Low dose epidural lidocaine/sufentanil is effective for outpatient lithotripsy

Lumbar epidural analgesia was administered to 60 ASA class 1 & 2 patients with 3 ml test dose of 1.5% lidocaine and bolus of 20 ml of 0.5% lidocaine containing 0.5 microgram/kg sufentanil. Bilateral decreased lumbar cold perception was accepted as evidence of analgesia despite persisting pinprick sensation in thoracic dermatomes. Oxygen saturation (SpO2), respiratory rate, cardiovascular parameters and leg muscle strength were monitored throughout and until 1 hour afterwards. Midazolam provided light sedation and atropine bradycardia control. Verbal communication was maintained. ESWL could start within 6-10 minutes of bolus, with analgesia adequate in 86% of patients, the rest being "rescued" with 5-10 ml 0.5% lidocaine or analgesic doses (20-30 mg IV) of ketamine. Leg weakness developed in 14%, with 1 patient fully paralyzed. All resolved within 1 hour. Topical urethral analgesia was used in males where cystoscopy preceded ESWL. Phenylephrine was required once for nild systolic hypotension, otherwise blood pressures were stable. Two of 4 patients experiencing pruritus needed naloxone relief. Itching appeared in skin recovering from sensory block while visceral analgesia persists. Excessive respiratory depression was not seen.