Operating room ventilation with laminar air flow ceiling and a local laminar air flow system near the operating table for the patient

Abstract

The aim of this study is to determine how the air flow from a unidirectional air flow (UAF) system and a local ventilation system will interact with each other. The study analyzes the air circulation near the operating table at different air flow velocities from both systems. The air flow velocities correspond to the usual range of velocities that are recommended by norms and guidelines. The research was approached by numerical and experimental studies. The thermal plume of the patient was measured by Particle Image Velocimetry (PIV) and thermography (IR) and compared with the results from the numerical case. A mesh independency study was made for the numerical case. The study showed that velocities ≥0.2 m/s from the UAF, depending on the height of the room, can overcome the thermal plume generated by a human subject with a moderate activity (100÷120W). The velocities from the local ventilation system need to be higher with at least one step, in accordance with the distance from the ventilation system to the operating wound, in order to avoid disturbances generated from the UAF system.

Virus-laden droplet nuclei in vortical structures associated with recirculation zones in indoor environments: A possible airborne transmission of SARS-CoV-2

“…Jet dispersion has been widely documented in fluid mechanics ( Li et al, 2020 ), and it presents the formation of recirculation flow around the jet (see Fig. 1 a), as reported by ventilation studies conducted by Tacutu et al (2019 , 2021 ). On the other hand, the air patterns in an indoor environment present the formation of recirculation zones in the corners of the room by an internal airflow interaction, as shown in Fig.…”

“…a) formation of a recirculation zone and b) inhibition of a recirculation zone. Images taken from Tacutu et al (2019) . …”

“…Then high bioaerosol concentration (96 cfu m −3 ) was found in some regions, while droplets were entrained towards the airflow in other zones (10 cfu m −3 ). Tacutu et al (2019 , 2021 ) studied the air circulation near an operating table under the UAF, known as the LAF scheme. Numerical simulation exhibited the formation of a peripheral recirculation by jet dispersion, a recirculation zone behind the operating table, and a recirculation zone on the patient by the thermal plume ( Fig.…”

Experimental and numerical study on the thermal plumes of a standing and lying human in an operating room

“…The aspects mentioned above are typical issues related to the design of air distribution strategies and the prediction of the resulting indoor environment, especially in spaces where the dynamics are complex due to the large number of people and equipment. Operating Rooms (ORs) are such spaces in which the dynamics of the air is extremely complex, given the specific environment (multiple human presence and equipment, interactions between different flows), aspects that can affect/contaminate the operating area (Tacutu, Nastase, and Bode 2019;Tacutu, Nastase, and Bode 2019a;Tacutu, Nastase, and Bode 2019b).…”