Bisetto Shayne P, Melo Cristiano F, Carregaro Adriano B
Department of Veterinary Medicine, School of Animal Science and Food Engineering, University of São Paulo, São Paulo, SP, Brazil.
Department of Veterinary Medicine, School of Animal Science and Food Engineering, University of São Paulo, São Paulo, SP, Brazil.
Vet Anaesth Analg. 2018 May;45(3):320-328. doi: 10.1016/j.vaa.2017.12.004. Epub 2018 Jan 17.
To evaluate dexmedetomidine, midazolam and dexmedetomidine-midazolam for sedation and antinociception in tegus.
Prospective, crossover, randomized, blinded study.
Six healthy tegus (Salvator merianae) weighing 1.6±0.3 kg.
Tegus were administered intramuscularly saline (0.5 mL; CON), dexmedetomidine (0.2 mg kg; DX), midazolam (1 mg kg; MZ) and dexmedetomidine-midazolam (same doses; DM). Heart rate (HR) and respiratory frequency (f) were recorded before treatment (baseline) and 15, 30 minutes, 1, 2, 3, 4, 6, 8, 12 and 24 hours after the treatments. Sedation scores were recorded according to resistance to manual restraint, posture and response to noxious stimulus, at baseline and 5, 10, 15, 30 minutes, 1, 2, 3, 4, 6, 8, 12 and 24 hours after the treatments. Antinociception was evaluated by measurement of latency of limb withdrawal reflex (LWR) to thermal stimulus, recorded at baseline and 15 minutes, 1, 2, 4, 8, 12 and 24 hours after the treatments.
Lower HR (DX and DM) and f (MZ, DX and DM) than CON were measured 15 minutes after the treatment and for up to 6 hours. Sedation was mild to moderate in MZ, deep in DM and absent in DX, although animals showed behavioral changes in DX, with increase in aggressiveness. Median (interquartile range) duration of sedation were 170 (50; 235) minutes in MZ and 230 (115; 235) minutes in DM. Recovery period was prolonged in both treatments, surpassing the duration of the experiment. Higher LWR than CON was detected from 15 minutes until 12 hours in DX and DM.
Midazolam provided sedation without antinociception, and dexmedetomidine provided antinociception without sedation. Drug combination increased the duration of sedation but not antinociception. Due to increased duration of sedation, reversal of effects with flumazenil and atipamezole should be considered after conclusion of clinical procedures.
评估右美托咪定、咪达唑仑及右美托咪定 - 咪达唑仑对南美蜥的镇静和镇痛作用。
前瞻性、交叉、随机、双盲研究。
6只健康南美蜥（萨尔瓦多蜥），体重1.6±0.3千克。
给南美蜥肌肉注射生理盐水（0.5毫升；CON）、右美托咪定（0.2毫克/千克；DX）、咪达唑仑（1毫克/千克；MZ）及右美托咪定 - 咪达唑仑（相同剂量；DM）。在治疗前（基线）以及治疗后15分钟、30分钟、1小时、2小时、3小时、4小时、6小时、8小时、12小时和24小时记录心率（HR）和呼吸频率（f）。根据对人工约束的抵抗、姿势及对有害刺激的反应，在基线以及治疗后5分钟、10分钟、15分钟、30分钟、1小时、2小时、3小时、4小时、6小时、8小时、12小时和24小时记录镇静评分。通过测量肢体对热刺激的退缩反射（LWR）潜伏期评估镇痛作用，在基线以及治疗后15分钟、1小时、2小时、4小时、8小时、12小时和24小时记录。
治疗后15分钟及长达6小时测量发现，DX和DM组的HR低于CON组，MZ、DX和DM组的f低于CON组。MZ组镇静为轻至中度，DM组为深度，DX组无镇静，但DX组动物有行为变化，攻击性增加。MZ组镇静的中位（四分位间距）持续时间为170（50；235）分钟，DM组为230（115；235）分钟。两种治疗的恢复期均延长，超过了实验持续时间。DX组和DM组在治疗后15分钟至12小时检测到LWR高于CON组。
咪达唑仑提供镇静但无镇痛作用，右美托咪定提供镇痛但无镇静作用。药物联合增加了镇静持续时间，但未增加镇痛作用。由于镇静持续时间增加，临床操作结束后应考虑用氟马西尼和阿替美唑逆转效应。
