Development of On-Demand Controller for Continuous Positive Airways Pressure

Continuous Positive Airway Pressure (CPAP) is one of the primary treatments for sleep apnea. In a conventional CPAP, the device produces a constant air pressure to maintain the opening of the respiratory tract. The common problem found in the conventional CPAP is discomfort due to long term air pressure during sleep. Further, in subjects who undergo training to strengthen upper airways muscles, the application of high air pressure during non-apnea period may reduce the muscular strength. In this work, we propose to develop an on-demand CPAP controller that follows the normal respiratory pressure during non-apnea event and produce a pre-set positive air pressure during the sleep apnea event. Not only improve the comfortability of the subjects, our method also useful for patients who plan to discontinue using CPAP in the future. Our proposed model was developed using LabView software. We simulated breathing signal to represent normal breathing and apnea condition. Then a proportional and integral control system was developed for regulating the air pressure. The results show that in 60 trials with several setting points, our model achieved the average rise time 0.75s, overshoot 3.79%, and settling time 1.72s. The total accuracy of the method was 100% in detection of sleep apnea events. Our method can be developed into a low-cost device for sleep apnea treatment in Indonesia.