• P G Atanassoff, E Alon, and B M Weiss.
• Department of Anesthesiology, University Hospital of Zürich, Switzerland.
• J Clin Anesth. 1994 Jan 1;6(1):47-51.

Study ObjectivesTo investigate whether equipotent doses of lidocaine and bupivacaine were equally effective for intercoastal nerve blockade (ICNB) and whether a lower amount of lidocaine would be comparably effective. To see whether plasma levels of lidocaine with and without epinephrine and of plain bupivacaine would reach toxic ranges. Finally, to evaluate the duration of postoperative analgesia following general anesthesia and regional anesthesia with two different local anesthetics.DesignRandomized, double-blind study, with control group administered general anesthesia.SettingGynecologic operating room of a university hospital.Patients48 adult ASA physical status I and II otherwise healthy patients undergoing lumpectomy.Interventions36 patients received ICNB of T3-T6 unilaterally using either 4 ml/segment of 1.5% lidocaine with epinephrine 3.75 micrograms/ml (n = 10, Group A), 4 ml/segment of 2% lidocaine with epinephrine 5 micrograms/ml (n = 13, Group B), or 4 ml/segment of plain 0.5% bupivacaine (n = 13, Group C). The control group consisted of 12 patients (Group D) who received a general anesthetic using propofol, alfentanil, and nitrous oxide in oxygen for induction and maintenance of anesthesia.Measurements And Main ResultsIn all three ICNB groups, the highest plasma concentrations were reached after 5 to 10 minutes following ICNB--i.e., a lidocaine plasma level of 2.77 +/- 0.5 micrograms/ml (mean +/- SEM) in Group A, a lidocaine plasma level of 2.78 +/- 0.2 micrograms/ml in Group B, and a bupivacaine plasma level of 1.44 +/- 0.2 micrograms/ml in Group C. There were no significant differences in plasma levels between 1.5% lidocaine and 2% lidocaine. For the first 90 minutes after surgery, higher postoperative pain scores were found in the control group than in the ICNB groups. Notably longer-lasting postoperative pain relief was achieved with plain bupivacaine. The number of women requiring postoperative analgesic medication, the time of first request, and the total amount of analgesic drugs administered during the 24 hours postoperatively were significantly lower in the regional anesthesia groups than in the general anesthesia group (p < 0.05).ConclusionsICNB is an alternative to general anesthesia for female breast surgery. Both lidocaine with epinephrine and plain bupivacaine in the doses used did not raise venous plasma concentrations to levels considered potentially toxic. With respect to duration of postoperative pain relief and analgesic drug request, the local anesthetics (in particular, bupivacaine) were found to be superior to general anesthesia.

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