Evaluation of dexmedetomidine and tramadol, associated with midazolam, in cats anesthetized with isoflurane, undergoing ovariohysterectomy

ABSTRACT The aim of this study was to compare cardiorespiratory changes and post-operative analgesia provided by dexmedetomidine or tramadol, associated with midazolam, in female cats. For that purpose, 18 healthy cats were assigned to two randomized groups: GDM, which received dexmedetomidine (10 µg/kg) and GTM, which received tramadol (2 mg/kg), both associated with midazolam (0.2 mg/kg) IM. After 15 minutes, anesthesia was induced with propofol (1.46±0.79 mL) and maintained with isofluorane. Ovariohysterectomy was performed and cardiorespiratory variables were registered 15 minutes after pre-anesthetic medication (M0), 15 minutes after anesthetic induction (M15), and every five minutes until the end of the surgical procedure (M20, M25, M30, M35 e M40). Pain evaluation started 30 minutes after the surgery (MP30) and sequentially at thirty-minute intervals (MP60, MP90, MP120). After MP120, each evaluation was registered at every hour (MP180, MP240 e MP360). Dexmedetomidine-midazolam association results in decreases on initial heart rate (HR) without clinical relevance and it is related to pronounced sedation, poor and less durable antinociception and vomiting events, when compared to tramadol-midazolam association. Both protocols indicate cardiorespiratoy stability and safety in cats undergoing ovariohysterectomy.摘要 本研究旨在比较右美托咪定（dexmedetomidine）或曲马多（tramadol）联合咪达唑仑（midazolam）对雌性猫的心肺功能变化及术后镇痛效果。为此，将18只健康雌性猫随机分为两组：GDM组（给予右美托咪定10 µg/kg）与GTM组（给予曲马多2 mg/kg），两组均联合咪达唑仑0.2 mg/kg经肌肉注射给药。给药15分钟后，采用丙泊酚（propofol，剂量为1.46±0.79 mL）诱导麻醉，并用异氟烷（isofluorane）维持麻醉。随后实施卵巢子宫切除术（ovariohysterectomy），并分别于麻醉前给药后15分钟（M0）、麻醉诱导后15分钟（M15）以及手术过程中每5分钟记录一次心肺变量，直至手术结束（M20、M25、M30、M35与M40）。术后30分钟（MP30）开始进行疼痛评估，之后每30分钟依次开展一次评估（MP60、MP90、MP120）；MP120之后，则每小时记录一次评估结果（MP180、MP240与MP360）。与曲马多联合咪达唑仑方案相比，右美托咪定联合咪达唑仑方案可使初始心率（HR）出现无临床意义的降低，且伴随显著镇静、镇痛效果较弱且持续时间较短以及呕吐不良事件。两种给药方案均表明，接受卵巢子宫切除术的猫心肺功能稳定且安全性良好。