Abstract: This invention provides a polarographic/amperometric measuring sensor, particularly useful for transcutaneous determination of the oxygen partial pressure (tcpO.sub.2) in the blood by means of a Clark-type electrode arrangement. According to the invention the counter electrode, preferably made of a noble metal, is disposed about the insulating material encasing the working electrode and is preferably made of the same noble metal as the working electrode. The measuring sensor can also be provided with a pH electrode for simultaneous determination of the carbon dioxide partial pressure (tcpCO.sub.2) in the blood.

Abstract: To enable conventional adapter assemblies used to accurately position a removable biosensor, to be used for measurements in the interior of the skull of small children, the disclosed is a support sleeve which ensures an axial length compensation, taking into account the thinner skull bone thickness, and at the same time ensures accurate alignment of the adapter assembly and the biosensor. The support sleeve also ensures a more even distribution of axial thrust forces when the adapter assembly and the biosensor are positioned. The support sleeve comprises an inwardly extending peripheral flange defining an annular space between the flange and a tubular element slidably inserted in the sleeve. A spring element disposed in the space assures adequate anchorage in the skull bone.

Abstract: The combined sensor with a thermostatted heating device (7, 23) for the simultaneous and continuous transcutaneous measurement of oxygen (O.sub.2) and of carbon dioxide (CO.sub.2) in the blood contains a measuring device (1) for the partial pressure of CO.sub.2 (pCO.sub.2), in which there is pure optical/spectrometric operation or which operates on the principle of pH measurement in a electrolyte (8), and which is separated from the measuring site on the skin by a membrane (13) which is permeable to both CO.sub.2 and light, and contains another measuring device (24, 25, 26) for the spectrometric measurement of the blood oxygen saturation (sO.sub.2). The advantage over a known pO.sub.2 /pCO.sub.2 combined sensor is that the combined sensor according to the invention can be operated at a low operating temperature of, for example, 42.degree. C.

Abstract: The combined sensor with a thermostatted heating device (7, 23) for the simultaneous and continuous transcutaneous measurement of oxygen (O.sub.2) and of carbon dioxide (CO.sub.2) in the blood contains a measuring device (1) for the partial pressure of CO.sub.2 (pCO.sub.2), in which there is pure optical/spectrometric operation or which operates on the principle of pH measurement in an electrolyte (8), and which is separated from the measuring site on the skin by a membrane (13) which is permeable to both CO.sub.2 and light, and contains another measuring device (24, 25, 26) for the spectrometric measurement of the blood oxygen saturation (sO.sub.2). The advantage over a known pO.sub.2 /pCO.sub.2 combined sensor is that the combined sensor according to the invention can be operated at a low operating temperature of, for example, 42.degree. C.

Abstract: Disclosed are apparatus and method for preventing hypoxic damage, relieving respiratory difficulties and conditioning breathing reflexes in a living human body. More particularly, at least one sensory stimulus is imparted to the body in response to a deviation from at least one adjustable physiological variable followed sequentially by delivery of a respiration restoring gas to the vicinity of the nose and mouth of the body.

Abstract: Disclosed is an adapter assembly for accurately positioning a removable biosensor implanted in the cranium or skull cap. The assembly comprises an outer sleeve member insertable into a hole bored through the skull cap and an inner sleeve member coaxial with the outer sleeve. The sleeve members are constructed so as to permit slidable insertion and removal of the biosensor and to ensure accurate, tilt-free alignment thereof, thus enabling precise, error-free measurement.

Abstract: Disclosed herein is a retainer assembly for applying a membrane to a physiological sensing unit for the transcutaneous determination of the magnitude of physiological quantities, particularly for measuring the partial pressure of gases in blood or the like. The assembly constitutes a preassembly of a membrane, with a clamping ring accommodating the membrane and having an annular recess receiving the rim of the membrane. The clamping ring has a lip in the form of an inwardly protruding annular edge for removably securing the clamping ring together with the membrane to the sensing unit by virtue of the lip resiliently snapping into a peripheral groove of the sensing unit, the lip defining the periphery of the annular recess. A retainer element is provided for temporarily and removably assembling the membrane with the clamping ring prior to assembly with the sensing unit.

Abstract: The method and the device based on it for the automatic calibration of measuring and indicating appliances used for the measurement and indication of the oxygen partial pressure in connection with polarographic sensors provide that a variable polarization voltage supplied by a polarization voltage generator (2), controlled by a central processor (4), is applied to a polarographic sensor (1). The resulting measuring signals of the sensor (1), after analog-digital conversion, are stored in a read-write memory (8). By comparing these with the desired current values stored in a read-only memory (7) the central processor (4) determines the theoretical residual current deviation from the zero value, which in turn is stored. The operating point is fixed at the point of the lowest slope within the operating range of the characteristic line.

Abstract: Disclosed herein is an arm deflecting drive system for strip chart recorders. The drive system mechanism includes a variable resistance structure which produces a position signal indicative of the angular position of the deflecting arm, which signal is proportional to the tangent of the position angle of the arm. The drive mechanism further includes a differential amplifier receiving both the position signal and a reference signal and generating a deflection signal related to the difference between the reference and position signals. In accordance with the invention, the variable resistance structure may include a track of electrically resistant material contoured to provide the tangential relationship between the position signal and the position angle or, alternatively, the track may be formed from an inhomogeneous material to provide such tangential relationship.

