Apparatus and method for electronically predicting pleural pressure from pulse wave signals

• US 6,669,632 B2
• Filed: 03/21/2002
• Issued: 12/30/2003
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toshiaki Shiomi
• Original Assignee: DENSO Corporation, Toshiaki Shiomi
• Inventors: Nanba, Shinji, Shiomi, Toshiaki, Ohsaki, Rie
• Primary Examiner(s): Hindenburg, Max F.
• Assistant Examiner(s): MALLARI, PATRICIA C
• Application Number:
  US10/101,835
• Publication Number:
  US 20020143261A1
• Time in Patent Office: 649 Days
• Field of Search: 600/300, 600/485, 600/500-507, 600/529-543, 600/561
• US Class Current: 600/300
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/03 Detecting, measuring or recording fluid pressure within the body other than blood pressure, e.g. cerebral pressure; Measuring pressure in body tissues or organs A61B5/205 takes precedence
• CPC Class Codes: A61B 5/4818 Sleep apnoea

Abstract

A pleural pressure is predicted from pleural pressure based upon pulse wave signals, which are continuously produced and picked up in a time sequential manner. A first variation signal indicative of a condition of a variation contained in the pulse wave signals is acquired based upon the pulse wave signals. A second variation signal representative of a condition of a variation contained in the first variation signal is acquired based upon the first variation signal. The pleural pressure is predicted based on a difference between the first variation signal and the second variation signal.

Claims

1. A pressure predicting apparatus for predicting pleural or esophageal pressure based upon pulse wave signals which are continuously connected to each other in a time sequential manner, the apparatus comprising:

first means for acquiring a first variation signal indicative of a condition of a variation contained in the pulse wave signals based upon the pulse wave signals;

second means for acquiring a second variation signal representative of a condition of a variation contained in the first variation signal based upon the first variation signal; and

prediction means for predicting a pleural pressure based on a difference between the first variation signal and the second variation signal.

2. The pressure predicting apparatus as set forth in claim 1, wherein the first variation signal corresponds to a first envelope produced by connecting peaks of waveforms to each other as to a signal indicative of respective pulse waves.

3. The pressure predicting apparatus as set forth in claim 1, wherein the first variation signal corresponds to a first amplitude ratio line produced by connecting points to each other, which are obtained by dividing an amplitude of a waveform of a signal indicative of respective pulse waves by a predetermined ratio.

4. The pressure predicting apparatus as set forth in claim 1, wherein the second variation signal corresponds to a second envelope produced by connecting peaks of respective waveforms in the first variation signal to each other.

5. The pressure predicting apparatus as set forth in claim 1, wherein the second variation signal corresponds to a second amplitude ratio line produced by connecting points to each other, which are obtained by dividing amplitudes of respective waveforms in the first variation signal by a predetermined ratio.

6. The pressure predicting apparatus as set forth in claim 1, wherein the pulse waves are measured at one of a rear side of a wrist, a shin of a foot or a forehead whose motion is small.

7. The pressure predicting apparatus as set forth in claim 1, further comprising:

calibration means for carrying out a calibration of the pleural pressure based upon either pulse wave data acquired during respiration while setting preselected pressure to both a nose and a mouth, or both air-sucking negative pressure generated by way of a sucking action and pulse wave data acquired by the air sucking action.

8. The pressure predicting apparatus as set forth in claim 1, further comprising:

motion detection means for detecting a body motion from the variation condition of the pulse wave signals.

9. The pressure predicting apparatus as set forth in claim 8, further comprising:

correcting means for correcting the predicted pleural pressure by the body motion detected from the pulse wave signals.

10. The pressure predicting apparatus as set forth in claim 8, wherein the motion detection means analyzes frequencies of the pulse wave signals to detect the body motion.

11. A medical apparatus, wherein a diagnosing operation as to one of a sleep apnea syndrome and an upper airway resistance syndrome is carried out by employing the pressure predicted by the pressure predicting apparatus as set forth in claim 1.

12. A medical apparatus, wherein a medical treatment effect as to one of a sleep apnea syndrome and an upper airway resistance syndrome is confirmed by employing the pressure predicted by the pressure predicting apparatus as set forth in claim 1.

14. A program comprising:

means for realizing a function of the pressure predicting apparatus as set forth in claim 1.

16. A program comprising:

means for realizing a function of the medical apparatus as set forth in claim 11.

17. The pressure predicting method as set forth in claim 16, wherein the first variation signal corresponds to a first envelope produced by connecting peaks of waveforms indicative of the pulse wave signals to each other.

18. The pressure predicting method as set forth in claim 16, wherein the first variation signal corresponds to a first amplitude ratio line produced by connecting points to each other, which are obtained by dividing an amplitude of a waveform of a signal indicative of respective pulse waves by a predetermined ratio.

13. A pressure predicting method for predicting pleural or esophageal pressure based upon pulse wave signals, which are continuously connected to each other in a time sequential manner, the method comprising steps of:

acquiring a first variation signal indicative of a condition of a variation contained in pulse wave signals;

acquiring a second variation signal representative of a condition of a variation contained in the first variation signal; and

predicting a pleural pressure based on a difference between the first variation signal and the second variation signal.

15. A diagnosing method executed by a computer, wherein a diagnosing operation as to a sleep apnea syndrome or an upper airway resistance syndrome is carried out by employing the pressure predicted by the pressure predicting method as set forth in claim 13.

19. The pressure predicting method as set forth in claim 13, wherein the second variation signal corresponds to a second envelope produced by connecting peaks of the respective waveforms in the first variation signal to each other.

20. The pressure predicting method as set forth in claim 13, wherein the second variation signal corresponds to a second amplitude ratio line produced by connecting points to each other, which are obtained by dividing amplitudes of respective waveforms in the first variation signal by a predetermined ratio.

21. The pressure predicting method as set forth in claim 13, wherein the pulse waves are measured at one of a rear side of a wrist, a shin of a foot or a forehead, whose motion is small.

22. The pressure predicting method as set forth in claim 13, further comprising the step of:

carrying out a calibration of the pressure based upon either pulse wave data acquired during respiration while setting preselected pressure to both a nose and a mouth, or both generating a negative pressure and acquiring pulse wave data during respiration and pulse wave data acquired by the air sucking action.

23. The pressure predicting method as set forth in claim 13, further comprising the step of:

detecting a body motion from the variation condition of the pulse wave signals.

24. The pressure predicting method as set forth in claim 23, further comprising the step of:

correcting the predicted pressure by removing the body motion detected from the pulse wave signals.

25. The pressure predicting method as set forth in claim 23, wherein the body motion is detected by analyzing frequencies of the pulse wave signals.

26. An examining method executed by a computer, wherein a medical treatment effect as to a sleep apnea syndrome or an upper airway resistance syndrome is confirmed by employing the pleural pressure predicted by the pressure predicting method as set forth in claim 13.