Make Patient Warming Part of Your Total Joints Protocols

Normothermia should be non-negotiable in outpatient orthopedics.

Success in total joint replacements relies on precision across every step of the perioperative journey — including something as seemingly simple as keeping patients warm.

Maintaining normothermia isn’t just about patient comfort. Hypothermia has been tied to impaired healing, increased bleeding, altered drug metabolism and a greater potential risk of infection. Warming is a low-effort, high-impact intervention that should be standard in joint replacement protocols, experts say.

“There are a broad range of outcomes that are worse when patients are hypothermic,” says Harriet Hopf, MD, professor and executive director of faculty development and academic affairs in the department of anesthesiology at the University of Utah in Salt Lake City. “Your body can’t deliver oxygen to wounds as effectively. Your neutrophils and platelets function less efficiently. Even a mild drop in temperature can affect how you heal.”

Stephen Incavo, MD, an orthopedic surgeon at Houston Methodist and co-author of a study on prewarming and total joint outcomes, believes that while randomized trials are difficult to perform in this space, hypothermia prevention is a critical factor.

“It’s hard to prove causality in these cases, but we know that hypothermia happens often — especially in colder ORs and with long pre-op waits — and it may contribute to infections, particularly in vulnerable patients,” he says.

A recent survey by Outpatient Surgery Magazine from a national sample of facilities shows variation in how warming is used. While 62% of respondents say they always warm patients, 38% report only doing so sometimes or occasionally.

“It’s easy to underestimate how fast patients get cold,” says David Etzioni, MD, a colorectal surgeon and researcher at Mayo Clinic in Phoenix. “When patients come in already vasoconstricted and we give them anesthesia, we redistribute their core heat to the periphery — and their temperature can drop by a degree or more in the first 30 minutes.”

Prewarming is powerful

These experts advocate for preoperative active warming — using not just blankets, which merely slow heat loss, but devices like forced-air warming gowns that actually raise body temperature. If you can raise peripheral temperature before anesthesia,” says Dr. Etzioni, “you buffer against the core temperature drop. Patients stay warmer, recover faster and feel better.”

Dr. Hopf says most outpatient centers can integrate warming into pre-op protocols without disrupting workflow. “We have patients put on forced-air warming gowns as soon as they arrive,” she notes. “They stay on through the procedure. It’s simple and they love it.”

Dr. Incavo agrees. “We ask patients to arrive early, and they may sit in pre-op for a long time wearing nothing but a hospital gown,” he says. “Preoperative forced-air warming in that setting is an effective strategy not only for comfort, but to help reduce hypothermia heading into surgery.”

Their advocacy of patient warming is backed by real-world data. Dr. Incavo’s retrospective study of 672 total joint arthroplasty patients found that implementing a protocol with forced-air warming and warmed IV fluids in pre-op reduced incidence of perioperative hypothermia by 30%. Only 26% of patients under the protocol were hypothermic at incision, compared to 37% previously.

The researchers also found that the largest drop in core temperature occurred between pre-op holding and induction of anesthesia — a window of vulnerability that is often overlooked. “That drop is almost guaranteed if patients arrive cold and vasoconstricted,” says Dr. Hopf. “You’re just redistributing core heat out to the periphery as soon as you give anesthesia. Prewarming blunts that.”

Dr. Incavo stresses the role of workflow in avoiding heat loss. “You don’t want a patient lying uncovered on a cold OR table longer than necessary during anesthesia or prepping,” he says. “The longer they’re exposed, the higher the risk of hypothermia.”

Combine measures for effectiveness

ACTIVE IMPACT Preoperative forced-air warming in an ASC setting is an effective strategy, not only for comfort but to help reduce hypothermia heading into surgery.

During surgery, warming is typically achieved through forced-air systems (used by 90% of respondents to the OSM survey), warmed fluids, underbody conductive pads or a combination. The key is targeting warming to the patient’s risk — and starting early.

“Short cases present a challenge,” notes Dr. Hopf. “Patients still get cold, but you don’t have time to warm them back up. That’s why prewarming matters even more in fast-turnover settings.”

For longer, higher-risk procedures such as total joints, warming should be aggressive and sustained across all phases of care. OSM survey respondents agreed, citing total joints procedures as cases where warming is especially important. These longer surgeries tend to involve significant fluid use, and impact patients who may be older or underweight — all risk factors for heat loss.

“If you’re doing outpatient total joints, warming should be baked into the protocol,” says Dr. Hopf. “It’s not just about comfort — it affects physiology, pharmacology and healing.”

Research backs this up. Another retrospective study involving Dr. Incavo from Houston Methodist Hospital found that 34% of total knee arthroplasty and 39% of total hip arthroplasty patients were hypothermic at incision. Even more concerningly, 65% of total hip patients remained hypothermic throughout the procedure.

Dr. Incavo emphasizes that hypothermia is rarely the sole cause of a complication — but it may be a contributing factor in complex cases such as total joints. “If a patient is elderly, frail, immunocompromised and has a long surgery, those risks compound,” he says. “Hypothermia might be the final straw that tips them toward a surgical site infection.” He adds that revision procedures, which can last four hours or more, require special vigilance. “The longer the procedure, the more aggressive you need to be in keeping that patient warm,” he says.

Team approach

Dr. Etzioni says the best patient warming results come from a team-based approach where anesthesia, nursing and surgical staff all know their roles. “It’s not one person’s job — it’s everyone’s,” he says. “If the warming protocol isn’t clear, patients will slip through the cracks.”

Dr. Incavo adds that even when evidence, protocols and clinical support are in place, there is still risk that warming protocols can be inconsistently applied at a facility — particularly in a fast-paced or resource-limited outpatient environment. It’s important, then, to regularly monitor and audit compliance among your providers. At Dr. Incavo’s institution, anecdotal evidence points to improved patient comfort and fewer warming-related delays after consistent protocols were implemented.

“Warming is underutilized in some places because it’s viewed as ‘one more thing to do,’” he says. “The literature isn’t overwhelmingly convincing, and OR teams prefer cooler rooms. But when you see fewer patients shivering in PACU and shorter recovery times, it makes a strong case.”

And that consistency matters. Outpatient Surgery Magazine survey data shows most facilities believe warming helps reduce PACU times (50%) and prevents surgical site infections (51%). Nearly 87% said warming offers clinical and economic benefits. And of course, there’s the comfort and patient satisfaction factor.

“There’s no single device or fix,” says Dr. Hopf. “The real secret to maintaining normothermia? Planning, effort and buy-in.” OSM