镇痛指数在全身麻醉腹腔镜阑尾切除手术中评估疼痛的有效性

Efficiency of pain threshold index in evaluating intraoperative pain during laparoscopic appendectomy under general anesthesia

目的探讨镇痛指数(pain threshold index,PTi)评估全身麻醉腹腔镜阑尾切除手术中5项操作诱发疼痛刺激的特点和准确性,以及PTi对不同镇静深度下电疼痛刺激的反应情况。方法本研究为前瞻性单臂研究,选取2019年8—12月在温州市中西医结合医院诊断为急性单纯性阑尾炎并择期行全身麻醉腹腔镜阑尾切除手术的患者资料。根据预试验结果,确定样本量为38例。将气管插管(stimulation1,S1)、皮肤切开(stimulation2,S2)、气腹建立(stimulation3,S3)、气腹撤退(stimulation4,S4)和牵拉阑尾(stimulation5,S5)操作前1 min与操作即刻(即零点)的PTi、心率(HR)及平均动脉压(MAP)数值差值定义为基础波动值(resting fluctuation value,RFV),以及操作后5 min内的最大值与零点的差值定义为波动幅度(Δ);将Δ与RFV的比值定义为相对上升常数(relative increasing constant,RIC)。S1后5 min至S2前3 min,调整丙泊酚用量使脑电双频指数(BIS)按60—50—40—30的数值梯度递减。每次BIS调整稳定2 min后,予经皮神经电刺激仪器刺激,共操作4次。观察上述各指标值间的差异。结果38例患者中,3例因术中使用阿托品、1例因PTi数据采集失败剔除,最终纳入34例。纳入患者的年龄为(41.6±2.2)岁,BMI为(23.2±0.6)kg/m 2,ASA分级Ⅰ级19例,Ⅱ级为15例。患者麻醉诱导前1 min的PTi、MAP、HR值分别为92.0±6.2、(75.0±10.7)mmHg(1 mmHg=0.133 kPa)、(76.0±9.2)次/min,RFV PTi、RFV MAP、RFV HR分别为3.17±0.94、(2.38±0.82)mmHg、(0.74±0.02)次/min。S1的ΔPTi、ΔMAP、ΔHR、RIC_(PTi)、RIC_(MAP)和RIC_(HR)值均显著高于S2、S3、S4和S5的对应值(P值均<0.001),S2的RIC_(MAP)值显著小于S4的对应值(P<0.05),S3的ΔPTi、ΔMAP、ΔHR、RIC_(PTi)和RIC_(MAP)值均显著高于S2、S4和S5的对应值(P值均<0.001),S4的RIC_(PTi)值显著高于S5的对应值(P<0.05)。S1、S2和S3的ΔPTi和RIC_(PTi)值均分别显著高于同操作时的ΔMAP、ΔHR值和RIC_(MAP)、RIC_(HR)值(P值均<0.05),S4的ΔPTi和RIC_(PTi)值均分别显著高于同操作时的ΔHR和RIC_(HR)值(P值均<0.05)。RIC_(PTi)诊断S1至S5刺激疼痛的最佳截断值分别为18.75、3.67、12.50、10.50和3.77,均高于同操作时的RIC_(MAP)和RIC_(HR)(P值均<0.05)。ΔPTi和RIC_(PTi)对70 mA电刺激的反应与BIS数值无显著相关性(r=0.56、0.61)。结论PTi相对上升幅度及疼痛诊断效能均高于MAP和HR,且不受镇静深度的干扰,是有效评估疼痛的指标。

Objective To investigate the accuracy and stability of pain threshold index(PTI)in evaluating pain stimuli during general anesthesia.Methods A prospective one-arm study was conducted to select patients who were diagnosed with simple acute appendicitis and underwent elective laparoscopic appendectomy under general anesthesia in Wenzhou Hospital of Integrated Traditional Chinese and Western Medicine from August to December 2019.According to the pre-test results,38 patients were chosen.The difference values of PTI,heart rate(HR)and mean arterial pressure(MAP)1 min before and immediately after operation of tracheal intubation(stimulation 1,S1),skin cutting(stimulation 2,S2),pneumoperitoneum establishment(stimulation 3,S3),pneumoperitoneum retreat(stimulation 4,S4)and traction of the appendix(stimulation 5,S5)were defined as the resting fluctuation value(RFV).The difference between the maximum value within 5 min after immediate operation and the immediate operation was defined as the amplitude of fluctuation(Δ).Δ/RFV was defined as the relative increasing constant(RIC).From 5 min after S1 to 3 min before S2,bispectral index(BIS)decreased by 60-50-40-30 by adjusting the concentration of propofol,and electrical stimulation was applied to each gradient to simulate pain.Results Finally 34 patients were included in this study(3 were excluded due to atropine use during operation and 1 due to PTI acquisition failure).The mean age of the 34 patients was(41.6±2.2)years,BMI was(23.2±0.6)kg/m 2,and the ratio of ASA I to II was 19:15.PTI,MAP and HR were 92.0±6.2,(75.0±10.7)mmHg(1 mmHg=0.133 kPa)and 76.0±9.2/min before anesthesia induction respectively,and RFV PTI,RFV MAP and RFV HR were 3.17±0.94,(2.38±0.82)mmHg and 0.74±0.02/min respectively.ΔPTI,ΔMAP,ΔHR,RIC PTI,RIC_(MAP)and RIC_(HR)in S1 were significantly higher than those in S2,S3,S4 and S5(P<0.001).RIC_(MAP)in S2 was significantly lower than that in S4(P<0.05).ΔPTI,ΔMAP,ΔHR,RIC_(PTI)and RIC_(MAP)in S3 were significantly higher than those in S2,S4 and S5(P<0.001).RIC_(PTI)in S4 was significantly higher than that in S5(P<0.05).ΔPTI and RIC_(PTI)were significantly higher thanΔMAP,ΔHR,RIC_(MAP)and RIC_(HR)in S1,S2 and S3(P<0.05).ΔPTI and RIC_(PTI)were significantly higher thanΔHR and RIC_(HR)in S4(P<0.05).The best cutoff values of RIC_(PTI)for the diagnosis of S1-S5 were 18.75,3.67,12.50,10.50 and 3.77 respectively,which were higher than RIC_(MAP)and RIC_(HR)in the same operation.ΔPTI and RIC_(PTI)had no significant correlation with BIS depth(r=0.56,0.61).Conclusion The relative rise of PTI and the accuracy of pain diagnosis are greater than those of MAP and HR,which is not affected by BIS depth and makes PTI an effective indicator for pain evaluation.