无创通气管路漏气时自动触发对人机交互作用的影响

目的 研究涡轮供气、单管路呼吸机出现自动触发与管路漏气的关系及自动触发对人-机交互作用的影响.方法 对临床中常用的5种涡轮供气、单管路呼吸机,模拟肺和14名志愿者进行研究.以平台型漏气阀建立定量漏气装置,测定不同漏气级别时管路内的呼吸力学曲线.采用SPSS 10.0软件.数据以-x±s表示,组间均数比较采用方差分析.在模拟肺研究中采用logistic回归对自动触发与各变量间的相关性进行分析.结果 以双水平气道正压(BiPAP)模式工作时,在模拟肺研究中不同呼吸机出现自动触发次数占总测试次数百分比达24%～90%,自动触发的出现与漏气量呈正相关(β=0.709,相对危险度(OR)=2.032).在志愿者研究中,随着漏气量的增加,14名志愿者均出现自动触发,同时呼吸频率增快,潮气量减小.结论 在涡轮供气、单管路呼吸机,自动触发随管路漏气量增加而增多.自动触发可能与无创呼吸机在漏气增加时流速基线补偿不足有关.自动触发使受试者的通气效率降低.

The effects of auto-triggering on patient-ventilator interaction in noninvasive mechanical ventilation during air leak

OBJECTIVE: To study the relationship between air leak and auto-triggering in noninvasive positive pressure ventilation (NIPPV), and the effects of auto-triggering on patient-ventilators interaction. METHODS: Five different types of noninvasive ventilators, a lung simulator and 14 healthy volunteers were studied by using a quantificational air leak model and a spirometer which monitoring the pressure, flow and volume curve in the tube continuously. SPSS version 10.0 was used for statistical analysis. Data were presented as x +/- s, and means were compared with analysis of variance. RESULTS: In the study of lung simulator, the percentage of times of auto triggering in total testing times was from 24% -90% in the BiPAP mode in various ventilators. Air leaking capacity was the most crucial factor related to auto triggering (beta = 0.709, OR = 2.032). With increased air leak level, 14 volunteers all presented with auto triggering. All the volunteers' respiratory rate increased and tidal volume decreased with the increasing level of air leak. CONCLUSION: Auto-triggering occurred when air leak increased in NIPPV. The insufficient compensation of flow base line may be the cause for auto-triggering. Auto-triggering can impair patients ventilation.