Computer modeling of the operating room ventilation performance in connection with surgical site infection

Document Type : Article


1 School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran

2 School of Mechanical Engineering, Sharif University of Technology, Tehran, Iran

3 Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY


Surgical site infection (SSI) is a critical source of post-surgical complications in hospitals which affects 2.6% of all surgeries. The primary source of SSI is the deposition of flakes released from the exposed skin of the surgical staff or the patient on the exposed surgical wound. There is considerable interest to design an appropriate ventilation system to minimize SSI. In this study, a computational model for simulating the airflow and thermal conditions in an operating room is developed, and the transport and deposition of particulate contaminants near the surgical wound are analyzed. The results show the formation of a thermal plume over the wound tissue, which is typically at higher temperature than the surrounding. The thermal plume protects the wound from deposition of falling contaminants. The effects of particle size, surgical lights characteristics, and presence of partitions on the optimum inlet air velocity are also studied. Based on the results, the formation of thermal plume over the surgical lamps may easily disturb the ventilation airflow and impresses the optimum inlet air velocity accordingly. The present study provides a better understanding of airflow pattern and transport process in the operating rooms equipped with the UCV systems.


Main Subjects

1. Malone, D., Genuit, T., Tracy, J.K., et al. Surgical
site infections: reanalysis of risk factors", Journal of
Surgical Research, 103, pp. 89{95 (2002).
2. Kirkland, K., Briggs, J.P., Trivette, S.L., et al. The
impact of surgical-site infections in the 1990s: attributable
mortality, excess length of hospitalization,
and extra costs", Infection Control and Hospital Epidemiology,
20, pp. 725{730 (1999).
3. Stevenson, T.C., Experimental Investigation of Hospital
Operating Room Air Distribution (M.Sc. Thesis),
Georgia Institute of Technology, Atlanta, GA (2008).
4. Woods, J.E., Brayman, D., Rasmussen, R.W., et al.
Ventilation requirements in hospital operating rooms
- Part I: Control of airborne particles", ASHRAE
Transactions, 92, pp. 396{426 (1996).
5. Noble, W.C. Dispersal of bacteria from human skin",
International Symposium on Contamination Control,
Copenhagen, Denmark (1976).
6. Zamunar, N. Operating room environment with turbulent
ow", ASHRAE Technical Data Bulletin,
Hospital and Operating Room Ventilation, pp. 101-107
7. Memarzadeh, F. and Manning, A. Reducing risks of
surgery", ASHRAE Journal, 45, pp. 28{33 (2003).
8. Turner, R.S. Laminar air
ow", Journal of Bone and
Joint Surgery, 56, pp. 430{435 (1974).
9. Lidwell, O.M., Elson, R.A., Lowbury, E.J., et al.
Ultra clean air and antibiotics for prevention of postoperative
infection: A multi-center study of 8052 joint
replacement operations", Acta Orthopaedica Scandinavica,
58, pp. 4{13 (1987).
10. Charnley, J. Postoperative infection after total hip replacement
with special reference to air contamination
in the operating room", Clinical Orthopedics, 87, pp.
167{187 (1972).
11. Ferrazzi, P., Allen, R., Crupi, G., et al. Reduction
of infection after cardiac surgery: A clinical trial",
Annuals of Thoracic Surgery, 42, pp. 321{325 (1986).
12. Health technical memorandum 2025: ventilation in
healthcare premises", National Health Service (NHS)
Estates, London, UK (1994).
13. Humphreys, H., Stacey, A.R., and Taylor, E.W.
Survey of operating theatres in Great Britain and
Ireland", Journal of Hospital Infection, 30, pp. 245{
252 (1995).
14. Chow, T.T. and Yang, X.Y. Performance of ventilation
system in a non-standard operating room",
Building and Environment, 38, pp. 1401{1411 (2003).
15. Liu, J., Wang, H., andWen, W. Numerical simulation
on a horizontal air
ow for airborne particles control in
hospital operating room", Building and Environment,
44, pp. 2284{2289 (2009).
16. Woloszyn, M., Virgone, J., and Stephane, M. Diagonal
air distribution system for operating rooms
experiment and modeling", Building and Environment,
39, pp. 1171{1178 (2004).
17. Romano, F., Marocco, L., Gusten, J., et al. Numerical
and experimental analysis of airborne particles control
in an operating theater", Building and Environment,
89, pp. 369{379 (2015).
18. Wang, C., Holmberg, S., and Sadrizadeh, S. Numerical
study of temperature-controlled air
ow in comparison
with turbulent mixing and laminar air
ow for operating
room ventilation", Building and Environment,
144, pp. 45{56 (2018).
19. Loomans, M.G.L.C., de Visser, I.M., Loogman,
J.G.H., et al. Alternative ventilation system for
operating theaters: Parameter study and full-scale
assessment of the performance of a local ventilation
system", Building and Environment, 102, pp. 26{38
20. Sadrizadeh, S. and Holmberg, S. E ect of a portable
ultra-clean exponential air
ow unit on the particle
distribution in an operating room", Particuology, 18,
pp. 170{178 (2015).
B. Sajadi et al./Scientia Iranica, Transactions B: Mechanical Engineering 27 (2020) 704{714 713
21. Sadrizadeh, S., Holmberg, S., and Tammelin, A. A
numerical investigation of vertical and horizontal laminar
ow ventilation in an operating room", Building
and Environment, 82, pp. 517{525 (2014).
22. Ahmadi, G. and Li, A. Computer simulation of
particle transport and deposition near a small isolated
building", Journal of Wind Engineering & Industrial
Aerodynamics, 84, pp. 23{46 (2000).
23. Shams, M., Ahmadi, G., and Smith, D.H. Computational
modeling of
ow and sediment transport and
deposition in meandering rivers", Advances in Water
Resources, 25, pp. 689{699 (2002).
24. Nazridoust, K. and Ahmadi, G. Air
ow and pollutant
transport in street canyons", Journal of Wind Engineering
& Industrial Aerodynamics, 94, pp. 491{522
25. Sadrizadeh, S., Pantelic, J., Sherman, M., et al.
Airborne particle dispersion to an operating room
environment during sliding and hinged door opening",
Journal of Infection and Public Health, 11, pp. 631{
635 (2018).
26. Ufat, H., Kaynakli, O., Yamankaradeniz, N., et al.
Investigation of the number of particles in an operating
room at di erent ambient temperatures and inlet
velocities", International Journal of Ventilation, 17,
pp. 209{223 (2018).
27. Eslami, J., Abbassi, A., Saidi, M.H., et al. E ect of
supply/exhaust di user con gurations on the contaminant
distribution in ultra clean environments: Eulerian
and Lagrangian approaches", Energy and Buildings,
127, pp. 648{657 (2016).
28. Pourfarzaneh, A., Jafarian, A., and Kharinezhad
Arani, H. Numerical study of particulate turbulent

