Method for controlling a bi-level apparatus, and bi-level apparatus
First Claim
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1. A method for controlling a bi-level apparatus, comprising:
- using a flow sensor to repeatedly measure an airflow thereby obtaining measured airflow values;
choosing an expiration threshold value;
choosing an inspiration threshold value;
using a processor to repeatedly compare said airflow values with said expiration threshold value during an expiration mode;
switching to an inspiration mode if an airflow value is greater than said expiration threshold value in a comparison with said expiration threshold value;
using the processor to repeatedly compare said airflow values with said inspiration threshold value during said inspiration mode; and
using the processor to switch to said expiration mode if the airflow value is smaller than said inspiration threshold value in a comparison with said inspiration threshold value, wherein the processor performs the steps of;
storing a minimum airflow during said expiration mode;
choosing said inspiration threshold value equal to said stored minimum airflow immediately after switching to said inspiration mode;
storing a maximum airflow during said inspiration mode; and
choosing said expiration threshold value equal to said stored maximum airflow immediately after switching to said expiration mode, wherein during a time span shortly after said switching to said inspiration mode up to the end of said inspiration mode, said inspiration threshold value is chosen by the processor to be equal to a difference of a maximum of said airflow during said current inspiration phase minus a predetermined value.
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Abstract
This invention relates to a method for controlling a bi-level apparatus. The method includes repeatedly measuring an airflow, choosing an expiration threshold value and choosing an inspiration threshold value. Switching to an inspiration mode takes place if the airflow is greater than the expiration threshold value in a comparison with the expiration threshold value. A switching back to the expiration mode takes place if the airflow is smaller than the inspiration threshold value in a comparison with the inspiration threshold value. Moreover, the invention relates to a bi-level apparatus for performing the method.
25 Citations
25 Claims
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1. A method for controlling a bi-level apparatus, comprising:
- using a flow sensor to repeatedly measure an airflow thereby obtaining measured airflow values;
choosing an expiration threshold value;
choosing an inspiration threshold value;
using a processor to repeatedly compare said airflow values with said expiration threshold value during an expiration mode;
switching to an inspiration mode if an airflow value is greater than said expiration threshold value in a comparison with said expiration threshold value;
using the processor to repeatedly compare said airflow values with said inspiration threshold value during said inspiration mode; and
using the processor to switch to said expiration mode if the airflow value is smaller than said inspiration threshold value in a comparison with said inspiration threshold value, wherein the processor performs the steps of;
storing a minimum airflow during said expiration mode;
choosing said inspiration threshold value equal to said stored minimum airflow immediately after switching to said inspiration mode;
storing a maximum airflow during said inspiration mode; and
choosing said expiration threshold value equal to said stored maximum airflow immediately after switching to said expiration mode, wherein during a time span shortly after said switching to said inspiration mode up to the end of said inspiration mode, said inspiration threshold value is chosen by the processor to be equal to a difference of a maximum of said airflow during said current inspiration phase minus a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- using a flow sensor to repeatedly measure an airflow thereby obtaining measured airflow values;
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13. A respiratory apparatus, comprising:
- a fan;
a pressure sensor for determining an overpressure under which air is provided by said fan;
a flow sensor for measuring an airflow;
a processor connected to said pressure sensor and said flow sensor, to which a pressure signal is fed from said pressure sensor and an airflow signal from said flow sensor, said processor storing a sequence of instructions and being suitable for executing said instructions, said processor performing the following when executing said instructions;
repeatedly obtaining measured airflow values from said airflow signal;
choosing an expiration threshold value;
choosing an inspiration threshold value;
repeatedly comparing said airflow values with said expiration threshold value during an expiration mode;
switching to an inspiration mode if an airflow value is greater than said expiration threshold value in a comparison with said expiration threshold value;
repeatedly comparing said airflow values with said inspiration threshold value during said inspiration mode; and
switching to said expiration mode if the airflow value is smaller than said inspiration threshold value in a comparison with said inspiration threshold value, wherein the processor is adapted for storing a minimum airflow during said expiration mode;
choosing said inspiration threshold value equal to said stored minimum airflow immediately after switching to said inspiration mode;
storing a maximum airflow during said inspiration mode; and
choosing said expiration threshold value equal to said stored maximum airflow immediately after switching to said expiration mode, wherein during a time span shortly after said switching to said inspiration mode up to the end of said inspiration mode, said inspiration threshold value is chosen to be equal to a difference of a maximum of said airflow during said current inspiration phase minus a predetermined value. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
- a fan;
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25. A respiratory apparatus, comprising:
- a fan;
a pressure sensor for determining an overpressure under which air is provided by said fan;
a flow sensor for measuring an airflow; and
means for processing a pressure signal from said pressure sensor and an airflow signal from said flow sensor, said processing means repeatedly obtaining measured airflow values from said airflow signal;
choosing an expiration threshold value;
choosing an inspiration threshold value;
repeatedly comparing said airflow values with said expiration threshold value during an expiration mode;
switching to an inspiration mode if an airflow value is greater than said expiration threshold value in a comparison with said expiration threshold value;
repeatedly comparing said airflow values with said inspiration threshold value during said inspiration mode; and
switching to said expiration mode if the airflow value is smaller than said inspiration threshold value in a comparison with said inspiration threshold value, wherein the processing means is adapted for storing a minimum airflow during said expiration mode;
choosing said inspiration threshold value equal to said stored minimum airflow immediately after switching to said inspiration mode;
storing a maximum airflow during said inspiration mode; and
choosing said expiration threshold value equal to said stored maximum airflow immediately after switching to said expiration mode, wherein during a time span shortly after said switching to said inspiration mode up to the end of said inspiration mode, said inspiration threshold value is chosen to be equal to a difference of a maximum of said airflow during said current inspiration phase minus a predetermined value.
- a fan;
Specification