by moving said slider relative to said base, comprising:

syringe diameter means for detecting a capacity of said plunger to provide digital diameter information;

data storage means for storing specification data of various types of syringes manufactured by various manufacturers;

switching means for selecting predetermined specification data for said various syringes of a predetermined manufacturer among said various manufacturers; and

comparing means for comparing said information from said syringe diameter means, with said respective specification data of said syringes to determine which syringe has been mounted on said base.