Abstract:
A method and apparatus for the indirect measurement of blood pressure is disclosed. Pressure is applied to a cuff attached to a patient adjacent a blood vessel and a quantity repressentative of the patient's blood pressure is measured as the applied pressure is changed. A table of values of the quantity as the applied pressure is changed is formed. Valves of the table are selected as spurious high and low values in response to predetermined criteria and new values assigned to the selected values which reduces the error in calculating systolic and diastolic blood pressures from the table.
Abstract:
@ A connector (3) for connecting a transducer (1) to a monitor (2) in a system for monitoring physiological conditions in humans and other animals includes means (4) for transforming the impedance level of signals from the transducer to a level appropriate for the monitor and for drawing and adapting power from the monitor for effecting this impedance transformation. The connector (1) may also include one or more of the following means (5) a mechanism for adjusting the offset or sensitivity of the signal from the transducer; a mechanism for detecting the absence of the transducer; a mechanism for detecting an open circuit between the monitor and the transducer; a device for converting power drawn from the monitor to direct current where the power drawn from the monitor is, before conversion, either sine wave or pulsed; a mechanism for regulating the current from the monitor; and a mechanism for eliminating common-mode voltage errors from the transducer signal.
Abstract:
Disclosed is a pulse rate monitor having means for electro-optically detecting any variation of blood flow rate in the capillaries of earlobe; means for determining in terms of pulse rates so to which rank an exercise taken by a user belongs to; and means for informing him of the result of the decision thus made with the aid of sound or artificial voice using words.
Abstract:
An automatic blood pressure measuring apparatus including an occluding device having a cuff to apply a pressure to a body member of asubject, and a blood-pressure determining device to determine a blood pressure according to a variation in a pulse wave in relation to a change in the cuff pressure. The apparatus comprises a detector for monitoring a blood circulatory system of the subject, and generating signals representing an abnormality associated with the circulatory system. The apparatus further comprises a control device for actuating the occluding device to apply the cuff pressure to the body member, and causing the blood-pressure determining device to execute a predetermined series of blood-pressure measuring steps to measure the blood pressure, thereby permitting an automatic measurement of the blood pressure of the subject when the blood circulatory system is found abnormal by the detector.
Abstract:
A heartbeat rate indicator comprises a detection electrode (1) for receiving an electrocardiac potential signal, an amplifier circuit (3) for amplifying the electrocardiac potential signal, a filter circuit (4) for removing noise from the amplified electrocardiac potential signal, an an amplitude detection circuit (5) for detecting pulses having an amplitude greater than a predetermined amplitude. An absolute value circuit (8) produces an absolute value signal from the output signal of the filter circuit, the absolute value signal being fed to the amplitude detection circuit.
Abstract:
A simplified method of determining tissue blood flow such as cerebral blood flow is provided by calculating the partial derivatives with respect to flow rate constant (k) and partition coefficient (λ) of the sum of errors squared for calculated tissue concentration of a diffusible inert gas such as xenon minus measured tissue concentration of xenon based on CT numbers.
Abstract:
A sensor for trans-illumination of a blood perfused portion of flesh to measure light extinction during trans- illumination is disclosed. The sensor is preferably mounted on a fingertip but any digit or blood perfused portion of flesh will work. The sensor includes a first end for disposition on one side of the trans-illuminated flesh and a second end for disposition on the opposite and opposed side of the trans- illuminated flesh. A light source is mounted to the first side and a photo- sensor is mounted to the second side. If an elongated flexible strip is used, it is provided with adhesive and is suitably windowed that light is allowed to take an optical path through the finger. If no flexible strip is used, the two ends are aligned and secured to the flesh such that the light emitted takes an optical path through the finger. When the adhesive fastener is used, the effect of the light source and photo-detector substrates being integrated into the adhesive fastener is that they become, in effect, a part of the skin. The resulting device is resistant to accidental removal and avoids constriction of blood vessels. Most importantly, the low mass of the sensor itself and its conformance to, so as to effectively become a part of, the skin, prevents relative motion between the light source and sensor and the perfused flesh. This eliminates the common interference associated with the operation of conventional plethysmographs and oximeters.
Abstract:
An electronic device for measuring blood pressure, according to which either systolic pressure may be derived from mean pressure and diastolic pressure, or diastolic pressure may be derived from systolic pressure and mean pressure, whereby the time duration of the application of pressure to the patient's arm may be reduced because the pressure to be applied may only range substantially over between mean pressure and diastolic pressure or between systolic pressure and mean pressure. Additionally proposed is a means for improving the accuracy of the above- mentioned derivation of systolic pressure or diastolic pressure. As a result, considerable reduction in the time duration required for measurement may be reduced without any increase in measurement errors.