Cooling hairless skin speeds temperature drop in hyperthermia: study

By Bridgett Novak

NEW YORK (Reuters Health) - Applying chemical cold packs to smooth, hairless skin surfaces eases hyperthermia more quickly than traditional means, researchers reported January 17 at the annual meeting of the National Association of EMS Physicians in Tucson, Arizona.

"The current ideal treatment for hyperthermia is ice water immersion, which is what most major marathons utilize. However, it is generally not very practical," noted Dr. Brian Krabak, a sports medicine specialist at the University of Washington who wasn't involved in the research. The next thing most people try is placing ice packs on the neck, under the armpits or in the groin region.

A team at Stanford University decided to test the hypothesis that glabrous skin surfaces would be more efficient conductors. They put 10 volunteers through three different scenarios. Each exercised on a treadmill in a heated room while wearing two layers of insulated military garments from head to toe, with gloves on their hands and plastic bags on their feet. Their esophageal temperature (Tes) was monitored throughout. When their core temperature reached 39.2 degrees Celsius, they rested in the heated room.

Each participant did this three times (sessions were separated by no fewer than two days) - once with no cooling method; once with cold packs applied to the traditional areas (neck, armpits, groin); once with cold packs applied to the glabrous surfaces (cheeks, palms, soles).

With no treatment, their Tes dropped by 0.3 degrees Celsius in the first five minutes and then stabilized. Traditional cooling decreased their core temperature by 0.4 degrees Celsius in the first five minutes and then by another 0.17 degrees every 10 minutes during the 30-minute monitoring period. Applying cold packs to the glabrous skin surfaces resulted in a Tes decrease of 0.6 degrees in the first five minutes, followed by a steeper 0.3 degree drop every 10 minutes.

The same improvement was seen in all 10 study participants. Lead author Dr. John Lissoway told Reuters Health the difference was statistically significant.

Dr. Lissoway, now an emergency medical physician at Presbyterian Hospital in Albuquerque, was at Stanford when the study was conducted. He explains: "these non-hairy parts of the body are natural radiators, like the tongue in dogs or ears in rabbits. More blood is diverted to them, and thus when they are cooled, the blood circulates back and cools the body down quickly."

And speed is of the essence when treating overheated patients. "Studies suggest the longer someone is in severe hyperthermia, the higher the mortality rate," confirmed Dr. Krabak. "These findings could change the way we cool patients in the pre-hospital setting and could impact potential complications from hyperthermia."

(c) Copyright Thomson Reuters 2014. Click For Restrictions - http://about.reuters.com/fulllegal.asp