各位版主和许多战友比较关注麻醉学进展，经常介绍最新文献资料，使大家收益，在此感谢。
我在这里从另一个角度，也就是麻醉医师的基本功方面，开辟一个栏目。大家也许都能感觉到，书上内容很多，中文书条条框框很复杂，外文书滔滔不绝一大片。我科负责教育的 Dr. James Griffin 针对这个问题，把书上内容 “浓缩” 起来，做成卡片，分给住院医，实际上对主治医也是一个温故知新的作用。他的目的是让住院医生每日掌握一条信息。由于他讨论的几个问题，有连续性，我在这里把几个问题一起贴出，称其为 每周 一题。
我们这里学习的，不是高精尖技术，不是高级设备，也不是最新进展，更不是大师观点，而是住院医生的理念基本功。
第一次我来翻译。今后有战友愿意翻译，我可以协助。我有用词不当的，也欢迎大家指正。
本期题目为麻醉体位问题。看似简单，很多“资深”者也许会不屑一顾。但园子里有多少病人，
麻醉后有神经症状的报道。手术中，体位是麻醉医生的职责。我们做到了科学地摆放病人的体位了吗？
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Nov 9 - Discuss hemodynamic & resp. effects of lateral decubitus positioning
侧卧位对呼吸和循环的影响：
Discussion points.
Placement of a patient in the lateral decubitus position can result in significant mismatching of pulmonary ventilation-to-perfusion during mechanical ventilation of the lungs for a number of reasons. First, while in the lateral position the mechanically ventilated patient has relatively better ventilation of the superior lung, while the dependent lung is being ventilated less. The reasons for the dependent lung being ventila
ted less are condary to the loss of lung volume from compression by abdominal contents, mediastinal contents, and the structures ud to position the patient. The patient concurrently has better perfusion of the dependent lung, primarily condary to the effects of gravity. Together, the factors result in greater mismatching of ventilation and perfusion of the lungs during mechanical ventilation in a patient in the lateral decubitus position. Clinically, this may manifest as arterial hypoxemia.
Placement of a patient in the lateral decubitus position can result in compression of the inferior vena cava from the pressure of a kidney rest. This can lead to a decrea in venous return to the heart.
侧卧位可以因多种原因导致肺的通气／灌注比例失调：1，侧卧位患者机械通气时，其上肺通气相对较好，而下肺通气不好（注：文献中常把下肺称为 “依赖肺”dependent lung，我想其来源是，下肺是 “依赖重力的肺” weight-dependent lung 的缘故）。下肺通气不好的原因，是由于该肺受到腹腔内容物，纵隔，和固定病人体位的各类材料和结构挤压所致。
在病人下肺通气不良的同时，其血流灌注又因为重力的作用有所增加。这两个因素加起来的结果，就是侧卧位通气病人通气／血流比例失调，临床表现为动脉缺氧。
侧卧位病人也可因腰垫（kidney rest）压迫下腔静脉，导致回心血量减少。
References. Stoelting RK, Miller RD: Basics of Anesthesia, 4th ed. Philadelphia, Churchill Livingstone, 2000; p. 199; Miller RD: Anesthesia, 5th ed. Philadelphia, Churchill Livingstone, 2000; p. 578-582, 1686-1689.
山的成语————————————————————
Nov 10 - Discuss upper extremity positioning in the lat. decubitus position
侧卧位时上肢体位摆放：
spansion
hey oh
Discussion points.
An axillary roll properly placed under a patient in the lateral decubitus position supports the patient's chest and minimizes the risk of compression of the nerves and vesls in the axilla. The dependent brachial plexus may also be injured should the axilla be compresd sufficiently to compress the brachial plexus. Proper placement of the axillary roll is under the thorax caudad to the axilla. The radial pul may be checked periodically intraoperatively as a gross measure of compression of the vesls in the axilla. Alternatively, a pul oximeter may be placed on a finger of the dependent hand to ensure no compression of arteries has occurred.
