Systemic and Regional Blood Flow During Epidural Anesthesia with Epinephrine in the Rhesus Monkey

Hemodynamic and regional blood flow measurements were made in five rhesus monkeys before and 10, 20, 40 and 80 min after induction of high epidural anesthesia (T1) with lidocaine (1%) containing 1:200,000 epinephrine. Following induction of epidural anesthesia with epinephrine, there were significant decreases in heart rate, mean arterial pressure, cardiac output and myocardial and renal blood flow. The percentage of cardiac output received by the brain was significanly increased following epidural anesthesia with epinephrine, thus evidencing autoregulation to maintain cerebral blood flow. Vascular resistance in the lower extremity was significantly decreased during anesthesia, indicating arteriolar dilatation. Also, during anesthesia, the lungs received a significantly increased proportion of the microspheres, suggesting an increased peripheral arteriovenous shunting of microspheres due to the arteriolar dilatation.