Surgery – Diagnostic testing – Cardiovascular
Patent
1997-07-09
1999-02-23
Nasser, Robert L.
Surgery
Diagnostic testing
Cardiovascular
600494, 600490, A61B 500
Patent
active
058738363
ABSTRACT:
A method and apparatus is provided for distinguishing blood pressure sounds from noise in an automatic blood pressure monitoring system using the information contained in two microphone signals. Two microphones are placed on a patient along an axis of an artery to pick up blood pressure sounds. Pressure is applied to the artery such that the artery opens and closes during each heart cycle, the opening snap of the artery producing a blood pressure sound. The two microphone signals are sampled, filtered, and multiplied together to produce a microphone signal product. The microphone signal product is wave width filtered to remove therefrom portions of the signal having a wave width which is less than a selected minimum wave width value. A blood pressure sound is indicated as being detected when an amplitude of this wave width filtered microphone signal product exceeds a noise signal threshold level. The microphone signal product is also wave width filtered to remove therefrom portions of the signal having a wave width which is greater than a selected maximum wave width value. The amplitude of the resulting noise amplitude signal is used to adjust dynamically the noise signal threshold level in response to changing noise conditions. The detection of blood pressure sounds at a range of applied pressure levels is used to determine the systolic and diastolic blood pressure levels of the patient.
REFERENCES:
patent: 3773033 (1973-11-01), Rodbard et al.
patent: 3953794 (1976-04-01), Moore
patent: 4005701 (1977-02-01), Aisenberg et al.
patent: 4165491 (1979-08-01), Geffon
patent: 4245648 (1981-01-01), Trimmer et al.
patent: 4313445 (1982-02-01), Georgi
patent: 4396018 (1983-08-01), Sibley
patent: 4408614 (1983-10-01), Weaver et al.
patent: 4592365 (1986-06-01), Georgi
patent: 4649929 (1987-03-01), Weaver et al.
patent: 4819654 (1989-04-01), Weaver et al.
patent: 4840181 (1989-06-01), Yamaguchi
patent: 4938277 (1990-07-01), Niwa et al.
patent: 5031630 (1991-07-01), Hirano et al.
patent: 5135003 (1992-08-01), Souma
patent: 5337750 (1994-08-01), Walloch
patent: 5392781 (1995-02-01), Phillipps et al.
patent: 5482036 (1996-01-01), Diab et al.
patent: 5490505 (1996-02-01), Diab et al.
patent: 5649535 (1997-07-01), Voith
Kim-Gau Ng & Carolyn F. Small, "Survey of Automated Noninvasive Blood Pressure Monitors", J. Clinical Engineering, vol. 19, No. 6, pp. 452-475, Nov./Dec. 1994.
U.S. Patent Appl. S.N. 08/665,286, Method and Apparatus For Detecting Blood Pressure By Blood Pressure Sounds In The Presence of Significant Noise, by Alan R. Kahn, Dennis E. Bahr, and Kurt W. Allen, filed Jun. 17, 1996, notice of allowance mailed Apr. 25, 1997.
U.S. Patent Appl. S.N. 08/665,362, Coherent Pattern Identification In Non-Stationary Periodic Data and Blood Pressure Measurement Using Same, by Alan R. Kahn, Dennis E. Bahr, and Kurt W. Allen, filed Jun. 17, 1996.
Bernard Widrow, et al., "Adaptive Nosie Cancelling: Principles and Applications", IEEE Proceedings, vol. 63, No. 13, pp. 1692, 1710-1711, Dec. 1975.
Allen Kurt W.
Bahr Dennis E.
Kahn Alan R.
BP Sure, LLC
Nasser Robert L.
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