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A P R I L 2 0 1 4 | O U T P AT I E N T S U R G E R Y M A G A Z I N E O N L I N E
1. Why are surgical patients at risk?
Anesthesia impairs the body's ability to control vasoconstriction and
vasodilation — the natural reflexes used to maintain core temperature
— causing anesthetized patients to become poikilothermic, meaning
their core temperatures are directly related to environmental condi-
tions. Add to the mix cold OR tables, rapid air exchanges in the room
that essentially create breezes blowing across patients — especially
during ortho cases — and body heat that evaporates from open surgical
cavities, and you've got an environment conducive to the onset of
hypothermia.
2. What are the risk factors?
Some risk factors increase the potential for perioperative hypother-
mia, including age extremes, female gender, systolic blood pressure
less than 140mmHg, higher levels of spinal blockade, normal or
below-normal BMI, and history of diabetes with autonomic dysfunc-
tion.
Surgical factors that can also increase risks include longer procedures
and extended time under anesthesia, a large amount of exposed body
surface and certain surgical procedures: colorectal surgery, cholecys-
tectomy, hip arthroplasty and endoscopy.
3. Which warming methods work?
Actively warming during surgery and in recovery to warm hypothermic
patients is the gold standard. A multimodal approach to active warming
is best, and there are plenty of effective options to choose from —
forced-air units; underbody water-circulating mattresses; resistive heat-
ing blankets; and units that warm IV fluids, irrigations and blood. Tailor
intraoperative warming interventions to individual patients and types of
surgery. Assess patient positioning, incision size and surgical site loca-
P A T I E N T W A R M I N G
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