Wiesmann Thomas, Müller Stefan, Müller Hans-Helge, Wulf Hinnerk, Steinfeldt Thorsten
Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine, University Hospital Marburg, Philipps University, Marburg.
Department of Anesthesiology and Intensive Care Medicine, University Hospital Giessen, Justus-Liebig-University, Giessen.
J Pain Res. 2018 Jan 23;11:227-235. doi: 10.2147/JPR.S152230. eCollection 2018.
Nerve blood flow has a critical role in acute and chronic pathologies in peripheral nerves. Influences of local anesthetics and adjuvants on tissue perfusion and oxygenation are deemed as relevant factors for nerve damage after peripheral regional anesthesia. The link between low tissue perfusion due to local anesthetics and resulting tissue oxygenation is unclear.
Combined tissue spectrophotometry and laser-Doppler flowmetry were used to assess nerve blood flow in 40 surgically exposed median nerves in pigs, as well as nerve tissue oximetry for 60 min. After baseline measurements, test solutions saline (S), bupivacaine (Bupi), bupivacaine with epinephrine (BupiEpi), and bupivacaine with clonidine (BupiCloni) were applied topically.
Bupivacaine resulted in significant decrease in nerve blood flow, as well as tissue oximetry values, compared with saline control. Addition of epinephrine resulted in a rapid, but nonsignificant, reduction of nerve blood flow and extensive lowering of tissue oximetry levels. The use of clonidine resulted in a reduction of nerve blood flow, comparable to bupivacaine alone (relative blood flow at T60 min compared with baseline, S: 0.86 (0.67-1.18), median (25th-75th percentile); Bupi: 0.33 (0.25-0.60); BupiCloni: 0.43 (0.38-0.63); and BupiEpi: 0.41(0.30-0.54). The use of adjuvants did not result in any relevant impairment of tissue oximetry values (saturation values in percent at T60, S: 91.5 [84-95]; Bupi: 76 [61-86]; BupiCloni: 84.5 [76-91]; and BupiEpi: 91 [56-92]).
The application of bupivacaine results in lower nerve blood flow, but does not induce relevant ischemia. Despite significant reductions in nerve blood flow, the addition of clonidine or epinephrine to bupivacaine had no significant impact on nerve tissue oximetry compared with bupivacaine alone. Nerve ischemia due to local anesthetics is not enhanced by the adjuvants clonidine or epinephrine.
神经血流在周围神经的急性和慢性病变中起关键作用。局部麻醉药和佐剂对组织灌注和氧合的影响被认为是周围区域麻醉后神经损伤的相关因素。局部麻醉药导致的低组织灌注与由此产生的组织氧合之间的联系尚不清楚。
采用联合组织分光光度法和激光多普勒血流仪评估40只猪手术暴露的正中神经的神经血流，并进行60分钟的神经组织血氧测定。在基线测量后，局部应用测试溶液生理盐水（S）、布比卡因（Bupi）、含肾上腺素的布比卡因（BupiEpi）和含可乐定的布比卡因（BupiCloni）。
与生理盐水对照组相比，布比卡因导致神经血流以及组织血氧测定值显著降低。添加肾上腺素导致神经血流迅速但不显著减少，组织血氧测定水平大幅降低。使用可乐定导致神经血流减少，与单独使用布比卡因相当（与基线相比，T60分钟时的相对血流，S：0.86（0.67 - 1.18），中位数（第25 - 75百分位数）；Bupi：0.33（0.25 - 0.60）；BupiCloni：0.43（0.38 -
