The effect of stimulating versus nonstimulating catheters for continuous interscalene plexus blocks in short-term pain management

Abstract Study Objective To investigate whether placement, and use of stimulating catheters for interscalene brachial plexus blocks improves short-term postoperative analgesia. Design Controlled, prospective, randomized, pilot study. Setting University hospital. Patients 60 patients undergoing shoulder surgery. Interventions and Main Measurements The brachial plexus was identified using a stimulating needle. In conventional catheter group 1 (CC 1), local anesthetic (LA) was injected through the needle and catheters were advanced blindly thereafter. In catheter group 2 (CC 2), catheters were blindly inserted and LA was injected through the catheter. In the stimulating catheter group (SC), LA was injected only after catheter tip location was confirmed by nerve stimulation. Time required to perform the block, pain intensity at rest, and dynamic pain (defined movement: lifting of arm; numeric rating scale, 0-10), patient satisfaction (verbal rating scale, Likert scale), and plasma concentrations of ropivacaine were measured. Main Results Patients in the SC group had significantly decreased pain scores. The median block performance time was 6 minutes in CC 1 (CI 25%-75%: 4-8 min), 11 minutes in CC 2 (CI 25%-75%: 7-13 min), and 12 minutes in SC (CI 25%-75%: 10-24 min). Patient satisfaction and plasma concentrations of ropivacaine did not differ among the groups. Conclusions Stimulating catheters for interscalene plexus blocks improve postoperative analgesia at rest in patients undergoing shoulder surgery.