Apparatus for compensating for flow and pressure variances in pneumatic circuits

摘要

An apparatus and method for facilitating the respiration of a patient are disclosed which are particularly useful in treating mixed and obstructive sleep apnea and certain cardiovascular conditions, among others, by increasing nasal air pressure delivered to the patient's respiratory passages just prior to inhalation and by subsequently decreasing the pressure to ease exhalation effort. The preferred apparatus includes a patient-coupled gas delivery device for pressurizing the patient's nasal passages at a controllable pressure, and a controller coupled with the delivery device having a pressure transducer for monitoring the nasal pressure and a microcontroller for selectively controlling the nasal pressure. In operation, the controller determines a point in the patient breathing cycle just prior to inhalation and initiates an increase in nasal pressure at that point in order to stimulate normal inhalation, and subsequently lowers the nasal pressure to ease exhalation efforts. The invention further comprises an apparatus for compensating variances in a circuit used for supplying airway pressure to a patient's airway having a sensor proximal to a pneumatic circuit connection for ascertaining a circuit characteristic and producing a signal value representative thereof, as well as a memory storing a look-up table containing empirical values corresponding to known variances of pneumatic circuit connections and signal processor receiving and comparing the signal value with the empirical values to ascertain a deviation value, and a controller connected to the signal processor and source of breathing gas to control delivery of breathing gas in accordance with the deviation value an apparatus for compensating variances in a circuit used for supplying airway pressure to a patient's airway having a sensor proximal to a pneumatic circuit connection for ascertaining a circuit characteristic and producing a signal value representative thereof, as well as a memory storing a look-up table containing empirical values corresponding to known variances of pneumatic circuit connections and signal processor receiving and comparing the signal value with the empirical values to ascertain a deviation value, and a controller connected to the signal processor and source of breathing gas to control delivery of breathing gas in accordance with the deviation value.