Wang Hsien-Chi, Hung Cih-Ting, Lee Wei-Ming, Chang Kui-Ming, Chen Kuan-Sheng
Department of Veterinary Medicine, Veterinary Medical Teaching Hospital, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
Vet Radiol Ultrasound. 2016 Jan;57(1):8-15. doi: 10.1111/vru.12305. Epub 2015 Oct 15.
Dexmedetomidine is a highly specific and selective α2-adrenergic receptor agonist widely used in dogs for sedation or analgesia. We hypothesized that dexmedetomidine may cause significant changes in radiographic and echocardiographic measurements. The objective of this prospective cross-sectional study was to test this hypothesis in a sample of six healthy dogs. Staff-owned dogs were recruited and received a single dose of dexmedetomidine 250 μg/m(2) intravenously. Thoracic radiography and echocardiography were performed 1 h before treatment, and repeated 10 and 30 min after treatment, respectively. One observer recorded cardiac measurements from radiographs and another observer recorded echocardiographic measurements. Vertebral heart score and cardiac size to thorax ratio on the ventrodorsal projection increased from 9.8 ± 0.6 v to 10.3 ± 0.7 v (P = 0.0007) and 0.61 ± 0.04 to 0.68 ± 0.03 (P = 0.0109), respectively. E point-to-septal separation and left ventricle internal diameter in diastole and systole increased from 2.4 ± 1.1 to 6.6 ± 1.9 mm, 32.3 ± 8.1 to 35.5 ± 8.8 mm, and 19.4 ± 6 to 27.0 ± 7.2 mm, respectively (P < 0.05). Fractional shortening and sphericity index decreased from 40.7 ± 5.8 to 24.4 ± 2.9%, and 1.81 ± 0.07 to 1.58 ± 0.04, respectively (P < 0.05). Moderate-to-severe mitral regurgitation and mild pulmonic regurgitation occurred in all dogs after dexmedetomidine administration. Findings indicated that dexmedetomidine could cause false-positive diagnoses of valvular regurgitation and cardiomegaly in dogs undergoing thoracic radiography and echocardiography.
右美托咪定是一种高度特异性和选择性的α2-肾上腺素能受体激动剂，广泛用于犬类的镇静或镇痛。我们假设右美托咪定可能会导致X线和超声心动图测量结果发生显著变化。这项前瞻性横断面研究的目的是在6只健康犬的样本中检验这一假设。招募了工作人员自己拥有的犬，并静脉注射单剂量250μg/m(2)的右美托咪定。在治疗前1小时进行胸部X线摄影和超声心动图检查，并分别在治疗后10分钟和30分钟重复检查。一名观察者记录X线片上的心脏测量值，另一名观察者记录超声心动图测量值。腹背位投照时的椎体心脏评分和心脏大小与胸廓比值分别从9.8±0.6 v增加到10.3±0.7 v（P = 0.0007）和从0.61±0.04增加到0.68±0.03（P = 0.0109）。舒张期和收缩期的E点至室间隔距离以及左心室内径分别从2.4±1.1增加到6.6±1.9 mm、从32.3±8.1增加到35.5±8.8 mm以及从19.4±6增加到27.0±7.2 mm（P < 0.05）。缩短分数和球形指数分别从40.7±5.8降低到24.4±2.9%，以及从1.81±0.07降低到1.58±0.04（P < 0.05）。在给予右美托咪定后，所有犬均出现中度至重度二尖瓣反流和轻度肺动脉反流。研究结果表明，右美托咪定可能会在接受胸部X线摄影和超声心动图检查的犬中导致瓣膜反流和心脏扩大的假阳性诊断。
