Effect of heated‐air blanket on the dispersion of squames in an operating room

Abstract

High‐fidelity, predictive fluid flow simulations of the interactions between the rising thermal plumes from forced air warming blower and the ultra‐clean ventilation air in an operating room (OR) are conducted to explore whether this complex flow can impact the dispersion of squames to the surgical site. A large‐eddy simulation, accurately capturing the spatiotemporal evolution of the flow in 3 dimensions together with the trajectories of squames, is performed for a realistic OR consisting of an operating table (OT), side tables, surgical lamps, medical staff, and a patient. Two cases are studied with blower‐off and blower‐on together with Lagrangian trajectories of 3 million squames initially placed on the floor surrounding the OT. The large‐eddy simulation results show that with the blower‐off, squames are quickly transported by the ventilation air away from the table and towards the exit grilles. In contrast, with the hot air blower turned on, the ventilation airflow above and below the OT is disrupted significantly. The rising thermal plumes from the hot air blower drag the squames above the OT and the side tables and then they are advected downwards toward the surgical site by the ventilation air from the ceiling. Temporal history of the number of squames reaching 4 imaginary boxes surrounding the side tables, the OT, and the patient's knee shows that several particles reach these boxes for the blower‐on case.

Reducing Implant Infection in Orthopaedics (RIIiO): Results of a pilot study comparing the influence of forced air and resistive fabric warming technologies on postoperative infections following orthopaedic implant surgery

“…Mobilisation of non-sterile air from floor level [27], increased concentration of particles over the surgical site [28], elevated microbial counts in the operating theatre [29], and microorganisms found in both the hoses and blower systems [30][31][32][33], for example, could potentially be compromising the sterility of the surgical site. In addition, disruption of LAF by FAW has been shown in studies with neutral-buoyancy detergent bubbles [27 34], high-fidelity predictive fluid flow simulations [35] and modelling of temperature gradients [36]. An International Consensus meeting discussed these issues but agreed there was no direct evidence to definitively link FAW with an increased risk of SSIs [12], similar to several reviews on this topic [37][38][39][40].…”

Modeling Drop Deformation Effects in the Euler-Lagrange Prediction of Liquid Jet in Cross Flow

“…The numerical approach used in this work has been extensively applied to and validated for different applications [25,10,11,14,26,27,28,29]. As a first step in modeling dense spray atomization, the volumetric displacement effects of the carrier phase is isolated by masking shape deformation, coalescence, breakup and evaporation of liquid phase by performing LES simulation of a dense particle laden turbulent jet flow.…”

Bioheat Transfer Basis of Human Thermoregulation: Principles and Applications

“…Eventually, the warm air rises under buoyant action and may pass by the surgical field and instrument trays with the possibility of introducing infectious agents. There have been hundreds of reported infections by microbes typically found on floors, particularly in conjunction with joint implants, that have been attributed without explicit proof to transmission by FAW exhaust flow [81,82]. No mechanistic causative studies have been conducted on human subjects to establish whether there is a direct coupling effect between the convective flow of FAW exhaust gas and surgical site infections.…”