基于NDIR的呼吸末二氧化碳精确检测

发布时间：2018-06-02 08:32

本文选题：NDIR + 呼吸末二氧化碳　；参考：《天津科技大学》2017年硕士论文

【摘要】：在医学临床监测中,呼吸末二氧化碳(简称EtC02)是一项十分重要的生理参数,它可以同时反映患者的肺部通气功能状况和患者的血液循环功能与肺部血流状况。由于EtCO2监测具有无创、连续性等优点,近年来在医学临床中具有非常广泛的应用。患者呼气的温度、水汽、大气压都能影响EtC02检测的精度。目前,EtC02检测设备主要由国外厂家生产,国内较少见到。因此,我国自主研发高精度的EtC02检测系统应该有很大的市场潜力。本文研究的EtC02检测系统是基于非分光红外吸收气体检测技术(NDIR),并考虑了患者呼气的温度、水汽、大气压对EtCO2浓度检测结果的影响。这种技术基于Lambert-Beer定律,也就是利用探测器探测出红外光的衰减量来计算CO2浓度,具有灵敏度高、系统稳定和抗干扰能力强等优点。本文基于NDIR原理搭建了一套针对呼吸末二氧化碳中的温度、湿度、气体压力、C02气体浓度的智能监测系统,并对CO2气体浓度进行了标定,研究了温度、湿度、气体压力对CO2测量浓度的影响。本文利用CC2530芯片构成ZigBee无线传输系统,利用ATmega16A芯片构建硬件系统,在硬件平台部分介绍了系统功能实现的硬件构建,包括ATmega16A芯片电路、电平转换电路、稳压电路以及液晶显示模块的设计。为提高CO2检测结果的精度,本文研究了测量呼出气体中温度、湿度和气压对二氧化碳测量浓度的影响,并对温湿度传感器、二氧化碳传感器提前进行了标定,提高了传感器的测量精度。在软件部分主要介绍了上位机软件和下位机软件。上位机软件是利用LabVIEW编写的。下位机程序主要是用IAR开发的。本文设计了便于医疗人员操作的更加直观、方便的上位机操作界面,具有参数信息采集、信息显示、数据处理、数据存储四大功能。论文软件部分首先是对上位机开发平台进行了简单介绍,而后重点介绍了上位机参数信息采集、信息显示功能、数据处理与存储功能模块的实现。本文为了提高EtCO2测量精度,建立了温度、湿度、气体压力对CO2测量浓度的校正模型,对测量数据进行处理。首先用仿真数据建立了校正模型,利用验证集数据对校正模型进行了验证,结果表明,该校正模型提高了 EtCO2的测量精度。
[Abstract]:In medical clinical monitoring, end-respiratory carbon dioxide (EtC02) is a very important physiological parameter, which can reflect the pulmonary ventilation function, blood circulation function and pulmonary blood flow status of patients at the same time. EtCO2 monitoring has been widely used in medical clinic in recent years because of its advantages of noninvasive and continuous. Patient breath temperature, water vapor, atmospheric pressure can affect the accuracy of EtC02 detection. At present, EtC02 testing equipment is mainly produced by foreign manufacturers, less seen in China. Therefore, China's independent development of high-precision EtC02 detection system should have great market potential. In this paper, the EtC02 detection system is based on the non-spectroscopic infrared absorption gas detection technique. The effects of the patient's breath temperature, water vapor and atmospheric pressure on the detection results of EtCO2 concentration are considered. This technique is based on the Lambert-Beer law, that is, using detectors to detect the attenuation of infrared light to calculate the concentration of CO2, which has the advantages of high sensitivity, system stability and strong anti-interference ability. Based on the principle of NDIR, an intelligent monitoring system for temperature, humidity and pressure of CO _ 2 at the end of respiration is set up in this paper. The concentration of CO2 gas is calibrated, and the temperature and humidity are studied. The effect of gas pressure on the measured concentration of CO2. In this paper, CC2530 chip is used to construct ZigBee wireless transmission system, and ATmega16A chip is used to construct hardware system. In the part of hardware platform, the hardware construction of system function is introduced, including ATmega16A chip circuit, level conversion circuit. The design of voltage stabilizing circuit and liquid crystal display module. In order to improve the accuracy of CO2 detection results, the effects of temperature, humidity and pressure on the measurement concentration of carbon dioxide in the exhaled gas are studied in this paper, and the temperature and humidity sensors and carbon dioxide sensors are calibrated in advance. The measuring accuracy of the sensor is improved. In the software part, the host computer software and the lower computer software are mainly introduced. The upper computer software is written by LabVIEW. The lower computer program is mainly developed with IAR. In this paper, a more intuitive and convenient operation interface for medical personnel is designed, which has four functions: parameter information collection, information display, data processing and data storage. In the software part of the paper, the development platform of the host computer is introduced briefly, and then the realization of the module of the upper computer parameter information collection, information display, data processing and storage is introduced. In order to improve the accuracy of EtCO2 measurement, the calibration model of temperature, humidity and gas pressure for CO2 measurement concentration is established, and the measurement data are processed. First, the correction model is established with the simulation data, and the calibration model is verified by using the data of the validation set. The results show that the correction model improves the measurement accuracy of EtCO2.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP274

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