Tramadol in continuous intravenous infusion VS tramadol bolus during abdominal surgery in dog

Tramadol in continuous intravenous infusion VS tramadol bolus during abdominal surgery in dog Costa GL (1), Nastasi B (1), Musicò M. (1), Spadola F (1), CalabròP.( 2), Interlandi C. (1), (1) Department of Veterinary Sciences, University of Messina, Italy. (2) Board of Messina (ASP), Polo Universitario Annunziata 98168 Messina, Italy This clinical blinded trial study aims to compare the effects of tramadol administered as a constant rate infusion to that of tramadol administered as a single intravenous bolus on physiological paramenters and isoflurane requirements during elective ovary-hysterectomy in dog[1] [2]. In this study have been included forty female dogs. Anesthesia was performed by the administration of tiletamine/zolazepam 5mgkg-1 intravenously (IV) and acepromazine 0,05 mgkg-1 IV, oxygen and isoflurane. Animals were divided in two groups: Group A received 4mgkg-1 of tramadol IV as a single bolus, while group B received 1.5 mgkg-1 of tramadol IV as a single bolus followed by a tramadol constant rate infusion (CRI) at 2,6 mgkg-1h-1. The following parameters were recorded: heart rate, respiratory rate, blood pressure (systolic, diastolic, mean), body temperature, EtCO2, SpO2 and the concentration of inspired and expired isoflurane, they dose isoflurnane to increase or decrease depending on the variations of: heart rate, respiratory rate, blood pressure, EtCO2 . Data were compared with two-way ANOVA for repeated measures followed by Bonferroni test p < 0.05. The heart rate increased in both groups after administration of the tiletamine/zolazepam and acepromazine, however, after intubation and administration of tramadol, it decreased in both groups being the reduction significantly lower in group B p=0.000.The respiratory rate decreased after administration of the injectable anesthetics in both groups and remained constant during the entire surgery. The pressure remained within normal limits throughout, but in group B it is reduced more than basal p=0.000 .The SPO2 remained within physiological limits during the study 98/100%. The isoflurane inspired and expired levels were statistically lower in group B (2.3/2% VS 1.8/1.6%) p=0.000 . CRI of tramadol decreases isoflurane requirements compared to tramadol administered as a bolus[1] [2]. The presence of transient twitching was observed in individuals that received tramadol as a bolus while no side effects were observed in any of the animals belonging to group B. [1] De Wolff MH, Leather HA, Wouters PF. 1999 Effects of tramadol on minimum alveolar concentration (MAC) of isoflurane in rats. Br J Anaesth. 83,780-3. [2] Itami T ,Kawase K, Tamaru N et al, 2013 Effects of asingle bolus intravenous dose of ramadolon minimum alveolar concentration (MAC) of sevoflurane in dogs.J Vet Med Sci. 75,613-8.