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Patient-controlled analgesia device

  • US 5,232,448 A
  • Filed: 10/25/1991
  • Issued: 08/03/1993
  • Est. Priority Date: 12/05/1989
  • Status: Expired due to Term
First Claim
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1. An apparatus for patient-controlled delivery of a beneficial agent comprising(a) a dose reservoir for receiving and storing a dose of beneficial agent;

  • (b) inlet means to said dose reservoir for receiving the beneficial agent from an external supply;

    (c) outlet means to said dose reservoir through which the beneficial agent in said dose reservoir exits said dose reservoir; and

    (d) pump means partially defining said dose reservoir operative in response to an external force supplied to said pump means for drawing beneficial agent into said dose reservoir at a relatively constant rate and for discharging the beneficial agent out of said dose reservoir through said outlet means, said pump means comprising an annular shaped arcuate wall means terminating at a foot, said arcuate wall means having a constant wall curvature and wall thickness extending from said foot to a centrally located head means, said head means having a rigidity substantially greater than the rigidity of the arcuate wall means to restrict the compression of said pumping means substantially to the said arcuate wall means, said pump means compressed in response to an external force applied to said pump means so as to advance the beneficial agent from said dose reservoir to said outlet means, and upon removal of the external force the pump means returns to the uncompressed condition at relatively constant rate, wherein upon retuning to the uncompressed condition the pressure in said dose reservoir is lower ralative to the pressure in the external supply so that beneficial agent is drawn into said dose reservoir from the external supply via suction at a relatively constant rate.

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