Chen K P, Chen F S, Yu P Y, Chan H C
Department of Anesthesiology, China Medical College Hospital, Taiwan, R.O.C.
Acta Anaesthesiol Sin. 1996 Dec;34(4):209-12.
Propofol's greatest attributes are its pharmacokinetic properties which result in a rapid, clear emergency and lack of cumulative effects even after prolonged administration. It is a drug of popular choice for the maintenance of general anesthesia. The laryngeal mask airway (LMA), originally described by Dr. Brain is now a good alternative as the airway management technique. Because of its high success rate in securing a clinically acceptable airway in anesthetized patients, LMA has been proposed as a practical airway and conveyer for general anesthesia. This study was designed to observe and evaluate the feasibility of propofol infusion combined with N2O for maintenance of anesthesia, with a LMA as airway and conveyer during general anesthesia.
Sixty patients, ASA class I-II, aged 15-59 years, were selected for this study. They were scheduled for upper-limb orthopedic surgeries in supine position. No patient was premedicated. Intraoperative monitoring included electrocardiography, pulse oximetry, end-tidal carbon dioxide and automatic non-invasive blood pressure. The agents for induction of anesthesia included atropine 0.01 mg/kg, atracurium 5 mg, fentanyl 2-3 micrograms/kg, 2% lidocaine 1.5-2 mg/kg, propofol 2 mg/kg, and succinylcholine 1-1.5 mg/kg, all of which were given intravenously in sequence. After that laryngeal mask airway (LMA) was inserted. The position of LMA was confirmed by even undulation of chest wall and breathing sound. Anesthesia was then maintained with nitrous oxide in 40% oxygen and continuous propofol infusion. The pumping rate was set to start at 6 mg/kg/h. Muscle relaxation was achieved by intravenous tracrium given intermittently. All patients were mechanically ventilated with a ventilator incorporated to the anesthesia machine. The ventilator was set to give a tidal volume of 8 ml/kg at a rate of 12-14/min. At the end of the operation, the propofol infusion and nitrous oxide were simultaneously discontinued. The effect of muscle relaxant was antagonized by atropine 1.0 mg and neostigmine 2.5 mg intravenously. The LMA was removed while the patient was awake and able to open mouth at request. They were followed 24 h postoperatively for inquiring intraoperative awareness and other complaints.
No patient was noted to experience awareness during the intraoperative period. Regarding LMA insertion, success in the first attempt was seen in 55 patients (90.2%). Success in the second attempt was seen in 5 patients (8.2%). Failure was encountered in one patient (1.6%). The average time of emergence was 92 +/- 3.4 min. The average rate of speed of propofol infusion was 6.29 +/- 0.97 mg/kg/h.
The combination of propofol infusion and N2O with laryngeal mask as airway and recovery was a good alternative in administration of general anesthesia.
丙泊酚最突出的特性是其药代动力学性质，这使得它起效迅速、苏醒迅速，即使长时间给药也无蓄积效应。它是维持全身麻醉常用的药物。喉罩气道（LMA）最初由布雷恩博士描述，现在是一种很好的气道管理技术替代方法。由于其在为麻醉患者建立临床上可接受的气道方面成功率高，LMA已被提议作为全身麻醉的实用气道和输送工具。本研究旨在观察和评估丙泊酚输注联合氧化亚氮用于维持麻醉的可行性，在全身麻醉期间以LMA作为气道和输送工具。
选择60例年龄15 - 59岁、ASA分级I - II级的患者进行本研究。他们计划仰卧位行上肢骨科手术。所有患者均未进行术前用药。术中监测包括心电图、脉搏血氧饱和度、呼气末二氧化碳和自动无创血压。麻醉诱导药物依次静脉注射阿托品0.01mg/kg、阿曲库铵5mg、芬太尼2 - 3μg/kg、2%利多卡因1.5 - 2mg/kg、丙泊酚2mg/kg和琥珀胆碱1 - 1.5mg/kg。之后插入喉罩气道（LMA）。通过胸壁的均匀起伏和呼吸音确认LMA位置。然后用40%氧气和氧化亚氮维持麻醉，并持续输注丙泊酚。泵注速度设定为起始6mg/kg/h。通过间歇性静脉注射阿曲库铵实现肌肉松弛。所有患者均使用与麻醉机相连的呼吸机进行机械通气。呼吸机设置为潮气量8ml/kg，频率12 - 14次/分钟。手术结束时，同时停止丙泊酚输注和氧化亚氮吸入。静脉注射阿托品1.0mg和新斯的明2.5mg拮抗肌肉松弛剂的作用。当患者清醒且能按要求张口时拔除LMA。术后随访24小时，询问术中知晓情况及其他不适。
术中无患者出现知晓情况。关于LMA插入，55例患者（90.2%）首次尝试成功。5例患者（8.2%）第二次尝试成功。1例患者（1.6%）失败。平均苏醒时间为9（2）±3.4分钟。丙泊酚平均输注速度为6.29±0.97mg/kg/h。
丙泊酚输注联合氧化亚氮并以喉罩作为气道和恢复方式是全身麻醉给药的一种良好替代方法。
