Abstract: A multi-purpose polarographic oxygen-concentration transducer of the transcutaneous-measurement type, a face of it being laid against the tissue of interest, is able to generate signals beyond those indicating mere total oxygen concentration, and can additionally generate signals indicating concentration of oxygen chemically bound to blood hemoglobin, as well as also indicating pulse rate and pulse waveform, blood flow rate through the capillary network of such tissue, the elastic behavior of the capillaries, and the flow rate of blood through such tissue exclusive of that flowing through the capillary network. The transducer is thermostatically temperature-controlled and emits light onto the tissue against which it is laid and detects the light received back by reflection and/or by transmission of such light into and out of the tissue against which the transducer is laid.

Abstract: A dish transducer unit comprising a dish-defining structure into which a drop of sample fluid is dropped for contact with the electrical or electrochemical transducer of the transducer, both the dish-defining structure and the transducer unit being thermostatically heated. The technician presses a button to initiate a timer, whereupon a transducer warm-up period begins, during which the meter connected to the transducer is maintained inoperative, to preclude readings. When the transducer warm-up period ends, the meter becomes operative so that the technician can calibrate. Prior to completion of a timed calibration period, the technician must drop the sample into the dish-defining structure, or else the timer stops and the thermostatic heating is discontinued. If the sample is timely dropped, a sample warm-up period follows, during which the sample is heated and the meter again inoperative, followed by a reading-taking interval during which the meter is again operative.

Abstract: First and second probes are laid against the skin to transcutaneously measure perfusion and e.g., oxygen concentration and generate corresponding first and second signals. These signals are fed to a signal-processing unit which triggers an alarm whenever changes in these signals meet predetermined rate-of-change criteria. Among these criteria is parallel increase in both perfusion and e.g., oxygen concentration, parallel decrease in both perfusion and e.g., oxygen concentration, and unchanging perfusion accompanied by decreasing e.g., oxygen concentration. The probes are occasionally pressed against the skin, for example under the control of a timer, with a pressure in excess of 1 g/cm.sup.2, to occasionally induce hyperemic conditions and see whether parallel changes in perfusion and concentration result.

Abstract: A dish-electrode concentration transducer unit of the type into whose dish one or a few drops of blood, on the order of 20-50 microliters, is dropped. The dish-defining structure of the transducer unit is thermally conductive, and both it and the transducer of the unit are thermostatically temperature-controlled, in order that the transducer and the blood being investigated be maintained at requisite temperature. The transducer is, in assembled condition of the transducer unit, held in place pressed against the thermally conductive dish-defining structure so as to be in thermally conductive engagement therewith. Accordingly, the transducer of the unit can be replaced with involvement of the heating element or temperature sensor of the thermostatic system of the transducer unit, and certainly without accompanying replacement of the temperature sensor.

Abstract: A process and an arrangement for determining the perfusion factor of a gas in a sample, particularly of oxygen dissolved in blood flowing through biological tissue, includes measuring the amount of gas diffused from the sample by means of a polarographic cell which comprises a reference electrode having a heat conductive surface which is adapted to be placed in heat-transmitting relationship over a portion of the sample, and a sensor electrode in electrolytic contact with the reference electrode so as to generate a signal indicative of the amount of gas being diffused from the sample portion. A heating unit comprising a high frequency generator to establish a high frequency field in the sample is also provided for heating the sample diathermically to a desired temperature.

Abstract: A platinum oxygen-pressure measuring electrode is connected with a reference electrode. An indicating device for indicating the oxygen pressure is connected with both of the electrodes, and an arrangement is interposed between the electrodes and an object to be measured and has a surface which is to be placed against the object. The arrangement offers to the diffusion of oxygen from the surface to the measuring electrode a resistance which is greater than the resistance which is offered to such diffusion of the oxygen through the object to be measured.

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.