Monitoring total circulating blood volume and cardiac output

• US 6,299,583 B1
• Filed: 07/26/1999
• Issued: 10/09/2001
• Est. Priority Date: 03/17/1998
• Status: Expired due to Term

• Current Assignee: Cardiox Corporation
• Original Assignee: Cardiox Corporation
• Inventors: Eggers, Philip E., Eggers, Eric A., Eggers, Andrew R.
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US09/361,076
• Time in Patent Office: 806 Days
• Field of Search: 600/322, 600/341, 600/342, 600/368, 600/478, 600/479, 600/481, 600/486, 600/508, 600/526
• US Class Current: 600/526
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/0275 using tracers, e.g. dye dilution
• CPC Class Codes: A61B 5/028 by thermo-dilution
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/6853 with a balloon
• CPC Class Codes: A61M 2025/0002 with a pressure sensor at the distal end
• CPC Class Codes: A61M 2025/0003 having an additional lumen transmitting fluid pressure to the outside for measurement

Abstract

A system and method for measuring total circulating blood volume and cardiac output employing an analyte diffusion approach. The analyte sensor as well as the analyte-containing fluid infusion procedure may be carried out with instruments which are inserted in the bloodstream at peripheral locations of the body spaced from the heart. A controller is provided to automatically carry out these measurements as well as to provide threshold comparisons for alerting the practitioner to excursion in the parameters. The preferred analyte containing fluid is an ammoniacal fluid and the preferred sensed components is ammonia gas.

Claims

1. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte; and

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter; and

a readout responsive to said output signal for providing a perceptible output corresponding therewith.

2. The system of claim 1 in which said controller is responsive to control said analyte concentration sensor prior to said provision of said flow of analyte-containing fluid to provide said sensor outputs and derive a corresponding baseline value for concentration of said analyte, and is responsive to correlate said baseline value for concentration of said analyte with said time associated concentration values, said predetermined mass flow-rate said predetermined analyte concentration and said infusion interval to derive said output signal.

3. The system of claim 2 in which:

said select hemodynamic parameter is cardiac output; and

said controller is responsive to correlate said baseline value for concentration of said analyte, said predetermined mass flow rate, said predetermined analyte concentration and said peak value of said time associated concentration values to derive said output signal as corresponding with cardiac output.

4. The system of claim 2 in which said controller is responsive to a sequence of said baseline analyte concentration level outputs to derive a comparison analyte concentration level in blood corresponding with metabolic homeostasis of said body, and responsive to compare an inputted homeostasis threshold value corresponding with analyte concentration in blood for iatrogenesis with said comparison analyte concentration level in blood to derive a second output signal when said comparison analyte concentration level in blood represents a value greater than said inputted homeostasis threshold value.

5. The system of claim 1 in which said source of analyte-containing fluid is selected from the group consisting of:

ammoniacal fluid, heparin, ethanol, glucose and anesthesia agent.

6. The system of claim 1 in which:

said controller includes a real time clock providing a real time output;

said controller is responsive to said real time output with the contemporaneous derived occurrence of a said output signal to derive a time associated display signal; and

said readout is responsive to said time associated display signal to provide a visually perceptible display of the derived value of said select hemodynamic parameter and the time of its derivation.

7. The system of claim 6 in which:

said readout is responsive to each of a sequence of said time associated display signals to produce a trend defining graphics display thereof.

8. The system of claim 1 in which said analyte concentration sensor comprises:

an analyte concentration reactor having an output condition in response to the concentration of said analyte;

a support and transmission assembly for conveying said sensor outputs corresponding with said output condition to said controller; and

a membrane mounted upon said support and transmission assembly, permeable to said analyte, having an outer surface contactable with said blood and positioned to communicate said analyte with said reactor.

9. The system of claim 8 in which:

said analyte-containing fluid is ammoniacal fluid;

said membrane is permeable to ammonium ion (NH₄⁺);

said reactor comprises first and second electrodes immersed within an electrolyte sensitive to said ammonium ion; and

said controller controls said analyte concentration sensor to derive said sensor outputs as amperometric outputs.

10. The system of claim 8 in which:

said analyte-containing fluid is ammoniacal fluid;

said membrane is permeable to ammonium ion (NH₄⁺);

said reactor comprises first and second electrodes immersed within an electrolyte sensitive to said ammonium ion; and

said controller controls said analyte concentration sensor to derive said sensor output as potentiometric signals.

11. The system of claim 8 in which:

said analyte concentration reactor comprises an analyte-sensitive fluorescent material having a fluorescence intensity as said output condition;

said support and transmission assembly comprises a fiberoptic assembly; and

said controller controls said analyte concentration sensor by stimulating said fluorescent material through said fiberoptic assembly and deriving said sensor outputs as fluorescence intensity conveyed by said fiberoptic assembly.

12. The system of claim 8 in which:

said analyte concentration reactor comprises an analyte-sensitive fluorescent material stimulatable into fluorescence, the rate of quenching of said fluorescence being said output condition;

said support and transmission assembly comprises a fiberoptic assembly; and

said controller controls said analyte concentration sensor by stimulating said fluorescent material through said fiberoptic assembly and deriving said sensor outputs as said rate of quenching conveyed by said fiberoptic assembly.

