Abstract: A method and apparatus for filtering an electromyogram (EMG) signal from a raw signal which includes a contribution from an electrocardiogram (EKG) signal is disclosed. The method includes the steps of estimating an attribute (such as a Fourier transform) of both the EMG contribution to the raw signal and the EKG contribution to the raw signal and, dependent on both frequency spectrums, determining an EMG window in a frequency range and obtaining the EMG signal by passing it through a filter defined by the frequency range. The method is particularly used when monitoring a multi-channel electrical recording from a plurality of electrodes attached to a patient's diaphragm.

Abstract: In a method, device and computer program product for extracting an EMG signal out of a raw signal obtained with a number of electrodes, the electrodes being adapted to interact with a patient to obtain signals from the patient's diaphragm on respective channels associated with the electrodes, a signal-to-noise-ratio is determined for the raw signal in each channel, and a weighting factor is automatically determined dependent on the signal-to-noise ratio. The respective raw signals from the channels are weighted according to the weighting factors, and are summed in order to generate a sum signal that represents the total EMG signal contained in all of the raw signals.

Abstract: In a method and device for positioning a linear array of electrodes mounted on a distal end section of an elongated flexible member in a patient's respiratory airways at the level of the patient's diaphragm, a length of the elongated flexible member pre-determined to position the linear array of electrodes at the level of the patient's diaphragm is inserted through the patient's respiratory airways. Signals representative of an electrical activity of the patient's diaphragm (EAdi) are detected through the electrodes of the linear array, a presence or absence of ECG signal components is detected in the EAdi signals, and the position of the linear array of electrodes in the patient's respiratory airways is detected in response to the presence or absence of the ECG signal components in the EAdi signals.

Abstract: A control unit for a ventilator is arranged to receive, from each of a number of electrode pairs on an esophageal catheter a bioelectric signal having an ECG component. The control unit has a calculating unit that determines the ECG component of each of the bioelectric signals and a position unit that determines the position of the catheter in relation to the patient's diaphragm based on a comparison the amplitudes of ECG components of the bioelectric signals.

Abstract: A ventilator intended to be connected to a patient for breathing therapy has a control unit having an input for receiving EMG signals from an EMG detector and an output for an EMG based control signal and a pneumatic unit for generating breathing gas flows dependent on the EMG based control signal is described. The ventilator has a detector for determining a parameter related to breathing dynamics for the patient, this detector being connected to the control unit and control unit controlling the pneumatic unit dependent on the parameter related to breathing dynamics in the case of loss of EMG signals at the input.

Abstract: Function testing of a ventilator using an EMG or other bioelectric signal representative of the breathing of the patient to control ventilation is enabled by a simulating device for use with a breathing related device for monitoring and/or controlling a patient's breathing, the simulating device including a signal generator for providing a simulated bioelectric compound signal related to the patient's breathing function, and a contact for outputting the simulated bioelectric compound signal. The simulating device can also be used for training purposes and in the development of new ventilators.

Abstract: In a method, device and computer program product for filtering an EMG-signal out of a raw signal, obtained via a number of electrodes that are designed to be placed to detect signals from a diaphragm and that are functionally, respectively connected to signal channels, an EKG-signal and an EMG-signal are estimated out of the raw signal and, dependent on the estimated EKG signal and the estimated EMG signal, a window in a frequency region is determined within which the EMG signal is filtered out of the raw signal.

Abstract: In a method, device and computer program product for extracting an EMG signal out of a raw signal obtained with a number of electrodes, the electrodes being adapted to interact with a patient to obtain signals from the patient's diaphragm on respective channels associated with the electrodes, a signal-to-noise-ratio is determined for the raw signal in each channel, and a weighting factor is automatically determined dependent on the signal-to-noise ratio. The respective raw signals from the channels are weighted according to the weighting factors, and are summed in order to generate a sum signal that represents the total EMG signal contained in all of the raw signals.

Abstract: A valve assembly has a valve opening which can be sealed and un-sealed by movement of a membrane 6, a force generator, such as an electromagnetic force generator having a solenoid and armature arrangement, and a shaft that is operably connected to the membrane and which is movable along a movement axis under the influence of the generated force to move the membrane and thereby regulate the degree of opening of the valve. Bearing assemblies are provided to procure a magnetic suspension of the shaft, permit its movement along the axis, and also to optionally produce a magnetic biasing of the shaft in a direction along the axis, particularly in the absence of a generated force.

