Galvin Eilish M, Niehof Sjoerd, Verbrugge Serge Jc, Maissan Iscandar, Jahn Alexander, Klein Jan, van Bommel Jasper
Department of Anesthesiology, Erasmus University Medical Center, 3015 GD, Rotterdam, The Netherlands.
Anesth Analg. 2006 Jul;103(1):239-43, table of contents. doi: 10.1213/01.ane.0000220947.02689.9f.
We investigated the usefulness of peripheral flow index (PFI) measurement using a standard pulse oximetry digit probe for early prediction of successful regional blocks. Sixty-six patients scheduled for limb surgery underwent either axillary or sciatic block using a nerve stimulator technique with mepivacaine 1.5%. PFI, which is the ratio of the pulsatile versus the nonpulsatile component of the pulse oximetry signal, was recorded from 10 min before block insertion until 30 min afterwards. PFI recordings of the unblocked limb were similarly recorded. Pinprick and cold sensation were assessed at 5-min intervals until 30 min after blockade. An increase in PFI by a factor of 1.55 at 10 min after axillary block placement (P = 0.006), and 12 min after sciatic block placement (P = 0.001) was required to predict a successful block. The sensitivity and specificity of PFI was 100% for predicting axillary block outcomes at this time. Positive predictive value was 95% and negative predictive value was 93%. For sciatic blocks, sensitivity and specificity were 90% and 100%, respectively. The calculated positive predictive value at time 12 min for sciatic blocks was 94% and negative predictive value was 92%. At 15 min after block placement, cold and pinprick sensations had the same calculated values for sensitivity and specificity at 71% and 100%, respectively, for axillary blocks. For sciatic blocks, cold sensation had a sensitivity of 77% and a specificity of 100%, whereas pinprick had a sensitivity of just 20% with a specificity of 100%. We conclude that PFI provides a simple, early, and objective assessment of the success and failure of nerve blocks.
我们研究了使用标准脉搏血氧仪指套探头测量外周血流指数（PFI）对区域阻滞成功进行早期预测的有效性。66例计划进行肢体手术的患者采用神经刺激器技术，使用1.5%的甲哌卡因进行腋路或坐骨神经阻滞。PFI是脉搏血氧仪信号中搏动成分与非搏动成分的比值，在阻滞插入前10分钟至插入后30分钟进行记录。对未阻滞肢体的PFI记录也进行了类似操作。每隔5分钟评估一次针刺和冷觉，直至阻滞后30分钟。预测腋路阻滞成功需要在腋路阻滞放置后10分钟（P = 0.006）和坐骨神经阻滞放置后12分钟（P = 0.001）时PFI增加1.55倍。此时PFI预测腋路阻滞结果的敏感性和特异性均为100%。阳性预测值为95%，阴性预测值为93%。对于坐骨神经阻滞，敏感性和特异性分别为90%和100%。在12分钟时计算得出的坐骨神经阻滞阳性预测值为94%，阴性预测值为92%。在阻滞放置后15分钟时，对于腋路阻滞，冷觉和针刺觉的敏感性和特异性计算值分别为71%和100%。对于坐骨神经阻滞，冷觉敏感性为77%，特异性为100%，而针刺觉敏感性仅为20%，特异性为100%。我们得出结论，PFI为神经阻滞的成功与失败提供了一种简单、早期且客观的评估方法。
