[Optimal analgesic effect of continuous supraclavicular brachial plexus block with ropivacaine after shoulder surgery].

Background: Optimal dose of local anesthetics for supraclavicular brachial plexus block (BPB) is still unknown. We prospectively investigated the analgesic effect of ultrasound-guided continuous supraclavicular BPB with ropivacaine at different infusion rates.

Methods: Thirty-nine patients scheduled to undergo shoulder surgery were randomly assigned to four groups; receiving no continuous BPB (control group, n = 10), BPB with 0.2% of ropivacaine at an infusion rate of 4 ml x hr(-1) (n = 12), BPB with 6 ml x hr(-1) (n = 12) or BPB with 8 ml x hr(-1) (n = 5). All patients were permitted to receive nonsteroidal anti-inflammatory drugs (NSAIDs) after surgery. Visual analogue scale (VAS) for postoperative pain was assessed and frequencies of the requirement of NSAIDs were recorded in each group.

Results: The pain scores during 24 hours after surgery in the 6 ml x hr(-1) group (3-24 mm) were significantly lower than those in the 4 ml x hr(-1) group (4-42 mm) and control group (6-56 mm). Mean frequency of administrations of NSAIDs for 24 hours after surgery in the 6 ml x hr(-1) (0.8 +/- 0.8) group was significantly lower than that in the control group (1.7 +/- 1.0). Continuous administration in two cases in the 8 ml x hr(-1) group was discontinued due to leakage of local anesthetics and headache.

Conclusions: Continuous supraclavicular BPB with 0.2% ropivacaine at 6 ml x hr(-1) is effective for the pain management after shoulder surgery and is not an excess dose.