Role of Epinephrine in Regional Block Anesthesia With Etidocaine: A Double‐Blind Study

Fifty healthy females scheduled for abdominal hysterectomy were administered 1 percent etidocaine (20 ml.) for lumbar epidural block anesthesia. Use of a plain solution or a solution containing 1:200,000 epinephrine was pre-selected randomly and administered in a double-blind fashion. Measurements of onset and duration of sensory anesthesia did not vary significantly between the two groups. Motor anesthesia did have a faster onset in patients receiving solutions containing epinephrine but the duration or quality of motor anesthesia did not vary significantly.An additional five patients were given bilateral intercostal nerve block anesthesia with plain solutions of 0.5 percent etidocaine (60 ml.) for clinical comparison with previously studied patients who received similar blocks with solutions containing epinephrine. No apparent clinically significant difference was noted.Plasma levels of etidocaine were measured for both techniques. Although the plain solutions produced higher blood levels than the epinephrine containing solutions for both techniques, they were not significantly different. The conclusion of this study is that the addition of 1:200,000 epinephrine to solutions of etidocaine for lumbar epidural and intercostal nerve block may provide some protection against systemic toxicity but has little if any benefit on the clinical effects of the drug.