Ropivacaine 0.2% and lidocaine 0.5% for intravenous regional anesthesia inoutpatient surgery

Background: A longer-acting local anesthetic agent, such as ropivacaine, ma y offer advantages over lidocaine for intravenous regional anesthesia. The objectives of this study were to evaluate whether the findings of volunteer investigations with intravenous regional anesthesia with ropivacaine (whic h have shown prolonged analgesia after release of the tourniquet) translate s into improved pain control after surgery. Methods: With Human Investigation Committee approval and a double-blind stu dy design, 20 healthy patients with American Society of Anesthesiologists p hysical status I or II classification who were scheduled to undergo forearm and hand surgery were randomly assigned to administration of 40 nil of eit her 0.2% ropivacaine or 0.5% lidocaine for intravenous regional anesthesia. Evidence of central nervous system side effects, such as tightheadedness, tinnitus, and metallic taste, as well as cardiac arrhythmias, were evaluate d and treated (if necessary) after local anesthetic administration, before and during surgery, and after release of the tourniquet until discharge fro m the postanesthesia care unit. Regression of sensory anesthesia in the ner ve distributions of the forearm and hand was recorded. Verbal numerical pai n scores were monitored and quantified until the patients were discharged t o home from the postanesthesia care unit. Patient pain scores, side effect profiles, time to first oral intake, and total amount of oral analgesics we re recorded 24 h postoperatively. Results: Intravenous regional anesthesia with 0.2% ropivacaine and 0.5% lid ocaine provided equivalent levels of surgical anesthesia. After release of the tourniquet, the first evidence for return of sensation in the distribut ion of the five peripheral nerves occurred later in the ropivacaine group ( median, 20 min; range, 15-40 min) than in the lidocaine group (median, 1 mi n; range, 1-25 min). Verbal numerical pain scores were significantly lower at the time of admission, whereas during the remainder of the postanesthesi a care unit stay and later at home, the difference in verbal numerical pain scores between the two groups was no longer statistically significant. Conclusions. Ropivacaine 0.2% may be an alternative to 0.5% lidocaine for i ntravenous regional anesthesia in the outpatient surgical setting. Longer-l asting analgesia in the Immediate postoperative period may be due to a more profound and prolonged tissue binding effect of ropivacaine.