DETERMINATION OF LEAK DURING CPAP TREATMENT
First Claim
1. A method of determining a mask leak conductance in a patient respiratory device, comprising the steps ofdetermining a first estimate of leak conductance which responds relatively quickly to changes in leak conductance,determining a second estimate of leak conductance which responds more slowly to changes in leak conductance, anddetermining the mask leak conductance as a function of the first and second estimates of leak conductance.
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Accused Products
Abstract
In a CPAP or positive pressure ventilation system, leak is determined at each instant by a lookback for a time as long as single breath to establish the start of an averaging window over which low-pass filtered values used in the determination of a parameter of a leak model are averaged. A jamming index indicates whether the leak is rapidly changing. To the extent that jamming is high, the leak estimate used progressively changes from that using sliding breath-window averaging to a more robust and faster responding low-pass filter method, and adjustment of ventilatory support based on measures employing estimated respiratory flow is slowed down or stopped.
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Citations
12 Claims
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1. A method of determining a mask leak conductance in a patient respiratory device, comprising the steps of
determining a first estimate of leak conductance which responds relatively quickly to changes in leak conductance, determining a second estimate of leak conductance which responds more slowly to changes in leak conductance, and determining the mask leak conductance as a function of the first and second estimates of leak conductance.
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9. A method of providing ventilatory support to a patient, comprising the steps of:
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determining a jamming index indicative of an extent to which non-deliberate leak is uncompensated; adjusting a level of ventilatory support in accordance with said jamming index. - View Dependent Claims (11)
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12. A system of providing ventilatory support to a patient, comprising the steps of:
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determining a jamming index indicative of an extent to which non-deliberate leak is uncompensated; adjusting a level of ventilatory support in accordance with said jamming index.
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Specification