Intravenous injections are more than twice as safe when nurses use instructions written with them in mind, a new study shows. The findings have spurred British health officials to alter national injection guidelines.

Injection-related mistakes can arise when nurses struggle to find unambiguous directions that are relevant to their profession, wrote study lead Matthew Jones, M.D., from the University of Bath. Between 30% to 50% of intravenous doses are incorrect in some way — raising the potential for harm, he reported.

Differences in training affect how clinical information is understood, Jones said. Instructions in the United Kingdom are usually written by pharmacists using a format and language that makes immediate sense to other pharmacists, but not necessarily to nurses, he explained. “We need injection guidelines to be written in a way that is understood by nurses because they prepare and administer most injections.”

The study involved 273 nurses and midwives from four hospitals who regularly administer injections. Investigators identified where mistakes were being made and introduced changes to the instructions. When participants followed the modified guidelines, nearly two-and-a-half times more doses were given without mistakes. Injections were also completed faster and participants reported feeling more confident about their decisions, the researchers wrote.

“[B]usy, stressed staff need information to be presented in a way that is easy to understand and quick to find,” Jones concluded.

Full findings were published in the BMJ.