Avaliação eletrocardiográfica de cadelas (canis familiares) submetidas à infusão contínua com fentanil, lidocaína e cetamina com e sem adiçao de metadona durante cirurgia de ovariosalpingohisterectomia

Abstract

The search for analgesic techniques in the operative periods motivated the researchers to develop analgesia protocols for each stage of anesthesia. In the trans-anesthetic period, the most commonly used techniques are continuous infusion with association, generally with an analgesic agent (opioid), a local anesthetic and a dissociative anesthetic. Although these techniques provide adequate analgesia for the period, they lack greater power for the immediate postoperative period, since, by the pharmacology of the drugs used, this property would be difficult. Thus, the use of non-steroidal anti-inflammatory drugs began, however, due to the high incidence of adverse effects it becomes an alternative, sometimes unfeasible. For that matter, the search for long-term analgesic alternatives with the least occurrence of undesirable effects is the main motivator of this study, having as its main study object the use of methadone as an alternative because it is an opioid of latency and prolonged duration, although not commonly used in daily anesthetic practice due to the insufficient number of studies that assure its safety when it is used intravenously and associated with other analgesic agents and anesthetics. This study aimed to evaluate the cardiorespiratory changes provided by the addition of methadone to the continuous infusion with lidocaine, ketamine and fentanyl in dogs undergoing ovariosalpingohisterectomy under isoflurane anesthesia, where 20 adult female dogs from surgical routine of the University Veterinary Hospital of the Universidade Estadual do Maranhao, with variable body weight, classified as ASA I were used. In order to perform the analysis the animals were divided into two groups randomly, in which Group 1 with 10 dogs was submitted to continuous infusion of ketamine (10μg / kg / min), lidocaine (50ug / kg / min), fentanyl (0.03μg / kg / Min) and methadone (0.2mg / kg / min) and Group 2 received the same infusion without methadone, and during all procedures the animals had their physiological parameters monitored for future evaluation. Regarding the Heart Rate and electrocardiographic tracings, no significant differences between groups em times were observed. Therefore, it is possible to conclude that methadone addition into the continuous infusion with lidocaine, ketamine and fentanyll in female dogs undergoing ovariosalpingohisterectomy under isoflurane anesthesia did not cause cardiorespiratory changes and provided satisfactory analgesia in the immediate postoperative perio.