Early Postoperative Analgesic Evaluation of Intravenous Lidocaine Infusion or a Combination of Intraperitoneal and Incisional Lidocaine Splash in Female Dogs Undergoing Ovariohysterectomy

Combined intraperitoneal and incisional block provides effective perioperative analgesia but is limited in clinical practice. Intravenous lidocaine offers an alternative, although its analgesic efficacy remains controversial. This study compared the postoperative analgesic efficacy of lidocaine intravenous infusion with combined intraperitoneal and incisional lidocaine splash in dogs undergoing ovariohysterectomy. Thirty female dogs were randomized to intravenous infusion (IV), intraperitoneal and incisional splash (IP + SP), or control (C). Anesthesia included intramuscular acepromazine (0.03 mg/kg), intravenous propofol (4-6 mg/kg), isoflurane maintenance, and fentanyl (2 µg/kg) intravenous pre-incision. Group IV received intravenous lidocaine 2 mg/kg and then 50 μg/kg/min infusion. Group IP + SP received lidocaine 4 mg/kg intraperitoneally intraoperatively and 2 mg/kg as an incisional splash before skin closure. Controls received saline. Postoperative pain was assessed using the Glasgow Composite Measure Pain Scale-Short Form and analyzed using a linear mixed model. At 60 min, pain scores were 1.2 ± 0.4 (IP + SP), 1.6 ± 0.7 (IV), and 3.0 ± 2.8 (C) and at 120 min 1.3 ± 0.5, 1.4 ± 0.7, and 2.3 ± 0.8, respectively. Both treatments had significantly lower scores than controls (<i>p</i> = 0.004); IV and IP + SP did not differ. Therefore, intravenous lidocaine infusion may be an option for early postoperative analgesia in canine ovariohysterectomy.