Uptake and elimination of sevoflurane in rabbit tissues-An in vivo 19F magnetic resonance study

背景：氟化吸入麻醉剂的体内药代动力学研究可以使用^< 19>f磁共振波谱。以前的药代动力学研究主要是在大脑中进行的，因为它被认为是麻醉作用的部位。对其他组织的研究将使我们更准确地了解吸入麻醉药在全身的药代动力学。本研究利用体内19F MRS研究了七氟醚在家兔脑、肝、肌肉、静脉血和动脉血中的药代动力学，比较了各组织间药代动力学的差异以及各组织内摄取和消除的差异。方法：对22只家兔进行4.7特斯拉19F磁共振波谱，采用直径为1 cm的表面线圈检测脑（n-4）、肝（n-5）和肌肉（n-5），直径为1.3 cm的表面线圈检测动脉（n-4）和静脉（n=4）血液。结果：七氟醚给药120分钟，随后120分钟排出。摄取和消除动力学均符合双指数曲线，该曲线分为快、慢两部分。在一次摄取实验中，各组织达到最大光谱强度一半所需时间分别为动脉血1.5 min、肝脏4.5 min、脑12.7 min、静脉血13.1 min和肌肉27.3 min。在消除实验中，各组织达到最大强度一半的时间分别为动脉血2.4 min，肝脏5.5 min，静脉血12.5 min，脑20.4 min，肌肉26.7 min。结论：七氟醚在各组织中的摄取或消除能够通过双指数动力学表达。七氟醚在动脉血中的摄取和消除动力学迅速，几乎与潮末七氟醚动力学相似。其次是肝脏，其次是大脑，静脉血和肌肉。

Background : An in vivo pharmacokinetic study of fluorinated inhalational anesthetics is possible using ^<19>F magnetic resonance spectroscopy. Previous pharmacokinetic studies were performed mainly in brain as it is considered as a site of anesthetic action. Investigation of other tissues will give us more precise informations of the pharmacokinetics of inhalatlonal anesthetics in a whole body. In this study we investigated the pharmacokinetics of uptake and elimination of sevoflurane in brain, liver, muscle, venous blood and arterial blood of rabbits using in vivo 19F MRS in order to compare differences of pharmacokinetics among tissues and also differences between uptake and elimination in each tissue. Methods : In twenty two rabbits 19F magnetic resonance spectroscopy was conducted at 4.7 Tesla using a 1 cm diameter surface coil for brain (n-4), liver (n-5) and muscle (n-5), and a 1.3 cm diameter surface coil for arterial (n-4) and venous (n=4) blood.Results : Sevoflurane was administered for 120 min, followed by a 120-min period of elimination. Both uptake and elimination kinetics were best fit to a biexponential curve which was divided into the fast and slow components. During an uptake experiment times to reach half of the maximum spectroscopic intensity in each tissue were 1.5 min in arterial blood, 4.5 min in liver, 12.7 min in brain, 13.1 min in venous blood and 27.3 min in muscle. During an elimination experiment times to reach half of the maximum intensity in each tissue were 2.4 min in arterial blood, 5.5 min in liver, 12.5 min in venous blood, 20.4 min in brain and 26.7 min In muscle.Conclusions : Sevoflurane uptake or elimination in each tissue was able to be expressed by biexponential kinetics. Sevoflurane uptake and elimination kinetics in arterial blood were rapid and almost similar to end-tidal sevoflurane kinetics. Those in liver were next fastest followed by brain, venous blood and muscle.