Method and apparatus to measure blood flow and recirculation in hemodialysis shunts

  • US 5,685,989 A
  • Filed: 09/16/1994
  • Issued: 11/11/1997
  • Est. Priority Date: 09/16/1994
  • Status: Expired due to Term
First Claim
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1. A process for determining in an arterio-venous shunt blood flow in a cardiovascular circuit, comprising:

  • delivering blood from a circulating system outside the cardiovascular circuit into an upstream location in an arterio-venous shunt connected in the cardiovascular circuit and carrying a shunt blood flow;

    mixing said delivered blood with said shunt blood flow;

    removing a portion of the mixed blood from said arterio-venous shunt at a location in the shunt which is downstream from said upstream location and delivering the removed portion of mixed blood to the circulating system;

    changing a selected blood parameter in blood flowing in said circulating system to produce a distinguishable blood characteristic in blood which is delivered to the arterio-venous shunt;

    measuring the amount of distinguishable blood characteristic in said removed portion of mixed blood; and

    calculating the rate of flow of said shunt blood flow in said arterio-venous shunt from said measured amount of distinguishable blood characteristic.

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