Abstract:
A portable computer-based blood pressure monitoring system automatically measures heart rate and blood pressure using the auscultatory method. Measurements are performed at random time intervals to prevent the subject from affecting his blood pressure and heart rate due to the expected onset of measurement. Data representative of Korotkoff sounds and corresponding applied cuff pressures is stored in both digital form in a semiconductor random access memory (132) and in analog form on a serial magnetic tape recorder (112). The system automatically maintains occluding cuff pressure constant for a predetermined period after cuff inflation before performing measurements to prevent pneumatic ringing from affecting blood pressure measurements. After cuff deflation, values are derived which are representatives of the average of the highest Korotkoff sound level peaks and the average of all Korotkoff sound level peaks and serve to define a threshold value in relation to which the points of systolic and diastolic pressure measurements are determined.
Abstract:
Techniques for determining different parameters associated with an individual's blood pressure in a non-invasive manner. These techniques include generating a blood pressure waveform (16') corresponding to the individual's actual waveform whereby the mean blood pressure of the individual can be readily calculated. This is accomplished by either using a specifically selected cuff pressure (10m') or by ramping the cuff pressure as would be done in taking blood pressure.
Abstract:
A technique for generating certain arterial blood pressure related curves V/P and dV/dP (42, 43) of a given individual using cuff pressure peak to peak values (curve 40). This is accomplished using only these latter values and the individuals diastolic and systolic blood pressures.
Abstract:
An optical fiber fluid flow device is provided for in vivo determination of blood flow in arteries. The device includes a fiber optical fluid pressure measuring device having at least first and second optical fiber sensors which optical fiber sensors are positioned in the blood passage and in a restricted flow area in the blood passage and the two fiber optical pressure fluid sensors are connected to an interferometer associated with an opto-electronic demodulator which has an output signal representing the differential pressure between the two sensed areas. The device also has utility in industrial applications.
Abstract:
A method and apparatus for detecting amplitude variations in the rhythmic oscillations of a physiological response pattern in a frequency range of interest. A sensor (1) is used to detect an occurrence of an event in the cycle of a physiological response and the interval between each reoccurring event is timed and placed in a buffer (9). The output from the buffer (9) is read out at predetermined time intervals and fed to a filter (90) which determines the aperiodic portion of the signal and substracts that aperiodic portion to output a residual data signal. The residual data signal is fed to a band pass filter (94) which filters in a region determined by the predetermined frequency range of interest and which outputs to a calculation and display device (96) wherein the variance of the rhythmic oscillation is calculated and displayed.
Abstract:
A monitoring probe of tubular cross-section is arranged to be inserted into the oesophagus of a patient and there temporarily orientated during, for example, surgical work. The probe is provided with means for monitoring and indicating one or more functions or conditions of the body of the patient. Indicating means for indicating the body functions via conductors form together with the probe casing an inseparable unit, and the indicating means are arranged within an area determined by the cylindrical outer surface of the probe. The heart functions are arranged to be monitored and externally indicated by an accelerometer which is arranged in a damping fluid and which is also operative to monitor lung sound, and by two mutually spaced electrodes, each electrode and the accelerometer forming separate units, each of which is connected to the plastic casing of the probe in a manner such as to be inseparable therefrom, and in that a thermistor is arranged within the probe.
Abstract:
Des micro-bulles sont formees dans un liquide, p.ex. du sang de maniere a modifier leurs caracteristiques de transmission en ondes electromagnetiques et soniques transmises au travers de celui-ci, en dissolvant dans le sang un materiau particulaire solide, de preference une suspension dans un liquide porteur dans lequel le materiau particulaire est au moins temporairement stable, et dont les particules sont sensiblement exemptes de micro-bulles et ont une pluralite de vides remplis de gaz communiquant avec la surface des particules et constituant des noyaux pour la formation des micro-bulles, le rapport entre la masse des particules et le volume de gaz dans les vides etant suffisant pour rendre le liquide dans lequel le materiau particulaire est dissout supersature par rapport au gaz se trouvant dans les vides dans la zone du liquide entourant les micro-bulles lorsqu'elles sont formees.
Abstract:
A non-invasive continuous blood pressure meter that reproduces the arterial blood pressure waveform, comprising an inflatable flexible finger cuff (2) which incorporates an infrared transmitter (3) and receiver (5), and electronic circuitry (20) connected to the transmitter and receiver and controlling a dynamic compressor (18). The dynamic compressor (18) comprises a bellows (10) which is compressed by a linear motor (8), electrically activated by the electronics (20). The bellows (10) is connected to the inflatable cuff (2) by a flexible tube (14), to which is also attached an electronic pressure transducer (15), in such a way that the hollow spaces of the bellows (10), tubing (14), electronic pressure transducer (15), and cuff (2), form one complete closed air-filled space. When the inflatable cuff (2) is wound around the finger (1) and the electronics (20) are properly adjusted, the signal from the electronic pressure transducer (15) will very nearly correspond to instantaneous arterial blood pressure.
Abstract:
An esophageal cardiac pulse probe (10) includes a lumen (12) for insertion into the esophagus, the end of the lumen preferably being closed by a flexible diaphragm (24). Pressure variations imparted to the fluid within the lumen in response to sounds from the heart and the lungs are transmitted to an electrical transducer (46) which produces an electrical signal proportional to the time-varying frequency and intensity of the pressure variations. This signal is selectively filtered (60, 62) to effectively eliminate signal components due to respiratory noise and audible heart sounds and the resulting signal is fed to an appropriate visual display apparatus (68). Direct acoustic cardiac sound monitoring is also achievable with an earpiece (50) connected to the lumen (12). Several probe geometries and a method of cardiac pulse waveform monitoring are also disclosed.
Abstract:
A blood pressure measurement system includes a cuff, an automatic inflation-deflation device for supplying compressed air to the cuff, electronic circuits for discriminating Korotokov sounds, and display means for indicating both the maximum (systolic) and minimum (diastolic) values of blood pressure. The cuff is divided into two portions, namely a blood choking cuff portion and a sound collecting cuff portion. The variation of air pressure in the sound collecting cuff portion may be detected by a microphone sensor which is provided outside the cuff. The detected sounds are once separated into Korotokov sounds and heart sounds. Then both sounds are compared to confirm the simultaneous occurrence. These coincident sounds may be judged to be Korotokov sounds and used to measure blood pressure.