MONITORING VOLAEMIC CONDITION IN A HUMAN OR ANIMAL SUBJECT

• US 20140046153A1
• Filed: 12/15/2011
• Published: 02/13/2014
• Est. Priority Date: 12/16/2010
• Status: Abandoned Application

• Current Assignee: Stephen Frederick Woodford
• Original Assignee: Stephen Frederick Woodford
• Inventors: Woodford, Stephen Frederick
• Application Number:
  US13/994,866
• Publication Number:
  US 20140046153A1
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7271 Specific aspects of physiological measurement analysis A61B5/316, A61B5/349 and A61B5/374 take precedence
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: G16H 15/00 ICT specially adapted for medical reports, e.g. generation or transmission thereof
• CPC Class Codes: G16H 20/17 delivered via infusion or injection
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A method for processing data to monitor volaemic condition in a human or animal subject includes identifying one or more reference values for each of one or more haemodynamic variables; receiving haemodynamic data representing the one or more haemodynamic variables measured from the subject over time; for at least one of the one or more haemodynamic variables, comparing the haemodynamic data with the respective one or more reference values; and identifying the existence of abnormal volaemic condition in the subject when the comparison indicates a deviation from the one or more reference values for at least one of the haemodynamic variables. The method may be combined with a visual display of haemodynamic data in real time, ideally in conjunction with a visual indicator of ideal reference values.

Claims

1. A method for processing data to monitor volaemic condition in a human or animal subject, including the steps of:

(a) identifying one or more reference values for each of one or more haemodynamic variables;

(b) receiving haemodynamic data representing the one or more haemodynamic variables measured from the subject over time;

(c) for at least one of the one or more haemodynamic variables, comparing the haemodynamic data with the respective one or more reference values; and

(d) identifying the existence of abnormal volaemic condition in the subject when the comparison indicates a deviation from the one or more reference values for at least one of the haemodynamic variables.

2. A method according to claim 1 wherein the haemodynamic variables include one or more of Heart Rate (HR), Vascular Resistance, Elastance (E) and Stroke Volume (SV).

3. A method according to claim 2 wherein Vascular Resistance is adjusted by a multiplier to correct for heart rate effects, giving rise to instantaneous vascular resistance (iVR) as a haemodynamic variable.

4. A method according to claim 1 wherein the haemodynamic variables include one or more of Central Venous Oxygen Saturation (ScvO2), Haemoglobin (Hb), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Pulse Pressure (PP) and Mean Arterial Pressure (MAP).

5. A method according to claim 1 wherein the one or more reference values for at least one of the one or more haemodynamic variables is derived from actual haemodynamic data obtained from the subject.

6. A method according to claim 1 wherein the one or more reference values is determined from data obtained from a population of individuals.

7. A method according to claim 1, including the step of displaying on a display means:

a time-based chart representing received data values for at least one of the one or more haemodynamic variables; and

optionally, an indicator for the respective one or more reference values.

8. A method according to claim 1, including the step of:

calculating a ratio of received data value to reference value for at least one haemodynamic variable; and

displaying the calculated ratio on a display means.

9. A method according to claim 1, including one or more of:

(a) allocating a score for at least one of the haemodynamic variables in the data, the allocated score representing a degree of deviation from one or more reference values for that haemodynamic variable;

(b) determining an extent of abnormal volaemic condition according to one or more allocated scores; and

(c) determining an extent of abnormal volaemic condition according to a combined score from the allocated scores.

11. A method according to claim 8 including the step of determining a volaemic index by:

(i) calculating a sum total of;

(a) each ratio value calculated for each haemodynamic variable known to decrease with volume loss;

plus

(b) the inverse of each ratio value calculated for each haemodynamic variable known to increase with volume loss; and

(ii) dividing the calculated sum total by the number of haemodynamic variables considered in step (i).

12. A method according to claim 9 including one or more of:

(a) determining a reliability indicator for indicating the reliability of an allocated score, wherein an allocated score calculated using more variables has a higher reliability than a score calculated using fewer variables;

(b) adjusting an allocated score to have greater or lesser influence on determining the extent of abnormal volaemic condition, wherein the adjustment is based on one or more of;

(i) sensitivity of a haemodynamic variable to volume changes;

(ii) age, fitness, gender, weight or condition of the subject; and

(iii) therapies being administered to the subject;

(c) adjusting an allocated score to have greater or lesser influence on determining the extent of abnormal volaemic condition, wherein the adjustment is a weighting coefficient which is determined automatically by a processing device using reference data from a population of individuals, and subject-specific data provided to the processing device;

(d) adjusting an allocated score to have greater or lesser influence on determining the extent of abnormal volaemic condition, wherein the adjustment is a weighting coefficient which is determined on a case by case basis by a clinician; and

(e) adjusting an allocated score to have greater or lesser influence on determining the extent of abnormal volaemic condition, wherein the adjustment uses a hybrid of (c) and (d).

