ONE-TWO PUNCH Many ORs use both forced-air warmers and blanket warmers to prevent hypothermia. An increasing number of surgical facilties are also applying warming devices in pre-op, a preventive practice known as pre-warming.

Most every surgeon, anesthesia provider and surgical nurse has bought into the idea that normothermic patients do better. It's no longer a question of whether and why you should warm patients. The focus has shifted to:

• Should you pre-warm patients? Yes. Pre-warming patients at risk of hypothermia for at least 15 minutes before induction of anesthesia is getting popular.

• What's the preferred way to warm patients? Our survey of 216 readers found that warmed blankets and forced-air warmers are far and away the preferred methods of preventing hypothermia.

BEST PRACTICES
When Do You Warm Patients?

We asked our survey respondents to tell us when they typically warm patients:

• 63.3% do so pre-operatively
• 90.2% do so intraoperatively
• 76.7% do so post-operatively

"We warm in pre-op for total joints and any abdominal cases. All cases are warmed intra-op," says a respondent.

Banking patient's heat in pre-op
A growing body of evidence supports the clinical benefits of maintaining normothermia throughout the patient's surgical experience, starting in pre-op.

How many of your colleagues pre-warm patients before they're wheeled into the OR? One-third (33.2%) of the 216 OR leaders we surveyed pre-warm for all procedures, and 14.2% do so for procedures expected to last more than 1 hour. The thinking behind that hour-or-longer policy might be faulty, however, as studies have shown that core hypothermia can develop quickly in the hour immediately after the induction of anesthesia. In the first hour of anesthesia, an unwarmed surgical patient's core temperature can drop rapidly as anesthesia-induced vasodilation lets warmer blood from the core flow freely and mix with the cooler blood in the periphery. As the blood circulates, it cools until returning back to the heart, where it causes a drop in the core temperature.

Warming the patients' skin and peripheral tissues before induction or anesthesia prevents so-called redistribution hypothermia. If pre-warming occurs before the redistribution phase, you can reduce or eliminate hypothermia. Effective pre-warming "banks" the patient's heat so the patient arrives at the OR normothermic. If you forgo pre-warming, patients might arrive in the OR normothermic, but they'll arrive in PACU hypothermic.

"Our ideal is to pre-warm, and we do if they are a.m. admits," says a reader. "The non-scheduled cases don't always get pre-warmed." Another lamented the fact that she doesn't have enough warming devices to pre-warm all patients.

For another hospital in our survey, the policy is to pre-warm patients with a forced-air warmer if the anesthesia will last longer than 15 minutes. In a randomized study by Katie Hooven (2008), more than two-thirds (68%) of patients who were pre-warmed with a portable warming device remained normothermic during and after surgery. In comparison, only slightly more than two-fifths (43%) of the patients who weren't pre-warmed remained normothermic.

"Because the skin of the patient is warm, the need for the body to redistribute heat from the core to the periphery is reduced and normothermia is better maintained," says Deborah Edgeworth, BSN, CNOR, interim manager of surgical services of Genesis Medical Center in Davenport, Iowa.

For shorter cases — some estimate that 59% of outpatient procedures are 50 minutes or less — keep in mind that you don't have much time to warm patients in the OR, so pre-warming could prevent patients from arriving in PACU hypothermic.

"We warm all our patients," says Yanara Reda, BSN, RN, of Rockland and Bergen Surgery Center in Montvale, N.J. "If a patient is having a surgical procedure, it doesn't matter the type of anesthesia used. We have an obligation to have their best interests in mind."

Pre-warming methods cited in our survey include underbody conductive blankets and mattresses, warmed blankets, forced-air warming units, and heat-reflective blankets, gowns and caps. Often-times, survey respondents say they continue with these warming methods from the holding area, throughout surgery and into post-op.

WARMING TRENDS
Reader Survey on Patient Warming

Warming Modality*	Survey Says
Cotton blanket pre-warmed with a blanket warmer	87.5%
Forced-air warming blanket	77.8%
Forced-air warming gown	27.3%
Underbody warming†	18.1%
Conductive fabric electric heating	3.7%
Radiant warming device	3.2%
Heat-reflective blankets, gowns and caps	1.4%

* Survey respondents could check more than 1 response.
† Thermal mattress or bed pad on which the patient lies

How do you warm?
As you can see in the table on the left, warmed blankets and forced-air warmers are far and away the most popular methods of warming, based on our survey. It's not uncommon for facilities to use more than 1 warming modality. A common combo: a blanket warmer that cuts down on heat loss and a forced-air system that warms the patient's skin. "Research shows that using a blanket with a tightly woven sheet in pre-op helps keep patients warm without overheating with the forced air," says a hospital clinical nurse specialist. "We use the forced air on all patients in the OR, which follows them to PACU."

Mary Haskins, RN, CNOR, OR director and clinical supervisor of the Coastal Empire Plastic Surgery and Shanklin Plastic Surgery Center in Savannah, Ga., uses conductive fabric electric heating to warm all patients for all procedures.

Forced-air warming has a tremendous following, backed by 25 years of reliable use in ORs and a strong marketing presence. It's estimated that more than 50,000 Bair Hugger forced-air warming units are currently in use across the country. Bair Hugger consists of a portable heater/blower connected by a flexible hose to a disposable blanket that is positioned over (or in some cases, under) surgical patients. It costs around $16 per patient to use a Bair Hugger, compared to $6 to $7 for warmed blankets, says a source.

"Our patients are happy with warmed blankets. Our aim is to make them relax and feel comfortable, just like they would at home," says Mary Radke, RN, BSN, manager of the Dakota Surgery and Laser Center in Bismarck, N.D. "When you use just a warmed blanket, it makes the patient stay relaxed instead of having other devices put on you that make the patient feel more worried about the procedure. We place all our patients in a recliner, offer a warmed blanket and keep the lights turned low. We spend a lot of time at their chair side and it relaxes them. Then the doctor walks them back to the OR and we offer them another warm blanket."

Finally, we heard from 1 facility that heats its patients and cools its surgeons. It keeps the OR suites at a minimum temperature of 73 ?F to 74 ?F, and provides cooling vests for its physicians.