Use of ultrasound guidance and contrast enhancement: a study of continuous infraclavicular brachial plexus approach * S. DHIR and S. GANAPATHY Department of Anesthesiology and Perioperative Medicine, University of Western Ontario, London, ON, Canada Purpose: We describe our experience of combining the use of ultrasound (US) guidance with contrast enhancement and peripheral nerve stimulation for the insertion of infraclavicular brachial plexus catheters. Methods: Thirty patients scheduled to have upper limb surgery under regional block were studied. Under US guidance and peripheral nerve stimulation assistance, continuous peripheral nerve block needle and stimulating catheter were placed in the infraclavicular area. Needle and catheter tip location was confirmed with agitated 5% dextrose and seen under colour Doppler with US before injecting local anaesthetic (LA). Patients were evaluated in terms of onset times and efficacy of block. Post-operatively, on block recession a catheter was stimulated and visuali- zation of spread of LA during injection through the cathe- ter was done. Secondary block (subsequent to re-injection of LA) was assessed. Patients were followed-up for a week. Results: Mean time to onset of block was 19.7 ( 4.9) min. There were no incomplete blocks and all components of the plexus were blocked completely. Post-operatively, in 95.7% of patients, the spread of hand-agitated LA via the catheter could be seen by color Doppler with ultrasonography. All patients had excellent post-operative analgesia and high degree of satisfaction. There were no complications. Conclusion: Contrast enhancement with US guidance during infraclavicular brachial plexus block enables direct visualization of needle and catheter tip location. Our early experience suggests that this leads to successful initial and subsequent post-operative block. Further controlled studies are needed to compare this technique with more prevalent and conventional techniques of catheter insertion. Accepted for publication 22 October 2007 Key words: Infraclavicular brachial plexus block; colour Doppler ultrasonography; catheter technique. r 2008 The Authors Journal compilation r 2008 The Acta Anaesthesiologica Scandinavica Foundation U LTRASOUND (US) imaging has been shown to facilitate brachial plexus localization, improve the quality of blocks and onset times (1, 2). All ultrasonographic images depend on echoes being produced by insonated structures. Increasing the amount of echo producing substance in the inso- nated area will create more echoes and give addi- tional information with proper processing. Contrast enhancement depends on this concept (3). The role of contrast enhancement has not been studied in evaluation of peripheral neural tissue. Tsui et al. have reported the electrophysio- logical effects of 5% dextrose in water (D5W) on peripheral nerve stimulation in animals (4) and humans (5, 6). To date, there is no report on the use of US for evaluating the position of catheter in the infraclavicular area and its confirmation by agi- tated dextrose/drug (as contrast enhancers) with Doppler colour flow. We hypothesized that giving local anaesthetic (LA) through catheter positioned using US gui- dance with contrast enhancement will lead to high primary block success and reduce secondary (post- operative) catheter failure. We proposed to study this hypothesis. Methods One hundred adults of either sex, age 18–80 years (ASA physical status 1–4) were screened for an ongoing randomized control study. They were scheduled to have elective, ambulatory, open or arthroscopic, distal upper limb surgery and were *Presented in part at American Society of Regional Anesthesia annual meeting 2007. Best of meeting abstract A5. 338 Acta Anaesthesiol Scand 2008; 52: 338–342 Printed in Singapore. All rights reserved r 2008 The Authors Journal compilation r 2008 The Acta Anaesthesiologica Scandinavica Foundation ACTA ANAESTHESIOLOGICA SCANDINAVICA doi: 10.1111/j.1399-6576.2007.01563.x