A woman who developed a severe hospital infection after knee replacement surgery filed a lawsuit claiming the Bair Hugger, a forced-air surgical warming blanket, blew bacteria onto her body during surgery and caused her infection.

Plaintiff Mary N. of Kentucky underwent total knee replacement surgery in March when a Bair Hugger Forced Air Warming Device was used. She sustained an infection that required two revision surgeries and other procedures in less than six months, her Bair Hugger lawsuit claims.

Mary’s lawsuit says her infection was caused by the Bair Hugger, a device that forces air into a disposable blanket that is draped over a patient during surgery. The lawsuit says it can blow bacteria-tainted air directly onto a patient.

The blower itself could also become contaminated with bacteria. According to the Bair Hugger lawsuit, “This escaped air creates air flow currents that flow against the downward air flow of the operating room. As this warmed air rises, it deposits bacteria from the floor of the surgical room into the surgical site.”

About the Bair Hugger Warming System

The Bair Hugger is 3M’s version of a warming blanket. The purpose of the device is to help maintain a patient’s body temperature during surgery, which has proven to lessen bleeding, speed recovery time, and provide other benefits. For this reason, forced air warming systems are often used during hip or knee replacement surgery to help maintain a patient’s core body temperature as close to normal as possible.

Bair Hugger works like a forced-air heater, pushing warm air through a flexible hose into a blanket draped over a patient. To work as intended, the device discharges warm air over a patient’s body, but also releases air under the surgical table.

The air discharged under the table allegedly can cause germs and bacteria to become dispersed and recirculated, landing on a patient’s surgical site.

Studies Raise Concern About Bair Hugger Risks

Studies of forced-air warmers, including the Bair Hugger, have not conclusively determined they cause surgical site infections (“SSIs”), but the studies raise concern about the risk.

At least one study described air from the non-sterile areas as laden with pathogens, thereby compromising the surgical site’s sterility.

A 2011 study, “Forced-air warming and ultra clean ventilation do not mix,” published in Journal of Bone & Joint Surgery, proposed that the forced-air warmer’s disruption of the ultra-clean air along with its creation of convection currents drawing air from non-sterile areas are plausible explanations for what it found to be a significant association between using forced-air warmers and risk of SSIs.

Additionally, a 2012 study, “Do forced air patient-warming devices disrupt unidirectional downward airflow?” (Journal of Bone & Joint Surgery) and two 2013 studies — “Forced-air patient warming blankets disrupt unidirectional flow” (Bone & Joint Journal) and “Patient Warming Excess Heat: The Effects on Orthopedic Operating Room Ventilation Performance” (Anesthesia & Analgesia) — found forced-air warming significantly increased the number of airborne particles over the surgical cite.

The studies did not conclude the additional particles carried bacteria, but they found the increased particles a cause for concern.

Bair Hugger Lawsuits

A number of Bair Hugger lawsuits have been filed against 3M alleging that the heat generated by the device can redirect air circulation during surgery.

The Bair Hugger Lawsuit is Case No. 7:15-cv-00116-ART-HAI, in the U.S. District Court for the Eastern District of Kentucky, Pikeville Division.