EXAGGERATED ANESTHETIC REQUIREMENTS IN THE PREFERENTIALLY ANESTHETIZED BRAIN
EXAGGERATED ANESTHETIC REQUIREMENTS IN THE PREFERENTIALLY ANESTHETIZED BRAIN
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DOI：
10.1097/00000542-199312000-00015
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发表时间：
1993-12-01
期刊：
影响因子：
8.8
通讯作者：
SCHWARTZ, K
中科院分区：
文献类型：
--
作者：
ANTOGNINI, JF;SCHWARTZ, K
背景大脑被认为是麻醉剂作用的部位，但麻醉剂对其他部位也有影响，如脊髓。一个优先麻醉山羊脑模型被用来确定麻醉行动在brain.Methods的重要性：6只山羊麻醉异氟醚，气管插管和插入股动脉导管后，双侧颈部解剖进行分离颈外动脉和颈外静脉。结扎枕动脉以防止椎血进入颈动脉系统。（山羊没有直接的、显著的椎动脉对大脑的贡献，它们也没有颈内静脉。对照组异氟醚最低肺泡浓度（MAC）使用露爪钳作为疼痛刺激来确定。此后，将颅静脉血引流至气泡式氧合器中，其中异氟烷挥发罐与气流保持一致。根据氧合器排气中的异氟烷分压估计氧合器动脉异氟烷浓度。停止经肺给予异氟烷，并将经颈动脉输送的血液中的异氟烷分压增加至允许和阻止对露爪刺激做出反应的运动的分压所需的量。重建自体循环并再次测定MAC。转流前脑异氟烷需要量为1.2 +/- 0.3%（平均值+/- SD），转流期间优先麻醉脑时增加至2.9 +/- 0.7%，转流后降低至1.3 +/- 0.1%。结果支持皮质下结构的重要性，如脊髓，在产生有目的的运动，以响应全身麻醉下的疼痛刺激。
Background. The brain is assumed to be the site of anesthetic action, but anesthetics have effects elsewhere, such as the spinal cord. A preferentially anesthetized goat brain model was used to determine the importance of anesthetic action in the brain.Methods: Six goats were anesthetized with isoflurane; after tracheal intubation and insertion of a femoral arterial catheter, bilateral neck dissections were performed to isolate the external carotid arteries and external jugular veins. The occipital arteries were ligated to prevent vertebral blood from entering the carotid system. (Goats do not have direct, significant vertebral artery contributions to the brain, and they lack internal jugular veins.) Control isoflurane minimum alveolar concentration (MAC) was determined using a dew-claw clamp as the painful stimulus. Following this, cranial venous blood was drained into a bubble oxygenator in which an isoflurane vaporizer was placed in line with the gas flow. Oxygenator arterial isoflurane concentration was estimated from the isoflurane partial pressure in the oxygenator exhaust. Isoflurane administration via the lungs was discontinued and the isoflurane partial pressure in the blood delivered via the carotid artery was increased by an amount required to bracket the partial pressures permitting and preventing movement in response to dew-claw stimulation. The native circulation was reestablished and MAC determined again.Results. Cerebral isoflurane requirements were 1.2 +/- 0.3% (mean +/- SD) before bypass, increased to 2.9 +/- 0.7% during bypass when the brain was preferentially anesthetized, and decreased to 1.3 +/- 0.1% after bypass.Conclusions. The results support the importance of subcortical structures, such as the spinal cord, in the generation of purposeful movement in response to a painful stimulus under general anesthesia.