Introduction

Epidural administration of local anesthetics, α₂-adrenoceptor agonists, opioids and ketamine either alone or in combination for management of pain in dogs continues to gain popularity. Administration of these drugs is associated with changes in hematological, temperature and cardiopulmonary parameters.

Objectives

To evaluate the effects of lumbosacral epidural xylazine, lidocaine and their combination on hematological, temperature and cardiopulmonary parameters in dogs.

Methods

Fifteen healthy dogs were randomly assigned to three groups of five animals each. The first group was injected with 2% lidocaine at 4 mg/kg body weight, the second with 2% xylazine at 0.6 mg/kg body weight, and the third group with the drug combination of lidocaine and xylazine at 2 mg/kg and 0.3 mg/kg, respectively, in the same syringe. Changes in hematological, temperature and cardiopulmonary parameters were recorded over a 4-hour monitoring period.

Results

Lidocaine and xylazine caused significant decline in total erythrocytes count, packed cell volume and hemoglobin concentration. Significant changes in heart rate only occurred with epidural xylazine and lidocaine-xylazine combination. Significant decline in rectal temperature and respiratory rate was observed in all the three groups. Lidocaine-xylazine combination resulted in a significant bradycardia, hypothermia and respiratory depression compared to lidocaine alone and xylazine alone.

Conclusion

Significant cardiopulmonary depression and hypothermia should be anticipated particularly when lidocaine-xylazine and xylazine are used for epidural anaesthesia in dogs. Devoted monitoring is therefore imperative to avoid untoward outcomes.