右美托咪定对重症肌无力手术患者呼吸力学的影响

Effect of dexmedetomidine on respiratory mechanics indices in surgical patients with myasthenia gravis

目的探讨右美托咪定对重症肌无力手术患者呼吸力学的影响。方法将36例择期行手术治疗的重症肌无力患者随机分为右美托咪定组和对照组,每组18例。右美托咪定组麻醉诱导前给予泵入右美托咪定0.5μg/kg,对照组给予等量的生理盐水。分别于手术开始前(T0),单肺通气后30 min(T1)、肺复张后双肺通气15 min(T2),采集两组患者动脉血进行血气分析,记录氧合指数(Pa O2/Fi O2比值)、Pa CO2、呼气末二氧化碳(PETCO2)、潮气量、气道峰值压力(Ppeak)、气道平台压(Pplat),肺动态顺应性(Cdyn)和死腔量。比较两组患者右美托咪定及丙泊酚用量、吸痰量、急性肺损伤发生率、脱机拔管时间。结果两组的Pa O2/Fi O2、Ppeak、Pplat、肺Cdyn、死腔量比较,差异均有统计学意义(均P<0.05),两组的Pa O2/Fi O2、Ppeak、Pplat、肺Cdyn、死腔量均有随时间变化的趋势(均P<0.05),分组与时间均有交互效应(均P<0.05),其中在T1、T2时,与对照组比较,右美托咪定组Pa O2/Fi O2及肺Cdyn升高,Ppeak及Pplat降低,死腔量减少(均P<0.05)。与对照组比较,右美托咪定组丙泊酚用量及吸痰量更少,脱机拔管时间更短,急性肺损伤发生率更低(均P<0.05)。结论麻醉诱导前泵注右美托咪定可通过改善氧合功能、减少术中肺死腔量、提高患者肺Cdyn等,有效改善重症肌无力手术患者的呼吸力学。

Objective To investigate the effect of dexmedetomidine on respiratory mechanics indices in the surgical patients with myasthenia gravis. Methods Thiru-six patients with myasthenia gravis undergoing elective surgery were randomly divided into dexmedetomidine group and control group, with 18 cases in each group. The dexmedetonlidine group was given 0.5 μg/kg dexmedetonlidine before anesthesia induction, and the control group was given the same amount of normal saline. In the two groups, the arterial blood samples were collected from the patients to perform blood gas analysis before operation （ TO ）, at 30 rain after one-lung ventilation （T1） and 15 min after two-lung ventilation and pulmonary resuscitation （T2）, respectively. Blood oxygenation indices [ PaO2/fraetion of inspired oxygen （FiO2）ratio ], PaCO2, end-tidal carbon dioxide partial pressure（ PET CO2 ）, tidal volume, peak airway pressure （ Ppeak ）, airway plateau pressure （ Pplat ）, pulmonary dynamic compliance（Cdyn） and dead space volume were recorded. The dosages of dexmedetomidine and propofol, sputum aspiration amount, incidence rate of acute lung injury ,and duration of off-line extubation were compared between the two groups. Results There were significant differences in the PaO2/FiO2, Ppeak, Pplat, pulmonary Cdyn and dead space volume between the two groups （all P 〈 0.05 ）. PaO2/FiO2, Ppeak, Pplat, pulmonary/Cdyn and dead space volume showed a tendency to change over time in the two groups（ all P 〈 0.05 ） , and there was an interaction between grouping effect and time effect （ all P 〈 0. 05 ）. At T1 and T2, PaO2/FiO2 and pulmonary/ Cdyn increased as well as Ppeak, Pplat and dead space volume decreased in the dexInedetomidine group compared to the controls （ all P 〈 0. 05 ）. Compared to the control group, the dexmedetoinidine group had less propofol dosage and sputum aspiration amount, shorter duration of off-line extubation, and lower incidence rate of acute lung injury（ all P 〈 0.05 ）. Conclusion Pump infusion of dexmedetomidine before anesthesia induction can effectively improve the respiratory mechanics of surgical patients with myasthenia gravis by improving oxygenation function, reducing the amount of intraoperative lung dead space volume and increasing patients＇ pulmonary Cdyn.