腋窝卷（axillary roll）放在适当的位置，可以支持病人的胸廓，使胸廓抬高后，减少重力对腋窝神经和血管的压迫（注：从这点看，axillary roll 应该叫 chest roll）。低位的臂丛受压严重时，可以导致神经损伤。腋窝卷的正确使用方法，是放在腋窝的尾端的胸廓下。手术中，可定时查看病人的桡动脉脉搏，大致估计腋窝是否受压，也可以将血样饱和探头放
在低位手的手指上，确认动脉没有受到压迫。
References. Stoelting RK, Miller RD: Basics of Anesthesia, 4th ed. Philadelphia, Churchill Livingstone, 2000; p. 199; Miller RD: Anesthesia, 5th ed. Philadelphia, Churchill Livingstone, 2000; p. 1019-1021.
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Nov 11 - Discuss nondependent arm & lower ext. positioning in the lat. decub. position.
侧卧位手术时上面的上下肢摆放：
Discussion points.
The patient's legs while in the lateral decubitus position should be positioned such that th
e dependent leg is flexed at the knee and there is a pillow between the two legs. This helps to minimize stretch of the nerves of the dependent leg and distributes more evenly the weight of the legs, such that discrete pressure points are avoided. Indeed, there have been ca reports of arterial insufficiency of the dependent leg of patients undergoing hip arthroplasty in the lateral position leading to the need for subquent below-the-knee amputation.
anonymous proxy
The patient's nondependent arm while in the lateral decubitus position should be positioned on an elevated armboard or pillow above and in front of the patient's face. Alternatively, the arm may be suspended from a support bar that is well-padded. Both positions should limit the extension of the arm to less than 90 degrees at the shoulder.
alllike
病人侧卧位时，下方的下肢在膝关节位置弯曲，两腿间放一个枕头，这样可以减少下方肢体神经的牵拉，同时使双下肢的重量比较分散，避免明显的着力点。过去曾有报道髋关节置换术后，下方下肢动脉灌注不足，最终导致病人的膝关节下截肢的病例。
侧卧位手术时，位于上方的的上肢，可以放在一个抬高的小桌面上，或者病人前方的一个枕头上。也可以用侧柱悬挂，但悬挂装置需要很好的软垫。使用这两种方法，都要使上肢和肩膀的成角小于 90 度。
References. Stoelting RK, Miller RD: Basics of Anesthesia, 4th ed. Philadelphia, Churchill Livingstone, 2000; p. 199; Miller RD: Anesthesia, 5th ed. Philadelphia, Churchill Livingstone, 2000; p.p 1019-1021.
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Nov 12 - Discuss potential complications of the sitting position for surgeryasrted
坐位手术可能的并发症
Discussion points.
The sitting position is most often ud for neurosurgical procedures, especially in the posterior fossa. The advantages of the sitting position for posterior fossa craniotomies are improved surgical exposure, less required retraction of the brain, and facilitated jugular venous drainage leading to less bleeding.
Patients placed in the sitting position for a surgical procedure may become hypotensive, especially if hypovolemic. Additionally, patients may have decreas in cardiac output and cerebral perfusion pressures. Hypotension can be avoided by positioning the patient in gradual steps to allow for accommodation, by ensuring adequate hydration, and through the temporary administration of small dos of vasopressors.
The principal potential intraoperative complication of positioning a patient in the sitting position for surgery is a venous air embolism. Placing the head above the level of the hea
托词的意思
rt during the procedure facilitates the entrainment of room air. Patients undergoing craniotomies are especially at risk, given that veins in the bony cranium do not collap after being trancted. TEE, procordial doppler and ETCO2 monitoring can be ud to detect VAE.
