◆ Disease knowledge, medical knowledge, clinical knowledge and health science knowledge will help you recover from the disease (1). The measuring principle of Cq concentration monitoring is that the Cq concentration measuring instrument is placed in the expiratory tube of the ventilator, and the emitted infrared light reaches the photosensitive sensor through the expiratory gas. The higher the cq concentration, the weaker the infrared light reaching the sensor. The sensor inputs the perceived infrared light intensity information into the electronic calculator, and the calculator quickly calculates each finger according to the preset program and formula. In order to accurately determine the results, it is necessary to pay attention to: ① the sensor needs to be cleaned and calibrated; (2) placed correctly, without water accumulation; ③ Preheat for 3-4 minutes. L) end-tidal Cq concentration (i.e. dti CqC resistance? , c Cq) or end-expiratory Cq partial pressure (endti anti-Cq p perfusion S, kicking Cq). The relationship between CoCq and kicking C hatred: kicking CQ = atmospheric pressure xC 2 Cq%, and atmospheric pressure is about 100 E (750mmHg), so IkPa (7. SlnmHg) kicks C Hatred 21%CERCQ; If Cocq is 6%, the revenge of kicking C is IkPa (7. 5m working Hg) x6 = 6 intestines (45mmHg). Normal people kick C for revenge Cq = 0. 133? 0.40kPa (1-3mmHg), if (PaC revenge-kicking Cq) rises, it reflects that the ventilation blood flow ratio is abnormal. Clinical application: ① Monitoring kick Cq can guide the regulation of ventilation and avoid excessive or insufficient ventilation; ② Calculate VN/beep, the formula is: VN/beep = (Joe C Rui)/Joe C Qiu, and the normal VN/beep is between 0. 13-0.35, lung lesions can reduce alveolar ventilation or block blood perfusion, which can increase VN/beep value; ③ Selection of the best positive end-expiratory pressure: Generally speaking, the smallest positive end-expiratory pressure is the best positive end-expiratory pressure; ④ The Cq of spider reflects the change of circulatory function: in shock, heart failure or pulmonary infarction, the C-hate of powder drops sharply, while CO: can rise, which leads to the increase of C-hate of Pac. By analyzing the height, frequency, rhythm, baseline and shape of the cq waveform of exhaled breath, we can find out the situations such as insufficient or excessive ventilation, ventilator failure (pipe leakage or disconnection), abnormal breathing (Chen Yishi breathing, tidal breathing, sigh-like breathing) and so on. 2) C- hate output per minute (cq and np tolerance): refers to the amount of C- hate exhaled by patients per minute, which is an indicator of systemic metabolism. When the metabolism of chills, fever, pain, nervousness and before and after operation increases, the output of cq can be increased within a few minutes; Cq output decreased during anesthesia. 3) ineffective tidal volume: this part of gas does not participate in gas exchange in the lungs, so it is also called dead space ventilation. The normal value of invalid tidal volume is 100- 160 blood, and the low value may be pipeline leakage. 4) Effective tidal volume (effective tidal volume VO 1 uine): refers to the amount of gas exchanged in the lungs every time exhaled gas. Invalid tidal volume+effective tidal volume = tidal volume It is more meaningful to adjust the ventilator according to effective tidal volume than according to tidal volume. 5)E- conditional volume: also known as alveolar ventilation, it is the active volume exhaled every minute to participate in lung gas exchange. Effective ventilation = effective tidal volume x respiratory frequency. 6) Oxygen concentration monitoring: Most modern ventilators are equipped with oxygen sensors, which can automatically monitor oxygen concentration and set alarm limits. The purpose of monitoring the oxygen concentration of human body is to check whether the ventilator gives drugs accurately according to the preset oxygen concentration, so as to avoid severe hypoxemia caused by low actual human oxygen concentration or oxygen poisoning caused by high actual human oxygen concentration. This usually happens when the pressure of air source (oxygen or compressed air) is unstable or the air-oxygen mixer fails. 7) Monitor the temperature and humidity of the inhaler: Most ventilators are equipped with constant temperature humidifiers to heat the gas to 38℃ and saturated humidity. Source: The information is provided by Zhejiang Medical Association, and all rights reserved. It cannot be reproduced without permission.