HEMODYNAMIC AND PLASMA-CATECHOLAMINE RESPONSES TO EPINEPHRINE-CONTAINING PERIANAL LIDOCAINE ANESTHESIA

Despite the frequent use of large vol (30-40 ml) of epinephrine-containing local anesthetic solutions for ano-rectal surgery, little is known about the anesthetic-induced hemodynamic consequences. The heart rate, blood pressure and plasma catecholamine (norepinephrine and epinephrine) responses to the perianal injection of 40 ml of 0.5% lidocaine alone (n = 8) or 0.5% lidocaine with 1:200,000 epinephrine (n = 10) was measured in 18 healthy adults undergoing outpatient ano-rectal surgery. The mean .+-. SEM [SD of mean] plasma epinephrine concentration increased from a baseline of 42 .+-. 7 pg/ml to a peak of 622 .+-. 94 pg/ml 4 min after injection of epinephrine-containing anesthetic (P < 0.001). Lidocaine alone increased the mean plasma value from 36 .+-. 9 pg/ml (baseline) to only 69 .+-. 16 pg/ml (not significantly different) at its peak. Despite the increases in plasma epinephrine levels in the group receiving epinephrine-containing anesthesia, no changes in blood pressure, heart rate or plasma norepinephrine levels were observed. Given the advantages (including prolongation of the duration of anesthesia) of adding epinephrine to perianal local anesthetics, data support its safe use in healthy adults.