Wireless-sleep apnea monitoring system

Preface sleep apnea syndrome is a very common sleep breathing disorders, according to research in the United States, approximately 24% of the adult male and adult female, or 9% more than 200 million people suffering from this disease in China, Taiwan at least 35 000 people have this problem.

Whether in the diagnosis of patients generally suffer from sleep apnea refers to patients during sleep in apnea and hypopnea total more than 5 times per hour. Including apnea refers to sleep, appear for 10 seconds more respiratory air flow, low airflow ventilation means breathing does not completely stopped, only to the original 20% ~ 50%, while oxygen concentrations declined 4 percent of respiratory disorders. Current doctor diagnose sleep apnea syndrome often use night sleep apnea more physiological monitoring instrument that records all night sleep cycle, including apnea and breathing becomes shallow times, type, number, oxygen index, ECG changes, mouth and nasal cavity flow, thoracic and abdominal respiration, blood oxygen and other signals of the earlobe, snoring frequency. Use night sleep apnea more physiological monitors although accurate, but require them to wear a variety of instruments, must also be in a specific hospital professionals to conduct measurements, very inconvenient is also easy to affect patients sleep, so not suitable for long-term monitoring. Therefore General patients unless the very serious is not going to go into hospital for this check. What's more, many physiological sleep apnea monitor meter is an expensive instruments, General patients will not be buying their own measurement in the home, it is difficult to achieve universality. The system mainly directed against these disadvantages developed a simple, conscious of more low, affordable and suitable for home sleeping environment for long-term monitoring of the monitoring system to help physicians understand the patient's condition, and provides medical treatment process to improve traceability.

Research methods and system design for system block diagram 1.

This system consists of (1) physiological parameters meter and (2) the physiological parameters parser. Physiological parameters meter contains a physiological signal sensing devices, micro-controller. Physiological parameters parser is the use of Bluetooth wireless module receives physiological measurement meter as measured with physiological parameter data, analysis, and congenial operation screen is displayed, providing patients sleep physiology.

Figure 1 wireless-sleep apnea monitor system block diagram physiological parameters gauge · physiological signal sensing device heartbeat variations use of sensing components for optical sensors, the main use of human vascular cardiac contraction of blood flow and oxygen concentration will produce changes.

This system using optical coupler (CNY70) using optical reflection method detects vascular blood flow changes at the end. Figure 2-optical coupler CNY70 internal structure and principle of action.

Figure 2 optical coupler CNY70 internal structure and operation principle of the audio signal receiver is receiving sleep due to the obstructive snoring, this system uses a capacitive audio receivers as key components of the received signal, use receive wave pressure change vibrating membrane of displacement, causes the vibration film and aluminum shell of capacitance change with ultrasonic CT or weak, electric capacity to complete the conversion of impedance FET produces RECM, RECM REXT and change of partial pressure, resulting in a different output.

Figure 3-audio receiver internal structure and principle of action.

Figure 3 audio receiver internal structure and operation principle breathing sensor works is the use of breath will have ups and downs and chest, pulling the horizontal variable resistance resulting resistance value changes. · physiological signal sensing circuit 1. heartbeat sensor circuit diagram 4 block diagram for heartbeat sensor circuit.

Heartbeat is a change in the measurement sensor to signal to contain the DC bias voltage (DC Offset), heartbeat signal, breathing and muscle vibration, noise and high-frequency 60Hz, heartbeat signal to the desired signal, signal noise, therefore, be regarded as separate pre-filter circuit of hardware and software are two approaches to address different noise on the impact of the measure. Front filter circuit features can reduce software program for digital signal processing the required amount and time of operation, avoid causing signal processing delay. Figure 5 is the heartbeat of the waveform. Figure 6 as the heartbeat into digital signals of the waveform. Figure 7-heartbeat sensor circuit.

Figure 4 the heartbeat sensor circuit block diagram

6 the heartbeat converted waveform diagram 5 heartbeat signal waveform diagram before the conversion

Figure 7 heartbeat sensor circuit 2. snoring sensing circuit diagram 8 block diagram for snoring sensing circuit.

To the audio receiver measurements to snore signal contains a lot of noise and background noise, you must use the hardware filter high frequency, low frequency noise removal only snoring band signal, Smithson [1995] research shows snoring frequency is approximately 1 ~ 200Hz voice band, other sounds of frequency domain is broader. First of all by the audio receiver from the measured signals, signal amplification via 200Hz low pass filter to filter out other sound caused by noise. Figure 10 to convert the snoring signal digital signal of a wave. Figure 11 for snoring sensing circuit.

Figure 8 snoring sensing circuit block diagram

Figure 10 snoring signal converted waveform diagram 9 snoring signal conversion before the waveform

Figure 11 snoring sensing circuit 3. respiratory sensing circuit diagram 12 for respiratory sensing circuit block diagram.

Use of the ups and downs when thoracic breathing, pulling the horizontal variable resistance change resistance values resulting voltage change, by way of the signal amplifier, comparison to determine breathing circuit. Figure 13 for respiratory signal waveform. Figure 14 for respiratory sensing circuit.