13. The system of claim 8 in which:

said analyte concentration reactor comprises a Schottky diode array having a conductive polymer responsive to said analyte to effect a forward bias alteration as said output condition.

14. The system of claim 8 in which:

said analyte-containing fluid is ammoniacal fluid;

said membrane is permeable to gaseous ammonia (NH₃);

said reactor is a gaseous ammonia sensitive dye;

said support and transmission assembly is a fiberoptic colorimetric measurement assembly which quantitates a change in color of the dye to provide said sensor outputs; and

said controller is responsive to said sensor outputs and the pH exhibited by said blood to derive said analyte concentration values.

15. The system of claim 14 in which:

said controller derives a said analyte concentration value as total ammoniacal concentration in blood in correspondence with the expressions;

16. The system of claim 14 including:

a pH sensor configured for positioning within said bloodstream at a said peripheral region and controllable to provide a pH sensor output corresponding with the pH value of blood with which it is in contact; and

said controller effects control of said pH sensor to derive said pH sensor output and said pH exhibited by said blood corresponding therewith.

17. The system of claim 1 in which said analyte concentration sensor comprises an acoustic-wave sensor having an acoustic-wave delay line within an oscillator loop to derive said sensor outputs.

18. The system of claim 1 in which:

said analyte concentration sensor comprises;

a fiberoptic assembly extending from a proximal region to a tip;

a membrane permeable to said analyte, having an outer surface within said bloodstream and an inner surface spaced from said fiberoptic tip to define an analyte equilibration cavity; and

said controller includes a light transmission and reception assembly optically coupled with said fiberoptic assembly proximal region and actuable to derive said sensor outputs with respect to analyte at said equilibration cavity.

19. The system of claim 1 in which:

said analyte concentration sensor comprises;

a fiberoptic assembly extending from a proximal region to a tip, including an outer surface extending inwardly from said tip;

an end plug impervious to blood having an inwardly disposed surface spaced from said tip to define the length of an equilibration cavity;

a membrane permeable to said analyte, having an outer surface contactable with said bloodstream and extending sealingly about said outer surface and said end plug to define the rider of said equilibration cavity; and

said controller includes a light transmission and reception assembly optically coupled with said fiberoptic assembly proximal region and actuable to derive said sensor output with respect to analyte at said equilibration cavity.

20. The system of claim 1 in which:

said analyte concentration sensor comprises;

a fiberoptic assembly extending from a proximal region to a forward region located within said bloodstream, said forward region having a forward light transmission leg and a return transmission leg spaced from said forward transmission leg to define a gap; and

a membrane permeable to said analyte having an outer surface exposable to said blood in said bloodstream;

said membrane sealingly extending about said gap to define an equilibration cavity; and

said controller includes a light transmission assembly optically coupled with said fiberoptic assembly forward light transmission leg at said proximal region and including a light reception assembly optically coupled with said fiberoptic assembly return transmission leg at said proximal region and actuable to derive said sensor outputs with respect to analyte at said equilibration cavity.

21. The system of claim 1 in which:

said analyte concentration sensor comprises

a fiberoptic support and transmission assembly extending from a proximal region from which said sensor outputs are transmissible, to a distal end face;

a porous reactor support configured with a matrix of receptor pores and having a support thickness defined between a forward surface and a support rearward region;

an analyte concentration reactor confined within said matrix of receptor pores and having an output condition in response tot he concentration of said analyte;

a non-porous, optically transparent backer component having a forward region bonded with said support rearward region substantially non-invasive with said receptor pores and having an oppositely disposed backer rearward region spaced from said forward region a backer thickness and coupled with said fiberoptic support and transmission assembly distal end face with an optically transparent adhesive.

22. The system of claim 21 in which:

said reactor is an analyte-sensitive dye; and

said fiberoptic support and transmission assembly is configured to quantitate said output condition by the transmission to and reception from said reactor of light of predetermined wavelength.

23. The system of claim 1 in which:

said analyte-containing fluid is ammoniacal fluid;

said reactor is an ammonia sensitive dye;

said fiberoptic support and transmission assembly is configured for colorimetric evaluation of changes in color of said dye to derive said sensor outputs; and

said controller is responsive to said sensor outputs and the pH exhibited by said blood to derive said analyte concentration values.

24. The system of claim 23 in which:

said controller derives a said analyte concentration value as total ammoniacal concentration in blood in correspondence with the expressions;

25. The system of claim 21 in which:

said backer component backer thickness is in a range of about one to four mils.

26. The system of claim 21 in which:

said reactor support thickness is in a range of about one to four mils.

27. The system of claim 1 in which:

said analyte concentration sensor is mounted within a catheter configured for indwelling positioning within the heart.

28. The system of claim 1 in which:

said analyte concentration sensor is mounted within a pulmonary artery catheter at a location effective for positioning in adjacency with the pulmonary valve of the heart of said body.

