Journal of Hospital Infection: Forced-Air Warming An Infection-Control "Hazard" in Implant Surgery

StopSurgicalInfections.org recently submitted a press release regarding a review article published by Journal of Hospital Infection.  The press release is as follows:

Surgical-infection experts have unambiguously concluded that forced-air warming “...does contaminate ultra-clean air ventilation….” in the operating room. Their advice: Use air-free warming during implant surgery.

PRLog - Nov. 12, 2014 - MINNEAPOLIS -- “Infection Control Hazards Associated with the Use of Forced-air Warming in Operating Theatres," appears in the scientific publication of the Healthcare Infection Society, Journal of Hospital Infection. The article, in press, can be found on-line at www.journalofhospitalinfection.com/article/S0195-6701%2814%2900245-X/abstract?showall=true=

The authors, including surgeon D.L. Leaper, chair of the committee that drafted the UK’s surgical-site infection guidelines, summarized the findings of 10 peer-reviewed, published studies regarding the infection risks of forced-air warming.  Their conclusions:

• No studies have shown that forced-air warming (“FAW”) reduces surgical infections—other than in colorectal surgery.
• In implant surgery, even minor contamination of the operative field can be catastrophic.
• FAW devices contaminate the operative field.

Patient Advocate Warns Against Forced-Air Warming

A well-known patient advocate now urges surgical patients to avoid forced-air warming—even to change hospitals if necessary.

The advocate, Rosie Bartel, speaks from experience. Infected with MRSA during a knee-replacement procedure at a hospital using forced-air warming, Bartel has undergone 27 subsequent operations— including amputation of her leg to the hip. The MRSA remains active.

After researching how the pathogens rose from the floor of the operating room into the sterile field, Bartel concluded that Bair Hugger warming blew particles into her wound, causing the MRSA infection. 

Bartel has a website (www.RosiesDream.com) to share her findings and give her advice to patients. Click on the video below. She has some powerful things to say.

A former educator, Bartel works closely with Partnership for Patients and the Institute for Healthcare Improvement. She will be co-chair of IHI’s national conference this year.

Infection Risk from Forced-air Warming Considered; Study on Bacterial Contamination Recommended

International Orthopedic Consensus 

“We recognize the theoretical risk posed by forced air warming blankets,” concluded the Consensus Statement recently released by the International Consensus on Periprosthetic Joint Infection.  While not urging a change in practice, the Consensus Statement recommended that further studies be undertaken regarding the safety of forced-air warming (“FAW”) in orthopedic implant surgery.
Delegates from more than 50 countries and 80 different societies met in August 2013 to evaluate scientific literature and identify areas for further research.  Among the other conclusions relating to periprosthetic joint infections and the risk of airborne contamination:
 
1. Airborne particulate bacteria are a major source of contamination in the operating room.  The number of airborne bacteria around the wound is correlated to the incidence of periprosthetic joint infections.  Bacteria “circulate through the operating room via air currents.”

“Legg et al,” the Consensus Statement noted, “found increased particles above the surgical site when using FAW compared to radiant warming.” To be precise, the Legg study, published in Bone & Joint Journal, found 2,000 times more contaminant particles in the air over the wound with Bair Hugger forced-air warming than with air-free HotDog conductive warming.  With HotDog patient warming, only 1,000 particles per cubic meter of air were present. With Bair Hugger warming, the particle count was 2,174,000 per cubic meter, an increase of 217,300%.

New ECRI Guidance Expresses “Concern” About Forced-Air Warming in Implant Surgery

In the latest issue of Health Devices, ECRI Institute analyzed the safety of forced-air patient warming, concluding that thermal currents are “particularly worrisome” in implant surgery. Dr. Scott Augustine, inventor of both Bair Hugger and (air-free) HotDog patient warming and CEO of Augustine Temperature Management, comments.

Minneapolis, MN (PRWeb), April 17, 2013 -  After reviewing multiple published, peer-review articles addressing the consequences of the convection currents created by the waste heat produced by forced-air devices, ECRI stated:

• “The disruption of air-flow patterns is particularly worrisome in laminar-flow and ultraclean ORs, in which a wide variety of implant surgeries are performed.”
• “This is especially concerning during orthopedic surgeries because contamination of the surgical site may present a greater risk of developing a PJI, which is harder to treat and resolve than would be the case with SSIs in general.”

