In emergency medical services (or ambulance services), it is common to treat severe pain by administering morphine and similar substances intravenously. This is achieved by inserting an intravenous cannula into a vein.

“This is a good treatment, but in some situations, it can be challenging to insert a cannula, particularly when it’s dark, cold or windy at the scene. Some patients are also afraid of needles. In that case, it can take some time before patients receive satisfactory pain relief,” Fridtjof Heyerdahl, researcher at the Institute of Clinical Medicine at the University of Oslo (UiO), says.