Head Off Hypothermia

Keeping surgical patients warm and their core body temperature above 36ºC 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.

1. Understand your options

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 40ºC. 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.