Evidence of the risks of forced-air warming just keeps growing.

A study published online ahead of print in Anesthesia & Analgesia concludes that forced-air patient warming produces waste heat that disrupts operating room ventilation airflows over the surgical site, transporting non-sterile air to the area and hindering the ventilation system’s ability to clear potential airborne contaminants.

“There are some in our industry that would like you to believe that hot air doesn’t rise,” says Dr. Scott Augustine, “this study proves, once again, that that argument is insulting to science and common sense.”

Belani, et al, focused on contamination-sensitive surgery at the University of Minnesota, using a mannequin draped for total knee replacement.  Introducing neutral buoyancy bubbles near the mannequin’s head, researchers found a significant increase in bubble-count over the surgical site when forced air warming was used, as opposed to conductive fabric or the control.  The study states:

Evidence Growing Against Safety of Forced-air Patient Warming

Yet another peer-reviewed study—the third in the past five months—has been published showing that forced-air patient warming generates convection current activity in the vicinity of the surgical site, which could lead to contamination of the sterile field.

The study, published by Dr. Kiran Dasari in the March issue of Anaesthesia, is more evidence that a significant patient safety issue exists.  Surgeries with implanted foreign materials, like hip and knee replacements, could be greatly compromised depending on the type of warming technology used.

Another Study Shows the Risks of Using Forced-air Patient Warming

Researchers in the UK published a study in the February, 2012, issue of the Journal of Bone and Joint Surgery-Br examining the effects of forced-air warming on operating room airflow and surgical site sterility.

Summary:

“Forced-air warming resulted in a significant mean increase in the temperature (1.1°C vs 0.4°C, p<0.0001) and number of particles (1038.2 vs 224.8, p=0.0087) over the surgical site when compared with [HotDog®] warming, which raises concern as bacteria are known to require particles for transport.”
 

FAW's Impact on SSIs

“How can forced-air warming be unsafe when research shows that it reduces infections?”

This is a common question, and the best explanation was given by Yale scientist Dr. Marc Abreu in the October 2010 Anesthesiology News Review. In the article, titled New Concepts in Perioperative Temperature Management: Monitoring and Management, Dr. Abreu wrote that, “…any potential airborne contamination caused by FAW waste heat must have a negligible effect on soft tissue SSIs. However, patients undergoing surgery involving implanted foreign materials, especially for orthopedics, may be at higher risk for infection from airborne contamination.” (emphasis added)

The risk of infection with FAW, at least as established so far, is specific to ultra-clean surgeries involving implanted foreign materials: orthopedics, neuro, and cardiac. There is a fundamental difference in causation between soft-tissue infections and surgical infections involving implanted foreign materials—and that is the point commonly missed.

Posting in "Controversies in Hospital Infection Prevention" Blog

An infectious diseases expert from Richmond, Virginia posted information on his blog about the contamination risk of forced-air warming devices. The blog, titled, "Controversies in Hospital Infection Prevention" had this to say:

Bair Hugger vs HotDog
This morning's New York Times business section has an article about Dr. Scott Augustine, the inventor of the Bair Hugger, a device used in the operating room that uses forced air to keep patients warm so as to reduce postoperative infections. Perioperative warming is one of the Surgical Care Improvement Project (SCIP) metrics. The Bair Hugger is now made by Arizant and Dr. Augustine no longer has any connection to the product. He has invented a new warming product that uses conductive fabric, called the HotDog warmer, and now claims that the Bair Hugger causes infections. The New York Times article points out that there may be some theoretical concerns for infection caused by the Bair Hugger, but no definitive evidence.

We shared a new video with Dr. Edmond that is a snippet from a new CEU presentation that will soon be available about airflow disruptions in the operating room.

Addendum 12/30/10:
Dr. Scott Augustine emailed me about this posting and included a video which allows you to visualize the air currents when a forced air warming device is used. It's worth viewing and I think demonstrates plausibility for increased infection risk.