Patient Warming Pitfalls to Avoid

Patient Safety

By: Jared Bilski

Published: 9/27/2019

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One of surgery's most basic patient safety practices is riskier than you might think.


Active patient warming prevents hypothermia and many related complications such as cardiac trouble, impaired immune function, increased risk of infection and lengthier post-op stays. But you have to worry about an entirely new set of safety issues when staff don't follow proper warming protocols. Unfortunately, that occurs far more often than it should.

"Warming devices aren't benign pieces of equipment designed solely for patient comfort," says Michelle Feil, MSN, RN, CPPS, WCC, clinical practice leader at Penn Medicine in Philadelphia, Pa. "These are therapeutic medical devices that carry a real risk for patient harm."

Ms. Feil would know. She authored a Pennsylvania Patient Safety Authority report that analyzed 278 harmful or potentially harmful events associated with patient warming devices (osmag.net/7yCKNk). Here are a few of the real-world warming mishaps she discovered.

  • Thermal injuries. The most frequently reported type of patient harm in Ms. Feil's report come in a variety of forms, but they nearly all stem from the same root cause: Using warming devices in a manner that's not consistent with the manufacturers' Instructions for Use (IFU). For example, the report cited an example of a patient who'd been lying directly on top of a warming blanket during an appendectomy, which resulted in reddening of his skin and a small, reddened area on the right buttock. That usage went against the blanket's IFU, which specifically stated patients should never be positioned on top of the blanket, that they should only be covered by it.

Then there's the extremely dangerous practice of "free hosing," where the hose of a forced-air warming device is placed underneath surgical drapes or the blanket of a patient's bed or stretcher. This off-label use has resulted in a number of cases of serious patient burns because of the change in the distribution of the heat.

"If you place a hose underneath the drapes, you're focusing a very concentrated amount of heat in one area," says Victoria M. Steelman, PhD, RN, CNOR, FAAN, a patient safety expert and an associate professor at the University of Iowa College of Nursing in Iowa City. "And patients generally can't tell you if they're being burned."

Another seemingly harmless free-hosing practice that is anything but: Putting the hose under a blanket to warm the bed when the patient isn't on it yet. "That's not filtered air," says Dr. Steelman. "The practice creates aerosolized fibers from the blanket, and that's not a prudent thing to do."

It's not just the warming devices and blankets that are being used incorrectly and opening up patients to safety risks. Warming IV or irrigation fluid is a useful adjunct to patient warming that has shown to be effective in preventing hypothermia when combined with other warming methods. But facilities sometimes warm IV fluids in warming cabinets designed specifically for cotton blankets, a big no-no as the high temperatures have led to patients being burned.

CONSTANT MONITORING Non-invasive methods for measuring a patient's core body temperature throughout the perioperative period help to ensure normothermia is safely maintained.

"With fluid, the risk is that it's too hot or too cold," says Paul Austin, CRNA, PhD, a professor of nurse anesthesia at Texas Wesleyan University in Fort Worth. "You don't want to burn the patient, but on the other hand, you want the warmed fluid to be as efficacious as possible."

To prevent fluid-related harm, use a warming device with an integrated temperature monitoring system, which ensures the fluid is warmed to the recommended temperature, says Dr. Austin.

  • Inadequate temperature monitoring. While patient warming devices are specifically designed to maintain normothermia in surgical patients who can't thermoregulate their body temperature due to anesthesia, both hypothermia and hyperthermia can occur — especially when staff members aren't closely monitoring a patient's temperature or using warming devices correctly.

The Pennsylvania Patient Safety Authority's report says a surgical staff member set a warming blanket's temperature to 40 ?F instead of the desired 40 ?C. Because the patient was inadvertently being cooled, his body temperature dropped all the way down to 34.7 ?C (94.4 ?F), and he wound up being taken to intensive care postoperatively.

You must also be aware of the potential to overwarm patients, especially during cases in which most of the patient's body remains covered, such as procedures performed on head and neck areas, and during surgeries performed on pediatric patients.

"With kids, for something like a simple ear procedure, you can get them all covered up and put a warming device on them, then suddenly their temperature or their heart rate goes up," says Dr. Austin. These scenarios highlight a major problem with patient warming protocols: A lack of continuous patient temperature monitoring. "Recommendations suggest monitoring patients' temperatures in pre-op, during surgery and in post-op," says Dr. Steelman. "But staff in a lot of facilities do it just once in pre-op, and once in post-op.

"There's no reason that continuous monitoring can't be done," she adds, "because there's technology that lets staff do it in a non-invasive way."

For example, a temperature monitoring system is available that involves placing a disposable sensor on the patient's forehead. The sensor, which travels with the patient, connects to small control units placed in pre-op, the OR and PACU that display digital temperature readings.

  • Equipment issues. Ms. Feil's report cited equipment problems as one of the top safety issues associated with patient warming. Often these issues are maintenance-related and can be avoided altogether by following the manufacturers' IFUs on everything from cleaning the non-disposable surface with specified disinfectants to always using the disposable coverlets that come with forced-air warming devices as single-use items.

"Forced-air warming devices need to be cleaned, maintained and eventually replaced according to the manufacturers' written instructions," says Dr. Steelman. "That means you need to have bio-engineering checks done on a regular basis."

FLUID SITUATION Always store IV solutions in designated warming cabinets — not in units designed to warm cotton blankets.

Another practice should be adhered to religiously by staff: Cleaning the warming device's corrugated tubing. "It needs to be cleaned between each and every case," says Dr. Steelman.

Also be sure to regularly change filters on forced-air warming devices. "The filters typically have some type of integrated hour counter, so you know exactly when filters are supposed to be changed," says Dr. Austin.

  • Skin tears. You wouldn't expect skin issues to be a safety hazard associated with patient warming, but the Pennsylvania Patient Safety Authority report contained some concerning examples of tears caused by adhesive strips on the blanket and blisters that resulted from allergies to adhesives. These issues can be easily avoided with a few extra precautions. For example, be extra cautious when removing adhesives from certain patients, especially those older than 65 years, current steroid users and those with a history of previous skin issues.
The best safeguard

Patient warming might seem like a basic practice in today's high-tech world of surgery, but don't ignore the importance of understanding how to do it correctly. "Your staff needs hands-on training with devices," says Ms. Feil. "Hopefully, your vendor has a clinical specialist who answers any questions from staff members and teaches them how to use the equipment properly, because they need to know exactly how it works with real patients in real clinical situations." OSM

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