机械通气的气道湿化

发布时间: 2022/10/19 浏览次数: 2,410

机械通气的气道湿化

在正常生理状态下,吸入气体通过上呼吸道加温加湿作用达到BTPS状态,即气体温度达到37℃, 绝对湿度44mgH2O/L,相对湿度100%。而在正压通气或建立人工气道的情况下,呼吸机通过高压或高流速输送的气体较为干燥,使上呼吸道生理性加温加湿功能负担加重,此时,使用呼吸湿化器提供足够的湿化补偿就显得尤为必要。

 

 

上呼吸道可以提供吸入气体75%的湿度。在进行有创机械通气时,因人工气道的建立,上呼吸道被旁路,不能对吸入气体进行加温加湿时,湿化器就需要补偿丢失的这部分温度和湿度。吸入气体总的湿度需求是44mg/L,被旁路的75%气道湿化功能需要湿化器进行补偿,即0.75*44mg/L=33mg/L。因此,对有创通气患者进行主动湿化达到理想BTPS状态时,湿化器需要提供33-44mg/L 的湿度,对应的气体温度在34-41℃之间,相对湿度达100%来维持正常呼吸道的生理功能。

 

 

尽管呼吸湿化器可以保证Y型管处的气体温度达到41℃,依据ARRC指南建议Y型管处的最高气体温度是37℃,相对湿度是100%。ISO 组织认为:输送的气体温度持续在41℃以上会对患者带来潜在的热损伤,并把43℃作为热损伤的高温报警临界点。

 

 

在进行无创机械通气时,尽管上呼吸道的生理湿化功能保留,由于漏气通气的特点,单位时间内经过连接界面处的气流加大,使得患者上呼吸道水分丢失,导致上呼吸道湿化的负荷加重,黏膜湿度不足。此时,使用呼吸湿化器可显著提升吸入气体的温度及湿度,增加患者的依从性和舒适度,从而提高无创通气的成功率。

 

 

1. Lellouche F, Maggiore SM, Lyazidi A, Deye N, Taille S, Brochard L. Water content of delivered gases during non-invasive ventilation in healthy subjects. Intensive Care Med 2009;35(6):987-995.

2. Branson RD. Humidification of respired gases during mechanical ventilation: mechanical considerations. Respir Care Clin N Am 2006;12(2):253-261.

3. Holland AE, Denehy L, Buchan CA, Wilson JW. Efficacy of a heated passover humidifier during noninvasive ventilation: a bench study. Respir Care 2007;52(1):38-44.

4 Solomita M, Smaldone GC. Humidification and noninvasive ventilation. Respir Care 2007;52(1):24-25.

5. Chiumello D, Chierichetti M, Tallarini F, Cozzi P, Cressoni M, Polli F, et al. Effect of a heated humidifier during continuous positive airway pressure delivered by a helmet. Crit Care 2008;12(2):R55.

6. Lellouche F, Maggiore SM, Lyazidi A, Deye N, Taille´ S, Brochard L. Water content of delivered gases during non-invasive ventilation in healthy subjects. Intensive Care Med 2009;35(6):987-95.

7. Williams RB. The effects of excessive humidity. Respir Care Clin N Am 1998;4(2):215-228.

8. Kilgour E, Rankin N, Ryan S, Pack R. Mucociliary function deteriorates in the clinical range of inspired air temperature and humidity.Intensive Care Med 2004;30(7):1491-1494.

9.Shelly MP,Lloyd GM,Park GR(1988) A review of the mechanisms and methods of humidification of inspired gases.Intensive Care Med 14:1-9.

10. Shelly MP(1992) Inspired gas conditioning. Respir Care 37:1070-1080.

 

返回列表

© 2022 沈阳迈思医疗科技有限公司 辽ICP备2023010310号-2 证书编号:(辽)-非经营性-2018-0075 Powered by SE