Abstract: Disclosed herein is a retainer arrangement for applying a membrane to a physiological sensing unit for the transcutaneous determination of the magnitude of physiological quantitites, particularly for measuring the partial pressure of gases in blood or the like. The arrangement constitutes a preassembly of a membrane, with a clamping ring accommodating the membrane and having an annular recess receiving the rim of the membrane. The clamping ring has a lip in the form of an inwardly protruding annular edge for removably securing the clamping ring together with the membrane to the sensing unit by virtue of the lip resiliently snapping into a peripheral groove of the sensing unit, the lip defining the periphery of the annular recess. In accordance with the invention, an auxiliary retainer element, is provided for temporarily and removably assembling the membrane with the clamping ring prior to assembly with the sensing unit.

Abstract: Disclosed herein are a method and a retainer arrangement for applying a membrane to a physiological sensing unit for the transcutaneous determination of the magnitude of physiological quantities, particularly for measuring the partial pressure of gases in blood or the like. The invention proposes the preparation of a preassembly thus constituting a spare part which will be ready for application to the sensing unit when needed. The preassembly comprises a membrane, a clamping ring for removably assembling the membrane with the sensing unit, and means, including an auxiliary retainer element, for temporarily and removably securing the membrane to the clamping ring prior to assembly with the sensing unit.

Abstract: Disclosed herein is a method for the calibration of a sensing unit for determining the partial pressure of oxygen in contact with the sensing unit. The method is of the type using a zero-calibration solution in which the partial pressure of oxygen is maintained at zero by virtue of a binding agent present in the solution for chemically combining with the oxygen. The essential steps of the method include adding to the solution a color indicator for indicating that the zero-calibration solution contains unspent binding agent, contacting the sensing unit with the zero-calibration solution containing the unspent binding agent and the color indicator, energizing the sensing unit, and adjusting the sensing unit until it indicates zero concentration.The invention also compasses within its scope a calibration agent for use in the performance of the method for supplying the zero-calibration solution upon dissolution in water, as well as a container for storing the zero-calibration solution.

Abstract: For improving the class of measuring quality of ink jet recorders the invention provides for a rigid connection of the permanent magnet of the electromagnetic driving system with the securing point of the capillary tube within the ink supply system by means of a torsion-resistant coupling element. It is suggested to place the securing point of said coupling element with said capillary tube as close as possible adjacent to the exit nozzle so that deviations of deflection of the exit nozzle by tumbling motions of the nozzle are prevented. The torsion-resistant coupling element transmits the instantaneous value of the exit nozzle deflection from the securing point to the measuring value detector of the control system of the ink jet recorder. Preferably, the coupling element is a length of a glass tube supported for rotation about its axis by two bearings placed upstream and downstream of the permanent magnet.

Abstract: For the common mode rejection in an amplifier arrangement comprising preferably a plurality of operational amplifiers for a plurality of desired signals to be processed, which signals are superimposed by a stronger spurious signal, it is an object to supply the desired signals such as physiological measuring signals for EEG and EKG measurements at positive inputs of the respectively associated single amplifiers, while each negative input is connected to the junction of a voltage divider consisting of two resistors, which voltage divider is arranged between the respective amplifier output and a reference potential.

Abstract: An improves QRS detector is disclosed which utilizes a comparison between the arithmetic mean value of the filtered and full wave rectified EKG signal and such EKG signal reduced by a proportionality factor related to the ratio between the peak and mean value of a full wave rectified sinusoidal wave form. An adaptive threshold circuit is additionally disclosed which serves to increase the threshold value to the amplitude of detected QRS complexes.

Abstract: Disclosed herein is a medical diagnostic device for determining bleeding times and behavior of bleedings from a standardized wound, (hemmorrhagometry), wherein a flow of a rinsing liquid past the wound is established, thereby to cause the rinsing liquid to contact the wound. A photometric instrument or equivalent is provided for determining a characteristic of the rinsing liquid which is representative of the proportion of blood contained in the rinsing liquid having contacted the wound. The device of the invention is designed such that it permits controlling the temperature of the rinsing liquid and consequently of the bleeding location and of its surrounding area, in order to keep them on a preselected temperature.

Abstract: A measuring sensor head for determining the contents of gases in liquids, particularly for transcutaneous determination of oxygen in blood, as well as a method of manufacturing such sensor head are disclosed. In accordance with the invention, the gas-permeable membrane which covers the front face of the sensor head and which, during use, is applied to the human skin, is preshaped to assume a cap-shaped configuration. This eliminates previously occurring measuring errors due to uncontrollable stresses causing thickness variations generated in conventional membranes and, moreover, provides for an improved sealing effect between the housing of the measuring head and the membrane.

Abstract: A spring lancet holder for creating accurate standardized, reproducible puncture wounds in the skin for medical diagnostic purposes is disclosed in which accuracy and reproducibility is improved by minimizing the recoil transmitted to the lancet holder by actuation of the drive mechanism which pushes the lancet into the skin. In a preferred embodiment, a mass is shown which is caused to move in opposition to the motion of the lancet caused by a striker spring which is mounted between the lancet and the mass.

Abstract: A device is disclosed for applying a gas permeable membrane to an electrode. A collar is used to hold the membrane on the electrode. The device includes a guide bushing for forcing the collar over the membrane onto the electrode and includes a soft surface for maintaining a constant pressure against the membrane surface during the application.

Abstract: The perfusion rate in animal tissue is measured percutaneously at a specific locus, and at the same time the indicator concentration is percutaneously measured at the same locus so that the perfusion efficiency factor can be determined. Apparatus for carrying out the above method is also disclosed comprising, in combination, a first and a second wall means defining a first and a second surface, each placed in contact with animal tissue to be measured and respectively cooperating with first and second sensor means so that the temperatures of said surfaces can be compared and simultaneously processed with the measurement of the indicator concentration performed by a separate measuring means also in contact with the tissue, so that the perfusion efficiency factor can be determined.