US 4,178,918 A · Automatic blood pressure measuring and recording system

Abstract

A noninvasive blood pressure measuring and recording system includes an inflatable cuff for encircling a portion of the human body, a pump for inflating and deflating the cuff for selectively occluding an arterial vessel, a detector for detecting flow variation through the arterial vessel as cuff pressure is decreased, and a recorder for recording cuff pressure values corresponding to the detected flow variation. The pump is a reversible single stroke sleeve diaphragm pump pneumatically coupled to the cuff and provides a selected, repeatable linear rate of pressure change for accurate, repeatable measurements through an automatically controllable motor operating at a selected constant speed to actuate the pump. A speed control changes the linear rate of pressure change in response to detected flow variations to enhance accuracy of measurement of selected variations, such as those identified with the systolic and diastolic pressures. A variable volume ballast tank may be pneumatically coupled to the cuff and pump to accommodate different cuff sizes. Pressure and flow variation signals may be utilized to simply and easily provide one or more different representations or measurements of detected flow variations, including additional aural representation concurrent with the measurement process for aural diagnosis.

Claims10

Dependent claims

In a noninvasive blood pressure measuring and recording system of the type which includes an inflatable cuff forencircling a portion of the human body, means for inflating and deflating the cuff for selectively occluding an arterial vessel, means for detecting flow variations through the artery and means for recording the arm cuff pressure values corresponding to the detection of desired flow variations through the artery as cuff pressure is decreased, the improvement therein enabling reproducibility of cuff pressure decrease and controlled variability of constant rates of pressure decrease which comprises:

the means for inflating and deflating the cuff comprising a single stroke reversible pump having a piston, a cylinder and a flexible sleeve diaphragm, the piston being movable within the cylinder and joined thereto through the flexible sleeve diaphragm, the diaphragm being arranged to fit in a folded position between the cylinder and piston and to maintain a pressure seal therebetween, the piston, cylinder and diaphragm forming a variable volume, contained air chamber pneumatically coupled to the cuff,
controllable motor means operable at a preselected constant speed for moving the piston within the cylinder to vary the volume of the contained air chamber in a predetermined fashion, thereby to produce a corresponding predetermined and precise pressure variation in the inflatable cuff for accurate blood pressure measurements, and
control means for controlling the motor means during decrease of cuff pressure in response to the flow variation detection means to operate the motor means at a different preselected constant speed following initial detection of flow variations in the arterial vessel.

The improved noninvasive blood pressure measuring and recording system as claimed in claim1 wherein the control means for controlling the motor means includes a regulator circuit means for adjusting power supplied to the motor means, the flow variation detection means includes means for generating a signal and the regulator circuit means includes means to respond to the signal generated by the flow variation detection means to adjust the power supplied to the motor means.

Dependencies are inferred from the claim text.

Automatic blood pressure measuring and recording system

Life of this patent

Automatic blood pressure measuring and recording system

Life of this patent

Abstract

Claims10