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椎管内麻醉 Neuraxial Anesthesia. 长江大学临床医学院 外科教研室. 目的要求. 掌握蛛网膜下腔阻滞和硬脊膜外腔阻滞的分类、操作方法、注意事项和麻醉管理; 熟悉蛛网膜下腔阻滞和硬脊膜外腔阻滞的适应症和禁忌症,常见并发症及其防治; 了解蛛网膜下腔阻滞和硬脊膜外腔阻滞的作用机理;掌握其对机体生理的影响。. Introduction ——Correlated Anatomy. 三条韧带 ( 由外到内 ) 棘上韧带 supraspinous ligament 棘间韧带 interspinous ligament
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椎管内麻醉Neuraxial Anesthesia 长江大学临床医学院外科教研室
目的要求 • 掌握蛛网膜下腔阻滞和硬脊膜外腔阻滞的分类、操作方法、注意事项和麻醉管理; • 熟悉蛛网膜下腔阻滞和硬脊膜外腔阻滞的适应症和禁忌症,常见并发症及其防治; • 了解蛛网膜下腔阻滞和硬脊膜外腔阻滞的作用机理;掌握其对机体生理的影响。
Introduction——CorrelatedAnatomy • 三条韧带(由外到内) • 棘上韧带 supraspinous ligament • 棘间韧带 interspinous ligament • 黄韧带 ligamentum flavum (yellow ligament)
CorrelatedAnatomy • 脊髓由脊膜所包裹 • 脊膜(由内至外)分为: • 软膜 pia mater • 蛛网膜 arachnoid mater • 硬脊膜 dura mater • 两层:内膜、外膜 • 硬膜外腔 epidural space 硬脊膜内、外层之间的区域 • 蛛网膜下腔subarachnoid space 软膜和蛛网膜之间的区域
Classification of Neuraxial Anesthesia • 蛛网膜下腔阻滞麻醉Spinal Anesthesia • 硬膜外腔阻滞麻醉Epidural Anesthesia • 蛛网膜下腔与硬膜外腔联合阻滞麻醉Combined spinal-epidural Anesthesia ,CSEA • 骶管阻滞麻醉Caudal Anesthesia
第一节 蛛网膜下腔阻滞(脊麻)Section one Subarachnoid block (spinal anesthesia) 一、概述(outline) • 定义(definition) The agent is injected into the CSF(cerebrospinal fluid) in the subarachnoid space of the meninges (the three-layered covering of the spinal cord) using a lumbar interspace in the vertebral column. 局麻药 脑脊液 脊神经、背根神经节及脊髓表面
脊麻概述 • 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 (轻比重) 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 1.003~1.009)
脊麻概述 平面:According to the level of neural blockade high position: The sensory blockade >T4 Spinal anesthesia mid position: The sensory blockade≤T5—9 low position: The sensory blockade<T10. “saddle block” means that the level of neural blockade islimited to perineum(会阴) or hip (臀部). (鞍麻) “Unilateral block” means that the level of neural blockade is limited to unilateral lower extremity (单侧阻滞)
二、蛛网膜下隙阻滞的机制及其对生理的影响 (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 * Nf: nerve fiber (有髓鞘的本体感觉纤维) ▲ The differential level of block: Sympathetic block may be 2-4 segments higher than sensory block, which in turn is 1-4 segments higher than motor block.
2. 间接作用(全身影响): Indirect actions(systemic effects) ★ Cardiovascular manifestations——心血管系统影响 vasodilation of venous capacitance vessels capacity of venous return to heart Sympathetic Nf block arterial vasodilation BP systemic vascular resistance sympathetic cardiac accelarator fibers block HR
Indirect actions(systemic effects) ★Pulmonary manifestations(呼吸系统影响) • Tidal volume remains unchanged during high spinal anesthesia, and vital capacity decreases a small amount from 4.05 to 3.73 L 潮气量改变不明显,肺活量少量下降 • The rare respiratory arrest associated with spinal anesthesia is also unrelated to phrenic or inspiratory dysfunction but rather to hypoperfusion of the respiratory centers in the brainstem 呼吸暂停与脑干呼吸中枢血流灌注不足有关,与呼吸肌功能无关
★ Gastrointestinal manifestations(胃肠道影响) Spinal blocksympathetic block vagal tone a contracted gut with active peristasis (内脏收缩,蠕动 ) ★Urinary tract manifestations(泌尿系统影响) Renal blood flow is maintained through autoregulation, and there is little clinical effect on renal function from spinal block. 肾功能影响小
三、蛛网膜下腔阻滞的临床应用 (The clinical applications of subarachnoid block) (一)适应证(indications): • 下腹部手术,如:阑尾切除术、疝修补术 • 肛门及会阴部手术,如:痔切除术 • 盆腔手术,如:子宫切除、膀胱手术 • 下肢手术,如:截肢手术
( 二) 禁忌证(contraindications) • Absolutecontraindications • Infection at the site of injection • Patient refusal • Coagulopathy or other bleeding diathesis • Severe hypovolemia • Increased intracranial pressure • Severe aortic stenosis • Severe mitral stenosis
( 二) 禁忌证(contraindications) • Relative contraindications • Sepsis • Uncooperative patient • Preexisting neurological deficits • Demyelinating lesions • Stenotic valvular heart lesions • Severe spinal deformity
