APPARATUS AND METHOD FOR DETECTING AN APNEA USING SIGNALS SENSED IN DEPENDENCE ON THE BLOOD PRESSURE

• US 20100121207A1
• Filed: 04/22/2008
• Published: 05/13/2010
• Est. Priority Date: 04/27/2007
• Status: Abandoned Application

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Hofmann, Christian, Moersdorf, Hans-Joachim, Aschenbrenner, Stefan
• Application Number:
  US12/597,533
• Publication Number:
  US 20100121207A1
• Time in Patent Office: Days
• US Class Current: 600/500
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4818 Sleep apnoea

Abstract

The existence of an apnea may be inferred when, in a pulse wave signal which is provided and is detected in dependence on the blood pressure, a change in a waveform of the pulse wave signal meets a predetermined detection criterion.

Claims

1-21. -21. (canceled)

22. An apparatus for detecting apneas, comprising:

a provider for providing a blood pressure-dependent pulse wave signal; and

an evaluator for evaluating the pulse wave signal provided so as to infer the existence of an apnea when a low-frequency portion of the pulse wave signal falls below a predetermined threshold value,

the evaluator being configured to determine the time-variable threshold value for an evaluation time by averaging the low-frequency portion of the pulse wave signal within a time interval which comes before the evaluation time.

23. The apparatus as claimed in claim 22, wherein the provider is configured to provide a photoplethysmographically detected pulse wave signal.

24. The apparatus as claimed in claim 22, further comprising:

a low-pass filter for deriving the low-frequency portion of the pulse wave signal from the pulse wave signal.

25. The apparatus as claimed in claim 24, wherein the low-pass filter comprises a cutoff frequency which is below a pulse frequency.

26. The apparatus as claimed in claim 24, wherein the evaluator is configured to evaluate the pulse wave signal in terms of the pulse frequency so as to control the cutoff frequency of the low-pass filter such that said cutoff frequency is below the pulse frequency.

27. The apparatus as claimed in claim 22, wherein the provider comprises a photoplethysmography sensor.

28. The apparatus as claimed in claim 27, wherein the photoplethysmography sensor is configured to employ light of a single wavelength range.

29. The apparatus as claimed in claim 22, wherein the provider comprises a memory interface for reading out a pulse wave signal stored on an external medium.

30. The apparatus as claimed in claim 22, wherein the evaluator comprises a differentiator so as to determine a temporal derivation of the low-frequency portion of the pulse wave signal, the evaluator being configured to infer the existence of an apnea when the temporal derivation falls below the predetermined threshold value.

31. The apparatus as claimed in claim 22, comprising an alarm so as to perform an alarm action when the evaluator has inferred the existence of an apnea.

32. The apparatus as claimed in claim 31, wherein the alarm is configured to store, as an alarm action, the time of the detection of an apnea in an external memory.

33. The apparatus as claimed in claim 31, wherein the alarm is configured to store, as an alarm action, a measure of the severity of the detected apnea on the basis of the detection criterion.

34. The apparatus as claimed in claim 31, wherein the alarm is configured to activate, as an alarm action, a ventilation support, or to increase the support function thereof.

35. A method of detecting apneas, comprising:

providing a blood pressure-dependent pulse wave signal; and

evaluating the pulse wave signal provided so as to infer the existence of an apnea when a low-frequency portion of the pulse wave signal falls below a predetermined threshold value, the time-variable threshold value for an evaluation time being determined by averaging the low-frequency portion of the pulse wave signal within a time interval which comes before the evaluation time.

36. A computer readable medium having a computer program with program code for executing, when the computer program runs on a computer, a method of detecting apneas, said method comprising:

providing a blood pressure-dependent pulse wave signal; and

evaluating the pulse wave signal provided so as to infer the existence of an apnea when a low-frequency portion of the pulse wave signal falls below a predetermined threshold value, the time-variable threshold value for an evaluation time being determined by averaging the low-frequency portion of the pulse wave signal within a time interval which comes before the evaluation time.