Forced air warming devices are in widespread use in our orthopaedic surgical suites—and for good reason: Hypothermia can be a major factor in poor patient outcomes due to its negative impact on myocardial function, pharmacokinetics, and other aspects of patient physiology. While maintaining normothermia in surgical patients lowers the risk of postoperative surgical site infections, recent literature has raised concerns about an increased risk of infection in arthroplasty cases in which forced air warming was used.
The December 17, 2014 JBJS literature review by Sikka et al. focuses on this conundrum. It is a well-written summary of current knowledge that clearly outlines the deficiencies in the available data. The authors emphasize that the studies yielding both positive and negative findings are in most cases tainted with detection and selection bias related to industry-funded research designs. This is an area that is begging for a large randomized controlled trial.
However, because of the <1% overall incidence of infection following lower-limb arthroplasty, such a trial will require large numbers of patients. Also essential for such an investigation will be an experienced clinical trialist, meticulous methods, and an apriori definition of “infection.” It is doubtful that registry data analysis can adequately determine the efficacy of forced air warming in preventing major intraoperative adverse events or its impact on postoperative infection, but an analysis of all available data would be a good start.
I look forward to future well-designed studies in this area that will further clarify patient benefit as well as risk. In the meantime, Sikka et al. stress the importance of following all manufacturer instructions for use and maintenance of any patient-warming device.
Marc Swiontkowski, MD