Abstract: Method and apparatus for determining in a person's exhalation air the concentration of a specific substance in the blood by measuring the concentration of said substance and the concentration of water vapor in the exhalation air and utilizing a known relationship between these concentrations. When the method is applied the exhalation air is exhaled freely in a defined air volume having a predetermined composition, and said concentrations are measured in this air volume. The apparatus for working the method comprises a device (16) which defines a space for receiving the exhalation air, which has two mutually opposite openings through which the space communicates with the surrounding air, and means (18, 22, 23) for selective quantitative detection of said substance in the air in the defined space.

Abstract: A method in calibrating or checking an apparatus for determining in a person's exhalation air the concentration of a specific substance is disclosed. The apparatus comprises means for passing exhalation air along a free measuring length, and means for supplying air of a predetermined composition to the measuring length to produce an air flow along the length. A mixture of the substance and water in a specified concentration thereof inder instantaneous evaporation is injected into the air when supplied to the measuring length. The concentration of the substance and the concentration of water vapor in the air flow along the measuring length is determined. The substance gas flow and the water vapor flow are calculated, and the ratio thereof is compared with the specified concentration of the mixture.

Abstract: In a method an apparatus for vaporizing anesthetic liquids, in which a carrier gas is passed through a vaporizer so as to be saturated with vaporized anesthetic liquid, the vaporizer has a container, partially filled with anesthetic liquid, an inlet for a carrier gas, an outlet for carrier gas saturated with anesthetic and a pressure chamber. The carrier gas is supplied to the vaporizer at a pressure exceeding atmospheric pressure and is bubbled through the anesthetic liquid in the container in order to become saturated with anesthetic. The flow of gas at the outlet can be regulated as needed. Exact pressure and temperature conditions can be measured and/or regulated with a pressure meter, pressure regulator, thermometer and temperature regulator in order to regulate the partial pressure of anesthetic in the container.

Abstract: An anesthetic system has an external gas reservoir and three gas bellows arranged in the external gas reservoir to alternatingly collect or deliver breathing gas from and to a ventilator unit. In this manner a completely closed system is achieved with minimal consumption of, primarily, anesthetic. The bellows are regulated by a regulatory unit which, via a valve system, can selectively connect a source of drive gas to one or more of the containers in order to compress the gas bellows respectively contained therein. When no drive gas is supplied, each bellows passively expands.

Abstract: A number of different parameters related to carbon dioxide output of a patient are routinely determined in ventilator/anaesthetic systems. For this purpose, a ventilator/anaesthetic system for determining carbon dioxide parameters includes a ventilator unit in which a first flow meter is arranged to measure an expired flow of gas, and a carbon dioxide meter is arranged to measure the concentration of carbon dioxide in expired gas. Arranging the carbon dioxide meter in the ventilator/anaesthetic unit minimizes the equipment which must be located in the immediate vicinity of patient, and a faster, more sensitive carbon dioxide meter thus can be used.

Abstract: In conjunction with the diagnosis of conditions in and treatment of the lungs, a small amount of NO is supplied to the lungs in some cases. A gas mixture for this purpose is disclosed in which an inert, non-toxic trace gas is present in an exact concentration in relation to NO, in order to simply and safely control the amount of NO then supplied to the lungs. The amount of NO supplied can be determined by determining the concentration of the trace gas. A method and device for administering breathing gas to a patient together with the aforementioned gas mixture are also disclosed.

Abstract: In a method for supplying fresh gas in manual ventilation of a patient and in a ventilator system for practicing the method, the supply of fresh gas to a breathing bag is regulated. During inspiration, the breathing bag is squeezed, imposing an inspiration on the patient. A detector at the breathing bag senses when the patient exhales, and an identical flow of gas is fed to the system via an inspiratory valve, the flow of fresh gas is directed into the breathing bag and expired gas is prevented from entering the breathing bag. An expiratory valve simultaneously opens to conduct expired gas out of the system.

Abstract: A method and apparatus for the re-use of anesthetic gases which are not absorbed by a patient, in inhalation anesthesia make use of an adsorption filter during exhalation, the unused anesthetic gases being subsequently desorbed from the adsorption filter during inhalation, and being reintroduced into the respiration flow to the patient. The exhaled gas is supplied through an absorber for carbon dioxide before it is re-supplied to the patient. The apparatus includes a common line for the delivery and discharge of anesthesia and respiration gases to and from a patient. An adsorption filter for adsorption and desorption of anesthetic gases is arranged in this line.

Abstract: A method and apparatus for independent monitoring of a flow-through quantity and, potentially, of a concentration of a gas flow that is extremely small in comparison to a respiratory gas flow is provided. The valve for the control of this small gas flow can not be controlled via the overall gas flow. In order to be able to simply and reliably monitor the flow-through quantity and the concentration of this small gas flow without a gas analyzer and independently of gas flow regulators that are usually present, it is provided that the small gas flow be separately measured and compared to a value derived from the respiratory gas flow. Given the presence of prescribable criteria, an alarm is triggered and the flow-through quantity of the small gas flow is, for example, interrupted.

Abstract: This invention comprises a respirator intended for connection to human or animal airways. A first device for supplying and receiving respiratory gas to and from the airways so that the lungs can be ventilated is combined with a second devices that provides a valve-regulated separate supply of gas to the airways independently of the respiratory gas flow provided by the first device. The second device incorporates at least one line used to supply gas under pressure. Furthermore there are a number of valves connected in parallel to this line, which provide a pulsating gas supply, and a control unit that can be used to control at least some of the gas pulse characteristics.

