Evaluation of the effect of lidocaine epidural injection on immunological indices in dogs under total intravenous anesthesia submitted to ovariohysterectomy

This study aimed to evaluate the effects of epidural anaesthesia with lidocaine in combination with general anaesthesia with propofol on some immunologic indices in dogs undergoing ovariohysterectomy. Twelve adult dogs were anesthetized with propofol (induction: 7 mg/kg; maintenance: 0.4 mg/kg/min) and were then allocated into either groups of epidural saline (control) or epidural lidocaine (4 mg/kg; treatment). All the included animals underwent ovariohysterectomy operation. The immune responses, hematologic parameters and cortisol levels were assessed in the predetermined intervals. Evaluation of the innate immunity revealed higher significant levels in the bactericidal, lysozyme and myeloperoxidase activities at 4 hours after surgery in the treatment. In the humoral immunity, the total immunoglobulin level was significantly higher in the treatment. In the assessment of cellular immunity, higher significant values were detected in the delayed skin sensitivity to phytohemagglutinine injection after 48 and 72 hours in the treatment. Moreover, higher significant levels were observed in the number and percentage of lymphocytes as well as an increase in the percentage of monocytes in the treatment at 4 hours after the operation. Notably, the cortisol hormone in the treatment was lower than control at 4 hours of the surgery. In conclusion, epidural anaesthesia with lidocaine when added to general anaesthesia with propofol attenuated the suppression of the innate and cellular immune responses produced by anaesthesia and surgery in the dogs.