Comparison of haematological and haemodynamic alterations associated with lidocaine, bupivacaine, and ropivacaine epidural anaesthesia in dogs

Epidural anaesthesia is one among the most frequently used central neuraxial block techniques because of its simplicity and safety. This study aimed to assess the changes in haematological and haemodynamic parameters induced in dogs by epidurally administered lidocaine, bupivacaine, and ropivacaine together with dexmedetomidine in atropine-midazolam premedicated dogs subjected to elective ovariohysterectomy. A total of twenty-four adult dogs were allocated randomly (n=6) to 4 different groups, namely: A (dexmedetomidine), B (dexmedetomidine with lidocaine), C (dexmedetomidine with bupivacaine), and D (dexmedetomidine with ropivacaine). After a 10 minute premedication period, Dexmedetomidine @ 7 μg/kg, Lidocaine @ 4.4 mg/kg, Bupivacaine @ 2 mg/kg and Ropivacaine @ 2 mg/kg were dispensed into the epidural space. Different haematological and haemodynamic parameters were recorded during the study period. Haemoglobin levels showed a significant decline in Group B at the 30 and 90 minute with respect to baseline values. Packed cell volume, neutrophil and lymphocyte counts showed nonsignificant changes in all the groups relative to baseline. At 90 minutes, Group D exhibited a highly significant reduction (p < 0.05) in total leukocyte count compared to the other groups. Groups A, C and D exhibited significant variations in systolic, diastolic blood pressure, mean arterial pressure and haemoglobin oxygen saturation (SpO2) at various time points with respect to the baseline values. It was concluded that combining dexmedetomidine with lignocaine for epidural administration does not lead to haematological or haemodynamic instability.