30. The system of claim 1 in which:

said analyte concentration sensor comprises;

a rigid thin tube extending from a base region to a tip configured for positioning within said bloodstream and having an open, internal channel extending from said base region through said tip;

a fiberoptic assembly from which said sensor outputs are transmissible slideably positioned within said chamber and having an end face moveable from a retracted position outwardly from said tip;

a reactor support mounted upon said end face;

an analyte concentration reactor retained by said reactor support, having an output condition in response to the concentration of said analyte; and

said controller includes a light transmission and reception assembly optically coupled with said fiberoptic assembly which is actuable to derive said sensor output by the application of light of predetermined wavelength to said reactor.

31. The system of claim 30 in which:

said reactor support is a porous polymeric optically transparent component having a matrix of receptor pores; and

said analyte concentration reactor is confined within said matrix of receptor pores.

32. The system of claim 31 in which said analyte concentration sensor includes a non-porous, optically transparent backer component having a forward region non-adhesively bonded to said reactor support and an oppositely disposed rearward region adhesively bonded to said fiberoptic assembly end face.

29. The system of 28 in which:

said delivery assembly is mounted within said pulmonary artery catheter.

33. The method for determining hemodynamic parameter of a cardiovascular system wherein blood within a bloodstream is circulated to peripheral regions of the body, comprising the steps of.

(a) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined analyte concentration;

(b) providing fluid flow control apparatus having an input coupled in fluid flow communication with said source of analyte-containing fluid and actuable to provide a flow of said analyte-containing fluid at a mass flow rate at an outlet for an infusion interval;

(c) providing an analyte concentration sensor having a distal analyte responsive portion and a communication channel extending therefrom to a proximal region, and being controllable from said proximal region to provide sensor outputs corresponding with the sensed concentration of said analyte;

(d) providing a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow and an output positionable within said bloodstream through which said analyte containing fluid is expressible at said mass flow rate;

(e) providing a controller operatively responsive with said fluid flow control apparatus and coupled in controlling relationship with said analyte concentration sensor, and actuable to record the time of delivery of said analyte-containing fluid at the commencement of said infusion interval, responsive thereafter to control said analyte concentration sensor to effect provision of timed sequence of said sensor outputs and derive a corresponding sequence of time associated analyte concentration values, said time associated sequence of analyte concentration values rising in value toward a peak value and decreasing in value therefrom, responsive to correlate said time associated sequence of analyte concentration values, said mass flow rate and said time of delivery to derive an output signal representing a value corresponding with a select hemodynamic parameter;

(f) positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream at a said peripheral region;

(g) actuating said controller to derive said output signal; and

(h) providing a readout responsive to said output signal and having a perceptible output identifying the value of the hemodynamic parameter corresponding therewith.

34. The method for determining the total circulating blood volume of a cardiovascular system circulating blood within a bloodstream extending to a peripheral region of a body and exhibiting a pH value, comprising the steps of:

(a) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined analyte concentration;

(b) providing an analyte concentration sensor having a distal analyte responsive portion configured for positioning within said bloodstream and responsive to the presence of said analyte to provide sensor outputs corresponding with the sensed concentration of analyte;

(c) providing a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said source of analyte containing fluid and an output configured for positioning within said bloodstream;

(d) positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream;

(e) delivering said analyte-containing fluid from said source into said delivery channel at a time of delivery, and at a dose value defining mass flow rate, at said predetermined analyte concentration, and over an infusion interval;

(f) deriving a sequence of time associated analyte concentration values from said sensor outputs;

(g) monitoring said sequence of time associated concentration values and identifying a sequence thereof descending in value from a peak-defining inflection value; and

(h) deriving a value for total circulating blood volume by correlating said time of delivery, said dose value and identified sequence of time associated concentration values descending in value.

35. The method of claim 34 in which:

said step (d) includes the step of

(d1) prior to said step (e) deriving a baseline value corresponding with the concentration of said analyte in said body from said analyte concentration sensor outputs; and

said step (h) further correlates said baseline value to derive said value for total circulating blood volume.

36. The method of claim 35 including the step:

(i) deriving a value for cardiac output by correlating said baseline value for concentration of said analyte, said mass flow rate, said predetermined analyte concentration and said identified peak-defining inflection value.

37. The method of claim 35 in which:

said step (g) further identifies a sequence of said time associated concentration values rising in value towards said peak-defining inflection value; and

including the step;

(i) deriving a value for cardiac output by correlating said baseline value for concentration of said analyte, said mass flow rate, said predetermined analyte concentration, said infusion interval and an integrated value of said time associated concentration values.

38. The method of claim 34 in which said step (f) derivation of time associated concentration values is carried out in conjunction with a sensor output frequency of about one measurement per second.

39. The method of claim 34 in which said analyte-containing fluid source is selected from the group consisting of:

ammoniacal fluid, heparin, ethanol, glucose and anesthesia agent and excluding oxygen and carbon dioxide releasing fluid.

40. The method of claim 34 which said step (d) is carried out by positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream said peripheral region.

