Warming local anesthetics before injecting them significantly reduces the pain of the injection, according to new research published online in Annals of Emergency Medicine.

“Warming an injection is a cost-free step that emergency physicians can take to reduce pain from a shot,” said lead study author Dr. Anna Taddio of the University of Toronto in Canada.  “Patients often dread the sight of a needle, but doing something as simple as warming the injection to body temperature can make a painful part of an emergency department visit more tolerable.”

Researchers reviewed 18 studies involving 831 patients. Warming injections prior to administering them consistently produced a “clinically meaningful reduction in pain” regardless of how the shot was administered and whether a small or large amount was injected.

In the study, injections were warmed with water baths, incubators, fluid warmers, baby food warmers, a warming tray, and a syringe warmer.  Anecdotal reports suggest that some emergency physicians warm injections in their hands prior to administering them.

“Future research should examine the effects of warming local anesthetics for dental procedures and for procedures specifically involving children,” said Dr. Taddio.  “This is an area where a small change may make a big difference for a patient.”

Ouch-less Injections The Saturday Evening Post