Effects of epinephrine and phenylephrine on evoked potentials in a rat model of acute hemorrhagic shock / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of epinephrine and phenylephrine on evoked potentials in a rat model of acute hemorrhagic shock. Methods Eighteen SPF healthy male Sprague-Dawley rats, aged 11 weeks, weighing 250-350 g, were divided into 3 groups ( n=6 each) using a random number table meth-od acute hemorrhagic shock group ( HS group) , epinephrine group ( E group) and phenylephrine group ( P group). The animals were anesthetized with intraperitoneal 10％ chloral hydrate 300 mg∕kg and tracheos-tomized, and spontaneous breathing was kept. Acute hemorrhagic shock was induced by withdrawing 40％ of the blood volume from the right internal jugular vein. Epinephrine 2 μg·kg-1 ·min-1 ( 0. 01 mg∕ml, 0. 3 ml) and phenylephrine 20μg·kg-1·min-1 (0. 1 mg∕ml, 0. 3 ml) were intravenously infused after the end of blood letting in E and P groups, respectively. Mean arterial pressure ( MAP ) , somatosensory evoked po-tential (SSEP) and motor evoked potentials (MEP) were recorded before blood letting, at the time of with-drawing 20％of the blood volume, at the end of blood letting, and at 3 min after administration ( at the corre-sponding time point in group HS) . Results The MAP and amplitudes of MEP and SSEP were significantly decreased at the end of blood letting than at the time of withdrawing 20％ of the blood volume in three groups (P<0. 05). Compared with HS group, the MAP and amplitudes of MEP and SSEP were significantly in-creased at 3 min after administration in E group, and the MAP was increased at 3 min after administration ( P<0. 05 or 0. 01) , and no significant change was found in amplitudes of MEP and SSEP in P group ( P>0. 05) . Conclusion Epinephrine exerts no effect on evoked potential monitoring, however, phenylephrine affects the accuracy of evoked potential monitoring in a rat model of acute hemorrhagic shock.