What is it about heat that makes everything feel better? Fireplace, hot tub, heat packs, electric blankets, and hot chocolate have got to be the best inventions EVER.

How can we apply this in Medicine?

Trick of the Trade

Warm anesthetic solution prior to injection.

A meta-analysis of literature (18 studies) has shown that warming anesthetic fluid prior to injection results in less pain, as compared to room-temperature anesthetic. So while you are gathering and preparing the rest of your equipment, partially fill a small tub with warm water and let your lidocaine or bupivicaine bottle sit in it. It only takes a few minutes to warm the solution. Rubber duckies are optional. 

Thanks to Dr. Gemma Morabito for letting me know about this article. Here’s her photo of running warm water over the anesthetic vial before the procedure. Check out her Medicinadurgenza site post. If you are using Google Chrome, you can set the browser to translate the entire site from Italian to English.


Hogan ME, Vandervaart S, Perampaladas K, Machado M, Einarson TR, Taddio A. Systematic Review and Meta-analysis of the Effect of Warming Local Anesthetics on Injection Pain. Ann Emerg Med. 2011 – in press. PMID: 21316812


Michelle Lin, MD
ALiEM Founder and CEO
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco
Michelle Lin, MD


Professor of Emerg Med at UCSF-Zuckerberg SF General. ALiEM Founder @aliemteam #PostitPearls at Bio:
Michelle Lin, MD