US 5,928,155 A · Cardiac output measurement with metabolizable analyte containing fluid

Abstract

Cardiac output is measured utilizing a catheter in conjunction with the indicator dilution technique. Non-thermal analyte-containing fluid is used as the injectate. This fluid is biocompatible with and metabolizable within the body of the patient. An analyte concentration sensor is mounted upon the catheter and located downstream within the bloodstream from the port from which the analyte-containing fluid is expressed. Because of the matching of rapid concentration sensor response with an analyte-containing fluid which is metabolizable, the measurement of cardiac output may be carried out as often as about one to three minutes in conjunction with an infusion interval substantially less than the measurement frequency interval. The analyte-containing fluids are selected from a group consisting of ammoniacal fluid, heparin, ethanol, a carbon dioxide releasing fluid, glucose, and anesthesia agent. The system performs in conjunction with a microprocessor-driven controller which automates the measurement procedure and provides a display of cardiac output and various cardiovascular parameters.

Claims62

Dependent claims

Apparatus for determining the cardiac output of the cardiovascular system of the body of a patient, comprising:

a catheter, having an externally disposed proximal end region and an oppositely disposed measurement region position able within the bloodstream of the body;
an indicator channel within said catheter having a fluid input at said proximal end region connected with a controlled source of analyte containing fluid biocompatible with and metabolizable within said body and selected from the group consisting of:
ammoniacal fluid, heparin, ethanol, a carbon dioxide releasing fluid, glucose, anesthesia agent, and excluding oxygen, said indicator dilution channel extending to an infusion outlet at said measurement region from which said analyte containing fluid may be expressed;
and
an analyte concentration sensor, responsive to said analyte, having a forward assembly configured for flowing blood contact mounted with said catheter at said measurement region at a location spaced downstream from said infusion outlet when positioned within said bloodstream and having an analyte sensor or concentration sensor output transmissible to said proximal end region corresponding with a concentration level of said analyte within said bloodstream which is correlatable with said cardiac output.

2 more elements

A system for determining the cardiac output of the cardiovascular system of the body of a patient, comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined indicator concentration, said analyte being independent of the thermal energy content of said fluid;
fluid flow control apparatus coupled with said source of analyte-containing fluid and controllable to provide a flow of said analyte-containing fluid at a mass flow rate for an infusion interval at a fluid output;
a catheter having an externally disposed proximal end region and an oppositely disposed measurement region positionable within the bloodstream of said body;
an indicator channel within said catheter having a fluid input at said proximal end region connected in fluid transmission relationship with said fluid flow control apparatus fluid output and extending to an infusion outlet at said measurement region from which said analyte-containing fluid may be expressed into the bloodstream of said body;
an analyte concentration sensor, responsive to analyte within said bloodstream to provide a concentration sensor output, having a forward assembly contactable with flowing blood mounted with said catheter at said measurement region at a location spaced from said infusion outlet a dilution measurement distance downstream when positioned within said bloodstream and having a capability for providing said concentration sensor output with a rapidity effective to derive a cardiac output measurement as often as about every one to three minutes and in conjunction with said infusion interval substantially less than said measurement frequency interval;
a controller for controlling said fluid flow control apparatus and said analyte concentration sensor and responsive to each said concentration sensor output for deriving the value of the analyte concentration level within said bloodstream adjacent said forward assembly, responsive to effect control of said analyte concentration sensor to derive a baseline analyte concentration level output, then responsive to effect said flow of said analyte-containing fluid at a predetermined mass flow rate for said infusion interval and for simultaneously controlling said sensor during said infusion interval to derive a subsequent analyte concentration level output, responsive to correlate said baseline analyte concentration level output, said subsequent value for analyte concentration level output, and said predetermined mass flow rate to derive a first output signal representing a value corresponding with cardiac output;
and
a display responsive to said first output signal for providing a perceptible output corresponding therewith.