41. The method of claim 40 including the step:

(i) deriving a value for cardiac output in correspondence with the expression;

$\mathrm{CO}<br><br>\left(t_i\right)=\frac{K*m_I*\left[{\mathrm{IC}}_a-C_a<br><br>\left(t_i^{\mathrm{\prime <br><br>}}\right)\right]}{\left[C_a<br><br>\left(t_i^{\mathrm{\prime <br><br>}}\right)-C_a<br><br>\left(t_i\right)\right]}$

where;

CO(t_i,) is cardiac output measured at time (t_i), K is a constant, m_l is the fluid mass flow rate of ammoniacal fluid, ICa is total ammoniacal concentration of the analyte-containing fluid, Ca(t′

_I) is the total ammoniacal concentration in blood based upon said peak defining inflection value, and Ca(t_i) is the total ammoniacal concentration in blood based upon said baseline value.

42. The method of claim 34 in which said step (h) correlates said time of delivery and said identified time associated concentration values descending in value to derive a maximum increase value for said analyte within said bloodstream and correlates said maximum increase value with said dose value to derive said total circulating blood volume.

43. The method of claim 42 in which said maximum increase value is derived by regression analysis of said time associated sensor outputs descending in value with respect to said time of delivery.

44. The method of claim 43 in which said time of delivery is the mean of the time interval of occurrence of said infusion interval.

45. The method of claim 34 in which:

said analyte-containing fluid is an ammoniacal fluid; and

said step (f) is carried out by correlating said pH value and said sensor outputs.

46. The method of claim 34 including the steps of:

(i) selecting a homostasis threshold value corresponding with an analyte concentration level in blood for iatrogenesis;

(j) determining a baseline of analyte concentration in said bloodstream corresponding with metabolic homeostasis of said body; and

(k) determining whether said concentration of analyte determined at step (j) exceeds the threshold value at step (i).

47. The method of claim 34 in which:

said analyte-containing fluid is an ammoniacal fluid;

said step (b) provides said analyte concentration sensor distal analyte portion as being responsive to provide said sensor outputs in correspondence with the concentration of ammonia gas (NH₃) in said bloodstream;

said step (f) derives said time associated concentration values as representing the total ammoniacal concentration in blood in correspondence with the expressions;

48. The method of claim 34 in which:

said steps (d) includes the step of;

(d1) prior to said step (e) deriving a baseline value corresponding with the concentration of said analyte in said body from said analyte concentration sensor outputs;

said analyte-containing fluid is an ammoniacal fluid;

said step (b) provides said analyte concentration sensor distal analyte portion as being responsive to provide said sensor outputs in correspondence with the concentration of ammonia gas (NH₃) in said bloodstream;

said step (d1) derives said baseline value as representing the total ammoniacal concentration in blood in correspondence with the expressions;

49. The method of claim 48 in which:

said step (f) derives said time associated concentration values as representing the total ammoniacal concentration in blood in correspondence with the expressions;

50. The method of claim 47 in which:

(i) deriving a value for cardiac output by correlating said baseline value for concentration of said analyte, said mass flow rate, said predetermined analyte concentration and said identified peak-defining inflection value.

51. The method of claim 49 in which:

said step (g) further identifies a sequence of said time associated concentration values rising in value towards said peak-defining inflection value; and

including the step;

(i) deriving a value for cardiac output by correlating said baseline value for concentration of said analyte, said mass flow rate, said predetermined analyte concentration, said infusion interval and an integrated value of said time associated concentration values.

52. The method of claim 34 in which:

said analyte-containing fluid is an ammoniacal fluid;

said step (b) includes the step;

(b1) providing a pH sensor having a distal pH responsive portion configured for positioning within said bloodstream and having a pH sensor output corresponding with the pH value of blood with which it is in contact;

said step (d) includes the step;

(d1) positioning said distal pH responsive portion within said bloodstream; and

said step (f) is carried out by correlating said pH value and said sensor outputs.

53. The method of claim 52 in which said pH sensor and said analyte concentration sensor are provided being incorporated within a single catheter assembly insertable within said bloodstream.

54. The method of claim 34 in which:

said step (b) provision of an analyte concentration sensor incorporates said distal analyte responsive portion within a pulmonary artery catheter; and

said step (c) provision of a delivery assembly incorporates said delivery channel and said output within said pulmonary artery catheter.

55. The method of claim 54 in which said distal analyte responsive portion is provided at a location upon said catheter so as to be located in adjacency with the pulmonary valve of the heart of said body.

56. The method for determining hemodynamic parameters of a cardiovascular system wherein blood within a bloodstream is circulated to peripheral regions of the body and exhibits a pH value, comprising the steps of:

(a) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined analyte concentration;

(b) providing an analyte concentration sensor having a distal analyte responsive portion configured for positioning within said bloodstream and responsive to the presence of analyte to provide sensor outputs corresponding with the sensed concentration of analyte;

(c) providing a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said source of analyte-containing fluid and an output configured for positioning within the bloodstream;

(d) positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream;

(e) delivering said analyte-containing fluid from said source into said delivery channel at a time of delivery, a mass flow rate and over an infusion interval;

(f) deriving a sequence of time associated analyte concentration values from said sensor outputs;

(g) monitoring said sequence of time associated analyte concentration values and identifying a sequence thereof rising in value to a peak defining inflection value and descending in value therefrom; and

(h) deriving a value for a select one of said hemodynamic parameters by correlating said sequence of time associated concentration values, said mass flow rate, said infusion interval and said predetermined analyte concentration.

