Ventilator patient synchronization
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Accused Products
Abstract
A method and apparatus that provides an expert system for determining respiratory phase during ventilatory support of a subject. Discrete phase states are partitioned and prior probability functions and observed probability functions for each state are defined. The probability functions are based upon relative duration of each state as well as the flow characteristics of each state. These functions are combined to determine phase probabilities for each state using Bayes'"'"' theorem. The calculated probabilities for the states may then be compared to determine which state the subject is experiencing. A ventilator may then conform respiratory support in accordance with the most probable phase. To provide a learning feature, the probability functions may be adjusted during use to provide a more subject specific response that accounts for changing respiratory characteristics.
16 Citations
70 Claims
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1-42. -42. (canceled)
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43. A method for determining a subject'"'"'s respiratory phase during ventilatory support comprising the steps of:
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deriving airflow-related measures from a subject during successive respiratory cycles;
using said airflow-related measures to calculate probabilities of a plurality of phase states; and
determining a phase in the subject'"'"'s respiratory cycle from the calculated probabilities of said phase states. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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57. An apparatus for determining a subject'"'"'s respiratory phase during ventilatory support provided by a ventilator that furnishes a controlled supply of breathable gas to the subject'"'"'s airway comprising:
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a transducer for generating an airflow signal representative of respiratory airflow in the subject; and
a processor with programmed instructions for controlling the steps of;
deriving airflow-related measures from a subject during successive respiratory cycles;
using said airflow-related measures to calculate probabilities of a plurality of phase states; and
determining a phase in the subject'"'"'s respiratory cycle from the calculated probabilities of said phase states. - View Dependent Claims (58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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Specification