Control system and process for controlling the dispensing of fresh gas for an anesthesia device

Patent metadata

Field	Value
Publication number	US-11730911-B2
Application number	US-202016832028-A
Country	US
Kind code	B2
Filing date	Mar 27, 2020
Priority date	Mar 29, 2019
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A control system controls fresh gas dispensing for an anesthesia device, with a patient gas-measuring unit, an anesthetic-dispensing unit, a user interface, and a fresh gas regulation unit. With a transition from deactivated assistance mode to activated assistance mode, a processing unit receives a measured signal, a fresh gas signal and an assistance signal and calculates an end tidal anesthetic concentration over time based on a current volume flow, a predefined volume flow and on a current end tidal anesthetic concentration and stores this as a preset curve. A fresh gas correction signal is output upon the determined current end tidal anesthetic concentration leaving a surrounding range of the preset curve. A predefined volume flow curve is changed as a function of the correction signal. The volume flow of fed fresh gas is increased when the surrounding range is undershot and is reduced when the surrounding range is exceeded.

First claim

What is claimed is:

1. A control system for controlling a dispensing of a fresh gas for an anesthesia device, the control system comprising:
a gas measuring unit arranged in a breathing gas circuit of the anesthesia device and configured to determine an end tidal anesthetic concentration in the breathing gas circuit and to output a corresponding measured signal at regular time intervals;

an anesthetic dispensing unit configured to dispense an anesthetic in a fresh gas being fed to the breathing gas circuit;
a user interface configured to activate or deactivate an assistance mode of the control system when a corresponding user input is present and to output a corresponding assistance signal;
a fresh gas regulation unit arranged and configured to receive the assistance signal and, upon the assistance mode being activated, to regulate a reduction of a volume flow of the continuously fed fresh gas over time corresponding to a predefined volume flow curve, and to output a fresh gas signal at regular time intervals that indicates a current volume flow of the continuously fed fresh gas; and
a processing unit configured to receive the measured signal and the fresh gas signal and to determine therefrom the current volume flow of the fed fresh gas and the current end tidal anesthetic concentration in the breathing gas circuit and to receive the assistance signal and, upon the assistance signal indicating a transition from a deactivated assistance mode to an activated assistance mode based on the current volume flow, the predefined volume flow curve and the current end tidal anesthetic concentration, to calculate an expected future curve of the end tidal anesthetic concentration over time, and to output the expected future curve of the end tidal anesthetic concentration over time as a preset curve and to store the preset curve, wherein:

the processing unit is further configured to output a fresh gas correction signal at the fresh gas regulation unit as soon as the defined current end tidal anesthetic concentration in the breathing gas circuit leaves a surrounding range of the preset curve, which surrounding range is formed around the preset curve; and
the fresh gas regulation unit is further configured to receive the fresh gas correction signal and to change the predefined volume flow curve as a function of the fresh gas correction signal and to increase the volume flow of the continuously fed fresh gas upon the surrounding range being undershot and to reduce the volume flow of the continuously fed fresh gas when the surrounding range is exceeded compared to the predefined volume flow curve prior to the change, wherein the predefined volume flow curve comprises a degressive reduction of the volume flow over time.

2. A control system in accordance with claim 1 , further comprising an output unit signal connected to the processing unit, the output unit being configured to output the preset curve with the calculated expected future curve of the end tidal anesthetic concentration over time as a graphic view.

3. A control system in accordance with claim 1 , wherein the anesthetic dispensing unit is a manually controlled anesthetic dispensing unit configured to exclusively dispense anesthetic under manual control.

4. A control system in accordance with claim 1 , wherein:
the user interface is further configured to receive a fresh gas input and to output a corresponding fresh gas regulation signal; and
the fresh gas input comprises information about a minimal volume flow of the fresh gas to be fed to the breathing gas circuit, which minimal volume flow is to be provided by means of the fresh gas regulation unit.

5. A control system in accordance with claim 4 , wherein the fresh gas regulation unit is further configured to receive the fresh gas regulation signal and to select the predefined volume flow curve from a number of predefined volume flow curves based on the fresh gas regulation signal.

6. A control system in accordance with claim 1 , wherein:
the user interface is further configured to receive a limit concentration input and to output a corresponding limit concentration signal to the processing unit; and
the limit concentration input comprises information about a maximum end tidal anesthetic concentration to be provided to a patient to be supplied by the anesthesia device.

7. A control system in accordance with claim 6 , wherein:
the processing unit is further configured to output an additional fresh gas correction signal to the fresh gas regulation unit as soon as the defined current end tidal anesthetic concentration in the breathing gas circuit exceeds the maximum end tidal anesthetic concentration to be provided; and
the fresh gas regulation unit is further configured to reduce the originally predefined volume flow curve corresponding to the to the additional fresh gas correction signal, in response to the additional fresh gas correction signal.

8. An anesthesia device comprising a control system for controlling a dispensing of a fresh gas for an anesthesia device, the control system comprising:
a gas measuring unit arranged in a breathing gas circuit of the anesthesia device and configured to determine an end tidal anesthetic concentration in the breathing gas circuit and to output a corresponding measured signal at regular time intervals;
an anesthetic dispensing unit configured to dispense an anesthetic in a fresh gas being fed to the breathing gas circuit;
a user interface configured to activate or deactivate an assistance mode of the control system when a corresponding user input is present and to output a corresponding assistance signal;
a fresh gas regulation unit arranged and configured to receive the assistance signal and, upon the assistance mode being activated, to regulate a reduction of a volume flow of the continuously fed fresh gas over time corresponding to a predefined volume flow curve, and to output a fresh gas signal at regular time intervals that indicates a current volume flow of the continuously fed fresh gas; and
a processing unit configured to receive the measured signal and the fresh gas signal and to determine therefrom the current volume flow of the fed fresh gas and the current end tidal anesthetic concentration in the breathing gas circuit and to receive the assistance signal and, upon the assistance signal indicating a transition from a deactivated assistance mode to an activated assistance mode based on a current volume flow, the predefined volume flow curve and the current end tidal anesthetic concentration, to calculate an expected future curve of the end tidal anesthetic concentration over time, and to output the expected future curve of the end tidal anesthetic concentration over time as a preset curve and to store the preset curve, wherein:
the processing unit is further configured to output a fresh gas correction signal at the fresh gas regulation unit as soon as the defined current end tidal anesthetic concentration in the breathing gas circuit leaves a surrounding range of the preset curve, which surrounding range is formed around the preset curve; and
the fresh gas regulation unit is further configured to receive the fresh gas correction signal and to change the predefined volume flow curve as a function of the fresh gas correction signal and to increase the volume flow of the continuously fed fresh gas upon the surrounding range being undershot and to reduce the volume flow of the continuously fed fresh gas when the surrounding range is exceeded compared to the predefined volume flow curve prior to the change, wherein the predefined volume flow curve comprises a degressive reduction of the volume flow over time.

9. An anesthesia device in accordance with claim 8 , wherein: the

Assignees

• Draegerwerk Ag & Co Kgaa

Inventors

• Wruck Norbert
• Schmid Robert
• Pilz Ulf
• Wolansky Daniel

Classifications

• A61M16/104 Primary

  specially adapted for anaesthetics (A61M16/18 takes precedence) · CPC title

• A61M16/01

  specially adapted for anaesthetising {(A61M16/104, A61M16/18 take precedence)} · CPC title

• A61M16/18

  Vaporising devices for anaesthetic preparations · CPC title

• A61M2205/3379

  Masses, volumes, levels of fluids in reservoirs, flow rates · CPC title

• A61M2205/502

  User interfaces, e.g. screens or keyboards · CPC title