Analgesic Effect of Continuous Rate Infusion of Butorphanol in Unilateral Total Resection of Mammary Tumor in Dogs
Author(s): Kenichi Maeda, Honoka Nomura, Daiki Hotta, Takuma Matsui, Satomi Iwai, Shozo Okano
Unilateral resection of mammary gland tumor (MGT) induce severe pain and it is necessary to use narcotic analgesics. Butorphanol has a weak analgesic effect and is effective for moderate pain, but it is thought that effective analgesia can be obtained by combining with other analgesics. However, since the information of analgesic effect of butorphanol is limited, this study compared the analgesic effect of continuous rate infusion (CRI) of butorphanol with fentanyl, a narcotic opioid, in MGT unilateral resection. 14 dogs undergoing MGT unilateral resection at Kitasato University Veterinary Teaching Hospital were randomly assigned to the fentanyl administration group (F group, n=8) and the butorphanol administration group (Group B, n=6). All patients were induced anesthesia by propofol and maintained with isoflurane. In group F, fentanyl(0.005 mg/kg) was injected followed by CRI (0.005 to0.02 mg/kg/hr). In group B, after injected initial dose of butorphanol (0.1 mg/kg), CRI was started (0.2 to 0.4 mg/kg/hr). Bupivacaine (1 mg/kg) was infiltrated into the wound surface after tumor removal, and CRI was discontinued at the start of wound closure, and buprenorphine was IV. Heart rate and inhalational anesthesia concentration were recorded during anesthesia and the pain score was evaluated after recovered from anesthesia. There was no significant difference in heart rate, inhalation anesthetic concentration and the pain score between the two groups. It was found that analgesia with butorphanol was effective as same as fentanyl when combined with other analgesics. These results will provide choices of analgesic protocols for several surgical procedures.