【作者】 秦岭；

【导师】 应可净；

【作者基本信息】 浙江大学 ， 内科学（呼吸系病）， 2001， 硕士

【摘要】 一、背景 呼吸机支持是危重患者发生呼吸衰竭时抢救的重要手段，当引起呼吸衰竭的原发病得到控制，医生应积极评估患者情况，考虑能否撤机。适时撤机能减少呼吸机相关的并发症，提高抢救成功率。部分患者因各种原因撤机失败或撤机时间延长（超过48—72小时），有学者将此类患者称为难撤机患者。难撤机患者的撤机在很大程度上取决于撤机策略。不同撤机策略的比较主要有2个方面，即效率、效能两方面。有关难撤机患者的撤机策略的研究，目前在国际上尚有争议。在国内，撤机的研究仅停留在模式的比较研究，未见有针对难撤机患者的撤机策略研究。呼吸机撤机多凭临床医生的经验，缺乏规范化的策略，在一定程度上限制了危重病人的抢救成功率。为探讨难撤机患者不同撤机策略的效率、效能的差异及患者对不同撤机策略的依从性，我们设计了本研究。二、目的 本研究旨在比较难撤机患者的不同撤机策略：（1）压力支持（PSV）撤机：u）同步间歇指令通气十压力支持（幻＊＊仲SV）撤机；臼）其他撤机，包括T管撤机方式、持续气道正压通气（CPAP）撤机方式、同步间歇指令通气（SIMV）撤机方式，其效率、效能两方面的差异，及其对临床的指导意义。重点探讨PSV撤机的有关如何设置初始压力水平及渐降压力水平的具体步骤。三、方祛 难撤机思者入选标准：患者经综合治疗满足；Dfo床撤机标准后准备撤机，但出现下列情况之一为难撤机患者（）撤机试验大败或（）撤机时间延长（超过48——72小时）。然后将难撤机患者随机分入3组，按不同撤机策略进行撤机：（）PSV组；（2）SIMV＋PSV组；（）其他组，包括T管方式、CPAP方式、SIMV方式。比较不同撤机策略撤机起始R第14天的效能、效率。 PSV撤机组，先设定初始压力水平（Baseline PS），Baseline PS要求调节至患者 RR（25—30 bPm，V；35—8 PI瓜g，然后根据患者是否耐受逐渐降低压力支持（PS）水平。渐降PS的幅度是20％的Baseline PS，多为 2—4cmH。O，每 0．5—1小时降 20％，每天降 PS 2次以上。 SIMV＋PSV撤机组，先设定初始频率及 Baseline PS，初始频率为 80％的A／C时频率，根据患者是否耐受酌情渐降初始频率，至2－4次／分，再降 Baseline PS。 其他组：T管撤机、CPAP撤机为逐渐延长T管支持时间，SIMV撤机为设定初始频率为80％的A／C时频率，酌情渐降初始频率。 一2一四、结果1．三组患者撤机厂始时的性质、基础情况如年龄、COPD例数、撤机前呼 吸机支持的时间、呼吸频率、潮气量、浅快呼吸指数、每分通气量。 氧合指数无显著性差异（P＞0．05）。2．不同撤机策略的效率比较结果有显著性差异（P＜0．05），PSV撤机、 SIMV＋PSV撤机效率较高。3．不同撤机策略的效能比较采用Kaplan－M。ie。法计算不同撤机策略随时 间延珐的未撤机率，PSV组成功率为75％，SIMV＋PSV组成功率为76．9％， 其他组成功率为 40％，结果比较无显著性差异（P＞0．05）。PSV撤机、 SIMV＋PSV撤机患者失访数少，依从性好；其他撤机方式夫访数多， 依从性差。五、结论1．PSV撤机设置初始压力水平Baseline PS至患者RR＄25——30bern，V；35 —8 ml瓜g，临床有效可行。酌情渐降20％的Baseline PS以完成撤机， 撤机效率高，是安全、简单、患者依从性好的撤机策略。2．本研究策略性撤机优于传统撤机，提示策略性撤机全面评估患者、掌握 恰当撤机时机有重要意义，并证实动态观察浅快呼吸指数（f／VT）是策 略性撤机的重要指标。更多还原

【Abstract】 Background Mechanical ventilation (MV) is the major life-support modality during respiratory failure. Once the illness that precipitated respiratory failure (RF) has resolved, MV can be discontinued after the patient was carefully evaluated. Prompt weaning can reduce the ventilator-associated complications, lessen the patient’s suffering, decrease the medical fee and raise the success rate. Weaning can be achieved in 24-48 hours in majority of patients after the weaning indexes meet the requirement. But some patients become the difficult-to-wean patients because of weaning failure or the weaning duration exceeding 48-72 hours. The successful weaning in difficult-to-wean patients mainly relies on weaning protocol apart from the illness improvement. Weaning protocol is the standardized procedure that consisted of illness evaluation, ventilator mode’s select, and baseline parameters confirmation. Based on the above, the patient can be successfully weaned from the ventilator gradually according to the patients’ endurance. Merits of various weaning methods should be primarily based on efficacy (the fraction of patients successfully weaned) and efficiency (the time it takes to discontinue MV). The most sensitive way to test the differences in weaning time is to use survival analysis. Several studies onweaning methods have been performed in the past, but debate on the outcome continues. Two recent multicenter, randomized trials have demonstrated differences in outcome. Brochard and colleagues found PSV leading to significantly shorter weaning time compared to the combined T-piece and SIMV. Esteban and colleagues performed a similar study and concluded that a once-daily trial of T-picce breathing led to the most quickly weaning and the success of T-piece was significantly greater than SIMV and PSV. In China, weaning research have only been performed on different modes and the standardized protocol has never been developed. Ventilator weaning is the traditional physician-directed weaning and it leads to limitation of the success rate of weaning. To assess the difference on efficacy, efficiency and the compliance about three weaning protocols in difficult-to-wean patient, we carried out a prospective, randomized study.Object To compare the difference of efficacy, efficiency and compliance of different weaning protocols in difficult-to-wean patient. The key target of this study is how to set baseline PS level and how to decrease the baseline PS level gradually.Methods 37 difficult-to-wean patients who were divided into three groups were enrolled in this study after clinical evaluation reaching to the requirements. Group 1 (12 patients) were PSV protocol, group 2 (13 patients) SIMV+PSV and group3 (12 patients) other including T-piece, CPAP, SIMV. Standardized protocols were followed for each group. Results There were no significant difference in the main characteristic at theonset of the weaning procedure (P>0.05). On the comparison of weaning efficiency, the probability of continuing on MV which was calculated by using the Kaplan-Meier estimate was found to be significantly lower with PSV and SIMV+PSV (PO.05). On the comparison of weaning efficacy, the success rate with PSV (75%), SIMV+PSV (76.9), and other (40%) was found to be no significant difference (P>0.05).Conclusions To raise the weaning success, the most important and basic thing is to assess the patient’s clinical situation comprehensively and have the well judgement on the appropriate weaning time. Dynamic observation of f/Vt is the important index in protocol-directed-weaning. PSV weaning protocol is superior to other protocol such as SIMV, T-piece, and CPAP protocol. We can wean the patient by setting the baseline PS and gradually decreasing it according to the patient’s endurance. PSV weaning is the safe, easy-performed and well patients’ compliance protocol.更多还原