1. General Anesthesia

1．　全身麻醉

Induction of General Anesthesia General anesthesia can be induced by giving drugs intravenously, by inhalation, or by a combination of both methods.

全身麻醉的诱导　经静脉、吸入或两种方式联合给药都能诱导全身麻醉。

A Rapid-Sequence Induction: Anesthesia is most commonly induced by the method of rapid-sequence induction, in which rapid administration of an ultra-short-acting barbiturate (e.g., thiopental) is followed by a depolarizing muscle relaxant (e.g., succinylcholine). This allows anesthesia to be induced within 30 seconds and the trachea to be intubated within 60-90 seconds. Oxygen is usually given by mask beforehand to allow maximum time for intubation while the patient is apneic. A non-depolarizing neuromuscular blocking drug (e.g., vecuronium, atracurium, or pancuronium) can be substituted for succinylcholine, but the onset of paralysis is delayed by about 60 seconds.

A. 快速序贯诱导：诱导麻醉最常用的是快速序贯诱导方法，应用此法时先快速给予超短时作用的巴比妥（如硫贲妥钠)，接着给去极化的肌肉松弛剂（如琥珀胆碱)。这样能在30秒钟内诱导麻醉，60－90秒钟内行气管插管。通常事先给予面罩吸氧，使患者在呼吸暂停的时间达最大限度，可用以插管。可以用非去极化的神经肌肉阻滞剂（如维可罗宁、卡肌宁或潘可罗宁)代替琥珀胆碱，但麻醉的出现将延迟60秒钟。

Rapid-sequence induction minimizes the time during which the trachea is unprotected. Consequently, this method is often used in emergency surgery in patients who have eaten recently. The disadvantage of giving depressant drugs rapidly is that hypotension may occur in patients with questionable cardiovascular status or marginal circulatory volume.

快速序贯诱导能使气管不受保护的时间缩短至最低限度，所以常用于刚刚进食患者的急诊手术。快速给予抑制剂的缺点是心血管功能有问题或循环容量在临界水平的病人可发生低血压。

B Inhalation Induction: Inhalation of nitrous oxide plus a potent volatile anesthetic (e.g., halothane, enflurane, or isoflurane) can produce anesthesia within 3-5 minutes. After induction, a depolarizing or non-depolarizing neuromuscular blocking drug can be given intravenously to facilitate tracheal intubation. If there is some question about the difficulty of intubation, it can be attempted while the patient is breathing spontaneously, without giving a muscle relaxant. Although conditions for intubation may not be as good with this method, the patient will still be breathing if difficulties with intubation prolong the time before complete airway control is achieved.

B. 吸入诱导：吸入一氧化氮加上强有力的挥发性麻醉剂（如氟烷、安氟醚或异氟醚)，能在3－5分钟内诱导麻醉，诱导后可经静脉给予去极化或非去极化的神经肌肉阻滞剂，以利于气管插管。若认为气管插管不一定有困难，可不用肌肉松弛剂而在病人有自主呼吸时试行插管。尽管这样插管条件不如使用肌肉松弛剂好，但即使因插管困难推迟了达到完全气道控制的时间，病人也仍能维持呼吸。

The advantage of inhalation induction is that anesthetic drugs can be titrated according to the patient’s needs. This allows for administration of more precise doses and minimizes the risk of an accidental overdose with resultant cardiovascular depression. The disadvantages are a slower induction time and the lack of protection for the airway for a longer period of time.医学.全在线www.med126.com

吸入诱导的优点在于可根据病人的需要滴入麻醉剂，这能使给药剂量较为精确，并把意外过量导致心血管抑制的危险减少到最低限度。其缺点是诱导较慢以及气道缺乏保护的时间较长。

C Combined Intravenous-Inhalation Induction: Short-acting anesthetic drugs such as thiopental or diazepam are often administered intravenously before inhalation of a volatile anesthetic. This is done to minimize the discomfort of wearing the anesthetic mask and to facilitate inhalation of the anesthetic agent, which many people consider to have an offensive odor. This technique combines the advantages of both the intravenous and inhalation approaches. Anesthesia is induced rapidly, and anesthetic drug dosages can be titrated according to the patient’s requirements.

C.　静脉－吸入联合诱导：在吸入挥发生麻醉剂之前常经静脉给予短时麻醉剂如硫贲妥钠和安定，这样做能最大限度地减少带麻醉面罩的不适感，并利于麻醉剂的吸入――许多人认为麻醉剂气味难闻。这种方法结合了静脉和吸入两种方法的优点，麻醉诱导迅速并可根据病人的需要滴入麻醉剂。

Maintaining General Anesthesia The main objectives of general anesthesia are analgesia, unconsciousness, skeletal muscle relaxation, and control of sympathetic nervous system responses to noxious stimulation. Inhaled and intravenous anesthetics, narcotics, and muscle relaxants should be selected with specific pharmacologic goals in mind.

