Effects of lidocaine associated with detomidine on sedation of horses undergoing dental procedures

Abstract

Due to the growing increase in the dental routine in equine medicine, along with the need for patient sedation to perform this procedure, this study aimed to assess sedation by detomidine alone and/or associated with lidocaine under continuous infusion. Twenty-two horses from the dental routine of the veterinary hospital of the institution of origin were used. A jugular catheter was implanted on the day of study and animals were allocated into two distinct groups (n=11): GD, which received detomidine (20 µg kg−1), followed by continuous infusion (20 µg kg−1 h−1); and GDL, animals which received detomidine (10 µg kg−1) and lidocaine (1.3 mg kg−1), followed by continuous infusion of detomidine (10 µg kg−1 h−1) and lidocaine (25 µg kg−1 min−1). The assessed moments were as follows: M0, before catheter placement; M1, 5 minutes after bolus and beginning of infusion; M2, placement of mouth speculum; and M3, wear with an electric rasp. The assessed parameters were heart rate (HR), respiratory rate (f), systolic blood pressure (SBP), and intestinal motility. In addition to the clinical parameters, sedation was assessed by measuring head height in relation to the ground before (M0) and after treatment administration (M1) and during the dental procedure using a scale adapted for dental procedures. Statistical analysis was performed using the Shapiro-Wilk normality test by applying one-way RM ANOVA, followed by the Dunnett test for comparison in relation to M0, t-test, and Mann-Whitney test between groups (p ≤ 0.05). HR decreased by 20% at M2 and M3 compared to M0 only in GD, while SBP increased 35% at the same moments compared to M0 in GD and 27, 42, and 27% at M1, M2, and M3 compared to M0 in GDL, respectively. Intestinal motility decreased by 75% at all moments compared to M0 in both groups. Head height decreased by 67% in GD and 60% in GDL, with no difference between groups. Sedation scores provided by the scale did not differ between groups, with values of 1 [0–3] in GD and 3 [0–4] in GDL at M2 and 1 [0–3] in GD and 1 [1.5–3] in GDL at M3. Thus, sedation by the association between detomidine and lidocaine allowed reducing detomidine dose in half but offering similar results for dental procedures.