57. The method of claim 56 in which:

said step (d) includes the step of;

(d1) prior to said step (e) deriving from said analyte concentration sensor outputs a baseline value corresponding with the concentration of said analyte in said bloodstream; and

said step (h) further correlates said baseline value to derive said select one of said hemodynamic parameters.

58. The method of claim 56 in which:

said step (f) derivation of time associated concentration values is carried out in conjunction with a sensor output frequency of about one measurement per second.

59. The method of claim 56 in which said analyte-containing fluid source is selected from the group consisting of:

ammoniacal fluid, heparin, ethanol, glucose and anesthesia agent.

60. The method of claim 56 in which

(i) selecting a homostasis threshold value corresponding with an analyte concentration level in blood for iatrogenesis;

(i) determining a baseline of analyte concentration in said bloodstream corresponding with metabolic homeostasis of said body; and

(k) determining whether said concentration of analyte determined at step (j) exceeds the threshold value at step (i).

61. The method of claim 56 in which:

said analyte-containing fluid is an ammoniacal fluid;

said step (b) provides said analyte concentration sensor distal analyte portion as being responsive to provide said sensor outputs in correspondence with the concentration of ammonia gas (NH₃) in said bloodstream;

said step (f) derives said time associated concentration values as representing the total ammoniacal concentration in blood in correspondence with the expression;

62. The method of claim 56 in which:

said step (d) includes the step of;

(d1) prior to said step (e) deriving a baseline value corresponding with the concentration of said analyte in said body from said analyte concentration sensor outputs;

said analyte-containing fluid is an ammoniacal fluid;

said step (b) provides said analyte concentration sensor distal analyte portion as being responsive to provide said sensor outputs in correspondence with the concentration of ammonia gas (NH₃) in said bloodstream;

said step (d1) derives said baseline value as representing the total ammoniacal concentration in blood in correspondence with the expressions;

63. The method of claim 62 in which:

said step (f) derives said time associated concentration values as representing the total ammoniacal concentration in blood in correspondence with the expressions;

64. The method of claim 56 in which:

said analyte-containing fluid is an ammoniacal fluid;

said step (b) includes the step;

(b1) providing a pH sensor having a distal pH responsive portion configured for positioning within said bloodstream and having a pH sensor output corresponding with the pH value of blood with which it is in contact;

said step (d) includes the step;

(d1) positioning said distal pH responsive portion within said bloodstream; and

said step (f) is carried out by correlating said pH value and said sensor outputs.

65. The method of claim 64 in which said pH sensor and said analyte concentration sensor are provided being incorporated within a single catheter assembly insertable within said bloodstream.

66. The method of claim 56 which:

said step (b) provision of an analyte concentration sensor incorporates said distal analyte responsive portion within a pulmonary artery catheter.

67. The method of claim 66 in which said distal analyte responsive portion is provided at a location upon said catheter so as to be located in adjacency with the pulmonary valve of the heart of said body.

68. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

a blood by-passing assembly including;

a blood transport conduit extending from a proximal end to a distal tip, said distal tip being positionable in blood exchange relationship within said bloodstream

a blood sampling chamber coupled in blood exchange communication with said blood transport conduit proximal end, and

a pump coupled with said sampling chamber and controllable to urge the transport of blood from said bloodstream into said sampling chamber;

an analyte concentration sensor positioned within said blood sampling chamber, responsive to analyte within said blood and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte; and

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said pump and analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter; and

a readout responsive to said output signal for providing a perceptible output corresponding therewith.

69. The system of claim 68 in which said controller is responsive to control said pump and said analyte concentration sensor prior to said provision of said flow of analyte-containing fluid to provide said sensor outputs and derive a corresponding baseline value for concentration of said analyte, and is responsive to correlate said baseline value for concentration of said analyte with said time associated concentration values, said predetermined mass flow-rate said predetermined analyte concentration and said infusion interval to derive said output signal.

70. The system of claim 69 in which:

said select hemodynamic parameter is total circulating blood volume; and

said controller is responsive to correlate said baseline value for concentration of said analyte, said predetermined mass flow rate, said infusion interval, said time of delivery and said time associated concentration values descending in value from said peak to derive said output signal as corresponding with total circulating blood volume.

71. The system of claim 69 in which:

said select hemodynamic parameter is cardiac output; and

said controller is responsive to correlate said baseline value for concentration of said analyte, said predetermined mass flow rate, said predetermined analyte concentration and said peak value of said time associated concentration values to derive said output signal as corresponding with cardiac output.

72. The system of claim 69 which:

said select hemodynamic parameter is cardiac output; and

said controller is responsive to correlate said baseline value for concentration of said analyte, said predetermined mass flow rate, said predetermined analyte concentration, said infusion interval, and an integrated value of said time associated concentration values to derive said output signal as corresponding with cardiac output.

73. The system of claim 68 in which:

said select hemodynamic parameter is total circulating blood volume; and

said controller is responsive to correlate said predetermined analyte concentration, said predetermined mass flow rate and said infusion interval to derive a dose value, and is responsive to derive a maximum increase value for said analyte within said bloodstream by correlating said time associated concentration values descending in value with said time of delivery, and is responsive to said dose value and to said maximum increase value to derive said output signal as corresponding with total circulating blood volume.

