Clinical Characteristics of Prilocaine for Spinal Anesthesia in Ambulatory Surgery: Clinical Profile and Efficacy

Introduction:

Hyperbaric prilocaine is widely used internationally for outpatient orthopedic and perineal surgery because of its favorable recovery profile compared with other intermediate-acting local anesthetics, such as bupivacaine, and its lower incidence of transient neurologic symptoms compared with lidocaine. Recently approved for intrathecal use in Chile, prilocaine offers advantages including shorter onset time, faster motor recovery, and earlier return of bladder function.

Objective:

To describe the clinical use of intrathecal prilocaine in outpatient knee arthroscopy, including the characteristics of sensory and motor block, incidence of anesthesia-related complications, and hospital readmissions. The study hypothesizes that prilocaine enables rapid postoperative recovery, early ambulation, and a low incidence of complications such as urinary retention, nausea and vomiting, and hypotension.

Methods:

Following institutional ethics committee approval and written informed consent, a prospective descriptive study will be conducted in 50 ASA physical status I-II patients undergoing ambulatory knee arthroscopy. Spinal anesthesia will be performed using 40 mg of 2% prilocaine under standard monitoring, with supplemental oxygen and midazolam sedation. Surgical type and duration will be recorded. Outcomes will include sensory and motor block duration, time to ambulation, time to first voiding, time to discharge, and the occurrence of complications such as urinary retention, nausea and vomiting, and hypotension during recovery. As this is a convenience sample, no formal sample size calculation has been performed. Data will be analyzed descriptively and reported as means and standard deviations, without inferential statistical testing.