Numerical Simulation and Comparison of Two Conventional Ventilation Systems of Operating Room in the View of Contamination Control

In order to ensure a normalized and uniform internal environment in the poultry house, for large productions, new ventilation systems are needed. As part of this study, numerical simulations of the lateral ventilation system in the poultry house during the winter period of the year were performed. The result is the fields of velocities, current lines and pressures in the poultry house in a 3D setting. It was found that the supply valves located at a height of 200 mm from the floor work much more efficiently than in the traditional setting at a height of 400 mm. Installation of walls on the inside of the poultry house frame, as well as reducing the height of the floor improve the aerodynamics in the poultry house.

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Operating Theatre Ventilation Systems and Their Performance in Contamination Control: “At Rest” and “In Operation” Particle and Microbial Measurements Made in an Italian Large and Multi-Year Inspection Campaign

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17197275 ◽

2020 ◽

Vol 17 (19) ◽

pp. 7275

Author(s):

Francesco Romano ◽

Samanta Milani ◽

Roberto Ricci ◽

Cesare Maria Joppolo

Keyword(s):

Microbial Contamination ◽

Ventilation System ◽

Performance Testing ◽

Surgical Site Infections ◽

Design Parameters ◽

Airflow Rate ◽

Contamination Control ◽

Airborne Contamination ◽

Air Diffusion ◽

Ventilation Systems

In Operating Theatres (OT), the ventilation system plays an important role in controlling airborne contamination and reducing the risks of Surgical Site Infections (SSIs). The air cleanliness is really crucial in this field and different measurements are used in order to characterize the situation in terms of both airborne microbiological pollutants and particle size and concentration. Although the ventilation systems and airborne contamination are strictly linked, different air diffusion schemes (in particular, the Partial Unidirectional Airflow, P-UDAF, and the Mixing Airflow, MAF) and various design parameters are used, and there is still no consensus on real performance and optimum solutions. This study presents measurements procedures and results obtained during Inspection and Periodic Performance Testing (1228 observations) in a large sample of Italian OTs (175 OTs in 31 Italian hospitals) in their operative life (period from 2010 to 2018). The inspections were made after a cleaning procedure, both in “at-rest” conditions and “in operation” state. Inert and microbial contamination data (in air and on surfaces) are analyzed and commented according to four relevant air diffusion schemes and design classes. Related data on Recovery Time (RT) and personnel presence were picked up and are commented. The results confirm that the ventilation systems are able to maintain the targeted performance levels in the OT operative life. However, they attest that significant differences in real OT contamination control capabilities do exist and could be ascribed to various design choices and to different operation and maintenance practices. The study shows and confirms that the air diffusion scheme and the design airflow rate are critical factors. Beside large variations in measurements, the performance values, in terms of control of airborne particle and microbial contamination (in air and on surfaces), for P-UDAF systems are better than those that were assessed for the MAF air diffusion solution. The average performances do increase with increasing airflows, and the results offer a better insight on this relationship leading to some possible optimization.

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Numerical simulation of ancient natural ventilation systems of historical buildings. A case study in Palermo

Journal of Cultural Heritage ◽

10.1016/j.culher.2008.03.008 ◽

2009 ◽

Vol 10 (2) ◽

pp. 313-318 ◽

Cited By ~ 25

Author(s):

Carla Balocco ◽

Giuseppe Grazzini

Keyword(s):

Numerical Simulation ◽

Natural Ventilation ◽

Historical Buildings ◽

Ventilation Systems

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Stereo Augmented Reality in the Surgical Microscope

Presence Teleoperators & Virtual Environments ◽

10.1162/105474600566862 ◽

2000 ◽

Vol 9 (4) ◽

pp. 360-368 ◽

Cited By ~ 26

Author(s):

A. P. King ◽

P. J. Edwards ◽

C. R. Maurer ◽

D. A. de Cunha ◽

R. P. Gaston ◽

...

Keyword(s):

Numerical Simulation ◽

Augmented Reality ◽

Operating Room ◽

Focal Plane ◽

Optical Path ◽

Surgical Microscope ◽

Augmented Reality System ◽

Radiological Images ◽

Quantitative Assessments ◽

Better Than

This paper describes the MAGI (microscope-assisted guided interventions) augmented-reality system, which allows surgeons to view virtual features segmented from preoperative radiological images accurately overlaid in stereo in the optical path of a surgical microscope. The aim of the system is to enable the surgeon to see in the correct 3-D position the structures that are beneath the physical surface. The technical challenges involved are calibration, segmentation, registration, tracking, and visualization. This paper details our solutions to these problems. As it is difficult to make reliable quantitative assessments of the accuracy of augmented-reality systems, results are presented from a numerical simulation, and these show that the system has a theoretical overlay accuracy of better than 1 mm at the focal plane of the microscope. Implementations of the system have been tested on volunteers, phantoms, and seven patients in the operating room. Observations are consistent with this accuracy prediction.

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The effect of type of ventilation used in the operating room and surgical site infection: A meta-analysis

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.1316 ◽

2020 ◽

pp. 1-6

Author(s):

Jian Bao ◽

Jianhua Li

Keyword(s):

Vascular Surgery ◽

Surgical Site Infection ◽

Operating Room ◽

Hip Replacement ◽

Meta Analysis ◽

Conventional Ventilation ◽

Total Knee Arthroplasties ◽

Site Infection ◽

Room Ventilation ◽

Total Knee

Abstracts Background: The relation between type of ventilation used in the operating room and surgical site infection has drawn considerable attention with its conflicting results. A possible relationship between the type of ventilation used in the operating room and surgical site infection has been reported. This meta-analysis was performed to evaluate this relationship. Methods: A systematic literature search up to May 2020 identified 14 studies with 590,121 operations, 328,183 operations of which were performed under laminar airflow ventilation and 261,938 of which were performed operations under conventional ventilation. These articles reported relationships between type of operating-room ventilation with its different categories and surgical site infection: 10 studies were related to surgical site infection in the total hip replacement; 7 studies in total knee arthroplasties; and 3 studies in different abdominal and open vascular surgery. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated comparing surgical site infection prevalence and type of operating room ventilation using the dichotomous method with a random-effects or fixed-effects model. Results: No significant difference was found between operation performed under laminar airflow ventilation and conventional ventilation in total hip replacement (OR, 1.23; 95% CI, 0.97–1.56, P = .09), in total knee arthroplasties (OR, 1.14; 95% CI, 0.62–2.09; P = .67), and in different abdominal and open vascular surgery (OR, 0.75; 95% CI, 0.43-1.33; P = .33). The impact of the type of operating room ventilation may have no influence on surgical site infection as a tool for decreasing its occurrence. Conclusions: Based on this meta-analysis, operating under laminar airflow or conventional ventilation may have no independent relationship with the risk of surgical site infection. This relationship forces us not to recommend the use of laminar airflow ventilation because it has a much higher cost compared to conventional ventilation.

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