人工鼻和气体流量设置对气道内吸入气温度和湿度的影响

Effects of Heat and Moisture Exchanger Filter on Temperature and Humidity of Inspiratory Gas in Airway

目的:观察麻醉机呼吸环路气体低、中、高流量设置和呼吸环路加入人工鼻对气道内吸入气温度和湿度的影响。方法:选择60名ASA Ⅰ～Ⅱ级病人,随机分为6组,3组呼吸环路内加入人工鼻,流量设置分别是0.5,1.5,4.5 L/min;另3组不使用人工鼻,流量设置同上。应用温度湿度仪连续监测吸入气温度和相对湿度,公式计算绝对湿度。机械通气3min后的测量值设为基础值,然后纪录15,30,45和60 min的值。结果:随机械通气时间延长,人工鼻组的不同流量设置均显著增加气道内吸入气温度和湿度,当流量设置为0.5 L/min最高,其次是1.5L/min,再其次为4.5 L/min;不用人工鼻组,低、中、高流量设置显著影响气道内吸入气温度和湿度,随通气时间延长,流量为0.5 L/min时温度和湿度逐渐升高,1.5 L/min略有下降,4.5 L/min则明显降低。结论:人工鼻能补偿气体中、高流量时气道内温度和湿度的降低,低流量增加气道内的温度和湿度。临床采用低流量麻醉技术和人工鼻对保护病人气道粘膜有利。

Objective: Our aim was to investigate the effects of heat and moisture exchanger filter (HMEF) on temperature and humidity of inhaled gas in airway. Methods:Sixty patients ( ASA Ⅰ to Ⅱ )were selected and divided into 6 groups at random. The HMEF was used in 3 groups and the flow rates were 0. 5,1. 5 and 4. 5L/min . For the other 3 groups without HMEF, the flow rates were same as mentioned above. The temperature and relative humidity of inhaled gas were monitored continuously. Baseline values were set 3 minules after mechanical ventilation and then the values were recorded after 15, 30, 45, and 60 minutes. Absolute humidity was calculated by using formula. Results: With the lime of mechanical ventilation, different flow rates significantly increased the temperature and humidity of inhaled gas in the groups with HMEF. When the flow rate was 0. 5L/min, the temperature and humidity oi inhaled gas were the highest. Different flow rates also significantly affected the temperature and humidity of inhaled gas in the groups without HMEF. When the flow rate was 0. 5L/min, the. temperature and humidity increased gradually, and slightly decreased when the flow rate was 1.5L/min, and when the flow rate was 4. 5L/min, they decreased evidently. Conclusion; Loses of temperature and humidity of inhaled gas in groups using medium and high flow rates were compensated by HMEF. The temperature and humidity increased gradually when low flow rate was used. It was better for the airway mucosa to use low flow techniques and HMEF.