【正文】 （成人），麻藥必須將骶管充滿才能使 所有 骶 N阻滯 ▼ 腰骶部硬外間隙解剖結(jié)構(gòu)特殊 → 麻藥不易由骶側(cè)向腰側(cè) 擴(kuò)散 →麻醉范圍主要集中于肛門、會陰、臀部 →對生理 功能影響輕微 . ▼ 骶骨孔解剖變異多 → 成功率相對低（ 75— 80%) ▼ 骶管內(nèi)血管竇粗大 → 易出血、局麻藥中毒 . （現(xiàn)已用 L34↓ 代替骶麻） 第三節(jié) 蛛網(wǎng)膜下隙與硬脊膜外聯(lián)合阻滯麻醉 Section three Combination of spinal and epidural anesthesia ?蛛網(wǎng)膜下腔與硬膜外腔聯(lián)合麻醉 ?蛛網(wǎng)膜下腔阻滯： 鎮(zhèn)痛、運(yùn)動神經(jīng)阻滯 ?硬膜外腔阻滯： 長時(shí)間手術(shù)、神經(jīng)分離阻滯 ?穿刺方法 ?兩點(diǎn)法 ? 先行硬膜外腔穿刺術(shù)、再行蛛網(wǎng)膜下腔穿刺 ?一點(diǎn)法 ? 利用聯(lián)合穿刺針，在同一個(gè)位臵分別進(jìn)行硬膜外腔穿刺和蛛網(wǎng)膜下腔穿刺 Possible Clinical Advantages of Using Combined SpinalEpidural Anesthesia ? Initial epidural needle placement allows the spinal needle to be guided near the dura, minimizing the number of times the spinal needle tip impacts bone and potentially bees dulled. ? Lower local anesthetic blood levels are possible when an initial spinal anesthetic is used for operation, and the epidural catheter is used for analgesia. ? More rapid onset of spinal block allows the operative procedure to begin earlier, while the epidural catheter allows effective analgesia to be provided. ? During labor, an opioid may be injected via a small spinal needle and then epidural analgesia added if needed. ? Lower initial mass of drug may be used during spinal anesthesia, thereby minimizing the physiologic perturbations, while the epidural catheter is available to provide a higher level if needed. Question ? What are the major differences between subarachnoid block and extradural block? ? What are the methods for identifying the epidural space? ? What are the absolute contraindications to subarachnoid block and extradural block? Thanks For Your Attention！ The End 。 Total spinal anesthesia can occur following attempted epidural/caudal anesthesia if there is inadvertent intrathecal injection. Onset is usually rapid because the amount of anesthetic required for epidural and caudal anesthesia is 5–10 times that required for spinal anesthesia. Careful aspiration, use of a test dose, and incremental injection techniques during epidural and caudal anesthesia can help avoid this plication. ◆ 臨床表現(xiàn) (manifestation): ★ 全部脊 N支配區(qū)域無痛覺 (no sense of pain) ★ 嚴(yán)重低血壓休克 (severe hypotention) ★ 意識喪失 (unconsciousness) ★ 呼吸停止 (respiratory arrest) → 心跳停止 (cardiac arrest)（處理不及時(shí) ) ◆ 處理原則 (principle of treatment) 維持循環(huán)、呼吸功能 Treatment consists of supporting the airway, maintaining an adequate ventilation, and supporting the circulation. ? 人工通氣 : When respiratory insufficiency bees evident, supplemental oxygen is mandatory . Assisted ventilation, intubation, and mechanical ventilation may be necessary. ? 加速輸液 : Hypotention can be treated with rapid administration of intravenous fluid. ? 升壓藥等對癥處理 : Aggressive use of vasopressors. Bradycardia should be treated with atropine. ?異常廣泛阻滯 : The exception that the onset may be delayed for 1530minutes. The effects generally last from one to several hours. ● 注入常規(guī)劑量局麻藥后 → 異常廣泛的脊 N阻滯現(xiàn)象 .（并非全脊麻） ● 范圍雖廣，仍為節(jié)段性，骶 N支配區(qū)域、甚至腰部 N 功能仍正常 ● 廣泛阻滯緩慢發(fā)生 → 注入藥量后 2030min ● 胸悶、呼吸困難、說話無力、煩躁不安 → 通氣嚴(yán)重不 足 → 呼吸停止、 BP↓↓ ?穿破硬膜 : ◆ 原因 : ★ 操作因素 : ★ 病人因素 : ◆ 預(yù)防 : 嚴(yán)格操作規(guī)程 ◆ 穿破后處理 : ?穿刺置管損傷血管或?qū)Ч苓M(jìn)入并留滯于血管 導(dǎo)管誤入血管 → 注麻藥后立即出現(xiàn)全身中毒反應(yīng)而麻醉 作用缺如 . 處理：退管 12cm or換間隙重穿臵管 ?空氣栓塞： ?穿破胸膜：氣胸、縱隔氣腫 注氣試驗(yàn)時(shí) → 空氣進(jìn)入循環(huán) → 量多時(shí)致死 ?硬膜外血腫 (Epidural hematoma) ◆ Needle or catheter trauma to epidural veins often Causes minor bleeding , although this is usually benign and self clinical significant epidural hematoma can occur following epidural anesthesia, especially in the presence of abnormal coagulation