选择性脊髓给予乳化异氟醚模型建立及异氟醚制动机制探讨

目的建立并验证选择性脊髓给予乳化异氟醚的山羊模型,并初步探讨异氟醚的制动机制。方法18只成年山羊随机平分为选择性山羊脊髓给予乳化异氟醚组(动脉组)与乳化异氟醚全身麻醉组(静脉组)。动脉组和静脉组分别经降主动脉起始处和耳缘静脉以微量注射泵泵入乳化异氟醚。调节泵入乳化异氟醚速度至呼气末异氟醚浓度达到1个肺泡气最低有效浓度(MAC)后,维持平衡20 min。比较平衡后两组山羊不同取血部位(股动、静脉和颈动、静脉)血液中的异氟醚分压(Piso)。结果静脉组山羊各部位血液中Piso差异无统计学意义。动脉组山羊颈动、静脉血Piso比较,股动、静脉血Piso比较差异无统计学意义;但股动、静脉血中Piso〔分别为(11.15±6.06)mmHg、(9.28±5.07)mmHg,1 mmHg=0.1333 kPa〕约为颈动、静脉血中Piso〔分别为(6.07±3.60)mmHg、(5.36±2.99)mmHg〕的2倍(P<0.05)。静脉组山羊各部位血液中Piso与动脉组股动、静脉血中Piso比较差异均无统计学意义,但约为动脉组山羊颈动、静脉血中Piso的2倍(P<0.05)。结论成功建立选择性山羊脊髓给予乳化异氟醚模型,并提示脊髓可能是异氟醚制动作用的重要部位。

Model Establishment for Emulsified Isoflurane Delivered Selectively to the Goat Spinal Cord and Preliminary Research on the Immobility Mechanism of Isoflurane

OBJECTIVE: To develop a new model of preferentially delivering isoflurane to the goat spinal cord, and to explore preliminarily volatile anesthetic action sites. METHODS: Eighteen goats were randomly and equally divided into group artery and group vein. In group artery, emulsified isoflurane was infused into descending aorta for developing the model to deliver isoflurane to the goat spinal cord. In group vein, emulsified isoflurane was infused via the ear vein. After the end-tidal isoflurane concentration of 1 minimum alveolar concentration (MAC) was maintained for 20 min, the isoflurane partial pressures (P(iso)) in samples which were drawn from the femoral artery and the carotid artery were determined by a gas chromatography. RESULTS: In group vein, there was no statistical difference among all the P(iso). In group artery, the P(iso) of the femoral arterial blood was almost same as that in group vein, but the P(iso) of the carotid arterial blood was near half of that in group vein [(6.07 +/- 3.60) mmHg vs (10.21 +/- 2.41) mmHg, P < 0.05]. CONCLUSION: This new model permits preferentially to deliver the isoflurane to the in situ goat spinal cord, and the results support the importance of the spinal cord in suppressing nociceptive reflex under isoflurane anesthesia.