Jaeger Alison T, Pypendop Bruno H, Ahokoivu Hanna, Honkavaara Juhana
William R Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA, USA.
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
Vet Anaesth Analg. 2019 Nov;46(6):753-764. doi: 10.1016/j.vaa.2019.05.012. Epub 2019 Jun 17.
To characterize the cardiopulmonary effects of dexmedetomidine, with or without vatinoxan, in isoflurane-anesthetized cats.
Randomized, crossover experimental study.
A group of six adult healthy male neutered cats.
Cats were instrumented during anesthesia with isoflurane in oxygen. Isoflurane end-tidal concentration was set to 1.25 minimum alveolar concentration (MAC). Dexmedetomidine was administered using a target-controlled infusion system to achieve and maintain 10 target plasma concentrations ranging from 0 to 40 ng mL. Furthermore, vatinoxan or an equivalent volume of saline was administered using a target-controlled infusion system to achieve and maintain a target plasma concentration of 4 μg mL. Isoflurane concentration was adjusted after each change in dexmedetomidine concentration to maintain a concentration equivalent to 1.25 MAC. Heart rate (HR), arterial blood pressure, central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary artery occlusion pressure (PAOP), body temperature, cardiac output, arterial and mixed-venous blood gas and pH and drug concentrations were measured. Additional variables were calculated from the measurements.
Dexmedetomidine alone resulted in decreased HR, cardiac index, stroke index and oxygen delivery, and increased systolic, mean (MAP) and diastolic arterial pressure, CVP, PAP, PAOP, systemic vascular resistance index, rate-pressure product, left ventricular stroke work index and oxygen extraction ratio. Vatinoxan resulted in severe hypotension at target plasma dexmedetomidine concentrations <10 ng mL. Vatinoxan attenuated the cardiovascular effects of dexmedetomidine at the 10 and 20 ng mL targets, but MAP could be maintained above 60 mmHg only when isoflurane concentration was <1.25 MAC. Less improvement in cardiovascular function was seen with vatinoxan at the 40 ng mL target plasma dexmedetomidine concentration.
Vatinoxan, at the plasma concentration maintained in this study, attenuated the cardiovascular effects of dexmedetomidine in isoflurane-anesthetized cats. However, its administration resulted in hypotension, which may limit its clinical usefulness.
研究右美托咪定单独或与伐替考昔联合使用时，对异氟烷麻醉猫心肺功能的影响。
随机交叉实验研究。
一组6只成年健康雄性去势猫。
在氧气中用异氟烷对猫进行麻醉时进行仪器植入。将异氟烷呼气末浓度设定为1.25最低肺泡有效浓度（MAC）。使用靶控输注系统给予右美托咪定，以达到并维持10个目标血浆浓度，范围从0至40 ng/mL。此外，使用靶控输注系统给予伐替考昔或等量生理盐水，以达到并维持目标血浆浓度4 μg/mL。每次右美托咪定浓度改变后，调整异氟烷浓度，以维持相当于1.25 MAC的浓度。测量心率（HR）、动脉血压、中心静脉压（CVP）、肺动脉压（PAP）、肺动脉闭塞压（PAOP）、体温、心输出量、动脉血和混合静脉血的血气、pH值以及药物浓度。根据测量结果计算其他变量。
单独使用右美托咪定导致心率、心脏指数、每搏指数和氧输送量降低，收缩压、平均动脉压（MAP）和舒张压、CVP、PAP、PAOP、全身血管阻力指数、心率-血压乘积、左心室每搏功指数和氧摄取率升高。在目标血浆右美托咪定浓度<10 ng/mL时，伐替考昔导致严重低血压。在10和20 ng/mL目标浓度时，伐替考昔减弱了右美托咪定的心血管效应，但仅当异氟烷浓度<1.25 MAC时MAP才能维持在60 mmHg以上。在目标血浆右美托咪定浓度为40 ng/mL时，伐替考昔对心血管功能的改善作用较小。
在本研究维持的血浆浓度下，伐替考昔减弱了异氟烷麻醉猫中右美托咪定的心血管效应。然而，其使用导致低血压，这可能限制其临床应用。