坐位手术通常用于神经外科手术，特别是颅后窝手术。坐位手术的优点是暴露良好，脑组织牵拉少，颈静脉回流好，手术失血少。
作为手术的病人容易发生低血压，特别是容量不足时。病人也容易有心输出量减少，脑组织灌注压降低。通过慢慢改变体位，使病人逐步适应，保持容量，小剂量使用血管活性药物，可以避免低血压。
坐位手术的主要并发症使空气栓塞 （venous air embolism, VAE）。手术中，病人的头的位置高于心脏使空气更容易进入血管。开颅手术的患者危险更高，因为颅骨的静脉切开后不能塌陷。经食道超声，心前多普勒，潮末二氧化碳监测，可以用于检测到 VAE。
党的奉献精神References. Stoelting RK, Miller RD: Basics of Anesthesia, 4th ed. Philadelphia, Churchill
Livingstone, 2000; pp. 199-200; Miller RD: Anesthesia, 5th ed. Philadelphia, Churchill Livingstone, 2000; pp. 1024, 1027-1029, 1903-1906.
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Nov 13 - Discuss peripheral nerve injury- mechanism, risk factors, respon
外周神经损伤的机制，风险因素，和对策
Discussion points.
Peripheral nerve injuries have occurred in patients after regional anesthesia or dation as well as general anesthesia. Injury occurring to a nerve intraoperatively is usually due to compression or stretching of the nerve. The injury usually sustained to the nerve is neurapraxic, which is a loss of function without corresponding anatomic injury. The risk of
sustaining an intraoperative nerve injury can be minimized by carefully positioning patients and by using padding when and where appropriate. There is evidence to suggest that patients who experience intraoperative nerve injury may have preexisting conditions that made the injury unavoidable, even with proper positioning and padding.
Co-existing medical conditions that place a patient at an incread risk for a peripheral nerve injury include occupational trauma, congenital anomalies, cubital entrapment syndrome, hematomas, hypothermia, hypotension, prolonged tourniquet time, cigarette smoking, and dias such as diabetes mellitus, vitamin deficiency, alcoholism, or cancer.
Neurologic consultation obtained early after a peripheral nerve injury manifests in the postoperative period may be uful in detecting between acute injury and chronic injury. This can be accomplished through nerve conduction velocity and electromyographic studies. Signs of denervation from acute nerve injury are detected by an electromyogram
心理学史
18 to 21 days after the injury, emphasizing the importance of obtaining neurologic consultation before this time. It may also be uful to test the same nerve in the limb opposite the symptomatic one to exclude any preexisting nerve injury that is asymptomatic.
The usual recovery time from an intraoperative peripheral nerve injury is 3 to 12 months. In rare cas, injury can be permanent, particularly with stretch injury that results in disrupted axons.
外周神经在全麻，区域麻，和单纯镇静病人身上都会出现。手术当中出现的神经损伤多为压迫或牵拉所致。这样的神经损伤多为生理性／轻型失用型（neuropraxic）损伤，即神经功能的丧失但没有结构损伤。通过体位摆放中适当使用软垫尽量减少手术中神经损伤。有证据表明 ，手术当中有神经损伤的病人，有可能术前就有病情，这类患者即使术中有适当的体位和软垫，神经损伤也不可避免。
鼠目寸光是什么意思
病人的其他疾病也可以使病人的神经损伤的风险加大，这些疾病包括职业受伤，先天畸形，尺神经卡压综合征，血肿，低温，低血压，止血带时间过长，抽烟，糖尿病，维生素缺乏，酗酒，和癌症。
术后早期发现神经损伤后，可及时请神经内科会诊，通过神经传导速度和肌电图检查，以了解损伤是急性还是慢性的。急性神经损伤，在18 － 21 天内，肌电图可以表现出组织失去神经控制的表现，说明在这个时间前获得神经内科会诊是很重要的。有时也可以通过检查对侧同一个神经，排除病人原来就有，而又无特别症状的神经损伤。
手术中发生的外周神经损伤的恢复时间一般为 3－12 个月。永久神经损伤，偶尔也可以见到，特别是神经损伤涉及到神经元的患者。
References. Stoelting RK, Miller RD: Basics of Anesthesia, 4th ed. Philadelphia, Churchill Livingstone, 2000; pp. 202-203; Miller RD: Anesthesia, 5th ed. Philadelphia, Churchill Livingstone, 2000; p. 1029-1030.
