Abstract:
An improved probe for measuring abnormality of living human tissue is disclosed. The probe (23) is equipped with means (21, 22) for detecting the degree of contact of its measuring end portion (6) with the surface of an object of human tissue (13) and is capable of being applied through opening space for forceps in endoscops.
Abstract:
A hand held probe unit has an infrared sensitive thermopile mounted in a metal housing kept at a constant reference temperature by a regulator circuit. A waveguide tube, surrounded by a thermally insulative probe, directs infrared emissions to the thermopile. The thermopile and regulator circuit of the probe unit are electrically connected to processing circuitry in a chopper unit. Prior to taking a patient's temperature, the probe unit is mated with the chopper unit so that the thermopile detects infrared emissions from a reference target which is also kept at a constant reference temperature by another regulator circuit. The processing circuitry repeatedly acquires the output level of the thermopile and stores calibration data. The probe unit is then removed from the chopper unit, the probe is covered with an IR transparent, disposable speculum, and is inserted in the patient's external ear canal. The processing circuitry then determines the patient's core temperature by comparing the stored calibration data to the maximum output of the thermopile during a succession of ear canal samplings.
Abstract:
Cardiac output is measured utilizing an indicator, such as saline, which alters blood resistivity, and an electrically calibrated conductivity cell positioned at the tip of a catheter. The catheter with the tetrapolar conductivity cell at the top is inserted into a blood vessel for current injection to develop a potential which is proportional to blood resistivity for inscribing the dilution curve occurring due to injection of the indicator, which curve is utilized to determine blood flow or cardiac output.
Abstract:
Systems and methods are provided for diagnosing the death of a fetus in utero. A first ECG signal from the fetus is detected. A second ECG signal from the mother simultaneously is detected. The two ECG signals are displayed on a common time base and compared to determine whether an ECG component originating with the fetus is present in the first ECG signal.
Abstract:
Apparatus for detecting movement of an external or internal surface portion of a living organism (24) comprises a conductive loop (12) dimensioned for disposition on the surface portion for movement therewith, and means for generating a signal indicative of the inductance of the loop (12), changes in the signai being indicative of the extent of movement of the surface portion. The apparatus may be used to measure intrapleural pressure on a non-invasive basis.
Abstract:
A method of monitoring the depth of anaesthesia of a patient, comprising stimulating contractions in the oesophagus of the patient, for example using an inflatable oesophageal balloon 5, obtaining signals indicative of the oesophageal contractions using a sensor 21, 4, and deriving from the signals an output indicative of the rate of occurrence of signals having a magnitude greaterthan a preset threshold value, and apparatus for carrying outthe method. An alternative aspect comprises assigning a score value to each of a plurality of different bodily functions of a patient, for example heart rate, blood pressure, degree of sweating, and formation of tears, the said score values being indicative of a depth of anaesthesia or sedation, summing the score values, and producing an output from the summed score values indicative of the amount of anaesthetic to be fed to the patient.
Abstract:
A temperature responsive transmitter in which frequency varies linearly with temperature includes two identically biased transistors, T i , T 2 connected in parallel. A capacitor C l , which reflects into the common bases to generate negative resistance in parallel with the capacitor, is connected to the common emitters. A crystal 30 is in parallel with the capacitor and the negative resistance. Oscillations occur if the magnitude of the absolute value of the negative resistance is less than the positive resistive impedance of the capacitor and the inductance of the crystal. The crystal has a large linear temperature coefficient and a resonant frequency which is substantially less than the gain-bandwidth product of the transistors to ensure that the crystal primarily determines the frequency of oscillation. A high-Q tank circuit having an inductor, L, and a capacitor C 2 is connected to the common collectors to increase the collector current flow, which in turn enhances the radiation of the oscillator frequency by the inductor.
Abstract:
A device (50; 100) for calibrating optical-response tissue-examination apparatus is coupled between the sending and receiving components of the apparatus; the equipment is then run through a test cycle to thereby project selected light spectra into an inlet (119, 121) to the calibration device and receive such light as it emerges from the calibration device through an outlet (170) after passing along a tortuous path (122, 133, 128; 156, 158, 162, 164). The calibration device provides known, standardized light-transfer characteristics (diffusion and attenuation) which condition the detected emergent light energy in a known and precisely repeatable manner, whereby such conditioned light energy may be used to analytically characterize the optical-response apparatus itself. The calibration device incorporates a sample cell (154) whereby the emergent light energy may also be particularly characterized in terms of the known effects on light transfer caused by the selected media. Two or more such media may be utilized so that the emergent ligth characterized by each different media may be mutually compared, to thereby establish calibration constants for the overall optical capabilities of the optical-response apparatus under calibration. Thus, in subsequent operation of the calibrated apparatus, during actual tissue-examination, the calibration constants so determined may be used to modify nominal tissue-examination data and convert it into intrinsically accurate form which may be directly compared on a meaningful quantified basis to any other similarly calibrated tissue-examination apparatus.
Abstract:
An electrochemical cell sensor for monitoring oxidizable enzyme substrates in biological fluids situated in a housing and suitable for implantation in the body, including at least one oxygen or hydrogen peroxide sensing electrode containing a suitable oxidase enzyme, a reference electrode, and a counter electrode all in communication with biological fluids through one or more openings in the walls of the housing.