Method and apparatus based on combination of physiological parameters for assessment of analgesia during anesthesia or sedation

• US 7,367,949 B2
• Filed: 07/07/2003
• Issued: 05/06/2008
• Est. Priority Date: 07/07/2003
• Status: Active Grant

• Current Assignee: Instrumentarium Dental Incorporated (Envista Holdings Corporation)
• Original Assignee: Instrumentarium Dental Incorporated (Envista Holdings Corporation)
• Inventors: Van Gils, Marcus Johannis, Huiku, Matti Veli Tapani, Yli-Hankala, Arvi, Korhonen, Ilkka, Paloheimo, Markku
• Primary Examiner(s): Marmor, II; Charles A.
• Assistant Examiner(s): Natnithithadha; Navin
• Application Number:
  US10/614,749
• Publication Number:
  US 20050010116A1
• Time in Patent Office: 1,765 Days
• Field of Search: 600/481, 600483-486, 600500-526, 128/203.13, 128/203.14
• US Class Current: 600/483
• CPC Class Codes: A61B 2505/05 Surgical care
• CPC Class Codes: A61B 5/1106 to assess neuromuscular blockade, e.g. to estimate depth of anaesthesia
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/4821 Determining level or depth of anaesthesia A61B5/1106 takes precedence

Abstract

The invention relates to a method for monitoring a condition of a patient under anesthesia or sedation, whereupon one, two, three or more signals are acquired, and the signal(s) represent(s) cardiovascular and/or combined electrical biopotential on skull activity of the patient. From said signal or signals are derived or calculated at least two parameter values related to a quantity like waveform amplitude, waveform periodicity, waveform morphology, waveform variability, energy, power, signal complexity and frequency content. A predetermined mathematical index for probability of patient comfort is used, in which function said parameters are variables, and successively changing probability index values of said mathematical index is calculated.

Claims

1. A method for monitoring a condition of a patient under anesthesia or sedation, the method comprising the steps of:

acquiring at least a first signal representing a cardiovascular activity of the patient;

deriving, from said first signal, at least a first and a second parameter value, said first and second parameter values being related to two mutually different quantities selected from a group of quantities including waveform amplitudes, waveform periodicity, waveform morphology, and waveform variability;

applying a predetermined mathematical index for probability of patient comfort, in which index said at least first and second parameters are variables;

calculating successively changing values of said mathematical index; and

indicating said successive index values.

2. A method according to claim 1, wherein said first signal concerning cardiovascular activity is a blood volume signal measured non-invasively using photoplethysmography.

3. A method according to claim 2, wherein:

the quantity for said first parameter value is a pulse wave amplitude, or a dicrotic notch height in the pulse wave;

and the quantity for said second parameter value is a pulse rate, or a heart beat interval, or a temporal position of the dicrotic notch.

4. A method according to claim 1, wherein said first signal concerning cardiovascular activity is blood pressure signal measured using a pressure metering.

5. A method according to claim 4, wherein:

the quantity for said first parameter value is a systolic, diastolic or mean blood pressure, or a dicrotic notch height in the pulse wave;

and the quantity for said second parameter value is a pulse rate, or a heart beat interval, or a temporal position of the dicrotic notch.

6. A method according to claim 1, wherein said mathematical index for probability is a nonlinear equation.

7. A method according to claim 1, wherein said mathematical index for probability is a neural network algorithm.

8. A method according to claim 1, wherein said mathematical index for probability is based on a defined or fuzzy rule-based reasoning procedure.

9. A method according to claim 1, further comprising the step of normalizing said first and second parameter values on the basis their respective parameter values acquired over a predetermined fixed time window including or excluding the latest real-time parameter value.

10. A method according to claim 9, wherein said normalized parameter values are acquired from:

said patient prior to incision, or prior to intubation, or prior to starting anesthesia or sedation, or

group of patients prior to or during incision and/or intubation and/or anesthesia or sedation.

11. A method for monitoring a condition of a patient under anesthesia or sedation, the method comprising the steps of:

acquiring at least a first signal and a second signal representing a cardiovascular activity of the patient;

deriving, from said first signal and second signal, at least a first and a second parameter value, said first and second parameter values being related to two mutually different quantities selected from a group of guantities including waveform amplitudes, waveform periodicity, waveform morphology, and waveform variability;

applying a predetermined mathematical index for probability of patient comfort, in which index said at least first and second parameters are variables;

calculating successively changing values of said mathematical index; and

indicating said successive index values.

12. A method according to claim 11, wherein said first signal concerning cardiovascular activity is a blood volume signal measured non-invasively using photoplethysmography, or measured using a pressure metering.

13. A method according to claim 12, wherein the quantity for said first parameter value is a pulse wave amplitude, or a systolic, diastolic or mean blood pressure, or a dicrotic notch height in the pulse wave.

14. A method according to claim 11, wherein said second signal concerning cardiovascular activity is a cardiac excitation measured non-invasively using electrocardiogram.

15. A method according to claim 14, wherein the quantity for said second parameter value is a heart rate or inter beat interval of the electrical excitation.

16. A method according to claim 11, wherein said mathematical index for probability is a nonlinear equation.

17. A method according to claim 11, wherein said mathematical index for probability is a neural network algorithm.

18. A method according to claim 11, wherein said mathematical index for probability is based on a defined or fuzzy rule-based reasoning procedure.

19. A method according to claim 11, further comprising the step of normalizing said first and second parameter values on the basis their respective parameter values acquired over a predetermined fixed time window including or excluding the latest real-time parameter value.

20. A method according to claim 19, wherein said normalized parameter values are acquired from:

said patient prior to incision, or prior to intubation, or prior to starting anesthesia or sedation, or

group of patients prior to or during incision and/or intubation and/or anesthesia or sedation.