摘要:
An electroimpedance tomograph with a plurality of electrodes (1) is provided, which can be placed on the body of a patient and are connected via a selector switch (60) with a control and evaluating unit (20). The control and evaluating unit (20) cooperates with the selector switch (60) such that two electrodes each are supplied with an alternating current from an AC power source (22) and the detected analog voltage signals of the other electrodes are processed in order to reconstruct therefrom the impedance distribution of the body in the plane of the electrodes, wherein a symmetrical AC power source is used to reduce common-mode signals. To further suppress interferences due to common-mode signals, provisions are made for the control and evaluating unit (20) to be set up, furthermore, for detuning the common-mode signal of the alternating current on the body against the ground by means of a common-mode signal measuring electrode (4) and, based on this, the symmetry of the symmetrical AC power source such that the common-mode signal on the body is minimized, and the corresponding detuning parameters are stored for each electrode pair.
摘要:
An electroimpedance tomograph is provided with a plurality of electrodes (1), which can be placed on the body of a patient and are connected to a control and evaluating unit (20) via a selector switch (60). The control and evaluating unit (20) cooperates with the selector switch (60) such that two electrodes each are supplied with alternating current from an AC power source (22). The detected analog voltage signals of the other electrodes are sent into the control and evaluating unit (20) via a measuring amplifier (62) and AD converter (64) and are processed there in order to reconstruct the impedance distribution of the body in the plane of the electrodes therefrom. A symmetrical AC power source (22) is used to reduce common-mode signals. To make it possible to suppress errors due to common-mode signals, provisions are made for the control and evaluating unit (20) to be set up for making available an additional common-mode signal at an output during an adjusting mode of operation and to send it to the body via common-mode signal electrodes (4, 90) that can be placed on the body. The control and evaluating unit (20) is prepared, furthermore, to adjust the measuring amplifier (62) according to value and phase for each electrode pair connected by the selector switch (60) such that the common-mode signal at the output of the measuring amplifier (62) is minimized, and the adjusted parameters are stored for each electrode pair.
摘要:
A device and a process for determining the change in the functional residual capacity (FRC) in a simple manner. Based on a first respiration phase for mechanical respiration, a recruitment maneuver is performed for this during a second respiration phase, and respiration is switched back to mechanical respiration during a third respiration phase. Reference values Uref/1, Uref/3 are formed from the end-expiratory values of the impedance measured signals U during the first respiration phase and the third respiration phase, and the difference ΔU (ΔFRC) between the reference value Uref/3 of the third respiration phase and the reference value Uref/1 of the first respiration phase is an indicator of the change in the functional residual capacity of the lung of the test subject.
摘要:
A device for supplying a patient with breathing gas, in which an initially high initial pressure Paw(t=0) applied from the outside is automatically lowered by means of a control circuit to a lower inspiratory pressure Paw(t) as soon as a pulmonary internal pressure Plung(t) threatens to exceed a predetermined pulmonary target pressure Plung,soll. Overinflation of the lungs due to the respiration is thus ruled out according to the present invention. The device permits, moreover, rapid filling of the lungs with breathing gas and makes thus possible a comparatively long phase of expiration. A process is also provided for regulating a respirator and for respirating a patient.
摘要:
A device for supplying a patient with breathing gas, in which an initially high initial pressure paw(t=0) applied from the outside is automatically lowered by means of a control circuit to a lower inspiratory pressure paw(t) as soon as a pulmonary internal pressure plung(t) threatens to exceed a predetermined pulmonary target pressure plung,soll. Overinflation of the lungs due to the respiration is thus ruled out according to the present invention. The device permits, moreover, rapid filling of the lungs with breathing gas and makes thus possible a comparatively long phase of expiration. A process is also provided for regulating a respirator and for respirating a patient.
摘要:
Operating a respirator with an inspiration pressure-vs.-time curve (1), which has an airway target pressure (paw—target) and a PEEP (3), in which the inspiration pressure-vs.-time curve (1) reaches the airway target pressure (paw—target) on a ramp-like curve (17) starting from a starting airway pressure (paw—Start), which is greater than the PEEP (3).
摘要:
A process with a corresponding device for lung ventilation involves recording an image of the lung status with an electric impedance tomography (EIT) system (2) and the total area of ventilated lung areas is determined by a computing unit (4) from all image values, subsequently divided into at least two lung areas and the extent of the homogeneity of the ventilated lung areas is determined by comparison of the impedance changes within these areas. In case of a homogeneity rated as being too low, the respiration pressures are increased step by step by means of the respirator (1) and the respiration pressure at which the greatest possible homogeneity is obtained from subsequently determined status images is determined by means of the EIT system (2). The respiration pressure is subsequently lowered again by the respirator (1) until the computing unit (4) detects a reduction in the homogeneity of ventilated lung areas, so that the respiration pressure is subsequently increased again by means of the respirator (1) to the last value at which no reduction in the homogeneity of the ventilated lung areas occurred.
摘要:
A method, system and device are provided for the determination of leaks in a respirator. An inspiraton pressure pinsp is recorded during an inspiration time Tinsp with a measuring device. The inspiration pressure pinsp is varied during consecutive breaths I. Leaks are determined as to leak volumes VLi from the product of pinspi and Tinspi in accordance with the equation VLi=A×pinspiB×Tinspi while the parameters A and B are determined in an analyzing unit by a regression model with pinsp as the regressor.
摘要:
The invention relates to a method for recognizing the respiratory phases of a patient for controlling a ventilating apparatus. The time-dependent trace of a signal, which represents the respiratory flow curve and is emitted by a signal device, is determined and from this trace, a trigger criterium is obtained for the switchover of the ventilating apparatus from the expiration phase into the inspiration phase and/or from the inspiration phase into the expiration phase. The method is improved in that even for chronically obstructive patients, a reliable and early recognition of the inspiration and expiration attempts is possible. A significant increase of the slope of the respiratory flow curve between each two zero crossovers of this curve is used as a trigger criterium.
摘要:
A respirator for breath-supporting respiration has improved sensitivity of triggering breathing support. A pre-inspiratory inspiratory gas flow is set, which flows off via the expiration valve (9). The closing pressure pv of the expiration valve is measured with a pressure sensor (11) in the process. The gas flow is increased in case of an inspiratory effort of the patient to the extent that the closing pressure pv of the expiration valve (9) is restored. Breath support is generated when the difference between the preset gas flow and the gas flow that is needed to maintain the closing pressure pv at a constant level exceeds a predetermined threshold value.