Figure 12 respiratory sensing circuit block diagram

Figure 13 respiration signal waveform

Figure 14 respiratory sensing circuit · CPU and display power

Road, Figure 15 shows the CPU and the system shows the circuit. CPU is using shengqun Semiconductor Co., Ltd. produces HT46R24 microcontrollers, which consists of A Port and Port C driver 15 * 4 Chinese display-LCD, as physiological parameters data display, Port B to physiological parameters and timer input, while Port D the MAX232 quasi-phase conversion do serial transmission.

Figure 15 CPU and display circuit · firmware physiological parameters measurement ditital program are as follows: in the physiological parameters measurement to avoid reading into the body of the error signal when turning, the use of multiple read way avoid, when the signal changes, continuous read and each read room joined some time delay, after the signal read than on is the same, this way you can reduce the signal read error rates.

When processing is complete of physiological parameters information stored in the buffer with a micro-controller, and through the Chinese type LCD display as measured with physiological parameters. Bluetooth wireless module, the key will be stored in the micro-controller for internal buffer of the physiological parameters data via RS-232 serial transmission between your computer and personal data communication. Physiological parameters parser to Visual Basic6.0 as a development tool, via Bluetooth wireless module receives from physiological parameters meter physiological parameters transferred data, stored in a database and associate each time point of physiological parameters for analysis, connecting Excel treats each time point measurement of physiological parameter information for analysis and integration to graphs showing each point in time, let the physiological changes of status in the diagnosis of physicians.

Results in Figure 16, on the grounds of the hospital had the correct data is the actual simulation of the system measured curves of the diagram.

This system provides a set of normal sleep respiratory physiological parameter data and graphs to increase physician in comparison and judgment of convenience.

Figure 16 physiological parameters after PATA cable analysis results indicated above in Figure 16 is not suffering from sleep apnea sleep respiratory physiology; is suffer from below the sleep apnea patients sleep sleep physiology.

Table 1 as Figure 16 individual color curves represent meaning. Figure 16 curve analysis and comparison can be found, sleep apnea syndrome patients sleep apnea is usually accompanied by snoring, sleep apnea, heart frequency at the same time domain has a very significant decrease, so it can judge the suffer from sleep apnea patients in the long term is not acceptable for the treatment of sleep apnea, the heart is not in sleep a beating but easy to suffer from diseases of the cardiovascular system.

Concluding remarks in the design of single-chip microcontroller software, must be based on the timeline as a benchmark, measuring various physiological parameters, in order to identify the individual reconstruction physiological parameters.

In order for the physiological parameters measurement meter volume miniaturization, you must select a low consumption power and size of the smaller components, and use the micro-controller so that the overall power consumption is minimized. Bluetooth wireless transmission modules for low power consumption and high security of wireless data transmission equipment. Measurement in physiological parameters, you must set the physiological signal sensing device fixed to the patient's body, because sleeping head, body movement and flip, easily lead to measurement equipment for peeling and incorrect measurement data, incorrect measuring how much affect the physician's assessment of the symptoms. So the physiological parameters measurement meter sensor size must be small, fixed easily, easily fall off and avoid affecting patients with sleep, physiological parameters of data processing, you must first use filter, noise removal, it only shows the real Sleep disordered breathing on the physiological parameters of the waveform, this is easier to get accurate physiological parameters, thereby improving the accuracy of the diagnosis doctor. In addition, to meet the physiological parameters gauge within the circuit module, the system's power supply is very important. Traditional power handling is determined by the electricity company provides 110V 60Hz (Editor's Note: this indicator for Taiwan power) of power through a weight, volume, no small transformers, after rectifier and voltage in order to get the voltage required for the system, but this procedure because the temperature easily leads to heat not exactly the components easily damaged. In order to let the physiological parameters meter small volume, light weight, and will not produce high-temperature, physiological parameters gauge adopts the market 110V 60Hz converted to 5V 1A power converter, providing micro-controller, and then through the DC-DC-double group-power converters into sensing circuit module ± 5V power supply, compared to the past, not only the difficulty of reducing power design, making it more convenient to carry.

References: 1.

Mariano Cabrero-canosa, Elena Hernandez-pereira, and Vicente Moret-Bonillo, ‘Intelligent Diagnosis of Sleep Apnea Syndrome.’IEEE engineering in medicine and biology magazine, March 2004:72-81.2. Varady et al., ‘A Novel Method for the Detection of Apnea and Hypopnea Events in Respiration Signals.’IEEE Tran. Biomed. Eng., 2002; Vol. 49, September: 936-941.3. ASYALI et al., ‘Assessment of Closed-Loop Ventilatory Stability in Obstructive Sleep Apnea.’ IEEE Tran. Biomed. Eng., 2002; Vol. 49, March: 206-216.4. Varady et al., ‘On-line Detection of Sleep Apnea During Critical Care Monitoring.’ Proceedings of the 22"d Annual EMBS International Conference, July 23-28, 2000, Chicago IL.5. China Taiwan tssm