Anti-clogging liquid administration apparatus and method

Claim 3

The method of infusing liquid into a patient according to claim 1, wherein in the step of detecting depletion of substantially the supply of liquid in the reservoir is detected; and in the step of infusing liquid thereafter, the liquid in residual supply is infused into this patient at said slower rate.

Claim 4

The method of infusing liquid into a patient according to claim 1 wherein in the step of detecting, the weight of the reservoir and liquid therein is detected as an indication of said selected volume of liquid; and in the step of infusing liquid thereafter, liquid is delivered at said second delivery rate in response to the weight of the reservoir and liquid therein attaining a selected value.

Claim 5

The method of infusing liquid into a patient according to claim 1 wherein said liquid delivery conduit includes a drop forming chamber; and in the step of detecting, the occurrences of liquid drop formation are detected as an indication of said selector volume of liquid in the step of infusing liquid thereafter, liquid is delivered at said second delivery rate in response to the number of drop formation occurrences attaining a selected value.

Claim 6

The method of infusing liquid into a patient according to claim 1 wherein said liquid delivery conduit includes a drop forming chamber; and in the step of detecting, the occurrence of liquid drop formation is detected as an indication of said selector volume of liquid in the step of infusing liquid thereafter liquid is delivered at said second delivery rate in response to the absence of drop formation.

Claim 7

The method of infusing liquid into a patient according to claim 1 wherein the step of infusing liquid is performed by positive displacement pumping.

Claim 8

The method of infusing liquid into a patient according to claim 6 wherein in the step of detecting, the product of stroke volume times stroke rate is detected as an indication of volume of infused liquid; and in the step of infusing liquid thereafter, liquid is delivered at said second delivery rate in response to the product of stroke volume and stroke rate attaining a selected value.

Claim 9

Apparatus for infusing liquid from a reservoir into a patient through a liquid delivery conduit including an intravascular conduit which is inserted into a patient, the apparatus comprising: liquid-delivery control means communicating with the liquid-delivery conduit at a location therealong intermediate the reservoir and needle, said liquid-delivery control means being operable in a first mode in which liquid is delivered thereby at a selected rate and in a second mode in which liquid is delivered thereby at a rate slower than said selected rate during operation in the first mode and sufficient to flush the intravascular conduit to prevent clogging by formation of blood clots therein; and detector means coupled to said liquid-delivery control means for converting the operation thereof from the first mode to the second mode in response to detection of a condition which is representative of the volume of liquid delivered.

Claim 10

Apparatus for infusing liquid from a reservoir into a patient through a liquid delivery conduit including an intravascular conduit which is inserted into a patient, the apparatus comprising: liquid-delivery control means communicating with the liquid-delivery conduit at a location therealong intermediate the reservoir and needle, said liquid-delivery control means being operable in a first mode in which liquid is delivered thereby at a selected rate and in a second mode in which liquid is delivered thereby at a rate slower than said selected rate during operation in the first mode and sufficient to flush the intravascular conduit to prevent clogging by formation of blood clots therein; and detector means coupled to said liquid-delivery control means for converting the operation thereof from the first mode to the second mode in response to detection of a condition which is representative of the volume of liquid delivered.

Claim 11

Apparatus as in claim 8 wherein said detector means includes a weight sensor for producing said conversion in operation of said liquid-delivery control means in response to the weight of said reservoir and its contents attaining a selected value.

Claim 12

Apparatus as in claim 8 wherein said conduit includes a drop-forming chamber and said detector means includes a drop detector disposed with respect to said drop-forming chamber for producing the conversion in operation of said liquid-delivery control means in response to the absence of drop formation in drop-forming chamber.

Claim 13

Apparatus as in claim 8 wherein said conduit includes a drop-forming chamber and said detector means includes a drop detector disposed with respect to said drop-forming chamber for producing the conversion in operation of said liquid-delivery control means in response to the total number of drops formed attain a selected value.

Claim 14

Apparatus as in claim 8 wherein said liquid-delivery control means includes valving apparatus for introducing variations in obstruction to fluid flow through the liquid-delivery conduit.

Claim 15

Apparatus as in claim 8 wherein said liquid-delivery control means includes positive displacement pumping apparatus.

Claim 16

Apparatus as in claim 13 wherein said detector means responds to the product of stroke volume times stroke rate of said pumping apparatus attaining a selected value to convert operation of said liquid-delivery control means from said first mode to said second mode.