74. The system of claim 73 in which said controller is responsive to derive said maximum increase value by regression analysis of said time associated sensor outputs descending in value.

75. The system of claim 68 in which said source of analyte-containing fluid is selected from the group consisting of:

ammoniacal fluid, heparin, ethanol, glucose and anesthesia agent.

76. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

said controller is responsive to control said analyte concentration sensor prior to said provision of said flow of analyte-containing fluid to provide said sensor outputs and derive a corresponding baseline value for concentration of said analyte, and is responsive to correlate said baseline value for concentration of said analyte with said time associated concentration values, said predetermined mass flow-rate, said predetermined analyte concentration and said infusion interval to derive said output signal;

said select hemodynamic parameter is cardiac output;

said controller is responsive to correlate said baseline value for concentration of said analyte, said predetermined mass flow rate said predetermined analyte concentration and said peak value of said time associated concentration values to derive said output signal as corresponding with cardiac output; and

a readout responsive to said output signal for providing a perceptible output corresponding therewith.

77. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

said controller is responsive to control said analyte concentration sensor prior to said provision of said flow of analyte-containing fluid to provide said sensor outputs and derive a corresponding baseline value for concentration of said analyte, and is responsive to correlate said baseline value for concentration of said analyte with said time associated concentration values, said predetermined mass flow-rate said predetermined analyte concentration and said infusion interval to derive said output signal;

said select hemodynamic parameter is cardiac output;

said controller is responsive to correlate said baseline value for concentration of said analyte, said predetermined mass flow rate, said predetermined analyte concentration, said infusion interval, and an integrated value of said time associated concentration values to derive said output signal as corresponding with cardiac output; and

a readout responsive to said output signal for providing a perceptible output corresponding therewith.

78. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

said select hemodynamic parameter is total circulating blood volume;

said controller is responsive to correlate said predetermined analyte concentration, said predetermined mass flow rate and said infusion interval to derive a dose value, and is responsive to derive a maximum increase value for said analyte within said bloodstream by correlating said time associated concentration values descending in value with said time of delivery, and is responsive to said dose value and to said maximum increase value to derive said output signal as corresponding with total circulating blood volume; and

a readout responsive to said output signal for providing a perceptible output corresponding therewith.

79. The system of claim 78 in which said controller is responsive to derive said maximum increase value by regression analysis of said time associated sensor outputs descending in value.

80. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

a readout responsive to said output signal for providing a perceptible output corresponding therewith;

said select hemodynamic parameter is total circulating blood volume;

said controller includes an inputting assembly manually controllable to provide a total circulating blood volume threshold value;

said controller is responsive to said total circulating blood volume threshold value to retain it in memory;

said controller is responsive in the presence of a given output signal corresponding with a given value for total circulating blood volume and to said memory retained total circulating blood volume threshold value to derive an alarm signal when said given value for total circulating blood volume is greater than or equal to said total circulating blood volume threshold value; and

said readout is responsive to said alarm signal to provide a perceptible alarm output.

81. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

a readout responsive to said output signal for providing a perceptible output corresponding therewith;

said select hemodynamic parameter is total circulating blood volume;

said controller includes an inputting assembly manually controllable to provide a total circulating blood volume threshold value;

said controller is responsive in the presence of a given output signal corresponding with a given value for total circulating blood volume and for said memory retained total circulating blood volume threshold value to derive an alarm signal when said given value for total circulating blood volume is less than or equal to said total circulating blood volume threshold value; and

said readout is responsive to said alarm signal to provide a perceptible alarm output.

82. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

a readout responsive to said output signal for providing a perceptible output corresponding therewith;

said select hemodynamic parameter is total circulating blood volume;

said controller includes an inputting assembly manually controllable to provide a rate of change of total circulating blood volume threshold value;

said controller is responsive to said rate of change of total circulating blood volume threshold value to retain it in memory;

said controller is responsive in the presence of a given output signal corresponding with a given value for total circulating blood volume and to a previous such value for total circulating blood volume to derive a current total circulating blood volume rate of change value, and is responsive to said rate of change of total circulating blood value threshold value and to said current total circulating blood volume rate of change value to derive an alarm signal when said current total circulating blood volume rate of change value is greater than or equal to said rate of change of total circulating blood volume threshold value; and

;

said readout is responsive to said alarm signal to provide a perceptible alarm output.

83. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

a readout responsive to said output signal for providing a perceptible output corresponding therewith;

said select hemodynamic parameter is total circulating blood volume;

said controller includes an inputting assembly manually controllable to provide a rate change of total circulating blood volume threshold value;

said controller is responsive to said rate of change of total circulating blood volume threshold value to retain it in memory;

said controller is responsive in the presence of a given output signal corresponding with a given value for total circulating blood volume and to a previous such value for total circulating blood volume to derive a current total circulating blood volume rate of change value, and is responsive to said rate of change of total circulating blood value threshold value and to said current total circulating blood volume rate of change value to derive an alarm signal when said current total circulating blood volume rate of change value is greater than or equal to said rate of change of total circulating blood volume threshold value; and

;

said readout is responsive to said alarm signal to provide a perceptible alarm output.

84. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

a readout responsive to said output signal for providing a perceptible output corresponding therewith;

said select hemodynamic parameter is total circulating blood volume;

said controller is responsive in the presence of a current output signal corresponding with a current value for total circulating blood volume and is responsive to a previous value for total circulating blood volume corresponding with a previous output signal to derive a warning signal when said previous value is greater than said current value; and

said readout is responsive to said alarm signal to provide a perceptible alarm output.

85. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analytic concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

a readout responsive to said output signal for providing a perceptible output corresponding therewith;

said select hemodynamic parameter is total circulating blood volume;

said controller is responsive in the presence of a current output signal corresponding with a current value for total circulating blood volume and is responsive to a previous value for total circulating blood volume corresponding with a previous output signal to derive a warning signal when said previous value is less than said current value; and

said readout is responsive to said alarm signal to provide a perceptible alarm output.

86. A system for determining hemodynamic parameters of a cardiovascular system said cardiovascular system circulating blood within a bloodstream extending to peripheral regions of a body comprising:

a source of analyte-containing fluid biocompatible with and metabolizable within said body and said fluid having a predetermined analyte concentration;

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 predetermined mass flow rate at an outlet for an infusion interval having a time of delivery;

a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said fluid flow control apparatus and an output positioned to express said flow of analyte-containing fluid within said bloodstream for dilutional movement therewith;

an analyte concentration sensor positioned within said bloodstream, responsive to analyte within said bloodstream and controllable to provide sensor outputs corresponding with the sensed concentration of said analyte;

a controller coupled in controlling relationship with said fluid flow control apparatus and said analyte concentration sensor, responsive to control said analyte concentration sensor to provide said sensor outputs and to derive corresponding analyte concentration values, responsive to control said fluid flow control apparatus to effect provision of said flow of said analyte-containing fluid at said outlet for said infusion interval, responsive to a sequence of said analyte concentration values, as time associated analyte concentration values, said sequence exhibiting time associated concentration values rising in value toward a peak value and descending in value, therefrom, responsive to correlate said time associated concentration values, said predetermined mass flow rate, said predetermined analyte concentration and said infusion interval to derive an output signal representing a value corresponding with a select said hemodynamic parameter;

a readout responsive to said output signal for providing a perceptible output corresponding therewith;

said system including;

a blood by-passing assembly including;

a blood transport conduit extending from a proximal end to a distal tip, said distal tip being positionable in blood exchange relationship within said bloodstream;

a blood sampling chamber coupled in blood exchange communication with said blood transport conduit proximal end,

a pump coupled with said sampling chamber and actuable to urge the transport of blood from said bloodstream into said sampling chamber; and

said analyte concentration sensor is positioned within said bloodstream at said blood sampling chamber and is responsive to analyte within said chamber.

87. The system of claim 86 in which said pump is actuable to return blood from said blood sampling chamber into said bloodstream.

88. The system of claim 86 in which said pump is actuable and the control of said controller.

89. The method of claim 86 in which said maximum increase value is derived by regression analysis of said time associated sensor outputs descending in value with respect to said time of delivery.

90. The method for determining hemodynamic parameters of a cardiovascular system wherein blood within a bloodstream is circulated to peripheral regions of the body and exhibits a pH value, comprising the steps of:

(a) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined analyte concentration;

(b) providing an analyte concentration sensor having a distal analyte responsive portion configured for positioning within said bloodstream and responsive to the presence of analyte to provide sensor outputs corresponding with the sensed concentration of analyte;

(c) providing a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said source of analyte-containing fluid and an output configured for positioning within the bloodstream;

(d) positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream;

(e) delivering said analyte-containing fluid from said source into said delivery channel at a time of delivery, a mass flow rate and over an infusion interval;

(f) deriving a sequence of time associated analyte concentration values from said sensor outputs;

(g) monitoring said sequence of time associated analyte concentration values and identifying a sequence thereof rising in value to a peak defining inflection value and descending in value therefrom;

(h) deriving a value for a select one of said hemodynamic parameters by correlating said sequence of time associated concentration values, said mass flow rate, said infusion interval and said predetermined analyte concentration; and

wherein said step (h) derives a value for total circulating blood volume as said select one of said hemodynamic parameters by correlating said time of delivery, said predetermined analyte concentration, said infusion interval and identified sequence of time associated concentration values descending in value from said peak defining inflection value.

