不同麻醉深度对舌下微循环的影响

Effect of various anaesthesia depth on the sublingual microcirculation

目的观察不同麻醉深度对舌下微循环的影响。方法 20例行甲状腺手术且ASA分级Ⅰ~Ⅱ级患者。静脉注射咪达唑仑0.05 mg·kg^(-1)、舒芬太尼0.3μg·kg^(-1)、罗库溴铵0.6 mg·kg^(-1),持续静脉靶控输注丙泊酚3.0 mg·L^(-1)进行麻醉诱导和麻醉维持,气管插管后行机械通气。目标靶浓度每隔4 min增加0.5 mg·L^(-1)进行BIS值调节。分别在T1[脑电双频指数(BIS)基础值]、T2(50<BIS≤60)、T3(40<BIS≤50)和T4(30<BIS≤40)4个时点应用旁流暗视野技术(SDF)测定患者舌下微循环状态,选择舌下微血管(直径≤25μm)灌注血管密度(PVD)、总血管密度(TVD)、灌注血管比例(PPV)和微血管流动指数(MFI)作为评价指标。同时考察4个时点的平均动脉压(MAP)、心率、体温和动脉血气情况。结果与T1比较,T2时PVD、TVD和PPV下降(P<0.01),MFI差异无统计学意义(P>0.05);T3时PVD、TVD、PPV和MFI均下降(P<0.05);T4时PVD、TVD、PPV和MFI下降明显(P<0.01);T2和T3相比,PVD、TVD、PPV和MFI差异无统计学意义(P>0.05)。结论将BIS值控制在≤40~50范围,能在较好地抑制手术引起的应激反应的同时,对微循环影响较小,且能保持血流动力学的相对稳定。

Objective To investigate the effects of different depth of anesthesia on sublingual microcirculation. Methods ASA gradeⅠ-Ⅱpatients （n=20） were scheduled for elective thyroid surgery and included in the prospective observational study. Midazolam 0.05 mg·kg, sufentanil 0.3μg·kg-1 and rocuronium 0.6 mg·kg-1 were administrated intravenously to induce anesthesia which was then maintained by continuous intravenous infusion of propofol. Target medication concentration increased 0.5 mg·L-1, regulated based on BIS. The patients underwent endotracheal intubation and mechanical ventilation. Sublingual microcirculations were evaluated by sidestream dark field （SDF） imaging at T1 （BIS baseline ）, T2 （50 〈BIS≤60）, T3 （40〈BIS≤50） and T4 （30〈BIS≤40） respectively. Vascular （ with diameter equal or less than 20μm） perfusion vessel density （PVD）, total vessel density （TVD）, the proportion of perfused vessels （PPV） and microvascular flow index （MFI） were recorded. Mean arterial pressure （MAP）, heart rate, body temperature and blood gas analysis were also compared at these four points simultaneously. Results Compared with T1, PVD, TVD and PPV decreased （P 〈 0.01） at T2; PVD, TVD,PPV and MFI decreased （P〈0.05） at T3;PVD, TVD, PPV and MFI decreased significantly （P〈0.01） at T4;PVD, TVD, PPV and MFI presented no difference between T2 and T3 （P〉0.05）. Conclusion When BIS value sit between 40 and 50, it can best inhibit stress response and attenuate the agitation of microcirculation.