Apparatus and process for anesthetizing a patient

A ventilation arrangement for artificial ventilation of a patient that is at least temporarily connected to a patient-side coupling unit, the ventilation arrangement comprising:

• a ventilator configured to perform a sequence of ventilation strokes and to expel with each ventilation stroke a respective quantity of a breathable gas mixture comprising oxygen;
• a signal-processing control unit;
• and
• a gas mixture supply unit,
• wherein the ventilation arrangement provides a ventilation circuit and is configured to guide the respective quantity of breathable gas mixture expelled in each ventilation stroke in the ventilation circuit to the patient-side coupling unit,
• wherein the ventilation arrangement is configured to guide a quantity of a gas mixture exhaled by the patient from the patient-side coupling unit in the ventilation circuit to the ventilator,
• wherein the gas mixture supply unit is configured to expel an additional gas mixture,
• wherein the ventilation arrangement is configured to guide the expelled additional gas mixture to a feed point and at the feed point into the ventilation circuit,
• wherein the control unit is configured to capture a specification specifying that the gas mixture supply unit is to expel the additional gas mixture at a target volume flow specified by the specification,
• wherein the control unit is configured, in response to capturing the specification, to predict a propagation duration depending on the specified target volume flow, the propagation duration being the time span beginning at a time at which the gas mixture supply unit expels the additional gas mixture in accordance with the captured specification and ending at a time at which that the expelled additional gas mixture reaches the feed point,
• wherein the control unit is configured, depending on the predicted propagation duration, to control the gas mixture supply unit such that the controlled gas mixture supply unit expels the additional gas mixture, in accordance with the captured specification, such that the additional gas mixture reaches the feed point within an expiration phase and/or within an intermediate phase,
• wherein an expiration phase is a period during which an exhaled gas mixture flows from the patient-side coupling unit to the ventilator, but no breathable gas mixture flows due to a ventilation stroke from the ventilator to the patient-side coupling unit, and
• wherein an intermediate phase is a period during which no breathable gas mixture flows due to a ventilation stroke from the ventilator to the patient-side coupling unit and no exhaled gas mixture flows from the patient-side coupling unit to the ventilator.