Huybrechts Isabelle, Barvais Luc, Ducart Anne, Engelman Edgard, Schmartz Denis, Koch Marc
Department of Anesthesiology, Erasme University Hospital, Free University of Brussels, Brussels, Belgium.
J Cardiothorac Vasc Anesth. 2006 Oct;20(5):664-7. doi: 10.1053/j.jvca.2006.04.004. Epub 2006 Aug 8.
Pupillary reflex dilation (PRD) secondary to noxious stimulation accurately predicts sensory block during combined lumbar epidural/general anesthesia. Therefore, the adequacy of PRD-guided thoracic epidural infusion during general anesthesia for thoracotomy was studied.
Prospective study.
University hospital.
Thirteen patients undergoing thoracotomy.
An epidural catheter was placed at the T3-T4 level with initial infusion rate of 5 mL/h of ropivacaine 0.5%. Propofol/remifentanil target-controlled infusion was used for induction and maintenance of general anesthesia. Remifentanil effect site concentration was maintained constant at 0.5 ng/mL during surgery. By using a portable pupillometer, PRD secondary to tetanic stimulation of the C8, T2, and T4 segments were evaluated. Ropivacaine flow rate was adapted half hourly, according to PRD testing and a predefined algorithm. At the end of surgery, PRD was tested in the 3 investigated segments, and general anesthesia was stopped. After emergence, these zones were tested for their sensitivity to cold. Pain was evaluated by using the visual analog scale.
Pain scores were <3 of 10 in 84.6% of the patients. Mean PRD was 0.9 +/- 0.6 mm in unblocked levels versus 0.2 +/- 0.5 mm in blocked segments (p = 0.02). PRD >or= 0.5 mm was predictive of incomplete block (sensitivity 76%, specificity 79%, and positive predictive value 86%). PRD >or= 1 mm was highly predictive of inadequate block (sensitivity 73%, specificity 91%, and positive predictive value 94%).
PRD-guided continuous thoracic epidural analgesia under low-dose remifentanil/propofol anesthesia is feasible and ensures good postoperative analgesia.
有害刺激继发的瞳孔反射性扩张（PRD）能准确预测腰段硬膜外联合全身麻醉期间的感觉阻滞情况。因此，本研究探讨了PRD指导下全身麻醉开胸手术期间胸段硬膜外输注的充分性。
前瞻性研究。
大学医院。
13例行开胸手术的患者。
在T3 - T4水平放置硬膜外导管，初始输注速率为0.5%罗哌卡因5 mL/h。采用丙泊酚/瑞芬太尼靶控输注诱导并维持全身麻醉。手术期间瑞芬太尼效应室浓度维持在0.5 ng/mL不变。使用便携式瞳孔计评估C8、T2和T4节段强直刺激继发的PRD。根据PRD测试和预定义算法，每半小时调整一次罗哌卡因流速。手术结束时，在3个研究节段测试PRD，并停止全身麻醉。苏醒后，检测这些区域对冷的敏感性。采用视觉模拟评分法评估疼痛。
84.6%的患者疼痛评分＜3分（满分10分）。未阻滞节段的平均PRD为0.9±0.6 mm，而阻滞节段为0.2±0.5 mm（p = 0.02）。PRD≥0.5 mm可预测阻滞不全（敏感性76%，特异性79%，阳性预测值86%）。PRD≥1 mm高度预测阻滞不足（敏感性73%，特异性91%，阳性预测值94%）。
在低剂量瑞芬太尼/丙泊酚麻醉下，PRD指导的连续胸段硬膜外镇痛是可行的，并能确保良好的术后镇痛效果。
