Fisher Q A, Shaffner D H, Yaster M
Department of Anaesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD 21287-5842, USA.
Can J Anaesth. 1997 Jun;44(6):592-8. doi: 10.1007/BF03015441.
Detection of intravascular injection of local anaesthetic during placement of regional blocks in children by using epinephrine-induced tachycardia or hypertension may produce false positive and false negative findings. This study evaluates ECG changes as markers of intravascular injection of local anaesthetics with epinephrine, during placement of epidural blocks in children.
Observational study in a teaching hospital of all epidural anaesthetics administered to paediatric patients during one year. General anaesthesia, where used, was not controlled. An ECG rhythm strip was recorded during test dose injection and analyzed for changes in rate, rhythm, and T-wave configuration.
During the study period, 742 paediatric epidural blocks were administered. There were 644 caudal (284 without catheters), 97 lumbar, and one thoracic epidural anaesthetics. Satisfactory placement was achieved in 97.7% of patients. Intravascular injection was detected in 42 (5.6%) of epidural anaesthetics (3.8% and 6.7% of straight needle and catheter injections, respectively). Detection was by immediate aspiration of blood in six patients, and by heart rate increases > 10 bpm in 30. Five had heart rate decreases suggesting a baroreceptor response. Five had heart rate increases < 10 bpm that were possible responses to noxious stimuli. Of 30 patients with known intravascular injection and for whom ECG strips were available, 25 (83%) had T-wave amplitude increases > 25%, and 29 (97%) had ECG changes in T-wave or rhythm in response to the epinephrine injection. There were no false positives.
In order to reduce risks associated with epidural anaesthesia in children, epinephrine should be added to the local anaesthetic test dose, the ECG should be monitored continuously for changes in heart rate, rhythm, and T-wave amplitude. Epidural injections should be given in small increments.
在儿童区域阻滞置管期间，通过使用肾上腺素诱发的心动过速或高血压来检测局部麻醉药的血管内注射可能会产生假阳性和假阴性结果。本研究评估心电图变化作为儿童硬膜外阻滞置管期间含肾上腺素局部麻醉药血管内注射的标志物。
在一家教学医院对一年内给予儿科患者的所有硬膜外麻醉进行观察性研究。使用的全身麻醉未进行控制。在注射试验剂量期间记录心电图节律条，并分析心率、节律和T波形态的变化。
在研究期间，共进行了742例儿科硬膜外阻滞。其中有644例骶管阻滞（284例未置管）、97例腰段硬膜外麻醉和1例胸段硬膜外麻醉。97.7%的患者置管成功。在42例（5.6%）硬膜外麻醉中检测到血管内注射（直针注射和置管注射分别为3.8%和6.7%）。6例患者通过立即回抽出血液检测到，30例通过心率增加>10次/分钟检测到。5例心率下降提示压力感受器反应。5例心率增加<10次/分钟可能是对有害刺激的反应。在30例已知血管内注射且有心电图条的患者中，25例（83%）T波振幅增加>25%，29例（97%）对肾上腺素注射有T波或节律的心电图变化。无假阳性结果。
为降低儿童硬膜外麻醉相关风险，应在局部麻醉药试验剂量中加入肾上腺素，应持续监测心电图以观察心率、节律和T波振幅的变化。硬膜外注射应小剂量递增给药。
