A noninvasive blood pressure monitoring and controlling device is provided which selectively stimulates the human body's own baro-receptors with electromagnetic or ultrasonic wave energies.

Method and apparatus are disclosed for linearly pressurizing a cuff, affixed to the limb of a patient, with gas from a liquified gas tank, monitoring Korotkoff sounds that appear and disappear during cuff pressurization to ascertain approximate systolic and diastolic blood pressures as cuff pressurization is in process, halting pressurization at a point slightly higher than the approximate systolic blood pressure and then immediately depressurizing the cuff at a regulated rate to actually measure and determine true systolic blood pressure. Following the determination of systolic blood pressure, the cuff is depressurized at a rapid rate down to a point slightly higher than the approximate diastolic blood pressure and is then depressurized again at the regulated rate again to actually measure and determine true diastolic blood pressure. When a Korotkoff sound cannot be found during attempted actual measurement of the diastolic blood pressure, the currently prevailing cuff pressure is raised by a predetermined amount and the cuff is then vented again at the regulated rate to remeasure and redetermine diastolic blood pressure for the purpose of covering any fluctuation in the patient's blood pressure.

There is disclosed herein a blood pressure alarm system for use in a dialysis machine whereby alarms may be activated, and a blood pump deactivated if the actual blood pressure increases above or decreases below predetermined levels. The levels are determined by setting a particular blood pressure point and setting the amount by which the pressure can vary above and below the set point. A memory is provided for storing the set point and preventing variation of the set point with time. The dialysis machine and alarm system can malfunction under certain conditions and protection circuitry operates the alarms if a malfunction occurs.

There is disclosed herein a blood pressure alarm system for use in a dialysis machine whereby alarms may be activated, and a blood pump deactivated if the actual blood pressure increases above or decreases below predetermined levels. The levels are determined by setting a particular blood pressure point and setting the amount by which the pressure can vary above and below the set point; the range of variation is sometimes referred to as the alarm window. A digital memory is provided for storing the set point and preventing variation of the set point with time.

A pressure monitoring system for use with an electrofluidic device for sensing pressure includes a pump for supplying fluid to the electrofluidic sensing device. An electrical switching circuit controls the supply of fluid to the sensing device and is responsive to the external pressure level applied to the sensing device; this circuit also cyclically causes the supplied pressure to vent when the pressure of supplied fluid inside the sensing device is substantially equal to the applied external pressure, and then start the fluid supply to the device over again. This system further includes a measuring element for detecting the pressure level of the supplied fluid, and a digital meter for displaying the analogous detected pressure level during supply of the fluid.