【正文】
縮, 無(wú)明顯全身反應(yīng) . 常用 1:20萬(wàn) (高血壓病人禁用 ). ◆ 局麻藥濃度選擇 決定硬膜外阻滯范圍的最主要因素 —— 麻醉藥容量 決定硬膜外阻滯深度和作用持續(xù)時(shí)間 —— 麻醉藥濃度 ◆局麻藥的混合使用: 起效快 +起效慢 潛伏期短 長(zhǎng)效 +短效 維持時(shí)間長(zhǎng) 混合 → ◆ 注藥方式 : ● 注射試驗(yàn)量 (test dose):35ml. 目的 :排除誤入蛛網(wǎng)膜下隙的可能; ● 注入增加量 (incremental dose): 注入試驗(yàn)量 510min,如無(wú)腰麻征象 →可每隔 5min注入 35ml,直至阻滯范圍滿(mǎn)足手術(shù)要求; ● 追加維持量 (maintain dose):首次總量的 1/2—1/3。椎管內(nèi)麻醉 Neuraxial Anesthesia 夏 瑞 Introduction——Correlated Anatomy ? 三條韌帶 (由外到內(nèi) ) – 棘上韌帶 supraspinous ligament – 棘間韌帶 interspinous ligament – 黃韌帶 ligamentum flavum (yellow ligament) Correlated Anatomy ? 脊髓由脊膜所包裹 ? 脊膜 (由內(nèi)至外 )分為: – 軟膜 pia mater – 蛛網(wǎng)膜 arachnoid mater – 硬脊膜 dura mater ? 兩層:內(nèi)膜、外膜 ? 硬膜外腔 epidural space 硬脊膜內(nèi)、外層之間的區(qū)域 ? 蛛網(wǎng)膜下腔 subarachnoid space 軟膜和蛛網(wǎng)膜之間的區(qū)域 Correlated Anatomy Classification of Neuraxial Anesthesia ?蛛網(wǎng)膜下腔阻滯麻醉 Spinal Anesthesia ?硬膜外腔阻滯麻醉 Epidural Anesthesia ?蛛網(wǎng)膜下腔與硬膜外腔聯(lián)合阻滯麻醉 Combined spinalepidural Anesthesia ,CSEA ?骶管阻滯麻醉 Caudal Anesthesia 第一節(jié) 蛛 網(wǎng) 膜 下 腔 阻 滯(脊麻 ) Section one Subarachnoid block (spinal anesthesia) ? 定義 ( definition) The agent is injected into the CSF(cerebrospinal fluid) in the subarachnoid space of the meninges (the threelayered covering of the spinal cord) using a lumbar interspace in the vertebral column. 局麻藥 腦脊液 脊神經(jīng)、背根神經(jīng)節(jié)及脊髓表面 一、概述 (outline) 第一節(jié) 蛛 網(wǎng) 膜 下 腔 阻 滯 Section one Subarachnoid block (spinal anesthesia) ?比重: According to the differences of gravity between the local anesthetic and CSF Hyperbaric solution: It is heavier than CSF,and it can be made (重比重 ) by the addition of glucose. Hypobaric solution: It is lighter than CSF,and it can be made (輕比重 ) by the addition of sterile water. Isobaric solution: It is nearly equal to gravity of CSF, and it is (等比重 ) mixed with CSF(at least 1:1). (The gravity of CSF is ~ ) 概述 (outline) 平面: According to the level of neural blockade Spinal anesthesia high position: The sensory blockade > T4 mid position: The sensory blockade≤T5—9 low position: The sensory blockade< T10. ―saddle block‖ (鞍麻) means that the level of neural blockade is limited to perineum(會(huì)陰 ) or hip (臀部 ). “Unilateral block‖ means that the level of neural blockade is limited to unilateral lower extremity (單側(cè)阻滯 ) 一、概述 (outline) 二、蛛網(wǎng)膜下隙阻滯的機(jī)制及其對(duì)生理的影響 (The mechanism of action and physiologic responses) 1. 直接作用 (Direct actions) : ▲ The site of action: The principal site of action is the nerve root. ▲ The sequence of block: Autonomic Nf* sensory Nf motor Nf myelinated Ar Nf * (有髓鞘的本體感覺(jué)纖維 ) ▲ The differential level of block: Sympathetic block may be 24 segments higher than sensory block, which in turn is 14 segments higher than motor block. Nf: nerve fiber 2. 間接作用 (全身影響 ): Indirect actions(systemic effects) ★ Cardiovascular manifestations——心血管系統(tǒng)影響 Sympathetic Nf block vasodilation of venous capacitance vessels capacity of venous return to heart a