Get on Board with Prewarming

Patient Safety Patient Experience Infection Prevention Anesthesia

By: Heather Kooiker, MSN, RN, CNL, CNOR, CRNFA

Published: 8/26/2021

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Efforts to prevent perioperative hypothermia should begin when patients are in pre-op.


At my most recent full-time clinical role in a hospital, there was a significant issue with post-op infections in patients who underwent colon procedures. We instituted a colon bundle that included prewarming patients for at least 30 minutes and SSIs in these patients dropped significantly. The results were so good that by the time I left, the hospital was considering prewarming all surgical patients.

The proposed expansion was a good idea. Research shows that poor outcomes such as SSIs, pressure injuries, prolonged recovery times and patient dissatisfaction occur when you don’t maintain patients’ core temperatures. Here are the important things to keep in mind if you’re trying to institute a warming program at your facility.

• Start in pre-op. Patients’ core temperatures often drop from the time they leave pre-op to the time they’re positioned on the OR table. There are multiple reasons for this, including the fact that many facilities still use warmed cotton blankets instead of active warming measures. Things only get worse once patients are in the OR, where they’re in a room that’s significantly colder and they’re wearing nothing but a gown. Cotton blankets do a much better job helping to maintain patients’ surface temperatures than they do with keeping core temperatures where they need to be — at 36°C.

An active warming protocol is better suited to maintaining patients’ internal temperatures, which is what matters when it comes to infection prevention. There’s no such thing as too much warming, so I recommend keeping patients actively warmed for at least 30 minutes in pre-op. Prewarming helps to ensure patients are able to remain normothermic once they enter the cold OR environment. Maintaining normothermia is important in all three phases of care, but it all starts in the pre-op bay.

Warmed Patients Vulnerable to Pressure Injuries
EMERGING RESEARCH
SENSITIVE AREA Patient warming increases vascularity at pressure points such as the heels and sacrum, making those areas particularly vulnerable to pressure injuries.  |  University of Nebraska Medical Center

Active warming measures help to reduce the risk of pressure injuries (PIs) by maintaining tissue viability. However, research suggests that the practice can cause PIs in addition to preventing them.

The oxygen consumption of cells increases as the tissue temperature increases, which has been shown to weaken the intercellular connections reducing the tolerance of the superficial skin structures to pressure and shear. This is where the balancing act comes into play. 

Studies have found that some positions can cause considerable heat trapping (~3 °C rise) between the weight-bearing body and the support surface, and that heat can continue to impact the soft tissue even after the pressure has been relieved.

Still, you need to mitigate the poor outcomes related to hypothermia while protecting the skin. 

That’s why it’s important to actively warm patients, because you want to prevent post-op complications associated with hypothermia, but also implement as many evidence-based pressure injury interventions as possible to prevent PIs, especially if the patient is in the supine position for their procedure and an underbody warming device is used to prevent hypothermia.

Protocols are being worked on now that would call for cooling pressure areas while maintaining normothermia on the rest of the body. In the meantime, keep patients’ heels off the bed. Pad the appropriate areas of patients with five-layer silicone or foam dressing. Collaborate with your team to do some interoperative micromovement techniques on patients during all three phases of surgical care. 

Make sure when patients are transferred to the PACU, they’re not positioned in a way that will continue to put pressure on the same body parts that there was pressure on during their procedures.

Maintaining patients’ core temperatures and doing everything possible to prevent perioperative hypothermia remains the critical goal to strive for during every case. But so is the very important balancing act of making sure these hypothermia-prevention techniques don’t play a role in causing one of the very things warming practices are designed to prevent. 

— Heather Kooiker

• Universal buy-in. Efficiency is the ruler in surgical settings, so corners tend to get cut. Pre-op staff try to get patients into the OR as quickly as possible, and therefore only see them for a short period of time. They’re often so busy keeping up with a busy surgical schedule that potential bad outcomes stemming from perioperative hypothermia — vasoconstriction, tissue hypoxia and a decreased ability to fight infection — aren’t in the forefront of their minds.

To change this mindset, educate frontline staff with studies about the effectiveness of active warming measures from your own facility as well as  similar organizations. Remind staff that the research clearly shows that warming results in fewer negative complications and is an integral part of the best patient care they can provide. The next step with the nurses is to make standardized warming protocols are part of their pre-op workflow. They’re busy doing several things to get patients ready for the OR. Lock in active warming as one of those things that needs to be done each time, but give them a voice and the autonomy to decide where the new extra step will fit in with the workflow.
Once you have some agreement with staff about warming procedures, it’s time to make your facility’s policy match. That means talking to leadership. Any new program costs money, and new additional costs generally come from the manager’s budget. So, when you approach them, you must speak in leadership’s love language — and that language is fiscal responsibility.

Keep in mind they’re trying to perform the difficult and tricky task of balancing best practices with the bottom line. That’s why it’s crucial to go into that conversation heavily armed with benchmarked quality indicators. Perform root-cause analyses on SSI cases and show them that perioperative hypothermia was likely the culprit. Show them national research and recommendations about evidence-based best practices that recommend all patients be warmed in some fashion, and then extol the virtues of active warming — from pre-op through post-op — as it pertains to maintaining core temperatures. Then remind them that hypothermia is attributed to poor outcomes that are non-reimbursable. For instance, CMS reimbursement is tied to hospital-acquired conditions due to hypothermia such as SSIs, pressure injuries, periop hemorrhage or hematoma, post-op sepsis and wound dehiscence. 

Offer clear ways to save money within your proposal. If you’re lobbying for a new forced-air warming system, explain that you don’t necessarily need every type of warming blanket offered by companies. An upper blanket, designed to cover a patient from the waist up, can also be used lengthwise and maneuvered into any configuration you’ll need. 

There are also fluidized blankets, mattresses that circulate warm water under a patient, convective warming systems, as well as innovations on the horizon regarding warmed tables and mattresses.

Active warming is currently the best way to maintain normothermia. It’s clear that combining prewarming with intraoperative warming is more effective at preventing hypothermia than warming in the OR alone. Preoperative warming gives you the best odds to succeed in the difficult task of maintaining patients’ core temperature as they’re transported through the three phases of surgical care. OSM

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