Frequently Asked Questions

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Air-free HotDog Patient Warming is safer for surgeries involving implanted foreign materials—such as orthopedic and cardiac surgery—because there is no waste heat disrupting the sterile field with contaminants. Rising waste heat from Forced-air Warming contaminates the sterile surgical field above the table with dirty air from the floor by generating convection currents. There is an increasing body of peer-reviewed evidence published on this issue. (Research)

Click for the full Cleaning Guidelines. The cleaning process takes 30 seconds or less. The blankets can be cleaned in the OR by wiping with a low- to intermediate-level disinfectant—whatever is currently used to wipe surfaces like the OR table. The Blankets are designed for easy cleaning: the outer shell is non-porous and heat-sealed to eliminate crevices. The CDC says noncritical items (only come in contact with intact skin) like HotDog Blankets are safe and present virtually no risk of cross-contamination. Also, HotDog cables are much easier to wipe down than a forced-air warming corrugated hose. For more information see this video on cleaning:


HotDog Blankets are ideally suited for pre- and post-op warming. Lower or full-body Blankets can provide active warmth for as low as $1/patient. It’s a much less expensive option than disposable Forced-air Warming gowns or piles of warmed cotton blankets. (Savings)

HotDog offers an underbody warming mattress that can be placed on the OR table and used to warm patients from below. Underbody warming is great at preventing heat loss and maintaining patients’ core temperature. Effective rewarming requires Blankets, which can be used in conjunction with a Mattress. Details are found here.

Yes. Procedures where the patient is positioned in steep Trendelenburg historically result in high rates of hypothermia due to the small surface area available for warming. The WaffleGrip Trendelenburg Positioner effectively prevents the patient from sliding on the table while still providing warmth under the patient.

Yes. The heater fabric is completely radiolucent. However, each warming Blanket and Mattress has parallel buss bars that run along the long edge of the warming device. These can be seen on x-ray. In addition, the area around the sensor is also radio-opaque. See the Underbody Warming brochure for a diagram of the radiolucent areas of a warming Mattress. If x-raying will be done (through the chest cavity, for example) then the mattress should be positioned such that the imaging area does not contain the sensor or buss bar.

Yes. Warming is very difficult during spine surgery with open-frame tables due to exposed surface area (radiant heat loss). HotDog is able to warm with up to four Blankets  and one Mattress at the same time in order to maximize surface area and warming effectiveness. See what Blankets to use and how to position them here (Positioning Guide).

Yes. HotDog Warming Mattresses should be placed over the RF Assure Detection Mat and operated as normal before and during the surgery. Prior to using the RF Assure Detection Mat to run a scan for any missing sponges, turn off the HotDog Patient Warming System at the controller, just as RF Surgical advises the powering down of other equipment, such as the Bovipad. Once the scan is complete–usually taking no more than 10-15 seconds–it is possible to once again power up the HotDog Patient Warming Controller, if desired.

The U5XX series combines both patient warming and electrosurgical grounding, so there is no need for an additional return electrode pad.

However, when using the U1XX series, placing the Mattress underneath the grounding pad will diminish the thermal effects of the HotDog mattress. If the warming Mattress is on top of the grounding pad, the surgeon may see a diminished effect at the active electrode. There is usually an indication from the grounding pad controller if there is not a good ground. Consult with the grounding pad manufacturer for more specifics.

The most successful approach is to stagger the mattress and the grounding pad. Make sure the HotDog Mattress’s sensor is in contact with the patient’s torso for best warming results.

Dr. Scott Augustine and his team developed Bair Hugger® Forced-air Warming 25 years ago. After decades of research and development, his team is arguably the world’s experts in patient temperature management. While proud of what Bair Hugger has done for patients, technology evolves. HotDog was developed to address some of the unintended consequences that come from blowing hot air in the OR. In addition, reusable, air-free HotDog is a lower-cost, clinically superior and more environmentally friendly solution to patient warming.

The FDA has mostly remained silent with regard to addressing the safety of forced-air patient warming systems in orthopedic implant surgery. On August 30, 2017, the FDA sent an ‘Information About Use’ Letter to Healthcare Providers regarding Thermal Regulating Systems urging clinicians to report adverse events and reiterating the importance of warming. A full FAQ on this Letter is available by PDF.

Instead of responsibly addressing Bair Hugger’s safety issues, 3M has resorted to a variety of indefensible tactics such as attacking top tier journals, respected researchers, and Dr. Augustine. In addition, they have attempted to impart a false sense of safety by citing irrelevant studies and false “facts.”  Websites like Safe Patient Warming and The Facts About Forced-Air Warming (FAWfacts), and packets of information and marketing pieces, like “Spread Good Science,” when read critically, provide no credible evidence that Bair Hugger is safe in orthopedic implant surgeries. ATM has created a webpage ( that addresses each “fact” presented by 3M with the real facts.

It would if the air weren’t heated. Orthopedic surgeons have demonstrated that waste heat rises even if there is laminar-flow ventilation in the OR. Flow obstructions—like lights and personnel—are synergistic malefactors that contribute to the rising heat. See details at This contamination has been linked to implant infections.

Published research shows a 74% reduction in deep joint infections after discontinuing the use of forced-air patient warming. Ventilation disruption was associated with a significant increase in deep joint infections for FAW versus patient groups in which forced-air warming was discontinued and patients were warmed with conductive fabric blankets and mattresses. (N=1,437 cases; 2-5 years period P=0.028) Click here for an abstract of the study. (JBJS study abstract)

No. Consult Cleaning and Safety Information for more detail. HotDog products are considered “non-critical items,” meaning they only come in contact with intact skin. According to the CDC, “Virtually no risk has been documented for transmission of infectious agents to patients through noncritical items…” Another thing to consider is that the risk of contamination may actually be greater with FAW. FAW is only partially disposable. The blower and hose are used with thousands of different patients, sometimes moving from one OR to another. One published study showed that 92% of FAW blowers are contaminated with bacteria, and 58% internally generated and emitted germ-sized particles (Albrecht, AJIC, 2011). The contamination is significant because high-velocity air blows across the germ colonies. The contaminated hot air vents under the drapes, mixes with “dirty” floor air and rises into the sterile field.

Yes. ECRI Institute just published a comprehensive evaluation of HotDog patient warming. We encourage everyone to read it. ECRI subscribers can access it at Not sure if you’re an ECRI subscriber? Email or call (610) 825-6000 ext. 5891. To request a printed copy, email

The incident in question occurred in the UK in 2014. It was reported in the press that the injury was caused by HotDog, and our competitors have been using it to scare customers ever since.  The injury, however, was NOT caused by HotDog and the hospital has provided this letter (PDF) exonerating HotDog in the incident.

How could HotDog be blamed in the media in the first place?

A burn occurred, so the first thought was that it was the warming system.  A subsequent investigation by the UK’s Medical and Healthcare products Regulatory Agency (“MHRA”), however, determined that HotDog was not at fault in the incident. The HotDog mattress passed every test to which UK regulators subjected it. They could not make the temperature rise without the controller alarming. Beyond that, the cause of the injury was not investigated once the hospital admitted criminal negligence.  The facts actually show that it was more than likely an electrosurgical burn from a loose grounding electrode.

Could this happen at my hospital?

No. HotDog has numerous built-in safety features (hardware and software), as well as inherent physical properties of its semi-conductive fabric that prevent any type of significant injury of this nature from possibly occurring.