5 more elements

The method for determining the cardiac output of the cardiovascular system of the body of a patient, comprising the steps of:

(a) providing a catheter having a proximal end region and extending to a measurement region, an indicator channel within said catheter having a fluid input at said proximal end region and extending to an infusion outlet at said measurement region from which analyte-containing fluid may be expressed, an analyte concentration sensor mounted with said catheter having a forward assembly contactable with flowing blood at said measurement region at a location spaced from said infusion outlet a dilution measurement distance, responsive to the presence of an analyte to provide an output corresponding with the concentration of analyte in blood and having a capability for providing said output within an infusion interval achieving a cardiac output measurement frequency interval of about one to three minutes;
(b) positioning said catheter within the bloodstream of said body, locating said measurement region at the heart region of the patient in a cardiac output measurement orientation wherein said analyte concentration sensor is downstream within said bloodstream from said infusion outlet;
(c) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined indicator concentration, said analyte being independent of the thermal energy content of said fluid;
(d) deriving a baseline value corresponding with the concentration of said analyte in said bloodstream from said concentration sensor output;
(e) delivering said analyte-containing fluid from said source into said indicator channel input at a predetermined mass flow rate for said infusion interval;
(f) deriving a subsequent value corresponding with the concentration of said analyte in said bloodstream from said concentration sensor concentration output during said infusion interval;
and
(g) deriving a value for the cardiac output of the heart of the body by correlating said baseline value, said subsequent value, said indicator concentration, and said predetermined mass flow rate.

5 more elements

The method for determining the cardiac output of the cardiovascular system of the body of a patient, comprising the steps of:

(a) providing a catheter having a proximal end region and extending to a measurement region, an indicator channel within said catheter having a fluid input at said proximal end region and extending to an infusion outlet at said measurement region from which analyte-containing fluid may be expressed, an analyte concentration sensor mounted with said catheter having a forward assembly contactable with flowing blood at said measurement region at a location spaced from said infusion outlet a dilution measurement distance, responsive to the presence of an analyte to provide an output corresponding with the concentration of analyte in blood;
(b) positioning said catheter within the bloodstream of said body, locating said measurement region at the heart region of the patient in a cardiac output measurement orientation wherein said analyte concentration sensor is downstream within said bloodstream from said infusion outlet;
(c) providing an analyte-containing fluid selected from the group consisting of:
ammoniacal fluid, heparin, ethanol, carbon dioxide releasing fluid, glucose, anesthesia agent, and excluding oxygen;
(d) deriving a baseline analyte concentration value in said bloodstream from said concentration sensor concentration output;
(e) delivering said analyte-containing fluid from said source into said indicator channel input at a predetermined mass flow rate for an infusion interval;
(f) deriving a subsequent analyte concentration value during said infusion interval from said concentration sensor output;
and
(g) deriving a value for the cardiac output of the heart of the body by correlating said baseline analyte concentration value, said subsequent analyte concentration value and said predetermined mass flow rate.

6 more elements

A system for determining the cardiac output of the cardiovascular system of the body of a patient, comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and selected from the group consisting of:
ammoniacal fluid, heparin, ethanol, carbon dioxide releasing fluid, glucose, anesthesia agent, and excluding oxygen;
fluid flow control apparatus coupled with said source of analyte-containing fluid and controllable to provide a flow of said fluid at a mass flow rate for an infusion interval at a fluid output;
a catheter having an externally disposed proximal end region and an oppositely disposed measurement region positionable within the bloodstream of said body;
an indicator channel within said catheter having a fluid input at said proximal end region connected in fluid transfer relationship with said fluid flow control apparatus fluid output and extending to an infusion outlet at said measurement region from which said analyte-containing fluid may be expressed into the bloodstream of said body;
an analyte concentration sensor responsive to said analyte within said bloodstream to provide a concentration sensor output, having a forward assembly contactable with flowing blood mounted with said catheter at said measurement region at a location spaced from said infusion outlet a dilution measurement distance downstream within said bloodstream;
a controller for controlling said fluid flow control apparatus and said analyte concentration sensor, responsive to derive a baseline analyte concentration level in blood, then responsive to effect a flow of said analyte-containing fluid into said catheter fluid input at a predetermined mass flow rate for said infusion interval, responsive to derive a subsequent value for analyte concentration level in blood during said infusion interval, and responsive to correlate said baseline analyte concentration level in blood, said subsequent analyte concentration level in blood and said predetermined mass flow rate to derive a first output signal representing a value corresponding with cardiac output;
and
a display responsive to said first output signal for providing a perceptible output corresponding therewith.

6 more elements

Dependencies are inferred from the claim text.

Cardiac output measurement with metabolizable analyte containing fluid

Life of this patent

Cardiac output measurement with metabolizable analyte containing fluid

Life of this patent

Abstract

Claims62