The purpose of this study was to evaluate needle-guided ultrasound for internal jugular venous cannulation in a large university anesthesia department, to determine cumulative cannulation success by method, to determine first-pass cannulation success by method and operator, and to determine arterial puncture by method and operator. Study Design: Prospective, observational, and randomized. Blinding was not possible. Cohort size was calculated for 80% power to detect a technique difference, with significance defined as p < 0.05. Setting: Operating rooms of the Hospital of the University of Pennsylvania. Participants: Elective surgical patients requiring internal jugular venous cannulation. Interventions: Cannulation of the internal jugular vein occurred by needle-guided ultrasound (NGU) or by ultrasound without a needle guide. Main Results: Four hundred thirty-four procedures were studied in 429 patients. NGU significantly enhances cannulation success after first (68.9%-80.9%, p = 0.0054) and second (80.0%-93.1%, p = 0.0001) needle passes. Cumulative carmulation success by the seventh needle pass is 100%, regardless of technique. The needle-guide specifically improves first-pass success in the junior operator (65.6%-79.8%, p = 0.0144). Arterial puncture averages 4.2%, regardless of technique (p > 0.05) or operator (p > 0.05). Conclusions: Although the needle guide facilitates prompt cannulation with ultrasound in the novice operator, it offers no additional protection against arterial puncture. This may be because of a lack of control of needle depth rather than needle direction. A possible solution may be biplanar ultrasound for central venous cannulation. (c) 2005 Elsevier Inc. All rights reserved.