Head Off Hypothermia

Keeping surgical patients warm and their core body temperature above 36 ?C is not only critical to their comfort, but also their safety. Unplanned perioperative hypothermia can lead to an increased risk of surgical site infection, prolonged duration of anesthesia and longer recovery times. Research shows the benefits of maintaining normothermia include reduced infection rates by up to 64%, a reduction in hospital length of stay by up to 40% and a subsequent reduction in healthcare costs by $2,500 to $7,000 per patient. However, research has also shown that up to 70% of surgical patients become hypothermic during surgery. That's somewhat concerning, considering that keeping patients normothermic during their stay reduces risks of suffering post-op complications, facilitates faster discharges and improves their satisfaction with the surgical experience. On which side of 70% do your facility's outcomes fall? If your patients warming protocols could use a boost, here are a few fundamentals to follow.

Passive warming methods provide insulation against heat loss, but alone won't prevent patients from becoming hypothermic. With passive warming, a layer of insulating material is placed on the patient's skin. This method relies on the patient's metabolic heat production and keeps that heat from escaping. Adding just one layer of insulation with passive warming can reduce heat loss by about 30%. Additional layers can be added to reduce marginal heat loss, but adding numerous layers does not prevent significant heat loss.

Active warming, however, prevents hypothermia by warming patients with an external source of heat. There are several options from which to choose:

• Forced-air warming distributes heated air generated by a power unit through a specially designed downstream blanket resulting in heat transfer to the covered body surface. This method is easy to use, effective and relatively inexpensive.
• Conductive fabric devices warm patients by sending heat through table pads or under- and over-body blankets.
• Circulating water devices operate by passing heated water within mattresses, blankets or garments. These devices are not as effective in maintaining core temperatures when compared with forced-air warming because the mattress, for example, needs unimpeded high thermal contact with well-perfused skin. Also, pressure or heat necrosis may result if the water temperature exceeds 40 ?C. The water temperature should be even lower for patients with arterial vascular insufficiency.
• Fluid warmers. Although warm IV fluids do not significantly increase patients' core temperature, the infusion of unwarmed fluids, especially in large volumes, can significantly cool the patient.

After active prewarming was implemented, patients who were pre-warmed were 53% more likely to remain normothermic during surgery than those who were not. When patients were not pre-warmed, only 38% of them remained normothermic during surgery. So, we found, it's worth spending the extra 10 to 30 minutes prior to surgery to achieve and maintain normothermia throughout the perioperative care continuum. (Ideally, it's best to pre-warm patients at least a half-hour before anesthesia induction. If there's a time constraint, efforts should be made to prewarm the patient for at least 10 minutes before induction.)

There are a few instances when a patient may not be actively prewarmed. If a patient is not warmed in the preoperative phase of care, then warming should be performed in the OR. AORN recommends that a patient should not be taken to the OR with a core temperature below 36 ?C. A patient arriving at a facility with a temperature below that threshold needs to be warmed until they achieve normothermia before the procedure begins. Postoperatively, active warming should continue if the patient's temperature is below 36 ?C, they complain of being cold or they're actively shivering.

When patients arrive for surgery, especially in warm climates or the summer months, they might report that they're comfortable and often may not want to be actively warmed. Many patients decline warming as they may not realize how critical it is to maintain their core body temperature. Staff should therefore be educated on the importance of prewarming, so that they can in turn educate patients on its many safety and satisfying benefits. OSM