Goffin Pierre, Mejia Jorge, Prats-Galino Alberto, Morales Lorena, Panzeri Miriam, Sala-Blanch Xavier
Masters Degree in Advanced Medical Skills. Regional Anesthesia Based on Human Anatomy, University of Barcelona, Barcelona, Barcelona, Spain.
Anesthesia and Intensive Care, MontLégia Hospital, Groupe Santé CHC, Liège, Belgium.
Reg Anesth Pain Med. 2022 Aug 9. doi: 10.1136/rapm-2022-103759.
Inadvertent intraneural injection is not infrequent during peripheral nerve blocks. For this reason, injection pressure monitoring has been suggested as a safeguard method that warns the clinician of a potentially hazardous needle tip location. However, doubts remain whether it is superior to the sonographic nerve swelling in terms of earlier detection of the intraneural injection.
An observational cadaveric study was designed to assess injection pressures during an ultrasound-guided intraneural injection of the median nerve. We hypothesized that the evidence of nerve swelling occurred elevated injection pressure (>15 pound per square inch) measured with a portable in-line monitor. 33 ultrasound-guided intraneural injections of 11 median nerves from unembalmed human cadavers were performed at proximal, mid and distal forearm. 1 mL of a mixture of local anesthetic and methylene blue was injected intraneurally at a rate of 10 mL/min. Following injections, specimens were dissected to assess spread location. Video recordings of the procedures including ultrasound images were blindly analyzed to evaluate nerve swelling and injection pressures.
31 injections were considered for analysis (two were excluded due to uncertainty regarding needle tip position). >15 pound per square inch was reached in six injections (19%) following a median injected volume of 0.6 mL. Nerve swelling was evident in all 31 injections (100%) with a median injected volume of 0.4 mL. On dissection, spread location was confirmed intraneural in all injections.
Ultrasound is a more sensitive and earlier indicator of the low-volume intraneural injection than injection pressure monitoring.
在周围神经阻滞过程中，不经意的神经内注射并不罕见。因此，注射压力监测被建议作为一种保障方法，用以提醒临床医生注意潜在危险的针尖位置。然而，在神经内注射的早期检测方面，它是否优于超声引导下的神经肿胀仍存在疑问。
设计了一项观察性尸体研究，以评估超声引导下正中神经内注射时的注射压力。我们假设，神经肿胀的证据出现在用便携式在线监测仪测量的注射压力升高（>15磅/平方英寸）时。对来自未防腐处理的人体尸体的11条正中神经进行了33次超声引导下的神经内注射，注射部位为前臂近端、中段和远端。以10 mL/分钟的速度将1 mL局部麻醉剂和亚甲蓝的混合物神经内注射。注射后，解剖标本以评估扩散位置。对包括超声图像在内的操作视频记录进行盲法分析，以评估神经肿胀和注射压力。
31次注射纳入分析（2次因针尖位置不确定而排除）。注射量中位数为0.6 mL后，6次注射（19%）达到>15磅/平方英寸。31次注射（100%）均出现明显的神经肿胀，注射量中位数为0.4 mL。解剖时，所有注射均证实扩散位置在神经内。
对于小剂量神经内注射，超声是比注射压力监测更敏感、更早的指标。
