Administration of CPAP treatment pressure in presence of apnea
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Accused Products
Abstract
CPAP treatment apparatus is disclosed having a controllable flow generator (34, 38, 40) operable to produce breathable gas at a treatment pressure elevated above atmosphere to a patient by a delivery tube (32) coupled to a mask (30) having connection with a patient'"'"'s airway. A sensor (44, 50, 56, 58) generates a signal representative of patient respiratory flow, that is provided to a controller (54, 62, 64). The controller (54, 62, 64) is operable to determine the occurrence of an apnea from a reduction in respiratory airflow below a threshold, and if an apnea has occurred, to determine the duration of the apnea and to cause the flow generator (34, 38) to increase the treatment pressure. In one preferred form the increase in pressure is zero if the treatment pressure before the apnea exceeds a pressure threshold. Below the pressure threshold the increase in pressure is an increasing function of the duration of the apnea multiplied by the difference between the pressure threshold and the current treatment pressure.
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Citations
63 Claims
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1-45. -45. (canceled)
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46. A method for the administration of CPAP treatment pressure comprising the steps of:
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supplying breathable gas to a patient'"'"'s airway at an initial treatment pressure, and repeatedly;
determining a measure of respiratory airflow;
determining the occurrence of an apnea from a reduction in said measure of respiratory airflow below a threshold;
determining the duration of said apnea; and
increasing the treatment pressure by an amount which is an increasing function of the duration of said apnea, and a decreasing function of the treatment pressure immediately before said apnea, wherein no increase in pressure is made for apneas of less than approximately 10 seconds duration, or for apneas where the treatment pressure immediately prior to the apnea is more than approximately 10 cm H2O, but otherwise, the lower the treatment pressure immediately prior to the apnea, and the longer the apnea, the greater the increase in treatment pressure, up to a maximum of approximately 8 cm H2O per minute of apnea. - View Dependent Claims (47, 48, 49, 50, 56, 57, 58, 59, 63)
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51. CPAP treatment apparatus comprising:
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a controllable flow generator operable to produce breathable gas at a pressure elevated above atmosphere;
a gas delivery tube coupled to the flow generator;
a patient mask coupled to the tube to receive said breathable gas from the generator and provide said gas, at a desired treatment pressure, to the patient'"'"'s airway;
a controller operable to receive input signals and to control operation of said flow generator and hence the treatment pressure; and
sensor means located at the flow generator, in the delivery tube or at the mask that generates a signal input to said controller from which patient respiratory airflow is determined;
and wherein said controller is operable to determine the occurrence of an apnea from a reduction in said respiratory airflow, determine the duration of said apnea, and cause said flow generator to increase CPAP treatment pressure by an increment that is an increasing function of said apnea duration and a decreasing function of the treatment pressure immediately prior to said apnea, said controller being operable such that no increase in pressure is made for apneas of less than approximately ten seconds duration, or for apneas where the treatment pressure immediately prior to the apnea is more than approximately 10 cm H2O, but otherwise, the lower the treatment pressure immediately prior to the apnea, and the longer the apnea, the greater the increase in treatment pressure, up to a maximum of approximately 8 cm H2O per minute of apnea. - View Dependent Claims (52, 53, 54, 55, 60, 61, 62)
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Specification