Method and apparatus for maintaining a defined respiratory gas flow pattern to a subject by identifying a transfer function of the connection system
First Claim
1. A method for regulating the supply of breathing gas to and the removal of expired gas from the respiratory system of a subject in a ventilator system having a ventilator unit connectable to the respiratory system of the subject, said method comprising the steps of:
- connecting a connection system to said ventilator unit, said connection system having a transfer function associated therewith identifying an influence of said connecting system on gas pressure and gas flow in said connection system;
setting a test gas flow pattern in said ventilator unit and supplying gas with said test flow pattern to said connection system;
measuring a response gas flow pattern arising from said test gas flow pattern;
determining said transfer function from said test gas flow pattern and said response gas flow pattern;
selecting a therapeutic gas flow pattern; and
setting a compensated gas flow pattern at said ventilator unit, dependent on said transfer function, for producing said selected therapeutic gas flow pattern, via said connection system, at said respiratory system of said subject.
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Accused Products
Abstract
A ventilator system has different sub-systems, such as a connection system, which influence the flow of breathing gas supplied to a patient'"'"'s respiratory system. The flow pattern of the breathing gas is particularly influenced by the connection system. In order to compensate for this influence to the greatest possible extent in the generation of breathing gas, the connection system'"'"'s transfer function is determined before the system is connected to the respiratory system. A gas flow with a specific gas flow pattern is generated with high accuracy in a ventilator unit. An ensuing gas flow pattern, only influenced by the connection system, is measured with high accuracy in a measurement unit in the ventilator unit. The transfer function for the connection system can be determined in a control unit from the known, generated gas flow pattern and the measured, ensuing gas flow pattern. The corresponding determination can be made for the respiratory system after a patient has been connected.
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Citations
20 Claims
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1. A method for regulating the supply of breathing gas to and the removal of expired gas from the respiratory system of a subject in a ventilator system having a ventilator unit connectable to the respiratory system of the subject, said method comprising the steps of:
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connecting a connection system to said ventilator unit, said connection system having a transfer function associated therewith identifying an influence of said connecting system on gas pressure and gas flow in said connection system; setting a test gas flow pattern in said ventilator unit and supplying gas with said test flow pattern to said connection system; measuring a response gas flow pattern arising from said test gas flow pattern; determining said transfer function from said test gas flow pattern and said response gas flow pattern; selecting a therapeutic gas flow pattern; and setting a compensated gas flow pattern at said ventilator unit, dependent on said transfer function, for producing said selected therapeutic gas flow pattern, via said connection system, at said respiratory system of said subject. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for regulating the supply of breathing gas to and the removal of expired gas from the respiratory system of a subject in a ventilator system having a ventilator unit and a connection system connectable to a subject'"'"'s respiratory system said connection system having a transfer function associated therewith identifying an influence of said connection system on gas pressure and gas flow in said connection system, said apparatus comprising:
means for setting a test gas flow pattern in said ventilator unit and for supplying gas with said test flow pattern to said connection system; means for measuring a response gas flow pattern arising from said test gas flow pattern; means for determining said transfer function from said test gas flow pattern and said response gas flow pattern; means for selecting a therapeutic gas flow pattern; and means for setting a compensated gas flow pattern at said ventilator unit, dependent on said transfer function, for producing said selected therapeutic gas flow pattern, via said connection system, at a subject'"'"'s respiratory system. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method for determining at least one mechanical lung parameter of a respiratory system of a subject in a ventilator system having a ventilator unit connectable to the respiratory system of the subject, said method comprising the steps of:
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connecting a connection system to said ventilator unit, said connection system having a transfer function associated therewith identifying an influence of said connection system on gas pressure and gas flow in said connection system; setting a test gas flow pattern in said ventilator unit and supplying gas with said test gas flow pattern to said connection system; measuring a response gas flow pattern arising from said test gas flow pattern; determining said transfer function from said test gas flow pattern and said response gas flow pattern; connecting said connection system to the respiratory system of the subject; supplying a second test gas flow pattern from said ventilator unit to the subject'"'"'s respiratory system via said connection system; measuring a second response gas flow pattern arising from said second test gas flow pattern; determining said mechanical lung parameter from said second gas flow pattern, said second response gas flow pattern and said transfer function. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification