Patent ID: 7914459

Claim:
An apparatus for delivering ventilatory support to a subject synchronized to the subject's respiratory phase, comprising: a means for providing a controlled supply of breathable gas to a subject's airway; a means for generating an air flow signal representative of the subject's respiration; and a processor to determine a phase of the subject's respiratory cycle and to control the supply of breathable gas delivered to the subject's airway; wherein said processor determines a phase in the subject's respiratory cycle by (a) designating a plurality of phase states within said subject's respiratory cycle, each phase including one or more phase states; (b) calculating a measure of the subject's respiration from said air flow signal; (c) determining probabilities for said subject being in each of said phase states based on said measure of respiration; and (d) identifying a phase in the subject's respiratory cycle from the determined probabilities of said subject's respiratory cycle being in each of said phase states; and said processor causes the delivery of a supply of breathable gas synchronized with the determined phase of the subject's respiratory cycle.