( 二) 禁忌证(contraindications) • Controversial contraindications • Prior back surgery at the site of injection • Inability to communicate with patient • Complicated surgery • Major blood loss • Maneuvers that compromise respiration • Prolonged operation
(三)麻醉前准备preanesthetic preparation • Equipment Respirator Monitor Oxygen • drugs Local anesthetic vasoactive agent
(四)常用局麻药: (Commonly used spinal anesthetic agents) ▲Procaine:procaine 150mg+csf2.7ml or + 5%G.S 2.7ml+0.1%Adr0.3ml. ▲Dicaine: 最常用重比重液(1-1-1溶液): 1%Dicaine 1ml+3-5% Ephedrine 1ml+10%G.S 1ml: 即:0.33%Dicaine(10-15mg) ▲Bupivacaine:常用重比重液: 0.75% Bupivacaine 2ml+10%GS 1ml 常用8-12mg
(五)蛛网膜下腔穿刺术: ( Performing a lumbar puncture) ●体位(Patient position): ★Sitting position: ★Lateral decubitus ★Prone position: ●定位(Identification of lumbar interspaces): A line drawn between both iliac crests usually crosses either the body of L4 or the L3-4 interspace. ●穿刺间隙(Lumbar interspace of penetration): L3-4. Performing a lumbar puncture below L1 in adults or L3 in children avoids needle trauma to the cord.
●穿刺方法(approachs): • 直入法midline approach The midline approach is the technique of first choice because it requires anatomic projection in only two planes and provides a relatively avascular plane. • 侧入法para-midline approach When difficulty in needle insertion is encountered with the midline approach, one option is to use the paramedian route, which does not require the same level of patient cooperation and reversal of lumbar lordosis for success.
(六)阻滞平面的调节 (regulating the level of blockade) 阻滞平面指皮肤感觉消失的界限 The level of sensory blockade can be assessed With pinprick. The motor blockade is two segments lower than the sensory blockade. 麻醉药注入蛛网膜下隙后,要在短时间内主动调节 和控制麻醉平面,达手术所需范围,但应避免平面 过高。
★麻醉平面的影响因素 factors postulates to be related to spinal anesthetic block height • 穿刺间隙 • 药物种类、浓度、剂量及比重 • 注药速度、针口方向 • 病人特征Patient characteristics
Factors Postulated to be Related to Spinal Anesthetic Block Height • Characteristics of anesthetic solution • Density • Amount (mass) • Concentration • Temperature • Volume • Vasoconstrictors
Factors Postulated to be Related to Spinal Anesthetic Block Height • Technique of injection • Site of injection • Direction of injection (needle) • Direction of bevel • Use of barbotage • Rate of injection • Characteristics of spinal fluid • Volume • Pressure (cough/strain/Valsalva) • Density
Factors Postulated to be Related to Spinal Anesthetic Block Height • Patient characteristics • Age • Height • Weight • Gender • Intra-abdominal pressure • Anatomic configuration of spinal column • Position
(七)麻醉中的管理 (intra-anesthesia management) ●BP↓and HR↓: 多发生于腰麻阻滞平面>T4者. ▼ 表现:BP↓:多发生于注药后15-30min, 伴HR↓. 严重者躁动不安、面色苍白. 小A扩张→外阻↓. ▼ BP↓原因:交感N阻滞 小V扩张→血液淤积于周围 血管系→回心血量↓→C.O.↓. ▼HR↓原因: vagal tone dominance ▼处理: 补充血容量:加快输液200-300ml. Ephedrine 5-10mg iv or 30mg im. HR↓→Atropine.
●呼吸抑制(inhibition of respiration): ▼原因:麻醉平面过高→肋间肌麻痹. 复合药的影响(杜氟等). ▼表现:胸式呼吸微弱、腹式呼吸增强.潮气量↓ 咳嗽无力、不能发声、紫绀. ▼处理:有效吸O2、扶助呼吸. (“全脊麻”→呼吸停止、BP↓、心停→CPR) ●恶心、呕吐(nausea and vomit): ▼诱因:BP↓↓→脑供血↓↓→兴奋呕吐中枢. 迷走N功能亢进→胃肠蠕动↑. 手术牵拉内脏. ▼处理:对症治疗
四、并发症Complications • 头痛postoperative headache • 原因:脑脊液外漏 • 处理:平卧至头痛消失,充分补充血容量,对症处理 • 尿潴留urinary retention • 原因:骶神经被阻滞 • 处理:导尿 • 较少见并发症 • 脑神经受累 • 假性脑膜炎 • 下肢瘫痪
特殊并发症 • 马尾神经综合征 • 原因:局麻药浓度过高 • 症状: • 下肢感觉和运动功能长时间不恢复 • 神经系统检查发现鞍骶神经受累 • 大便失禁、尿道扩约肌麻痹 • 处理: 对症治疗
第二节 硬脊膜外阻滞麻醉Section two Epidural anesthesia 一、概述(outline) • 定义(definition) 将局麻药注入硬脊膜外间隙,阻滞脊神经根,使其支配的区域产生暂时性麻痹。
第二节 硬脊膜外阻滞Section two Epidural anesthesia 一、概述(outline) 分类: 单次法:(少用) 延长麻醉作用时间. 连续法 提高硬膜外阻滞的可控性和安全性 高位:穿刺部位:C5-T6 中位:穿刺部位:T6-12 低位:穿刺部位:﹤T12 骶麻:穿刺部位:骶管
二、硬膜外阻滞的作用机制及其生理影响 (The mechanism of action and physiologic responses) ◆局麻药作用的部位(the site of action): ▲椎旁阻滞. ▲经根蛛网膜绒毛阻滞脊N根. ▲局麻药弥散过硬膜→蛛网膜下隙 →“延 迟”的脊麻.
