Outpatient Surgery Magazine, providing current information on Surgical Services, Surgical Facility Administration, Outpatient Surgery News and Trends, OR Excellence and more.
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needs unimpeded high thermal contact with well-per- fused 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 tempera- ture, the infusion of unwarmed fluids, especially in large volumes, can significantly cool the patient. 2. Prewarm in pre-op Anesthetic agents impair the body's ability to ther- moregulate itself. The combination of general and neuraxial anesthesia (for example, an epidural) increases the risk of inadvertent perioperative hypothermia. The effects of general and neuraxial anesthesia on thermoregulation are additive. When a patient receives both, they're at an increased risk for hypothermia. Redistribution hypothermia occurs during the first hour after induction of anesthesia and is a result of redistribution of body heat from the core to the periphery. The core temperature (head and trunk) is highly regulated by the hypothalamus and is not greatly affected by prewarming. However, when a patient is actively prewarmed, the tempera- ture of the peripheral tissue compartment (upper and lower limbs) is raised, thus narrowing the tem- perature gradient between the peripheral and core tissue compartments, and minimizing redistribution hypothermia. In short, prewarming patients increases their ability to maintain a normal core temperature after anesthesia induction. We recently implemented an evi- dence-based project focused on main- taining perioperative normothermia in ambulatory surgical patients. Previously, only passive warming with warm cotton blankets was used in the preoperative phase of care, while active warming with a forced-air warming device was used in the OR to maintain normothermia. Our project involved actively warming patients in the pre-op area to determine how that impacted their perioperative temperatures. After active prewarming was implemented, patients who were pre-warmed were 53% more like- ly 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 anes- thesia 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 36ºC. 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 36ºC, they com- plain of being cold or they're actively shivering. 3. Monitor OR temperatures The issue of bringing patients into chilly ORs has been a longstanding one. Often, the first thing 5 0 • O U T P A T I E N T S U R G E R Y M A G A Z I N E • O C T O B E R 2 0 2 0 WARM WELCOME One of the benefits of pre-warming patients is it reduces their anxiety levels before procedures.