Fiedler M A
Nurse Anesthesia Program, School of Health Related Professions, University of Alabama at Birmingham, USA.
AANA J. 1997 Aug;65(4):371-81.
Hypotension caused by reduced venous return to the heart is a common hazard during subarachnoid and epidural anesthesia. Reduced venous return can also cause severe bradycardia and even cardiac arrest. The infusion of a crystalloid intravenous preload prior to the injection of local anesthetic helps prevent these complications. Unfortunately, intravenous fluid preloading prior to subarachnoid or epidural block is neither appropriate for all patients nor is it always effective. Vasopressor infusions and lower extremity compression, though not completely studied, may allow for further decreases in the incidence of hypotension and bradycardia. When dosing an epidural catheter, making each dose a test dose and observing for signs of subarachnoid or intravascular injection decreases the incidence of hypotension, seizure, and cardiotoxicity. The pathophysiology of cardiac arrest and resuscitation is different during major conduction block due primarily to changes in peripheral vascular tone and venous return to the heart. Neural injury associated with regional anesthesia is due to needle trauma, hematoma, injectate toxicity, ischemia, and compression. Though neural injury is rare, it is more commonly associated with blocks performed in the lumbar region (spinals and epidurals) than in other types of blocks.
因回心血量减少导致的低血压是蛛网膜下腔麻醉和硬膜外麻醉期间常见的风险。回心血量减少还可导致严重心动过缓甚至心脏骤停。在注射局部麻醉剂之前输注晶体静脉预负荷有助于预防这些并发症。不幸的是，在蛛网膜下腔或硬膜外阻滞之前进行静脉补液预负荷既不适用于所有患者，也并非总是有效。血管加压药输注和下肢加压，尽管尚未得到充分研究，但可能会进一步降低低血压和心动过缓的发生率。在给硬膜外导管给药时，每次给药作为试验剂量并观察蛛网膜下腔或血管内注射的体征，可降低低血压、癫痫发作和心脏毒性的发生率。主要由于外周血管张力和回心血量的变化，在严重传导阻滞期间心脏骤停和复苏的病理生理学有所不同。与区域麻醉相关的神经损伤是由针刺创伤、血肿、注射剂毒性、缺血和压迫引起的。虽然神经损伤很少见，但与在腰部区域进行的阻滞（脊髓麻醉和硬膜外麻醉）相比，在其他类型的阻滞中更常见。
