Dexmedetomidine and atipamezole on renal blood perfusion in dogs assessed by doppler flowmetry and urinalysis

This study compared the intramuscular administration of 2.5 or 5 µg/kg of dexmedetomidine and subsequent reversal with atipamezole in domestic dogs, assessing the impact on renal function using Doppler ultrasound, urinalysis, and evaluation of cardiorespiratory and sedative effects. Twenty animals had their baseline measurements recorded (T0) and received 2.5 or 5 µg/kg of dexmedetomidine (G2.5 and G5, respectively). After 20 minutes, T1 was recorded, and atipamezole (25 or 50 µg/kg) was administered, and measurements were repeated 10 minutes later, T2 was recorded. Renal vascular flow was assessed by Doppler ultrasound using the semi-quantitative measurement of pulsatility (PI) and resistivity (RI) indices of the left kidney. Heart rate (HR), respiratory rate (RR), systolic blood pressure (SBP), capillary refill time (CRT), rectal temperature, and sedation score (GRINT et al., 2009) were also recorded. Urine samples were collected at T0 and 6 hours after dexmedetomidine administration. HR decreased significantly at T1 and T2 compared with T0 in G2.5 (27.8% and 27.0%, respectively) and G5 (41.1% and 31.2%, respectively). G5 CRT (seconds) increased significantly at T1 compared with T0 (1.8 ± 0.63 vs. 1.4 ± 0.52). RI and PI at T1 were significantly higher in G5 compared with G2.5, but at T2, both values returned to T0 levels. Urinalysis results showed no statistically significant differences. Both doses induced cardiorespiratory changes, with greater effects observed in G5, as demonstrated by Doppler ultrasound. Atipamezole effectively restored RI and PI to baseline values.