17. A method according to claim 1 including the step of selecting automatically a course of action targeted at restoring one or more of the haemodynamic variables toward the one or more reference values by interrogating a collection of pooled data indexing haemodynamic variables and therapeutic effectors obtained from a population of individuals.

34. A system for monitoring an abnormal volaemic condition in a human or animal subject, the system including:

(a) at least one processing means for executing steps according to the method of claim 1;

(b) a user interface including display means for displaying haemodynamic data and/or a ratio of actual to reference values for one or more haemodynamic variables; and

(c) a data interface for receiving data representing the one or more haemodynamic variables measured from the subject.

35. A system according to claim 34 including an alert driver for generating an alarm or communicating an alert when a score exceeds a threshold value.

10. (canceled)

13-16. -16. (canceled)

18. A non-transitory computer readable medium storing a computer program comprising instructions for controlling a processing means to execute a process for monitoring an abnormal volaemic condition in a human or animal subject, wherein the instructions cause the processing means to:

(a) receive one or more reference values for each of one or more haemodynamic variables;

(b) receive haemodynamic data representing the one or more haemodynamic variables measured from the subject over time;

(c) for at least one of the one or more haemodynamic variables, compare the haemodynamic data with the respective one or more reference values; and

(d) identify the existence of abnormal volaemic condition when the comparison indicates a deviation from a reference value for at least one of the haemodynamic variables.

19. A non-transitory computer readable medium according to claim 18 storing a computer program including instructions causing a processing means to calculate one or more reference values for at least one of the one or more haemodynamic variables using actual haemodynamic data previously obtained from the subject.

20. A non-transitory computer readable medium according to claim 18 storing a computer program wherein the instructions cause the processing means to receive one or more reference values from memory means in communication with the processing device, wherein the one or more reference values has been determined using data obtained from a population of normo-volaemic individuals.

21. A non-transitory computer readable medium according to claim 18 storing a computer program, wherein the instructions cause the processing means to generate a display signal for causing a display means to present:

a time-based chart of data values representing at least one of the one or more haemodynamic variables; and

optionally, an indicator for the respective one or more reference values.

22. A non-transitory computer readable medium according to claim 18 storing a computer program, wherein the instructions cause the processing means to perform steps including one or more of:

(a) calculating, for at least one haemodynamic variable, a ratio of actual data value to one or more reference values displaying the calculated ratio on a display means;

.

(b) calculating a score for at least one of the haemodynamic variables in the data, the calculated score representing a deviation of a data value from a reference value and estimating an extent of abnormal volaemic condition according to one or more calculated scores; and

(c) calculating a score for a plurality of haemodynamic variables and estimating an extent of abnormal volaemic condition by combining the calculated scores.

25. A non-transitory computer readable medium according to claim 22, storing a computer program wherein the instructions cause the processing means to apply a weighting coefficient to one or more of the calculated scores, wherein the weighting coefficient is selected for a particular haemodynamic variable based on one or more of:

sensitivity of a haemodynamic variable to volume changes;

age, fitness, gender, body mass or physiological condition of the subject; and

a therapy being administered to the subject.

26. A non-transitory computer readable medium according to claim 25 storing a computer program, wherein instructions cause the processing means to select automatically, the weighting coefficient applicable to a haemodynamic variable.

27. A non-transitory computer readable medium according to claim 25 storing a computer program, wherein the instructions cause the processing means to receive an input from a clinician which indicates the weighting coefficient applied to a score calculated for a haemodynamic variable.

28. A non-transitory computer readable medium according to claim 18 storing a computer program, wherein the instructions cause the processing means to interrogate a database indexing haemodynamic variables and therapeutic effectors and identify a course of action targeted at restoring one or more of the haemodynamic variables toward a reference value, and generating a user interface signal configured to cause a user interface to present the identified course of action to a user.

39. A system for monitoring an abnormal volaemic condition in a human or animal subject, the system including:

(a) at least one processing means for executing the computer program stored by the non-transitory computer readable medium of claim 18;

(b) a user interface including display means for displaying haemodynamic data and/or a ratio of actual to reference values for one or more haemodynamic variables; and

(c) a data interface for receiving data representing the one or more haemodynamic variables measured from the subject.

40. A system according to claim 39 including an alert driver for generating an alarm or communicating an alert when a score exceeds a threshold value.

23-24. -24. (canceled)

29. A method of representing visually a state of the circulation of a human or animal subject, including the steps of:

(a) charting on a display means in substantially real time, data obtained from the subject representing one or more haemodynamic variables of the subject; and

(b) charting on the display means a reference value indicative of substantially normal values for one or more of the charted haemodynamic variables.

30. A method according to claim 29 wherein charting the data obtained from the subject includes presenting time-elapsed changes in the data values.

31. A method according to claim 29 including the step of calculating deviation of the data obtained from the subject from a relevant reference value and optionally, charting the calculated deviation on the display means.

33. A method according to claim 31 wherein the deviation is calculated as an average or a rolling average of values occurring in a finite time period.

32. (canceled)

36-38. -38. (canceled)