Ultrasound with topical anesthetic rapidly decreases pain of intravenous cannulation.

Objectives: Physicians and nurses in the emergency department rarely use topical anesthesia when starting intravenous (IV) lines because of time constraints and lack of data on patients' perception of the pain associated with this procedure. Ultrasound pretreatment of skin increases permeation rates of hydrophobic topical medications, including topical lidocaine. The objective of this study was to demonstrate that ultrasound treatment followed by brief application of topical anesthetic decreases the patients' perception of the pain of IV cannulation.

Methods: This was a randomized, controlled, prospective trial performed in a university hospital emergency department. Eighty-seven consecutive English-speaking, subcritically injured or ill adult patients able to give consent who were receiving an IV line as part of their care were enrolled. The intervention was a brief ultrasound treatment using the SonoPrep (Sontra Medical Corp., Franklin, MA) therapeutic ultrasound device (frequency, 53-56 kHz) followed by 5 minutes of 4% liposomal lidocaine cream and standard-care IV cannulation, or standard care alone. Participants rated their pain on a visual analog scale. Researchers assessed the site after IV insertion and 20-36 hours later. The primary outcome was participants' subjective pain score, and the secondary outcome was site skin irritation.

Results: The ultrasound group reported significantly less pain (p<0.001), with 80% of treated participants reporting pain scores
Conclusions: The SonoPrep ultrasound device applied to skin for 15 seconds followed by 5 minutes of 4% liposomal lidocaine cream significantly reduced patients' perception of the pain of an IV start when compared with standard care. There were no adverse side effects noted in any participant during the 36 hours of the follow-up period.