Abstract: A feedback controller for regulating respiratory gas in a mechanical breathing aid system has a comparator means for periodically generating, in a current breathing cycle, an error signal representing the difference between a value of a gas parameter measured for gas within the system and a target value of the gas parameter, and a control signal generator for processing the error signal in accordance with a control function to generate a control signal usable in the regulation of the respiratory gas. The controller has a variable value integral gain stage which provides an input to an integrator element. An adaption unit determines, for the current breathing cycle an extreme value of the periodically generated error signal and varies the value of the integral gain used in the integral gain stage for a next breathing cycle dependent on a rate of change of the value of the extreme error signal with value of the integral gain.

Abstract: A valve assembly HAS an element movable in a mechanical journal arrangement relative to a valve opening to establish an opening position of a valve, and A control unit for controlling the application of an oscillatory electromagnetic force to the element (8) having an known peak amplitude to cause the element to execute a sympathetic oscillatory motion as a friction reducing maneuver. The control unit is adapted to control the peak amplitude of the oscillatory electromagnetic force to sequentially apply a number of different peak amplitudes, each during a different measurement period. A monitor detects changes in the opening position of the valve during each of the measurement periods and provides a measure thereof. A processor is connected to the control unit and to the monitor to determine a working amplitude of the oscillatory electromagnetic force at which the detected changes will be minimized and to supply the determined working amplitude to the control unit.

Abstract: A valve assembly has a valve opening which can be sealed and un-sealed by movement of a membrane 6, a force generator, such as an electromagnetic force generator having a solenoid and armature arrangement, and a shaft that is operably connected to the membrane and which is movable along a movement axis under the influence of the generated force to move the membrane and thereby regulate the degree of opening of the valve. Bearing assemblies are provided to procure a magnetic suspension of the shaft, permit its movement along the axis, and also to optionally produce a magnetic biasing of the shaft in a direction along the axis, particularly in the absence of a generated force.

Abstract: A valve assembly HAS an element movable in a mechanical journal arrangement relative to a valve opening to establish an opening position of a valve, and A control unit for controlling the application of an oscillatory electromagnetic force to the element (8) having an known peak amplitude to cause the element to execute a sympathetic oscillatory motion as a friction reducing maneuver. The control unit is adapted to control the peak amplitude of the oscillatory electromagnetic force to sequentially apply a number of different peak amplitudes, each during a different measurement period. A monitor detects changes in the opening position of the valve during each of the measurement periods and provides a measure thereof. A processor is connected to the control unit and to the monitor to determine a working amplitude of the oscillatory electromagnetic force at which the detected changes will be minimized and to supply the determined working amplitude to the control unit.

Abstract: In a method for controlling an expiratory valve in a ventilator during expiration, including a stage in which the expiratory valve is opened almost completely for a first interval. Opening the expiratory valve almost completely results in a reduction in expiratory resistance. Thus in the first interval of flow or pressure in the expiratory part of the ventilator, a determination is made when the flow or pressure in the expiratory part meets a condition. A second interval is started when the flow in the expiratory part meets the condition and the expiratory valve is regulated during the second interval in order to attain a pre-set end pressure in the expiratory section.

Abstract: An apparatus for supplying a breathing gas to a patient has a gas supply for generating a flow of breathable gas during an inspiration and an expiration phase of a patient breathing cycle. An inspiration line is provided having an inlet through which a flow of breathing gas from the supply can pass as well as an expiration line through which an expiration gas from the patient can flow. A flow controller is provided for selecting, during an inspiration phase, a first flow path for gas from the supply into the inlet and for selecting, during the expiration phase, a second flow path for gas from the supply in a direction across a venturi outlet of the expiration line, to enhance removal of expiration gas therefrom by venturi suction.

Abstract: In a method for controlling an expiratory valve in a ventilator during expiration, the expiratory valve is opened substantially fully for a first interval. Fully opening the expiratory valve has the advantage of minimizing the expiratory resistance a patient needs to overcome. Keeping the expiratory valve open as long as possible during expiration, without losing control of positive end expiratory pressure (PEEP), is therefore advantageous. An optimal system is achieved. In a method wherein pressure in the expiratory section of the ventilator is measured during a second interval, the expiratory valve is regulated so a predetermined end pressure is obtained in the expiratory section, and at least one parameter, directly or indirectly related to control of the expiratory valve, is determined, and a determination is made from that parameter as to whether the next first interval for the next expiration should be longer than, shorter than or as long as the first interval.

Abstract: A device for compensating for flow resistance in an expiratory section of a ventilator system has a bellows system whose increase in volume during expiration is regulated by a regulatory device and a control unit, so that expired gas fills the bellows system. The increase in volume is regulated according to values measured for pressure so virtually complete compensation for flow resistance is attained. Pressure is measured with a first pressure gauge located by the bellows system, and a second pressure gauge located by the patient. The device can be a separate apparatus which is connectable to a ventilator, or can be totally integrated into the ventilator.