Lin Guan-Yu, Robben Joris H, Murrell Joanna C, Aspegrén John, McKusick Brett C, Hellebrekers Ludo J
Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, The Netherlands.
Vet Anaesth Analg. 2008 Mar;35(2):141-53. doi: 10.1111/j.1467-2995.2007.00365.x. Epub 2008 Jan 4.
To evaluate cardiovascular and respiratory effects and pharmacokinetics of a 24-hour intravenous constant rate infusion (CRI) of dexmedetomidine (DMED) during and after propofol (PRO) or isoflurane (ISO) anaesthesia in dogs.
Prospective, randomized, cross-over study.
Ten healthy adult Beagles.
Instrumented dogs received a DMED-loading bolus (25 microg m(-2)) at time 0 followed by a 24-hour CRI (25 microg m(-2) hour(-1)), with PRO or ISO induction/maintenance of anaesthesia during the first 2 hours (PRO and ISO treatment groups, respectively). Cardiovascular, respiratory, blood gas, airway gas, serum chemistry variables and DMED plasma concentration data were collected at -15, 5, 15, 30, 45, 60, 90 and 120 minutes. A number of cardiorespiratory and tissue oxygenation variables were calculated from the above data. After the 2-hours of anaesthesia, heart and respiratory rates and electrocardiograms were recorded and DMED plasma concentrations were determined for up to 26 hours.
Vasopressor effects and the decrease in heart rate (HR) and cardiac index induced by DMED were greater for PRO than ISO, but were within clinically acceptable ranges. Adequate oxygenation was maintained above the critical O(2) delivery level. The overall incidence of unfavourable arrhythmias was low and tended to vary inversely with HR. Mean DMED plasma concentration ranged from 0.23 to 0.47 ng mL(-1) for both groups during the 24-hour CRI with a mean elimination half-life of approximately 0.46 hour. CONCLUSION AND/CLINICAL RELEVANCE: DMED CRI resulted in typical alpha(2)-agonist induced haemodynamic changes with minimal respiratory effects, and appeared to be an efficacious adjunct during and after PRO or ISO anaesthesia in healthy dogs.
评估在犬丙泊酚（PRO）或异氟烷（ISO）麻醉期间及之后，右美托咪定（DMED）24小时静脉恒速输注（CRI）对心血管和呼吸系统的影响以及药代动力学。
前瞻性、随机、交叉研究。
十只健康成年比格犬。
植入仪器的犬在时间0接受一次DMED负荷推注（25微克/平方米），随后进行24小时CRI（25微克/平方米·小时⁻¹），在前2小时分别用PRO或ISO诱导/维持麻醉（分别为PRO和ISO治疗组）。在-15、5、15、30、45、60、90和120分钟收集心血管、呼吸、血气、气道气体、血清化学变量和DMED血浆浓度数据。根据上述数据计算一些心肺和组织氧合变量。麻醉2小时后，记录心率和呼吸频率以及心电图，并测定长达26小时的DMED血浆浓度。
DMED引起的升压作用以及心率（HR）和心脏指数的降低，PRO组比ISO组更明显，但均在临床可接受范围内。在临界氧输送水平以上维持了足够的氧合。不良心律失常的总体发生率较低，且往往与HR呈反比变化。两组在24小时CRI期间，DMED平均血浆浓度范围为0.23至0.47纳克/毫升，平均消除半衰期约为0.46小时。结论及临床相关性：DMED CRI导致典型的α₂激动剂引起的血流动力学变化，呼吸影响最小，在健康犬的PRO或ISO麻醉期间及之后似乎是一种有效的辅助药物。