Abstract: A ventilator to be connected to the airways of a human or an animal includes several functional units, each functional unit being controlled and/or supervised by a separate microprocessor. At least one of the functional units has an analog control unit whereby the microprocessor only compensates for the coarseness in the regulating function of the analog control unit to increase the accuracy. This makes the ventilator efficient, accurate and safe.

Abstract: In a method and apparatus for reducing rebreathing of gas from the dead space (i.e., the volume of used gas, which during expiration has filled the airways and is brought back to the alveus at the following inspiration), at least during the final phase of expiration, a flow of used breathing gas is artificially evacuated from the patient through a gas conduit inserted into the patient's airway, the flow rate of evacuated gas being greater than the flow rate of the expiration gas which is being exhaled by the patient at the time. A flow of breathable gas is simultaneously supplied to the patient through gas conduit inserted in the airway, which may be the same conduit as is used for evacuation or a different conduit.

Abstract: A respirator has a bypass gas flow and respective valves in the inspiration and expiration lines for setting the gas flow through these lines. A control unit actuates the valves so that a respiratory cycle is produced and such that the bypass gas flow is maintained during expiration. The expiration pressure is identified by a pressure sensor. When this expiration pressure falls below a prescribed value, a new inspiration phase is triggered. To improve this triggering, the patient gas flow is identified by a flow meter, and the prescribed pressure value is varied dependent on the identified patient gas flow.

Abstract: A device for displaying a parameter value has at least one row of light-emitting diodes in which each light-emitting diode has a position input, and the device has a control circuit with address outputs connected to the position inputs. Faults, such as a short-circuit can be detected more easily by an improved interconnection of the address outputs and position inputs such that two adjacent address outputs are connected to two position inputs physically separated by at least one position input.

Abstract: In a respirator having an inspiration gas flow controlled by the expiration gas flow, in order to avoid triggering difficulties, particularly in the neonatal respiration therapy, the respirator is controlled such that a continuous gas flow flows through the inspiration and expiration lines. The gas flow is measured in the inspiration line by a gas flow sensor. The measured signal from the gas flow sensor is used to control a valve in the inspiration line, or a common line connected to the inspiration and expiration lines so that a constant gas flow is maintained in the expiration line.

Abstract: A ventilator for supplying and emitting respiratory gas to and from the airways of a human or an animal patient has a multiple-function safety valve located between a 10 control valve and the airways. The safety valve is biased in its closing direction by two springs, which apply force that corresponds to a predetermined overpressure, and is biased in its opening direction by a spring loaded piston, which applies force that exceeds the force of the springs. When electrical power is supplied to the ventilator, an electromagnet is energized. The electromagnet pulls the piston against the force of its spring load, and the safety valve closes. By means of a control device, the pressure in an inspiration section of the ventilator can be monitored and the electromagnet is disconnected at a programmed overpressure. In the event of a power failure, the safety valve will open and air can pass through the open safety valve to the airways.

Abstract: A knob assembly is disclosed for a control unit of a medical apparatus with a front panel. In order to transfer a turning setting movement through the front panel, a feed-through sleeve is rotatably arranged in the front panel and a knob core is movably arranged in the feed-through sleeve. On the control side of the front panel the feed-through sleeve and the knob core are enclosed by a manipulable element which, through application of pressure, can axially move the knob core in the feed-through sleeve. The knob core on the back side of the front panel moves a resilient locking washer from a locking position to an unlocked position so that turning of the manipulable element also will turn the feed-through sleeve. To improve the sealing at the feed-through location, the front panel is provided with a protection plate which is beaded outwards and surrounding the feed-through sleeve, with the manipulable element tightly enclosing the beaded protection.

Abstract: An apparatus, such as a ventilator, for regulating the flow-through amount of a flowing medium, such as a gas, has a valve with a variable orifice operated by a first regulating circuit with negative feedback. The regulating variable generated by the first regulating circuit controls the size of the orifice so that the difference between a desired value and an actual value for the flow-through amount os minimized, toward zero. To achieve rapid changes in the flow-through amount with a high regulating precision, at least one further regulating circuit is provided to which the regulating variable of the first regulating circuit is supplied as the desired value. The actual value for the further regulating circuit may be the measured position of the closure element for the orifice. The bandwidth and the gain can be optimized for each regulating circuit. The energy consumption can be lowered by current recovery and battery operation can be simplified, in the event of a power outage.

Abstract: An apparatus for the administration of a respiratory gas and at least one anaesthetic to a living being, in which apparatus the anaesthetic is vaporized in a vaporizing unit and is entrained in respiratory gas, acquires a safer and more accurate control of the anaesthetic concentration level by means of a regulating valve which controls the flow of respiratory gas through the vaporizing unit and in that a regulating device controls the regulating valve with such accuracy that a preselected concentration of vaporized anaesthetic in the respiratory gas is substantially fully maintained. To further increase the control of the apparatus it may also be provided with a feedback system for both the anaesthetic concentration level and the total flow.

Abstract: Equipment for administering gaseous anesthetic to a patient has at least one anesthetic reservoir serving as the originating source for anesthetic and a ventilator to which the gas is supplied from the reservoir, the ventilator being in communication with the breathing passages of a patient. To maintain the consumption of anesthetic gas as low as possible and to also assure that the patient is constantly ventilated with fresh anesthetic gas having a defined consumption, the exhalation gas from the patient is fed back to the originating anesthetic source via at least one filter in which predetermined gas components, such as water vapor and carbon dioxide are filtered out. The exhalation gas may be returned to the originating source either directly or through a compressor.