全身麻醉的维持　全身麻醉的主要目的在于无痛、意识消失、和骨骼肌松弛以及控制交感神经对不良刺激的反应。应该注意根据特殊的药理学目的来选择吸入或静脉麻醉剂、麻醉性镇痛药和肌肉松弛剂。

Although paralysis by muscle relaxants simplified exposure of the operative site and decreases the need for volatile anesthetics, many signs of anesthesia are absent in the paralyzed patient. It is essential that the anesthesiologist continuously assess the depth of anesthesia. Failure to do so may result in the patient being awake but paralyzed during the procedure.

尽管肌肉松弛剂所导致的麻痹使手术野易于暴露并减少挥发性麻醉剂的需要量，但麻痹病人缺乏许多麻醉征象。麻醉师必须持续不断地评估麻醉深度。如果做不到这一点就会导致在麻醉过程中病人清醒而肌肉麻痹的后果。

2. Regional Anesthesia

2．　区域了阻滞

A regional anesthetic is used when it is desirable that the patient remain conscious during the operation. Patients often have misconceptions about regional anesthesia that require detailed explanation of the safety of this technique. One disadvantage of regional anesthesia is the occasional failure to produce adequate anesthesia; another is hypotension due to sympathetic blockade. Regional anesthesia is used most often for surgery of the lower abdomen or lower extremities, since the effect of sympathetic blockade of these areas is minimal.

若需要病人手术期间保持清醒，可用区域麻醉阻滞。病人对区域麻醉常有误解，需要详细解释这一方法的安全性。区域麻醉的缺点之一是偶尔不能获得满意的麻醉，另外一个缺点是交感阻滞引起的低血压。区域麻醉最常用于下腹部和下肢的手术，因为这些部位交感阻滞影响极小。

Spinal & Epidural Blocks Spinal anesthesia is achieved by injecting a local anesthetic into the lumbar intrathecal space. This blocks the spinal nerve roots and dorsal root ganglia and probably also blocks the periphery of the spinal cord. Epidural anesthesia is accomplished by injecting a local anesthetic into the extradural (epidural) space. The epidural space is usually identified via the lumbar approach. The gastrointestinal tract is usually contracted with spinal and epidural anesthesia, facilitating exposure of the surgical site.

脊髓和硬膜外阻滞　将局麻药注射到腰部鞘内间隙可获得脊髓麻醉，阻滞了脊神经根和脊根神经节，可能也阻滞脊髓的外周部分。将局麻药注入硬膜外腔则产生硬膜外麻醉。一般通过腰部通路进入硬膜外腔。脊髓和硬膜外麻醉时胃肠道呈收缩状态有利于手术野暴露。

There are several complications of spinal anesthesia. Headache is the most common and is seen most frequently in young patients. The incidence is only 1% when a 25-gauge needle is used. For severe headache, a “blood-patch” epidural injection should be performed. This involves injecting 5-10 ml of the patient’s blood into the epidural space at the site of the previous lumbar puncture. Pain relief is usually prompt, and headache usually does not recur. This technique is thought to plug the leak of cerebrospinal fluid, restoring pressure in the subarachnoid space to normal.

脊髓麻醉有几种并发症，其中最常见的是头痛，且最多见于年轻病人。如果用25号针头，发生率仅为1%。对于严重的头痛应施行“血液缀片”硬膜外腔注入术，就是将5－10ml病人的血液经原腰区穿刺处注入硬膜外腔。通常，疼痛可即刻缓解，一般，头痛亦不再复发。据认为这一技术堵塞了脑脊液的外漏，使蛛网膜下腔的压力恢复正常。

Because spinal anesthesia blocks innervation of the bladder, administration large amounts of intravenous fluids may cause bladder distention, and a urethral catheter may be carried. This usually occurs with minor operations such as inguinal hernia repairs and can be avoided by keeping fluids to a minimum. Nausea and vomiting may occur when a spinal anesthetic is begun, especially if hypotension is present. If nausea and vomiting persist despite successful treatment of hypotension, diazepam or droperidol may be effective. Peripheral nerve damage is rare, occurring in one out of 10,000 cases.

因脊髓麻醉阻滞了膀胱的神经支配，大量静脉输液会引起膀胱膨胀，因此可能需要插导尿管。这种情况通常发生于很小的手术如腹股沟斜疝修补术，维持液体至最低量即可避免。在脊髓麻醉开始特别是有低血压时，会发生恶心呕吐。如果低血压治疗已经成功而恶心呕吐仍持续存在，用安定或氟哌啶可能奏效。外周神经损伤是很罕见的，发生于1/10,000的病例。

Complications from epidural anesthesia are the same as those for spinal anesthesia, with the exception of headache.

除头痛外，硬膜外麻醉的并发症与脊髓麻醉相同。

3. Nerve Blocks

3．　神经阻滞

Nerve blocks are most appropriate for surgery of the upper extremities. Intercostal nerve blocks are useful for postoperative pain relief. Overall, nerve blocks play a minor role in anesthesia because of the discomfort they cause the patient and the time they require.

神经阻滞最适用于上肢，肋间神经阻滞有助于缓解术后疼痛。总的说来，由于神经阻滞引起病人不适及所需时间长，因而在麻醉中起的作用很小。