Abstract: A method for determining pulmonary functional residual capacity (FRC). A given amount of indicator gas is delivered into the breathing gases flowing into the lungs of a subject in a selected number of sequential breaths. The amounts of indicator gas delivered during the selected number of breaths are summed to provide a cumulative total (.SIGMA.V.sub.in). The amount of indicator gas exhaled in the number of sequential breaths is summed to provide a cumulative total (.SIGMA.V.sub.out). An indication of the concentration of indicator gas in the lungs of the subject (F.sub.ET) is obtained for said two or more breaths. Using the quantities (.SIGMA.V.sub.in), (.SIGMA.V.sub.out), and (F.sub.ET) as measured variables, at least two measured value data sets are formed in which the product of the indicator gas concentration (F.sub.ET) and a regression coefficient comprising the functional residual capacity (FRC) plus the product of the cumulative total of exhaled indicator gas (.SIGMA.V.sub.
Abstract: A medical dosing device/method for providing small discrete volumes of gas, for example sulfur hexa fluoride or nitric oxide, to the breathing gases of a patient. The device includes a charging valve interposed between a gas supply and a dosing chamber. A discharge valve is connected between the dosing chamber and an outlet of the device. The dosing chamber has a pressure sensor connected to a control means for the valves. In operation, the control means closes the discharge valve and opens the charging valve until a predetermined pressure is sensed in the dosing chamber. The charging valve is closed and thereafter the discharge valve is opened to supply gas from the dosing chamber until the pressure sensed by the pressure sensor falls to a second, lower level. The discharge valve is then closed. The gas so discharged forms the volume of gas.
Abstract: The invention relates to a procedure for determining the relative concentration or composition of different kinds of haemoglobin, such as oxyhaemoglobin, deoxyhaemoglobin and dyshaemoglobins, and/or dye components contained in blood in a non-invasive manner using the light absorption caused by different haemoglobin varieties and/or dye components, in which procedure light signals are transmitted at at least two predetermined wavelengths to a tissue comprised in the patient's blood circulation, the light signal transmitted through the target under measurement and/or reflected from it is received and the proportion of the intensity of the pulsating light signal received at each wavelength is determined in relation to the total intensity of the light transmitted through the tissue or reflected from the tissue.
Abstract: A radiation source assembly and transducer incorporating same are suitable for use in measuring spectral absorption properties of a substance to be analyzed, such as a gas. The radiation source assembly has an optical axis. A measuring radiation source provides radiation in the direction of the axis and a reference radiation source provides radiation in the direction of the axis. An optical diffuser is spaced from the radiation sources along the axis. Radiation from the measuring radiation source and radiation from the reference radiation source are applied to the diffuser and the diffuser forms an exiting radiation beam for the assembly from the radiation of the measuring radiation source and reference radiation source. The exiting radiation beam extends along the axis.
Abstract: The invention relates to an additional feature for use in a measuring sensor which is used for analyzing mediums spectroscopically. The measuring sensor comprises: a radiation source (1), emitting radiation which travels through a first window (3a) of a sample chamber (2), an absorption length (L1) and further a second window (3b) of the sample chamber (2), the sample chamber being provided, if necessary, with flow connections for a gas mixture; at least done detector (9), which is optically directed towards the second window; at least one optical filter (8), which is permeable to a certain wavelength band, or a radiation dispersion device between the radiation source and the detector. Between the first sample chamber window and the radiation source, the feature comprises a length (L2) and/or, between the second window and the detector, a length (L3), totalling at least about 20% of the absorption length.
Abstract: Infrared radiator has a heating element (1) heated by electric current and a first thermocouple (2) thermally coupled to the heating element to measure its temperature. According to the invention, the first thermocouple (2) is electrically so connected to the heating element (1) that the electric current used to heat the heating element flows through the thermocouple. The invention allows the temperature of the heating element to be measured without the use of a separate temperature detector, which would cause problems.
Abstract: A measuring device for determining the concentration of such gas components from a gas mixture, which includes collision dilation of the absorption lines constituting the absorption spectral bands for measuring objects. The device comprises a non-dispersive concentration measuring sensor (20), which includes: a measuring chamber (6) containing a gas mixture to be analyzed; a radiation source (17) for emitting over a wavelength range which includes an absorption spectral band used in concentration determination; a detector (18) receiving radiation that has passed through the measuring chamber and for producing a first signal (7) therefrom; as well as an optical bandpass filter (16) positioned between the detector and the radiation source. The measuring device further comprises a second measuring sensor (4) for identifying the viscosity or some other viscosity-related feature of a gas mixture to be analyzed and for producing a second signal (9).
Abstract: A method and apparatus for measuring a blood alcohol content value by means of a breath alcohol concentration as well as for securing the reliability of this measured value. The apparatus comprises: sensor elements (1) for obtaining a measured alcohol concentration value from an incoming exhalation air stream; sensor elements (1) for obtaining a measured carbon dioxide concentration value from the same exhalation air stream (9); as well as first output elements (2) for producing, if necessary, a result proportional at least to a blood alcohol content.
Abstract: A method and an arrangement for processing respiratory gas of an intubated patient, wherein the level of humidity of the inhalation gas is increased, if necessary, before the gas is supplied to the patient. To provide accurate and correctly timed humidification, the patient's respiratory volume is measured, the amount of water discharged from the patient is determined on the basis of the measured respiratory volume, and a desired amount of water, dependent on the amount of water discharged from the patient, is supplied to the patient's respiratory tract during the next respiratory phase(s).
