Dexamethasone as a ropivacaine adjuvant for ultrasound-guided interscalene brachial plexus block: A randomized, double-blinded clinical trial.

STUDY OBJECTIVE: The purpose of this study was to evaluate the effect of intravenous or perineural dexamethasone added to ropivacaine on the duration of ultrasound-guided interscalene brachial plexus blocks (BPB). DESIGN: Randomized clinical trial. SETTING, PATIENTS AND INTERVENTIONS: Sixty ASA physical status I-II patients with elective shoulder arthroscopic surgeries under interscalene brachial plexus blocks were randomly allocated to receive 20ml of 0.75% ropivacaine with 1ml of isotonic saline (C group, n=20), 20ml of 0.75% ropivacaine with 1ml (4mg) of perineural dexamethasone (Dpn group, n=20), or 20ml of 0.75% ropivacaine with 1ml of isotonic saline and intravenous 4mg dexamethasone (IV) (Div group, n=20). A nerve stimulation technique with ultrasound was used in all patients. MEASUREMENTS: The onset time and duration of sensory blocks were assessed. Secondary outcomes were pain scores (VAS) and postoperative vomiting and nausea (PONV). MAIN RESULTS: The duration of the motor and sensory block was extended in group Dpn compared with group Div and group C (P<0.05). In addition, within 24h, group Dpn presented lower levels of VAS and lower incidence of PONV as compared with the other groups. Moreover, there was a significant reduction on onset time between group Dpn and the other groups. CONCLUSIONS: Perineural 4mg dexamethasone was more effective than intravenous in extending the duration of ropivacaine in ultrasound-guided interscalene BPB. Moreover, Dpn has significant effects on onset time, PONV, and VAS.