Efeitos da infusão contínua de propofol associado ou não ao fentanil na motilidade ruminal em bezerros (resultados parciais)

This study evaluates ruminal motility before, during and after continuous infusion of propofol with or without fentanyl in Holstein calves kept under spontaneous ventilation. Four healthy animals, with an average age of nine months, weighing on average 130.0 kg, underwent two treatments, at least one week apart. The two treatments consisted of induction with IV propofol 4.0 mg/kg (GP); and IV propofol 3.0 mg/kg with fentanyl 0.001 mg/kg (GF). On the first day two animals were assigned to each group randomly while in the following experiment the order was reversed. Anesthesia was maintained by continuous infusion of propofol, 0.6 mg/kg/min, IV, with or without fentanyl, 0.001 mg/kg/hour. The ruminal auscultation occurred early (IJ) and at the end of fasting (FJ); immediately before anesthesia induction (MB); 15, 30, 45 and 60 minutes after induction (M15, M30, M45 and M60, respectively), and in the recovery period, every 10 minutes until the measured value returned to the value obtained in IJ (time of ruminal normalization). Scores were assigned to the ruminal movements, 0.5 (incomplete movement) and 1.0 (full movement). The results were submitted to the Shapiro-Wilk and Wilcoxon tests. The median (minimum/maximum) of elapsed times, from the end of the infusion until the ruminal normalization were 30 (10/50) and 40 (20/50) minutes in GP and GF, respectively, and did not differ significantly between themselves (p = 0.25). There was no change in rumen motility between groups at any time. In addition, during anesthesia, there was total suppression of motility. Changes in rumen motility induced by propofol/fentanyl combination did not differ from propofol alone. This association did not prolong the time until normalization of rumen motility.