Process and device for controlling the breathing gas supply

#The present invention pertains to a process for controlling at least one parameter of the breathing gas supply of a respirator with a patient connected to it as well as to a corresponding control device.

#The parameters of breathing gas supply by the respirator, e.g., the respiration pressure, the breathing gas flow or the respiration rate, are usually set in advance and are then checked for their validity at greater time intervals. If the patient's respiration need changes, this is then taken into account during the treatment when the parameters of the breathing gas supply are correspondingly adapted after a recent check of the respiration need. A breathing gas supply is therefore obtained that may not be oriented uninterruptedly on the patient's current needs.

#DE 198 08 543 C2 discloses a process by which the mechanical properties compliance, resistance and, finally, the muscle pressure of the respiratory system of a patient can be determined during both spontaneous breathing and mechanical respiration, and the patient's breathing is disturbed only minimally. The compliance is the quotient of the displaced breathing gas volume and the change in the airway pressure, and the resistance is the quotient of the change of the airway pressure and the change in the breathing gas flow. The muscle pressure is defined as the percentage of the airway pressure caused by the patient's own effort. This process makes it possible to perform the continuous determination of the muscle pressure of the patient and thus to monitor the intensity of his spontaneous breathing. An occlusion, during which the respiration or spontaneous breathing of the patient is interrupted by closing corresponding valves on a respiration tube leading to the patient, is brought about for this purpose for a short time at different points in time during the individual breathing strokes. The mechanical properties of the lungs can be determined from the measured values for the airway pressure and the breathing gas flow. The muscle pressure is in turn determined from these variables.

#In the drawings:

#The FIGURE shows a respirator, with which the process according to the present invention can be carried out.

#Referring to the drawings in particular, the FIGURE shows a respirator, with which the process according to the present invention can be carried out. A ventilator 100 supplies a patient 300 connected to the respirator with breathing gas. A brief disturbance in the breathing gas supply, brought about, e.g., by occlusion of the airways, is carried out by a disturbance device or disturbing means 101 in the expiration branch of the respirator. A first sensor 200, which measures the airway pressure PAW, is arranged in the respirator. The breathing gas flow d/dt V is measured by a second sensor 201, which is likewise arranged in the respirator. The values measured by the first sensor 200 and the second sensor 201 are sent to an evaluating and control unit 800. The resistance RL and the compliance C of the patient's lungs are first calculated there from the measured values, and the airway pressure PAWC is subsequently calculated. The evaluating and control unit 800 compares the calculated airway pressure PAWC with the airway pressure PAW actually measured by the first sensor 200. If the muscle pressure PMUS=PAWC−PAW is positive, the ventilator 100 is actuated by the evaluating and control unit 800 such that the respiration pressure is increased. If PMUS=PAWC−PAW is negative, the respiration pressure generated by the ventilator 100 is reduced. The respiration pressure is maintained only when the muscle pressure PMUS is close to zero.

#While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.