Effects of Sedation with Medetomidine and Dexmedetomidine on Doppler Measurements of Ovarian Artery Blood Flow in Bitches

Abstract

The aim was to evaluate if medetomidine and dexmedetomidine affected arterial ovarian blood flow in dogs. The dogs were randomly assigned to two different groups. In Group 1, medetomidine (10 µg/kg) was administered intramuscularly and, in Group 2, dexmedetomidine (5 µg/kg) was used. After a preliminary exam, arterial blood pressure (BP) was measured and a duplex Doppler ultrasonographic examination of both ovarian arteries was performed. Twenty minutes after the administration of medetomidine or dexmedetomidine, BP and ovarian Doppler ultrasonography were repeated. High quality tracings of ovarian artery flow velocity were obtained in all dogs and Doppler parameters: Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV) and Resistive Index (RI) were measured before and after drug administration in the left (LO) and right (RO) ovaries. PSV and EDV values decreased significantly after drug administration (p < 0.05) compared to the non-sedated values, but no differences were found between the LO and RO (p > 0.05). The RI was not affected by drugs administration in neither of the groups studied (p > 0.05). In conclusion, the administration of medetomidine or dexmedetomidine causes a decrease in blood flow velocity in the ovarian artery and may be a good choice to avoid excessive bleeding prior surgeries in which ovariectomy.

Emotional temperaments in advanced pregnant goats and its relationship with the feto-maternal blood flow and placentome echotexture

“…maternal heart rates were substantially lower in the sedated conditions compared to the non-seated conditions. In general, alpha 2-adrenoceptor agonists (such as xylazine) cause a peripheral phase of vasoconstriction, hypertension, and reflex bradycardia, followed by a central phase or effect of decreased sympathetic tone, bradycardia (decreased heart rate), and hypertension (Nicolás-Barceló et al 2021 ). A previous investigation on goats found that xylazine sedation significantly reduced heart rate, cardiac output, and Doppler hemodynamic parameters of the pulmonary artery, aortic, and mitral inputs (Mandour et al 2020 ).…”

“…Administration of xylazine resulted in decreased stress levels (lower cortisol levels) during the laparoscopic embryo transfer and enhanced the pregnancy rate of recipient goats (Aghamiri et al 2022 ). Administration of medetomidine or dexmedetomidine (alpha 2 agonist sedatives like xylazine) in bitches significantly decreased the blood flow to the ovarian arteries and may be a wise alternative to prevent excessive bleeding before the ovariectomy (Nicolás-Barceló et al 2021 ). Sedation of animals may be important, especially during the late gestation stage and handling of dystocia cases, to minimize the anxiety fear, and distress, and to facilitate the successful performance of diagnostic or therapeutic procedures, and during conservative or surgical obstetrical procedures, providing patient comfort and cooperation.…”