When you have a patient whose veins are not particularly palpable, sometimes it is a good idea to apply heat to the area which will increase blood flow and make the veins juicier. So would you typically reach for a warm wet rag or a dry heat source?
There is a study that shows “dry heat was 2.7 times more likely than moist heat to result in successful IV insertion on the first attempt, had significantly lower insertion times, and was more comfortable.”
In the study dry heat cabinets were used to heat towels but other options for dry heat can be a hot water bottle or heating pad. Sometimes simply using body heat and holding a hand over the area can be beneficial as well. Read more about the study results at the link below.