七氟醚对犬自发性交感神经活动、Aδ和C躯体交感反射及相关血流动力学变化的影响。

The effect of sevoflurane on spontaneous sympathetic activity, A delta and C somatosympathetic reflexes, and associated hemodynamic changes in dogs.

作者信息

Ma D, Wang C, Pac Soo C K, Chakrabarti M K, Lockwood G G, Whitwam J G

机构信息

Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, England.

出版信息

Anesth Analg. 1998 May;86(5):1079-83.

PMID:9585302

Abstract

UNLABELLED

This study examined the effect of sevoflurane on spontaneous renal sympathetic nerve activity (RSNA), A delta- and C-fiber-mediated somatosympathetic reflexes, and hemodynamic changes in anesthetized dogs. RSNA, and A delta and C reflexes evoked by electrical stimulation of the radial nerve were observed in multifiber recordings of efferent activity in renal sympathetic nerves. Sevoflurane was administered at 1%, 2%, 3%, and 4% end-tidal concentrations for periods of 20 min. The mean A delta reflexes decreased by 20%, 39%, and 54% (P < 0.05 to < 0.01), and the C reflexes decreased by 38%, 62%, and 74% (P < 0.05 to < 0.01) at concentrations of 2%, 3%, and 4%, respectively. The relatively greater effect on C reflexes was significant (P < 0.05) and comparable with the effect of mu-opioids. There was no change in mean RSNA, heart rate (HR), and cardiac output (CO) up to 3% sevoflurane, but these decreased by 36%, 24%, and 13% (P < 0.05), respectively, at 4% sevoflurane. Sevoflurane 1%-4% caused a virtually linear reduction in systemic vascular resistance (SVR) from 7% (P < 0.05) to 44% (P < 0.05), together with a reduction in mean arterial pressure (MAP) that was significant for concentrations greater than 2%. The results indicate that sevoflurane causes a greater depression of C compared with A delta reflexes, and that the reduction in MAP was entirely due to a decrease in SVR up to 3%, whereas at 4% sevoflurane, reductions in sympathetic activity, HR, and CO also contributed its depressor effect.

IMPLICATIONS

The relatively greater depressant effect of sevoflurane on C compared with A delta nociceptive somatosympathetic reflexes is similar to mu-opioids. The hypotensive effect of sevoflurane was significant at 2% concentration, whereas heart rate, cardiac output and sympathetic activity were reduced only at concentrations greater than 3%.

摘要

未标注

本研究考察了七氟醚对麻醉犬的肾交感神经自发放电活动（RSNA）、Aδ纤维和C纤维介导的躯体交感反射以及血流动力学变化的影响。在肾交感神经传出活动的多纤维记录中，观察了RSNA以及桡神经电刺激诱发的Aδ和C反射。以1%、2%、3%和4%的呼气末浓度给予七氟醚，持续20分钟。在2%、3%和4%的浓度下，平均Aδ反射分别下降了20%、39%和54%（P<0.05至<0.01），C反射分别下降了38%、62%和74%（P<0.05至<0.01）。七氟醚对C反射的影响相对更大，差异有统计学意义（P<0.05），且与μ阿片类药物的作用相当。在七氟醚浓度达3%时，平均RSNA、心率（HR）和心输出量（CO）均无变化，但在七氟醚浓度为4%时，它们分别下降了36%、24%和13%（P<0.05）。1% - 4%的七氟醚使体循环血管阻力（SVR）从7%（P<0.05）至44%（P<0.05）呈几乎线性降低，同时平均动脉压（MAP）降低，浓度大于2%时差异有统计学意义。结果表明，与Aδ反射相比，七氟醚对C反射的抑制作用更强，且在七氟醚浓度达3%时，MAP降低完全是由于SVR下降所致，而在七氟醚浓度为4%时，交感神经活动、HR和CO的降低也对其降压作用有贡献。