Conditions: Osteoarthritis, Hip
Keywords: Arthroplasty, Hip, Replacement Anesthesia, Local Anesthesia Conduction Bupivacaine Dexamethasone Preanesthetic Medications Nerve Block Lumbar Plexus Block Analgesia Glucocorticoids Local Anesthetics
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 115
Healthy volunteers: yes

Brief summary:
This study will investigate the ability of systemic dexamethasone to prolong the sensory block duration for lumbar plexus nerve blockade.

Detailed description:
The purpose of this randomized, double-blinded, placebo-controlled trial is to examine the equivalency of two different doses of dexamethasone when given intravenously as an adjuvant medication for postoperative pain management. Specifically, this study will investigate the prolongation of time to recovery of sensation following a lumbar plexus block in patients undergoing total hip arthroplasties. The investigators hypothesize that dexamethasone will prolong the sensory block time when compared to placebo and that similar results will be obtained in the 4 mg arm when compared to the 8 mg arm. The primary end point will be time to sensory recovery in the femoral nerve cutaneous distribution (part of the lumbar plexus) as determined by pin-prick sensation assessment. Secondary endpoints will include, but are not be limited to: time to first opioid administration, total opioid consumption over 30 hours, and rest and incident verbal numerical pain scores at 6,12,18,24 and 30 hours post block placement.

Arms:
arm 1: Following lumbar plexus nerve block administration using bupivacaine and epinephrine, 4 mg of systemic dexamethasone will be administered to this group intravenously. The volume given intravenously will be identical for all groups. arm 2: Following peripheral nerve block using bupivacaine and epinephrine administration, 8 mg of systemic dexamethasone will be administered to this group intravenously. The volume given intravenously will be identical for all groups. arm 3: Normal saline will be used as a placebo control group given at the same time and in the same manner as the experimental groups following peripheral nerve block administration. The volume given intravenously will be identical for all groups.

Interventions: intervention 1: Dexamethasone intervention 2: Bupivacaine intervention 3: Epinephrine intervention 4: Lumbar Plexus Nerve Block intervention 5: Saline
Intervention descriptions: intervention 1: A lumbar plexus nerve block will be performed for patients undergoing hip arthroplasty. A total of 25cc's of 0.25% bupivacaine with 1:400,000 epinephrine will be administered for postoperative analgesia. Surgical anesthesia will be provided either by an intrathecal spinal block or general anesthesia. Successful blockade will be assumed if the patient has a decrease or loss of pinprick sensation in the femoral nerve distribution, which innervates the anterior thigh. If no evidence of blockade is present, testing will occur again at 30 minutes post block. Testing will be performed with a 25 gauge Whitacre needle and once present the area of testing will be marked with a surgical marking pen so that repeat sensory testing can be undertaken at that same site over the course of the study. The subjects will then receive dexamethasone (4 or 8 mg) or placebo (saline) based on arm placement. intervention 2: Bupivacaine will be used in lumbar plexus nerve block mixture. intervention 3: Epinephrine will be used in lumbar plexus nerve block mixture. intervention 4: This is the procedure that will be performed. intervention 5: Patients randomized to the placebo group will receive normal saline intravenously.

Protocol document: