Mechanical and Aerospace Engineering

MAE 297 Seminar

Effect of Forced-Air Warming Blowers on the Dispersion of Squames in an Operating Room

Sourabh V. Apte Oregon State University


Microbial skin colonizers, such as Staphylococcus aureus, are known as a major cause of surgical site infections in operating rooms (OR). These bacteria typically colonize on human skin cells or squames (size ~4-20 microns) which are routinely shed by humans, roughly about 10M particles per day. To prevent perioperative hypothermia, hot air blowers are commonly used to force warm air into a plastic blanket and onto the patient’s skin. This hot air gives rise to turbulent, buoyant, thermal plumes that can potentially lift-off squames scattered on the OR floor. The interaction between the ultra-clean ventilation flow from the ceiling and the rising plumes from near the operating table plays a critical role in the dispersion of the squames. Whether such forced air warming devices and resultant thermal plumes can increase the probability of squames reaching the surgical site is a major unresolved problem in this field. Although the rate of health-care associated surgical-site infections is significantly low (< 2.2%), the small risk is still responsible for a huge additional cost on our healthcare system ($10 billion per annum).

Owing to the size and complexity of the above thermal-fluids problem and the associated cost, no detailed, in-situ experimental measurements or predictive simulations of the flow have been performed. Hence, we use a predictive numerical tool such as large-eddy simulation (LES) to obtain three-dimensional, time-dependent flowfield in a real OR including a patient undergoing knee surgery, medical staff members, and other medical devices. We use Lagrangian particle tracking to accurately capture the dispersion of squames. Simulations with the blower turned on and off are used to contrast the flow patterns and particle dispersion. The probability of squames reaching the surgical site is evaluated. These simulations highlight a major need for future studies in this biomedical application.

Sourabh Apte is a Professor  of Mechanical Engineering at  Oregon State University. He  received his doctorate degree  in Mechanical Engineering at  Pennsylvania State  University (2000) and was an  engineering research  associate at Stanford  University’s Center for  Integrated Turbulence  Simulation (2000‐2005). His  research focuses on  numerical algorithms for  DNS and LES of complex  flows. Applications of current  interest are particle‐laden  turbulent flows, sprays, oxycoal combustion, turbulence  in porous media, fluidstructure interaction among  others.

Date(s) - 10/26/2017
4:00 pm - 5:00 pm

1062 Bainer Classroom


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