Low-dose, low-concentration levobupivacaine plus fentanyl selective spinal anesthesia for knee arthroscopy: a dose finding study.

Abstract

Selective sensory spinal anesthesia preserves lower limb motor function and thus facilitates postanesthesia care unit (PACU) bypass and reduces ambulation recovery time. We compared the ambulation time and PACU bypass rate after using 3 low-dose, low-concentration levobupivacaine-fentanyl spinal solutions (5, 4, and 3 mg + 10 μg) in a double-blind study consisting of 90 patients (ASA physical status I and II) scheduled to undergo knee arthroscopy. The 3-mg dose was halted because of a large number of inadequate blocks (50%). Twenty-three percent and 80% of patients from groups 5 mg and 4 mg, respectively, bypassed the PACU (P = 0001). Ambulation took place after 70 minutes (30-130 minutes) (median [range]) in group 5 mg and 45 minutes (23-120 minutes) in group 4 mg (P = 0006). Four milligrams levobupivacaine plus 10 μg fentanyl produced adequate surgical anesthesia with the shortest time to ambulation and the highest PACU bypass rate.