Alarm actuation arrangement for an automatic blood pressure recorder

• US 4,050,452 A
• Filed: 04/21/1976
• Issued: 09/27/1977
• Est. Priority Date: 09/26/1975
• Status: Expired due to Term

• Current Assignee: Milstein Medical Research Foundation Incorporated
• Original Assignee: Milstein Medical Research Foundation Incorporated
• Inventors: Lee, Arnold S. J.
• Primary Examiner(s): Howell, Kyle L.
• Application Number:
  US05/678,989
• Time in Patent Office: 524 Days
• Field of Search: 128/2.05 A, 128/2.05 G, 128/2.05 M, 128/2.05 Z, 128/2.05 Q, 340/279, 346/33 ME
• US Class Current: 600/496
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 8/04 Measuring blood pressure
• CPC Class Codes: G01D 15/14 Optical recording elements; Recording elements using X-or nuclear radiation
• CPC Class Codes: G01D 9/28 Producing one or more recordings, each recording being of the values of two or more different variables G01D9/38, G01D9/40 take precedence
• CPC Class Codes: Y10S 128/90 Blood pressure recorder
• CPC Class Codes: Y10S 128/901 Suppression of noise in electric signal

Abstract

An alarm actuating circuit associated with an automatic blood pressure recorder is triggered when a patient'"'"'s systolic or diastolic pressure does not fall within a prescribed range. The recorder is associated with a pneumatic regulator including a constant-volume reference chamber and associated pressure-sensitive inflation and deflation valves to effect a precise linear depressurization of an inflatable cuff which has been applied to the patient and pressurized to a value higher than the patient'"'"'s systolic pressure. Pulses obtained from an ultrasonic or other suitable detector sensitive to movements of the patient'"'"'s arterial wall in synchronism with the blood flow surges as the cuff is depressurized below the patient'"'"'s systolic pressure are integrated and then translated into variable-duration marking impulses. Such impulses are successively applied to the actuating input of a pen or other marker associated with an X-Y recording chart, the pen being linearly scanned along one chart axis at the constant depressurization rate of the cuff. During such scan, the pen records, on the chart, a linear pattern of marks each of which has a length corresponding to the duration of the marking impulse then applied to its actuating input.

Claims

1. In an apparatus for automatically detecting and recording a succession of time-spaced blood flow surges occurring while a variable external pressure applied to a patient'"'"'s artery is decreased over a first range including the systolic to diastolic pressure range of the patient, the apparatus comprising an inflatable cuff for applying the external pressure to the artery, means for pressurizing the cuff to a first predetermined value corresponding to the upper end of the first range, means operative when the cuff has reached the first value for depressurizing the cuff, and means for detecting successive blood flow surges caused by successive movements of the artery as the cuff is depressurized the improvement comprising an arrangement for actuating an alarm means if the first blood pressure surge during said depressurization does not occur within a prescribed interval commencing a fixed time after the start of depressurization of the cuff, when said depressurization proceeds at a substantially linear rate, the prescribed interval being indicative of an acceptable range of systolic pressures, the arrangement comprising, in combination, means coupled to the detecting means for generating an indicating pulse upon the occurrence of the first blood flow surge, normally enabled gating means interconnecting the output of the indicating pulse generating means and the alarm means for normally operating the alarm means upon the occurrence of the indicating pulse, means rendered effective upon the start of depressurization of the cuff for generating an auxiliary pulse having a duration equal to the prescribed interval, means for delaying the auxiliary pulse by the fixed time, and means applying the delayed auxiliary pulse to the gating means for disabling the gating means for the duration of the auxiliary pulse.

2. In a machine for automatically detecting and recording a succession of time-spaced blood flow surges occurring while a variable external pressure applied to a patient'"'"'s artery is decreased over a first range including the systolic to diastolic pressure range of the patient, the apparatus comprising an inflatable cuff for applying the externall pressure to the artery, means for pressurizing the cuff to a first predetermined value corresponding to the upper end of the first range, means operative when the cuff has reached the first value for depressurizing the cuff through the first range, and means for detecting successive blood flow surges caused by successive movements of the artery as the cuff is depressurized, the improvement comprising an arrangement for actuating an alarm means if the last blood flow surge during such depressurization does not occur within a predetermined interval occurring a fixed time prior to the conclusion of the depressurization of the cuff through the first range when said depressurization proceeds at a substantially linear rate, the predetermined interval being indicative of an acceptable range of diastolic pressures, the arrangement comprising, in combination, means rendered effective when the cuff has been depressurized through the first range for generating a control pulse, normally enabled gating means interconnecting the output of the control pulse generating means with the alarm means for normally operating the alarm means upon the occurrence of the control pulse, means for generating an indication pulse upon the occurrence of the last blood flow surge during depressurization of the cuff, the indicating pulse having a duration equal to the predetermined interval, first means coupled to the output of the indicating pulse generating means for delaying the indicating pulse by the fixed time, and means for coupling the delayed indicating pulse to the gating means for disabling the gating means.

3. Apparatus as defined in claim 2, in which the indicating pulse generating means comprises, in combination, means coupled to the detecting means for generating a succession of spaced first pulses corresponding to the successive detected surges, and second delay means coupled to the output of the indicating pulse generating means for normally delaying each first pulse by a first preset time, the second delay means including means rendered effective when each such first pulse applied to the input of the second delay means is not followed by a further such pulse within a second preset time for inhibiting the appearance at the output of the second delay means of the delayed first pulse, the second preset time being selected to be greater than the longest interval between detected blood flow surges, whereby the delayed first pulse corresponding to the last blood flow surge during the depressurization of the cuff constitutes the sole output of the second delay means to form the indicating pulse.