Guns are used by law enforcement personnel to deliver a lethal impact on a center mass area of a “bad guy” threatening the lives of others. Although this type of gun doesn’t belong on EMS personnel, I’ve found one that can be used effectively to “shoot” a laser beam into a subject and help you assess them.
The same infrared temperature gun that heating and air conditioning technicians use effectively every day to read the temperature in structures can also be used to detect baseline temperatures and temperature changes in the field.
Before you go shooting down my EMS MacGyver tool, let me first review the role of temperature in EMS assessment.
In addition to the skin’s key roles in maintaining our water content, insulating us from extremes of heat and cold, and acting as a barrier to protect us from infection, one of its major functions is regulating body temperature by changing the amount of blood circulating through the skin’s surface. When a person is poorly perfused, the body pulls blood away from the surface of the skin and diverts it to the core of the body.(1)
This diversion of blood results in cool, moist or clammy skin and is a good initial assessment indicator of hypoperfusion and inadequate circulatory system function (i.e., shock). Personal touch is invaluable during assessment to pick up on the cool feel of the skin when a patient is in the early stages of shock, suffering from mild hypothermia or has inadequate tissue perfusion. The skin will often feel cold when a patient is in profound shock, or has hypothermia or frostbite.1 So let’s be clear: Personal touch should never be replaced by a tool.
For internal temperature monitoring, specially designed oral and rectal thermometers are the standard to obtain the core temperature of a patient. But just as thermal imagers used by the fire service to detect heat sources during and after a fire have proven to be an invaluable tool in finding victims in and around an emergency scene (see photo above), I’ve found that an infrared temperature gun can be an effective tool that can be used in conjunction with the valuable touch of the skin that’s taught in EMS training.
Infrared is basically heat radiation. Low-level infrared radiation carries information about the temperature distribution of the objects studied. It can also penetrate thick smoke, clouds and dust. This makes infrared cameras useful in search and rescue and firefighting by detecting body heat or finding people in a smoke-filled building. They’re widely used in astronomy, meteorology, oceanography and archeology. They’re also used in mechanical and electrical systems, animal studies, medicine, navigation, law enforcement, the military, as well as in food studies.(2)
The infrared temperature gun isn’t designed to be used in place of a “people” thermometer, and it isn’t as accurate as an oral or rectal thermometer because it isn’t designed to probe to the same depth. However, they can be effective when used in rehab situations to shoot readings off such areas as the forehead, temple, inner ear, mouth, cheek, neck or a nasal tunnel and present providers with a reasonable baseline temperature and trend of readings. And with septic shock on the horizon as a demon that could be tamed easier if detected sooner in the field, I believe temperature assessment will be a more important vital sign in the future.
They cost around $45 in a hardware store, offer a rapid way to “shoot” an area of the body, get a baseline temperature in that area and alert you to an obvious high or low temperature. But more importantly, the infrared temperature gun gives you a simple and fast way to determine changing trends in area temperature.
Infrared guns bounce a laser beam off a body surface and present a digital display of the temperature in that area. It’s best to avoid targeting areas where there’s tough skin or bone that hides the heat. If you shoot in the inner ear or a nasal passage, the temperature readings you get will be close to tympanic temperature accuracy. But, like a laser pointer, you have to be careful not to allow the beam to contact a subject’s eyes.
The above non-scientific photo series illustrates how this off-the-shelf “tool” works. I used ice cubes; Hawaiian Punch; a cool, wet towel; my pal Toby and myself as the test subjects. JEMS
1. AAOS. Emergency Care and Transportation of the Sick and Injured, Ninth Edition. Jones & Bartlett Learning: Sudbury, Mass. p. 278. 2006.
2. Cool Cosmos. Ask an Astronomer. http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ask_astronomer/faq/radiation.shtml
This article originally appeared in June 2011 JEMS as “Should EMS Crews Carry Guns? How infrared guns can help assess & save lives.”