Conditions: Disorder of Knee Anesthesia
Keywords: Knee Arthroscopy Levobupivacaine Spinal Anesthesia Motor Block
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 180
Healthy volunteers: no

Brief summary:
The purpose of this study is to evaluate motor block probability throughout time and clinical profile when using three different doses of HLBP 0.75% (7.5, 9.37 and 11.25 mg) by a unilateral spinal block technique.

Detailed description:
Previous IRB approval and informed consent, 180 ASA I-II adults under ambulatory knee arthroscopy will be randomly allocated to receive unilateral spinal anesthesia with 7.5 (group Levo-7.5, n=59), 9.37(group Levo-9.37, n=61) and 11.25 (group Levo-11.25, n=60) mg of HLBP 0.75% using a 27-gauge Whitacre needle at a rate of 0.1 ml/ seg. and lateral decubitus position maintained for 5 min after injection.

An independent observer will evaluate motor (modified Bromage scale) and sensory (transcutaneal electrical stimulation at T10, L1, L3, and S1 dermal segments) levels and presence of adverse events immediately after return to supine, at the end of surgery and each 10 min from admission to PACU until home discharge conditions.

Trans-cutaneal electrical stimulation (TES) will be made with a PNS (Ministim® model MS- IV, Organon, Dublin, Irland) using 50-Hz tetanus stimuli for 5 seg. from 10 to 60 mA 3,4.

Arms:
arm 1: Hyperbaric Levobupivacaine 0.75% Spinal Administration by a Whitacre Needle 27G. Dosage: 7.5 mg. Single Dose. arm 2: Hyperbaric Levobupivacaine 0.75% Spinal Administration by a Whitacre Needle 27G. Dosage: 9.37 mg. Single Dose. arm 3: Hyperbaric Levobupivacaine 0.75% Spinal Administration by a Whitacre Needle 27G. Dosage: 11.25 mg. Single Dose.

Interventions: intervention 1: Hyperbaric Levobupivacaine 0.75%
Intervention descriptions: intervention 1: Each 4 ml of the administred solution contains: Chlorhydrate Levogyre Bupivacaine 30 mg, Glucose 290.8 mg and water for injection c.s.

Protocol document: