title: Forced-air warming and ultra-clean ventilation do not mix: an investigation of theatre ventilation, patient warming and joint replacement infection in orthopaedics.
abstract: 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.
authors: South London Healthcare NHS Trust, Frognal Avenue, Sidcup, Kent DA14 6LT, UK.
authors: P D
authors: PD
authors: McGovern
authors: M
authors: M
authors: Albrecht
authors: K G
authors: KG
authors: Belani
authors: C
authors: C
authors: Nachtsheim
authors: P F
authors: PF
authors: Partington
authors: I
authors: I
authors: Carluke
authors: M R
authors: MR
authors: Reed
mesh_terms: D000368:Aged; D000391:Air Microbiology; D000392:Air Movements; D019643:Arthroplasty, Replacement / Q000009:adverse effects / Q000379:methods*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D001419:Bacteria / Q000302:isolation & purification; D006361:Heating / Q000009:adverse effects / Q000379:methods*; D006621:Hip Joint / Q000382:microbiology; D006801:Humans; D007430:Intraoperative Care / Q000009:adverse effects / Q000379:methods; D007719:Knee Joint / Q000382:microbiology; D008159:Lumbar Vertebrae / Q000601:surgery; D008348:Manikins; D009873:Operating Rooms; D016459:Prosthesis-Related Infections / Q000209:etiology; D013530:Surgical Wound Infection / Q000209:etiology; D014691:Ventilation / Q000379:methods*