Document Type: Full paper (Original article)
Department of Pharmacology and Veterinary Therapeutics, Faculty of Higher Studies Cuautitlán, Universidad Nacional Autónoma de México, México
Background: Analgesic and hemodynamic effects of ketamine in subanesthetic doses during surgical anesthesia and postoperative, are due to the action on the NMDAR. Aims: To evaluate the intraoperative cardiorespiratory effects provided by ketamine compared to lidocaine, both administered epidurally in bitches submitted to ovariohysterectomy. Methods: Thirty-six dogs of different breeds were used in a randomized, prospective and blinded clinical trial. Two groups were formed; GKET (ketamine 3 mg/kg, n=18) and GLIDO (lidocaine 4 mg/kg, n=18). Animals were premedicated with acepromazine 0.05 mg/kg intravenous. Anesthesia was induced with propofol 5 mg/kg intravenous. Anesthetic maintenance was performed with isoflurane in 100% oxygen. Every 5 minutes during surgery, heart rate (HR), respiratory rate (RR), esophageal temperature (°C), oxygen saturation (SPO2), end tidal carbon dioxide (ETCO2) and mean arterial blood pressure (MAP) were monitored. Results: Cardiorespiratory variables during anesthesia were within normal ranges. HR was significantly higher at 5 (108 ± 12 vs 95 ± 11) and 10 (110 ± 11 vs 97 ± 11) minutes in GKET compared to GLIDO after the start of surgery (P=0.03 and P=0.01, respectively). MAP was higher in GKET, (100 ± 23; 105 ± 35 and 103 ± 35 mmHg) in comparison with GLIDO (66 ± 7; 74 ± 10 and 67 ± 9 mmHg) at 20, 25 and 30 minutes (P=0.01; P=0.004; P=0.002, respectively). Mild hypothermia at 25 (36.5±1.3 °C) and 30 (36.5±1.4 °C) minutes in the GKET was recorded. Conclusion: Epidural administration of ketamine provides better hemodynamic stability, compared to the use of epidural lidocaine.