The aim of this study was to evaluate the cardiopulmonary effects, the quality of anesthesia and the post-anesthetic recovery of ketamine and xylazine premedication following intravenous (IV) continuous rate infusion of midazolam alone or in combination with fentanyl, in swine. Ten Landrace adult pigs that underwent endoscopy were evaluated. All pigs were premedicated with ketamine (4mg kg-1) and xylazine (2mg kg-1) by intramuscular administration. After twenty minutes, intravenous ketamine (2mg kg-1) was injected, following IV continuous rate infusion of midazolam (0.5mg kg-1 h-1 GM, n=5) or midazolam (0.25mg kg-1 h-1) plus fentanyl (4µg kg-1 h¹ GMF, n=5). Heart and respiratory rates, systolic arterial blood pressure, rectal temperature, arterial blood gases, quality of anesthesia and recovery, and time for recovery were investigated. Statistical analysis was performed with One-Way ANOVA, Tukey test and Mann-Whitney test (P<0.05). The quality of anesthesia was similar between treatments, and endoscopy was able to be performed in both groups. Cardiopulmonary variables and blood gases did not differ between groups. The recovery time was 98±15 and 79±17 minutes in GM and GMF, respectively, without significant difference between treatments. The quality of recovery did not differ between groups. The results allowed us to conclude that both treatments provide cardiopulmonary stability and were satisfactory to swine endoscopy. However, despite of absence of significant difference, shorter time of recovery was observed with midazolam/fentanyl infusion.
ketamine; xylazine; benzodiazepinics; opioids; pig
