A comparison of minidose lidocaine-fentanyl spinal anesthesia and local anesthesia/propofol infusion for outpatient knee arthroscopy

Traditional methods of spinal anesthesia have proven problematic in the outpatient setting. Minidose lidocaine-fentanyl spinal anesthesia (SAB(MLF)) may be the adaptation necessary to reestablish spinal anesthesia in this venue. One hundred patients scheduled for outpatient knee arthroscopy were randomized to receive either local anesthesia plus a titrated IV propofol infusion (LA/PI) or SAB(MLF) using 20 mg lidocaine 0.5% + 20 mug fentanyl. Patients received midazolam 0.02-0.03 mg/kg IV and fentanyl 0.75-1.0 mug/kg TV upon arrival in the operating room before lumbar puncture or propofol infusion. The propofol infusion was begun at 50-75 mug . kg(-1) . min(-1) and titrated to maintain patient comfort. Boluses (200-400 mug/kg) were given as needed. Local anesthesia included 30 mL lidocaine 1% with epinephrine 1:200,000 intraarticularly plus 10 mL at the portal sites. Three patients (6%) in the LA/PI group versus none in the SAB(MLF) group required general anesthesia. Airway support was required in 54% of the LA/PI patients and in none of the SAB(MLF) patients. Total operating room time (43 vs 45 min), time to home readiness (43 vs 45 min), actual discharge times (73.3 min in both groups), and the incidence of discharge >90 min (22% vs 24%) were the same for both LA/PI and SAB(MLF) groups. LA/PI and SAB(MLF) groups differed in terms of postoperative pruritus (8% vs 68%), pain (44% vs 20%), nausea (8% vs 22%), and ability to void before discharge (56% vs 32%). One patient in each group had mild difficulty initiating voiding at home, but neither required medical attention. In both groups, 90% of patients were either "satisfied" or "very satisfied" with their anesthetic. The two techniques provided comparable patient satisfaction and efficiencies both intraoperatively and in postoperative recovery and discharge. The efficiencies of these techniques were not dependent on special provisions of the physical plant or the practice model.