Cardiovascular and respiratory effects of epidural lidocaine and morphine administered in dogs anaesthetized with halothane

The present study was conducted to investigate the effects of epidural lido caine and morphine on cardiovascular and respiratory systems in dogs anesth etized with halothane. A mixture of 0.26 ml/kg 2 % lidocaine and 2 mg morph ine was introduced epidurally in 6 clinically healthy dogs anesthetized wit h halothane. The epidural administration of the mixture resulted in signifi cant reduction in heart rate (HR; from 30 to 90 min intervals; P < 0.05), s ystolic arterial blood pressure (SAP), mean arterial blood pressure (MAP) ( from 5 to 90 min intervals) and diastolic arterial blood pressure (DAP, fro m 30 to 120 min intervals) (P < 0.05). The cardiac output (CO) and the card iac index (CI) decreased significantly between minutes 75 and 105 and minut es 75-90 respectively (P < 0.05). The changes in respiratory parameters wer e insignificant. In conclusion, the epidural application of a mixture of lidocaine and morph ine was found to be a safe and effective method for achieving reliable anes thesia with minimal respiratory and moderate cardiovascular side effects.