Beardsley D, Holman S, Gantt R, Robinson R A, Lindsey J, Bazaral M, Stewart S F, Stevens R A
Department of Anesthesiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.
Anesth Analg. 1995 Aug;81(2):314-20. doi: 10.1097/00000539-199508000-00019.
Recent reports of transient neurologic deficits have raised concern about the potential toxicity of single-dose spinal 5% lidocaine in 7.5% dextrose. Two cases of volunteers who experienced minor local sensory deficits after slow (60 s) injections of 2 mL 5% lidocaine via Whitacre needles are described. One case was a result of a double injection because of a "failed" block. It seemed possible that the neurologic deficit in these cases resulted from neurotoxicity associated with maldistribution of local anesthetic. Using an in vitro spinal model, we investigated drug distribution resulting from injections through side-port spinal needles to determine whether the use of these needles could result in high local concentrations of hyperbaric solutions. A spinal canal model was fabricated using human magnetic resonance measurements. The model was placed in a surgical supine position and filled with lactated Ringer's solution to simulate the specific gravity of cerebral spinal fluid at 22 degrees C. A hyperbaric solution of phthalocyanine blue dye and dextrose (SG 1.042), simulating the anesthetic, was injected through three different needles (27-gauge 4 11/16-in. Whitacre, 25-gauge 3 1/2-in. Whitacre, 25-gauge 3 1/2-in. Quincke). Triplicate injections were done at rapid (2 mL/10 s) and slow (2 mL/60 s) rates, with needle side ports oriented in a sacral and cephalad direction. At slow rates of injection, using 27- or 25-gauge sacrally directed Whitacre needles, injections showed evidence of maldistribution with extrapolated peak sacral lidocaine concentrations reaching 2.0%. In contrast, distribution after slow injection through sacrally directed Quincke needles was uniform.(ABSTRACT TRUNCATED AT 250 WORDS)
近期关于短暂性神经功能缺损的报告引发了人们对单剂量脊髓注射5%利多卡因溶于7.5%葡萄糖溶液潜在毒性的关注。本文描述了两例志愿者在通过惠特克针缓慢（60秒）注射2毫升5%利多卡因后出现轻微局部感觉缺损的案例。其中一例是由于“阻滞失败”导致的重复注射。这些案例中的神经功能缺损似乎可能是由于局部麻醉药分布不均相关的神经毒性所致。我们使用体外脊髓模型，研究了通过侧孔脊髓针注射后的药物分布情况，以确定使用这些针是否会导致高比重溶液在局部产生高浓度。利用人体磁共振测量数据制作了一个椎管模型。将该模型置于手术仰卧位，并用乳酸林格氏液填充，以模拟22摄氏度时脑脊液的比重。通过三种不同的针（27号4 11/16英寸惠特克针、25号3 1/2英寸惠特克针、25号3 1/2英寸昆克针）注射模拟麻醉剂的酞菁蓝染料和葡萄糖的高比重溶液（比重1.042）。以快速（2毫升/10秒）和缓慢（2毫升/60秒）的速度进行三次重复注射，针的侧孔分别朝向骶部和头侧方向。在缓慢注射速度下，使用27号或25号朝向骶部的惠特克针注射时，显示出分布不均的迹象，推测骶部利多卡因峰值浓度达到2.0%。相比之下，通过朝向骶部的昆克针缓慢注射后的分布是均匀的。（摘要截取自250字）
