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US 2006/0079799 A1Published application
Ventilator patient synchronization
AssigneeResMed Limited
InventorsPaul Green, David Bassin
Life of this patent
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AssigneeResMed Limited
InventorsPaul Green, David Bassin
Estimating the term…
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.
1-42. (canceled)
A method for estimating a subject's respiratory phase in patient respiration by probability functions wherein the respiratory support of a ventilator can match the phase of the respiratory cycle of the patient comprising
A method for estimating a subject's respiratory phase comprising utilizing previously calculated state probabilities to adjust prior probabilities wherein the respiratory patterns or characteristics of the patient are learned.
A method and apparatus for improved ventilator patient synchronization wherein the most likely phase is determined on the basis of flow and rate of change of flow information using Bayes' theorem or some similar formula for assessing conditional probability comprising
A system providing ventilatory support that automatically adjusts the support to accommodate the patient's phase by adjusting a pressure gain associated with the particular state of the determined phase, wherein the probability for the phase L(Hi) is modified after calculations to improve subsequent determinations by adjusting L(Hi) to equal or approach the determined phase likelihoods L(HilFj) by a function of L(HilFj).
A ventilator apparatus having a processor programmed with an algorithm that accomplishes the following preferred method:
Dependencies are inferred from the claim text.