Comparison of medetomidine and dexmedetomidine as premedication in isoflurane anaesthesia for orthopaedic surgery in domestic sheep
Comparison of medetomidine and dexmedetomidine as premedication in isoflurane anaesthesia for orthopaedic surgery in domestic sheep
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DOI：
10.1046/j.1439-0442.2001.00354.x
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发表时间：
2001-05-01
期刊：
影响因子：
--
通讯作者：
Bettschart-Wolfensberger, R
中科院分区：
文献类型：
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作者：
Kästner, SBR;Von Rechenberg, B;Bettschart-Wolfensberger, R
本研究的目的是通过比较代表体外等效性的剂量关系下的麻醉需求和心血管变化，确定右美托咪定与美托咪定在接受骨科手术的绵羊中的效力。使用了24只未妊娠的雌性绵羊。本研究是一项盲法、随机、实验性试验。在麻醉诱导前5分钟，第1组静脉内接受5 μ g/kg体重（BW）的右美托咪定，第2组静脉内接受10 μ g/kg BW的美托咪定。用氯胺酮（2.0 mg/kg BW静脉注射）诱导麻醉，并在100%氧气中用异氟烷维持麻醉。监测呼气末麻醉药浓度（FEIso）、呼气末二氧化碳浓度（FECO 2）、呼吸频率（f（R））、直接动脉血压、心率（HR）和动脉血气。将数据随时间平均，并通过独立t检验和重复测量的方差分析来检验组间差异。维持手术麻醉平面所需的平均FEIso浓度在组间无差异（1：1.02 +/- 0.04%; 2：0.99 +/- 0.07%）。两组间HR、动脉血压、f（R）、FECo 2和动脉血气无差异。组1和组2的平均PaO 2分别为279.54 +/- 113.37 mmHg和220.21 +/- 102.15 mmHg，个体最小值分别为27.2 mmHg和58.5 mmHg。总之，5 μ g/ kg BW的静脉注射右美托咪定和10 μ g/kg的美托咪定对绵羊的异氟烷需求量和心肺参数具有相同的影响，表明了等效剂量关系。两种制剂均诱导个体绵羊出现中度至重度低氧血症。
The objective of the present study was to determine the potency of dexmedetomidine in relation to medetomidine in sheep undergoing orthopaedic surgery by comparing the anaesthetic requirements and cardiovascular changes at a dose relationship that represented equipotency in vitro. Twenty-four non-pregnant, female sheep were used. The study was carried out as a blind, randomized, experimental trial. Group 1 received 5 mug/kg bodyweight (BW) dexmedetomidine and group 2 received 10 mug/kg BW medetomidine intravenously 5 min prior to induction of anaesthesia. Anaesthesia was induced with ketamine (2.0 mg/kg BW intravenously) and maintained with isoflurane in 100 % oxygen. End expired anaesthetic concentration (FEIso), end expired carbon dioxide concentration (FECO2), respiratory frequency (f(R)), direct arterial blood pressures, heart rates (HR) and arterial blood gases were monitored. Data were averaged over time and tested for differences between groups by independent t-tests, and analysis of variance for repeated measures. Average FEIso concentrations required to maintain a surgical plane of anaesthesia were not different between groups (1: 1.02 +/- 0.04%; 2: 0.99 +/- 0.07%). There was no difference in HR, arterial blood pressures, f(R), FECo2 and arterial blood gases between groups. Average mean PaO2 were 279.54 +/- 113.37 mmHg and 220.21 +/- 102.15 mmHg with individual minimum values of 27.2 mmHg and 58.5 mmHg in groups 1 and 2, respectively. In conclusion, intravenous dexmedetomidine at 5 mug/ kg BW and medetomidine at 10 mug/kg have the same effects on isoflurane requirements and cardiopulmonary parameters in sheep, indicating an equipotent dose relationship. Both preparations induced moderate to severe hypoxaemia in individual sheep.