91. The method for determining hemodynamic parameters of a cardiovascular system wherein blood within a bloodstream is circulated to peripheral regions of the body and exhibits a pH value, comprising the steps of:

(a) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined analyte concentration;

(b) providing an analyte concentration sensor having a distal analyte responsive portion configured for positioning within said bloodstream and responsive to the presence of analyte to provide sensor outputs corresponding with the sensed concentration of analyte;

(c) providing a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said source of analyte-containing fluid and an output configured for positioning within the bloodstream;

(d) positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream;

(e) delivering said analyte-containing fluid from said source into said delivery channel at a time of delivery, a mass flow rate and over an infusion interval;

(f) deriving a sequence of time associated analyte concentration values from said sensor outputs;

(g) monitoring said sequence of time associated analyte concentration values and identifying a sequence thereof rising in value to a peak defining inflection value and descending in value therefrom;

(h) deriving a value for a select one of said hemodynamic parameters by correlating said sequence of time associated concentration values, said mass flow rate, said infusion interval and said predetermined analyte concentration; and

wherein;

said step (d) includes the step of;

(d1) prior to said step (e) deriving from said analyte concentration sensor outputs a baseline value corresponding with the concentration of said analyte in said bloodstream;

said step (h) further correlates said baseline value to derive a said select one of said hemodynamic parameters; and

said step (h) derives a value for cardiac output as said select one of said hemodynamic parameters by correlating said baseline value for concentration of said analyte, said mass flow rate, said predetermined analyte concentration and said identified peak-defining inflection value.

92. The method for determining hemodynamic parameters of a cardiovascular system wherein blood within a bloodstream is circulated to peripheral regions of the body and exhibits a pH value, comprising the steps of:

(a) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined analyte concentration;

(b) providing an analyte concentration sensor having a distal analyte responsive portion configured for positioning within said bloodstream and responsive to the presence of analyte to provide sensor outputs corresponding with the sensed concentration of analyte;

(c) providing a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said source of analyte-containing fluid and an output configured for positioning within the bloodstream;

(d) positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream;

(e) delivering said analyte-containing fluid from said source into said delivery channel at a time of delivery, a mass flow rate and over an infusion interval;

(f) deriving a sequence of time associated analyte concentration values from said sensor outputs;

(g) monitoring said sequence of time associated analyte concentration values and identifying a sequence thereof rising in value to a peak defining inflection value and descending in value therefrom;

(h) deriving a value for a select one of said hemodynamic parameters by correlating said sequence of time associated concentration values, said mass flow rate, said infusion interval and said predetermined analyte concentration; and

wherein;

said step (d) includes the step of;

(d1) prior to said step (e) deriving from said analyte concentration sensor outputs a baseline value corresponding with the concentration of said analyte in said bloodstream;

said step (h) further correlates said baseline value to derive said select one of said hemodynamic parameters; and

said step (h) derives a value for cardiac output as said select one of said hemodynamic parameters correlating said baseline value for concentration of said analyte, said mass flow rate, said predetermined analyte concentration, said infusion interval and an integrated value of said time associated concentration values.

93. The method for determining hemodynamic parameters of a cardiovascular system wherein blood within a bloodstream is circulated to peripheral regions of the body and exhibits a pH value, comprising the steps of:

(a) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined analyte concentration;

(b) providing an analyte concentration sensor having a distal analyte responsive portion configured for positioning within said bloodstream and responsive to the presence of analyte to provide sensor outputs corresponding with the sensed concentration of analyte;

(c) providing a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said source of analyte-containing fluid and an output configured for positioning within the bloodstream;

(d) positioning said analyte concentration sensor distal analytic responsive portion and said delivery assembly output within said bloodstream;

(e) delivering said analyte-containing fluid from said source into said delivery channel at a time of delivery, a mass flow rate and over an infusion interval;

(f) deriving a sequence of time associated analyte concentration values from said sensor outputs;

(g) monitoring said sequence of time associated analyte concentration values and identifying a sequence thereof rising in value to a peak defining inflection value and descending in value therefrom;

(h) deriving a value for a select one of said hemodynamic parameters by correlating said sequence of time associated concentration values, said mass flow rate, said infusion interval and said predetermined analyte concentration; and

wherein;

said step (d) is carried out by positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream at said peripheral region.

94. The method for determining hemodynamic parameters of a cardiovascular system wherein blood within a bloodstream is circulated to peripheral regions of the body and exhibits a pH value, comprising the steps of:

(a) providing a source of analyte-containing fluid biocompatible with and metabolizable within said body and having a predetermined analyte concentration;

(b) providing an analyte concentration sensor having a distal analyte responsive portion configured for positioning within said bloodstream and responsive to the presence of analyte to provide sensor outputs corresponding with the sensed concentration of analyte;

(c) providing a delivery assembly having a delivery channel with an input coupled in fluid flow communication with said source of analyte-containing fluid and an output configured for positioning within the bloodstream;

(d) positioning said analyte concentration sensor distal analyte responsive portion and said delivery assembly output within said bloodstream;

(e) delivering said analyte-containing fluid from said source into said delivery channel at a time of delivery, a mass flow rate and over an infusion interval;

(f) deriving a sequence of time associated analyte concentration values from said sensor outputs;

(g) monitoring said sequence of time associated analyte concentration values and identifying a sequence thereof rising in value to a peak defining inflection value and descending in value therefrom;

(h) deriving a value for a select one of said hemodynamic parameters by correlating said sequence of time associated concentration values, said mass flow rate, said infusion interval and said predetermined analyte concentration; and

wherein;

said select one of said hemodynamic parameters is total circulating blood volume; and

said step (h) correlates said time of delivery and said time associated concentration values descending in value to derive a maximum increase value for said analyte within said bloodstream and correlates said maximum increase value with a dose value corresponding with said predetermined analyte concentration, said infusion interval and said mass flow rate to derive said total circulating blood volume.