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Patient controlled infusion apparatus and method

  • US 5,084,021 A
  • Filed: 11/02/1990
  • Issued: 01/28/1992
  • Est. Priority Date: 11/02/1990
  • Status: Expired due to Term
First Claim
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1. Patient controllable fluid infusion apparatus comprising a fluid flow metering tube connecting set for attachment between a fluid source under pressure and a use site, which fluid flow metering tube connecting set comprisesa flexible metering connecting tube having connector means at its opposite inlet and outlet ends,said connecting and metering tube having a central bore which forms a first fluid flow impedance as a function of the cross-sectional size of said bore,a flow restricting rod having a flow-blocking cross sectional construction with an outer cross sectional size smaller than the cross sectional size of said bore,said rod being disposed within and extending along a selected longitudinal extent of said bore, to thereby form an effective fluid flow passageway bore cross section of reduced cross-sectional size around the outside of and along the longitudinal extent of said rod within said tube bore, which longitudinal extent of reduced cross-sectional size forms a second fluid flow impedance as a function of the longitudinal extent and cross-sectional size of said reduced cross-sectional size effective fluid flow passage way bore along the length of said rod within said bore,a fluid delivery syringe having a fillable fluid chamber from which fluid may be expelled by patient action,a fluid supply reservoir for enabling filling of said chamber, said fluid supply reservoir being connected to said inlet end of said metering connecting tube,and said outlet end of said metering connecting tube being connected in fluid supply relation to said syringe chamber,said fluid delivery syringe having a fluid outlet therefrom for patient controlled dispensing of fluid from its said chamber to a selected site after flow of fluid from said fluid source through said metering connecting tube and around said flow restricting rod as a function of and while maintaining a substantially constant pressure differential between said fluid source and said chamber.

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