We investigated the capacity of patient warming devices to disrupt the ultra-clean airflow system. We compared the effects of two patient warming technologies, forced-air and conductive fabric, on operating theatre ventilation during simulated hip replacement and lumbar spinal procedures using a mannequin as a patient. Infection data were reviewed to determine whether joint infection rates were associated with the type of patient warming device that was used.
Neutral-buoyancy detergent bubbles were released adjacent to the mannequin’s head and at floor level to assess the movement of non-sterile air into the clean airflow over the surgical site. During simulated hip replacement, bubble counts over the surgical site were greater for forced-air than for conductive fabric warming when the anaesthesia/surgery drape was laid down (p = 0.010) and at half-height (p < 0.001). For lumbar surgery, forced-air warming generated convection currents that mobilised floor air into the surgical site area. Conductive fabric warming had no such effect.
A significant increase in deep joint infection, as demonstrated by an elevated infection odds ratio (3.8, p = 0.024), was identified during a period when forced-air warming was used compared to a period when conductive fabric warming was used. Air-free warming is, therefore, recommended over forced-air warming for orthopaedic procedures.
- Patient Warming Devices
- Deep Joint Infection
- Hip Replacement
- Lumbar Spinal
- Operating Theatre Ventilation
- Airborne Contamination
The author or one or more of the authors have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article.
Supplementary material. A video demonstrating forced-air warming is available with the electronic version of this article on our website at www.jbjs.org.uk
- Received March 15, 2011.
- Accepted July 12, 2011.
- ©2011 British Editorial Society of Bone and Joint Surgery