Bachmann B, Biscoping J, Adams H A, Sokolovski A, Ratthey K, Hempelmann G
Abteilung Anaesthesiologie und Operative Intensivmedizin, Justus-Liebig-Universität Giessen.
Laryngol Rhinol Otol (Stuttg). 1988 Jul;67(7):335-9.
Infiltration anaesthesia is still relevant for the surgical treatment of patients in otorhinolaryngology. The injection of local anaesthetics in well vascularised areas constantly causes the danger of high plasma concentrations of local anaesthetics combined with undesirable side effects. In our study we tried to determine the development of plasma concentrations of local anaesthetics in patients scheduled for routine tonsillectomies and tympanoplasty.
In 45 patients the development of plasma concentrations was measured immediately after the injection at short intervals; the samples were obtained between 1 minute and 60 minutes after the first injection. Group 1: Lidocaine 0.5% with epinephrine (1:200,000) 15-20 ml for tonsillectomy (n = 18). Group 2: Lidocaine 0.5% with epinephrine (1:200,000) 8-15 ml for tympanoplasty (n = 15). Group 3: Prilocaine 1% with epinephrine (1:200,000) 8-15 ml for tympanoplasty (n = 15). For tactical reasons infiltration anaesthesia for the patients of group 2 was - in addition to general anaesthesia - applied by the otorhinolaryngologist, whereas the patients of groups 1 and 3 were operated exclusively under local anaesthesia.
Within the first minute after the initial injection plasma concentrations of the local anesthetic increased close to toxic threshold levels that are associated with undesirable systemic side effects. In the patients of group 1, who underwent tonsillectomy, plasma concentrations of 4-7 micrograms/ml were found during the first minute. The highest average values always appeared within the first five minutes: group 1 2.07 micrograms/ml, group 2: 0.45 micrograms/ml, and group 3: 1.15 micrograms/ml.
With infiltration anaesthesia in well vascularised areas it may happen that there are--mainly in the early stage--high plasma concentrations of the applied substances, although the total dose was below the known maximum. Despite careful technique (repeated aspiration test in two levels) at least partial intravascular injections are apparently not always avoidable according to the pharmacokinetic data. Our results demonstrate that in addition to a safe peripheral venous line and prophylactic oxygen therapy, intraoperative monitoring of blood pressure, heart rate, electrocardiogram and verbal patient monitoring is of advantage in this group of patients. In our opinion the "standby function" of an anaesthesiologist can avoid severe complications.
浸润麻醉在耳鼻喉科患者的外科治疗中仍具有重要意义。在血管丰富的区域注射局部麻醉药始终存在局部麻醉药血浆浓度过高并伴有不良副作用的风险。在我们的研究中，我们试图确定计划进行常规扁桃体切除术和鼓室成形术的患者局部麻醉药血浆浓度的变化情况。
对45例患者在注射后立即每隔短时间测量血浆浓度变化；在首次注射后1分钟至60分钟内采集样本。第1组：0.5%利多卡因加肾上腺素（1:200,000）15 - 20毫升用于扁桃体切除术（n = 18）。第2组：0.5%利多卡因加肾上腺素（1:200,000）8 - 15毫升用于鼓室成形术（n = 15）。第3组：1%丙胺卡因加肾上腺素（1:200,000）8 - 15毫升用于鼓室成形术（n = 15）。出于策略原因，第2组患者除全身麻醉外，由耳鼻喉科医生实施浸润麻醉，而第1组和第3组患者仅在局部麻醉下手术。
首次注射后1分钟内，局部麻醉药的血浆浓度升高至接近与不良全身副作用相关的中毒阈值水平。在接受扁桃体切除术的第1组患者中，第1分钟时血浆浓度为4 - 7微克/毫升。最高平均值总是出现在前5分钟内：第1组2.07微克/毫升，第2组：0.45微克/毫升，第3组：1.15微克/毫升。
在血管丰富的区域进行浸润麻醉时，可能会出现——主要在早期——所用药物的血浆浓度过高，尽管总剂量低于已知最大值。根据药代动力学数据，尽管技术操作谨慎（在两个层面重复进行回抽试验），但至少部分血管内注射显然并非总能避免。我们的结果表明，除了建立安全的外周静脉通路和预防性氧疗外，对这组患者进行术中血压、心率、心电图监测以及对患者进行言语监测是有益的。我们认为麻醉医生的“备用功能”可以避免严重并发症。
