The Unintended Consequence of Forced-Air Patient Warming

The waste air from forced-air warming is actually waste heat. The heat is not vented safely from the OR but instead rises into the ventilation airflow, mobilizing contaminated floor air into the sterile surgical field above the table.

Blog 2018-06-04T19:59:30+00:00

Video Evidence of the Vortex Caused by the Radiant Waste Heat from FAW Blankets

The video clip below is an excerpt from a nurse education course.  It shows the vortex-effect caused by the radiant waste heat from forced-air patient warming (FAW) blankets, similar to what was recently studied and published by orthopedic surgeons A.J. Legg and A.J.Hamer. The Legg and Hamer study, published in the Bone & Joint Journal in March 2013, is different than the four previous studies examining the unintended consequence of FAW.  Studies by Belani, Dasari, McGovern and a previous study by Legg all showed the mass effect of waste heat forming thermals under the drapes and rising from the floor to the surgical field.  The [...]

Study: Contamination Increased 2000x With Bair Hugger Warming

Minneapolis, MN: March 14, 2013— The use of Bair Hugger forced-air warmers during surgery creates convection currents that capture particles below the surgical table, lifting them into the sterile surgical field, according to research recently published by orthopedic surgeons. The waste heat radiating through the surgical drape induced the formation of tornado-like vortexes of rapidly spinning air near the surgical site. The vortexes sucked contaminated air from the operating room floor and deposited it over the surgical wound. 2,000 times more contaminant particles were found in the air over the wound with Bair Hugger warming than with air-free HotDog conductive warming. [...]

The Paradox of Forced-Air Patient Warming

Studies show that forced-air warming (FAW) reduces soft-tissue surgical infections. How can FAW be linked to increased deep-joint infections? The paradox is easy to explain: BIOFILM.  A bacterium that lands on a prosthetic implant can secrete a coating of biofilm that protects it from both antibodies and antibiotics. Bacteria in soft-tissue cannot form effective biofilm coatings. Secretion of biofilm allows a single airborne germ to cause a deep infection of a joint implant (Lidwell, 1983).  When the germ lands on the new implant, it protects itself in a biofilm coating and then sprouts weeks-to-months later as a catastrophic deep joint infection.  [...]

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 [...]

3M accuses Augustine of “instilling fear through misleading claims.” Really? Let’s look at the facts…

Four independent peer reviewed studies have been published showing that forced-air patient warming devices generate convection currents that disrupt the sterile field.  One such study (McGovern, JBJS-br, 2011) even showed a 74% decrease in deep-joint infection rates after discontinuing the use of forced-air patient warming. They switched to air-free HotDog patient warming (1250 patients, 2.5 years). Despite this strong evidence, 3M, the manufacturer of Bair Hugger® forced-air warming, has continued to obfuscate and assure the world that its forced-air warming products are universally safe.  In a recent letter to healthcare professionals, Bob Buehler, VP of 3M Patient Warming, even accuses us [...]

By | May 24th, 2012|0 Comments

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. The researchers investigated whether the floor-to-ceiling temperatures around a draped manikin in a laminar-flow theatre differed when using forced-air [...]

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-Brexamining 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.” Methods: The researchers studied the temperature and the number of particles over the surgical site comparing forced-air warming (Bair Hugger®), radiant warming (HotDog), [...]

Study Links Forced-air Warming to Infections: 3.8x Increase In Orthopedic Implant Cases

Previously, research studying the effects of forced-air warming on laminar flow operating theaters was limited to contamination…until now. The use of forced-air warming during orthopedic implant surgery was associated with a 3.8 times increase in deep joint infections as compared to warming patients without forced-air, according to a newly published study. The study, published in the November issue of the Journal of Bone and Joint Surgery (Br), was conducted by orthopedic surgeons at Northumbria Healthcare Trust in the United Kingdom. Reviewing hip replacement surgeries performed on 1,437 patients over 2.5 years, the study compared the incidence of deep joint infections on patients warmed [...]

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 [...]

Latest Evidence of Forced-Air Contamination — Must See

Here is the latest evidence of forced-air warming units contaminating the operating room by overcoming protective laminar flow ventilation. The room temperature tracer particles and bubbles are neutrally buoyant, which is to say they follow the air currents of the room. When forced-air warming units dump 900 watts of waste heat into the operating room, it is no surprise that we can visualize the effects: heat rises. Notice the laminar flow working properly with conductive fabric warming, or with forced-air "Heat OFF" as control. Then with "Heat ON" watch the stunning evidence of forced-air waste heat mobilizing air from the dirty floor [...]

By | February 15th, 2011|0 Comments