◆局麻药在硬膜外间隙的扩散(pervasion) ●局麻药的容积和浓度(volume and concentration): 容量→决定硬麻“量”的重要因素. 浓度→决定硬麻“质”的重要因素. ●注射速度(the speed of drug injection) : 注药过快→眩晕. ●体位、身高、年龄、妊娠(position,height,age,pregnancy) ●其他:动脉硬化(arteriosclerosis) 脱水(dehydration) →需药量↓. 休克(shock) ◆硬膜外间隙压力(pressure): 硬膜外间隙为负压(negative pressure):以颈部、胸部最高.
◆硬膜外阻滞的影响(systemic effects): ●CNS manifestations: ▼注药后一过性CSF pressure↑(过速→一过性 头晕). ▼局麻药逾量或注入V丛→大量局麻药进入循 环 →惊厥(convulsion). ▼连续法→较长时间内累积性吸收→精神症状 (psychological symptom)、幻觉(illusion).
● Cardiovascular manifestations: ▲神经性因素: 阻力血管(resistance vessels) ★ 节段性交感神经阻滞 扩张 容量血管(capacitance vessels) ★ 平面>T4→心交感N(cardiac sympathetic nerve)麻痹→HR↓ ▲药理性因素: ★局麻药吸收→平滑肌抑制 →抑制β-R→C.O.↓ ★局麻药中Adr吸收→兴奋β-R→C.O.↑ ▲局部因素: 注速快→CSF pressure↑→短暂C.O.反射性↑
●Respiratory manifestations: ▲阻滞平面的影响(effects of level of blockade): The level of sensory blockade<T8→呼吸功能无明显影响. The level of sensory blockade ≥T2-4→膈N(diaphragm nerve) 抑制→肺活量(vital capacity)↓ ▲局麻药种类、浓度的影响 ▲年老、体弱、久病者→平面过高→通气储备不足 ▲其他因素:
●Visceral manifestations: 肠蠕动↑ ●Effects on muscular tension: 运动N阻滞不全,但仍有肌松作用. ▲反射性松弛:传入Nf被阻滞. ▲局麻药吸收后→选择性阻滞运动N末梢.
硬膜外镇痛作用产生的机制 • 局麻药:阻滞感觉神经纤维 • 阿片类药物:与阿片受体结合 • 阻断疼痛反应的恶性循环,减少创伤部位致疼物质释放;减轻神经内分泌反射;抑制疼痛反应中的中枢敏化机制和外周敏化机制
三、硬膜外阻滞的临床应用(The clinical applications of epidural block) ( 一)适应症与禁忌症 • 适应症 indications • 颈部以下手术(以腹部以下为佳) • 镇痛 (术后镇痛、产科镇痛、慢性疼痛) • 禁忌症 contraindications • 低血容量未纠正 • 穿刺部位感染 • 菌血症 • 低凝状态
(二) 常用局部麻醉药物(Commonly used spinal anesthetic agents)
(三)注意事项 ◆局麻药中加用肾上腺素 减缓局麻药吸收速度、延长作用时间,局部轻度血管收缩,无明显全身反应. 常用1:20万(高血压病人禁用). ◆局麻药浓度选择 决定硬膜外阻滞范围的最主要因素 ——麻醉药容量 决定硬膜外阻滞深度和作用持续时间——麻醉药浓度 ◆局麻药的混合使用: 起效快+起效慢 潜伏期短 长效+短效 维持时间长 混合→
◆注药方式: ● 注射试验量(test dose):3-5ml. 目的:排除误入蛛网膜下隙的可能; ● 注入增加量(incremental dose): 注入试验量5-10min,如无腰麻征象 →可每隔5min注入 3-5ml,直至阻滞范围满足手术要求; ● 追加维持量(maintain dose):首次总量的1/2—1/3。
(四)硬膜外间隙穿刺术 • 病人体位 position • 侧卧位 • 坐位
硬膜外间隙穿刺术 • 穿刺方法 • 直入法 midline approach • 侧入法 paramidline approach • 穿刺位置 • 根据手术的需要决定 • 进入硬膜外腔的指征 • 过黄韧带的突破感 • 出现负压 • 回抽无脑脊液 • 插管顺利