Avaliação dos efeitos de duas soluções para anestesia local por tumescência em cadelas submetidas à mastectomia parcial sob anestesia geral inalatória

Abstract

Local anesthesia has been increasingly accepted and used in veterinary medicine, both in anesthetic protocols and in pain treatments. The association of local anesthesia by tumescence in general anesthesia protocols significantly reduces the use of inhaled anesthetic, improves recovery and provides trans and postoperative analgesia. The aim of this study was to evaluate the cardiovascular and respiratory parameters, temperature and isoflurane concentration expired in the transoperative period of bitches submitted to local anesthesia due to tumescence with lidocaine or ropivacaine associated with general inhalation anesthesia. Materials, Methods & Results: Twelve non-defined bitches, weighing between 5 and 15 kilograms (mean of 8.02 ± 2.90 kg standard deviation) and age between 5 and 13 years (mean 10.33 ± 2.60 years standard deviation) were used, classified as ASA I and ASA II, premedicated with 0.04 mg / kg of acepromazine and 2 mg / kg of meperidine administered intramuscularly, after thirty minutes of MPA, were divided into 2 groups with different local anesthesia treatments. Induction was done with the administration of propofol and the anesthetic maintenance performed with isofluorane administered through a calibrated vaporizer and anesthetic circuit and 100% O2 diluent flow suitable for the weight of the animal. After 5 minutes of isoflurane stabilization at 1.4% the infusion of the tumescence solutions was started subcutaneously for 10 minutes. In the lidocaine group (GL), the solution for tumescence was composed of 210 ml lactated ringer (RL) previously refrigerated at 8 to 12 ° C, 40 ml of 2% lidocaine hydrochloride without vasoconstrictor and 0.5 ml of adrenaline. In the ropivacaine (GR) group the solution consisted of 233.3 ml of lactated ringer at the same temperature as the previous solution, 16.7 ml of ropivacaine and 0.5 ml of adrenaline. Fifteen ml / kg of each infiltration solution was used throughout the surgical area to be operated, which was previously evaluated and demarcated by the surgical team. The cardiac, respiratory and temperature parameters were measured at different times: baseline (before drug application), 5 min after stabilization of isoflurane in 1.4 V%, 10 m after application of the solution by tumescence (PT), incision and removal of (GT), removal of the abdominal glands (GA), removal of the inguinal glands (GI), fixation of the vein and the pudendal artery (FVA) and surgical (S) synthesis. The surgery started after 25 minutes of induction and 10 minutes after the application of the tumescence solutions. Concomitant to the end of the surgery, the use of isoflurane was terminated and the last evaluations were made. Discussion: There was a reduction in adequate responses and nociceptive stimuli during the surgical procedure and a decrease in expired isoflurane concentration, considering that the values of heart rate, respiratory rate and blood pressure found during surgery were relatively lower than the baseline values and within the physiological limits for the In both groups. On the other hand, the temperature in GR presented lower values at all times, being framed in mild hypothermia. This contributed to statistical difference between groups. Further studies related to the described method are suggested, since the literature on tumescence anesthesia protocols in bitches submitted to mastectomy is still scarce.