PROTOCOL OF SEDATION AND ANTAGONISM (DEXMEDETOMIDINE-ATIPAMEZOLE) TO PERFORM DIAGNOSTIC ANALGESIA IN FRACTIOUS HORSES : PRELIMINARY STUDY

Purpose of the work: To assess the applicability of a new protocol of sedation and antagonism using dexmedetomidine (DEX) and atipamezole (ATZ) to perform diagnostic analgesia in fractious horses. Materials and methods: Six fractious horses (3 geldings and 3 mares) undergoing lameness investigation that required diagnostic analgesia were recruited. All the horses were admitted two days before the beginning of the study. During this period heart rate (HR), respiratory rate (RR), height of the head from the ground, mucous membranes colour, capillary refill time (CRT) and temperature were recorded. All the horses were sedated with DEX 2.5-5μg/kg and after 20 min ATZ 5μg/kg was administered. The degree of sedation was assessed using the visual analogue scale (VAS) and the numerical rating scale (NRS). The FC, FR, TRC were assessed at 3, 5, 10 and 15 min after both sedation and ATZ administration. Statistical analysis: The physiological parameters were analysed using ANOVA whereas Wilcoxon test was used for the sedation scales. Results: The values of HR and RR were significantly different after administration of DEX and ATZ at 3 and 5 min respectively. Statistical significance was also appreciated for height of the head from the ground, ataxia, tactile stimuli and visual stimuli. Ataxia and height of the head from the ground were improved starting from 3 min after administration of ATZ. Conclusion and clinical relevance: The protocol was successful in all cases, however in two patients ataxia was not completely abolished after ATZ administration. There is a potential for the protocol to be used in the everyday practice. However diffusion of the local anaesthetic after block must be born in mind.