Background and objectives The effect of intravenous dexamethasone on the duration of axillary plexus block performed using ropivacaine is not described. The aim of this study is to assess the effect of intravenous dexamethasone on the duration of axillary plexus block analgesia after distal upper arm surgery.

Methods In this prospective, randomized, placebo-controlled, double-blinded trial, consenting patients scheduled for hand or forearm surgery under ultrasound-guided axillary plexus block performed using 0.5 mL/kg of 0.475% ropivacaine, were randomized to receive an intravenous injection of either 8 mg/2 mL of dexamethasone (Dexa group) or 2 mL of saline (Control). The primary outcome was the time of first analgesic intake after axillary block. Secondary outcomes included motor or sensory block duration, total use of postoperative analgesics, and block-related complications.

Results Among the 98 patients included, 6 and 2 patients did not require postoperative analgesic intake in Dexa and Control groups, respectively (p=0.06). The time of first analgesic intake was significantly longer in the Dexa (20.9±9.3 hours) than in the Control group (14.7±6.6 hours, p<0.0004). Motor and sensory recovery occurred significantly later, and total analgesic consumption was lower in the Dexa than in the Control group. No nerve complication related to intravenous dexamethasone injection was recorded.

Conclusions This study showed that intravenous dexamethasone delayed for 6 hours the time to first analgesic intake after upper arm surgery under axillary plexus block performed with the long-lasting local anesthetic ropivacaine. This suggests that intravenous dexamethasone could be an interesting adjuvant to axillary plexus block.

Trial registration number NCT02862327