Introduction: Ultrasound-guided nerve blocks (UGNB) are increasingly used in emergency care. The hand-on-syringe (HS) needle technique is ideally suited to the emergency department setting because it allows a single operator to perform the block without assistance. The HS technique is assumed to provide less exact needle control than the alternative two-operator hand-on-needle (HN) technique; however this assumption has never been directly tested. The primary objective of this study was to compare accuracy of needle targeting under ultrasound guidance by emergency medicine (EM) residents using HN and HS techniques on a standardized gelatinous simulation model.
Methods: This prospective, randomized study evaluated task performance. We compared needle targeting accuracy using the HN and HS techniques. Each participant performed a set of structured needling maneuvers (both simple and difficult) on a standardized partial-task simulator. We evaluated time to task completion, needle visualization during advancement, and accuracy of needle tip at targeting. Resident technique preference was assessed using a post-task survey.
Results: We evaluated 60 tasks performed by 10 EM residents. There was no significant difference in time to complete the simple model (HN vs. HS, 18 seconds vs. 18 seconds, p=0.93), time to complete the difficult model (HN vs. HS, 56 seconds vs. 50 seconds, p=0.63), needle visualization, or needle tip targeting accuracy. Most residents (60%) preferred the HS technique.
Conclusion: For EM residents learning UGNBs, the HN technique was not associated with superior needle control. Our results suggest that the single-operator HS technique provides equivalent needle control when compared to the two-operator HN technique.