Abstract: Patient monitoring system for the monitoring of a patient's condition using monitoring parameters determined about the patient, said system comprising a central data processing unit (1), peripherals (2, 3, 4); parameter modules (5), each comprising a preamplifier (6) for preliminary amplification of a parameter signal, an A/D converter (7) for converting the parameter signal into digital form, and a first optic transmitter-receiver (8) for isolating the data transfer of the digital parameter signal; data transfer equipment for data communication between the first transmitter-receivers (8) of the parameter modules and the central data processing unit (1); a coupling frame (9), on which parameter modules (5) can be detachably mounted: parameter sensors (10) to be connected to the patient and a sensor cable (11) for each parameter sensor to pass the parameter signal from the parameter sensor to the preamplifier corresponding to the parameter concerned.
Abstract: A ventilator for intensified breathing that includes a single safety valve arranged in the gas mixture and inhalation conduit assembly. The single safety valve includes a restrictor valve for overpressure in the breathing system, a valve that allows breathing from the atmosphere, and a directional valve for inhalation. The safety valve is arranged and controlled by an electronic control system of the ventilator.
Abstract: Measuring detector and system for the measurement of gas flow, especially for the measurement of the pressure and/or flow of a patient's respiratory gas. The surface of the wall (2) of a flow channel (1) and/or the surface of a restricting element (3), said surface being in direct contact with the gas flow to be measured, is provided with an agent for reducing the contact angle (.theta.) of a water drop or a drop containing water to said surface in relation to the contact angle formed between a corresponding water drop and a corresponding surface not treated with such agent.
Abstract: The invention relates to a method and apparatus for determining the concentration of at least carbon dioxide in a gas mixture on the basis of the absorption of infrared radiation (2), said apparatus comprising: a radiation source (1), the radiation emitted thereby being aligned to travel through a measuring cell (4) containing a gas mixture (6) to be analyzed; an optical band-pass filter (10), which is transmissive to a first wavelength band and positioned on the path of radiation emerging from the measuring cell or entering into the measuring cell through which the radiation passes; and a first detector (14), positioned in the radiating direction downstream of said first band-pass filter and used for detecting the radiation intensity falling thereon. Said optical band-pass filter (10) has a band-pass which lies within the wavelength range of 4.38 .mu.m-4.47 .mu.m for measuring the total concentration of carbon dioxide by means of the absorption spectrum of a molecule .sup.13 CO.sub.
Abstract: An arrangement for preventing overfill of an anaesthetic liquid container of a vaporizer resulting from inclination, comprising a bent intermediate container for guiding anaesthetic liquid to the anaesthetic liquid container for vaporization and for removing a volume of gas equivalent to the filling of anaesthetic liquid from the anaesthetic liquid container. The intermediate container is arranged to form a common conduit for the anaesthetic liquid and the gas removed from the container, and to combine the liquid flow outlet level and the gas flow outlet level in such a way that the anaesthetic liquid is allowed to flow into the anaesthetic liquid container only when the liquid flow outlet level is below the gas flow outlet level. The bent intermediate container may be located interiorly of, or exterior to, the anaesthetic liquid container.
Abstract: The present invention relates to a procedure for measuring a patient's impedance. Based on the impedance, it is possible to monitor the patient's respiration and/or blood circulation. In the procedure, a plurality of electrodes (1a, 1b; 1d, 2; 2a) are connected to be patient and the changes in the impedance relationships between the electrodes (1a, 1b, 2) are measured. The invention makes it possible to use the same measuring conductors and measuring electrodes for impedance measurement as are used in ECG measurement.
Abstract: A method and an arrangement in connection with vaporizing an anaesthetic, in which an anaesthetic, vaporized in a vaporizer is mixed with fresh gas and delivered to be inhaled by a patient. In order to achieve a reliable operation, the prevailing ambient air pressure is measured, the measured air pressure is compared with a reference pressure and when the prevailing ambient air pressure deviates from the reference pressure, the anaesthetic agent concentration of the fresh gas/anaesthetic mixture to be passed to the patient is adjusted in relation to the variation in the ambient external air pressure.
Abstract: A method and an assembly for filling an anesthetic evaporator, comprises a filling device (1) connectable to a transport container (15) and having a filling head (2) which can be inserted in an attachment point (4) included in an evaporator (3), the filling device and evaporator being provided with conduits (5a, 5b, 6a, 6b) for passing an anesthetic and a substituting gas between the transport container and the evaporator and the assembly comprising a clamping implement (7) for tightening the filling head (2) against a packing surface of the conduits arriving in the attachment point (4) included in the evaporator and a valve element (8, 9), adapted to open and thus to allow a flow of the anesthetic and the substituting gas.
Abstract: An arrangement in connection with an anaesthetic liquid container, comprising a connector with the help of which an anaesthetic liquid container and a transport or supply container of anaesthetic liquid can be connected to one another for guiding the anaesthetic liquid from the transport or supply container to the anaesthetic liquid container and for removing a volume of gas equivalent to the anaesthetic liquid from the anaesthetic liquid container to the transport or supply container. In order to provide a reliable and tight connection, the connector comprises a conduit arrangement which, when connecting the anaesthetic liquid container and the transport or supply container to one another, is adapted to open first a flow connection exclusively to gas.
December 27, 1996
Date of Patent:
September 1, 1998
Erkki Heinonen, Antti Sarela, Jukka Kankkunen