ow to investigate recovery period in cleanrooms",
Scientia Iranica, 26(1) pp. 331-345 DOI: 10.24200/
SCI.2018.20322 (2019).
29. Chen, Q., Zhai, J., and Moser, A. Control of airborne
particle concentration and draught risk in an operating
room", Indoor Air, 2, pp. 154{167 (1992).
30. Zoon, W.A.C., var der Heijden, M.G.M., Hensen,
J.L.M., et al. In
uence of the shape of surgical lights
on the disturbance of the air
ow", Proceedings of
the 11th International Roomvent Conference, Busan,
South Korea (2009).
31. Sadrizadeh, S., Afshari. A., Karimipanah, T., et
al. Numerical simulation of the impact of surgeon
posture on airborne particle distribution in a turbulent
mixing operating theatre", Building and Environment,
110, pp. 140{147 (2016).
32. Sadrizadeh, S. and Holmberg, S. Surgical clothing
systems in laminar air
ow operating room: a numerical
assessment", Journal of Infection and Public
Health, 7, pp. 508{516 (2014).
33. Sadrizadeh, S., Tammelin, A., Ekolind, P., et al.
uence of sta number and internal constellation
on surgical site infection in an operating room", Particuology,
13, pp. 42{51 (2014).
34. Murakami, S., Kato, S., and Suyama, Y. Numerical
and experimental study on turbulence di usion elds
in conventional clean rooms", ASHRAE Transactions,
94, pp. 469{493 (1988).
35. Murakami, S., Kato, S., and Suyama, Y. Numerical
study of di usion eld as a ected by arrangement of
supply and exhaust openings in conventional
ow type
clean room", ASHRAE Transactions, 95, pp. 113{127
36. Chow, T.T. and Yang, X.Y. Ventilation performance
in the operating theatre against airborne infection:
numerical study on an ultra-clean system", Journal of
Hospital Infection, 59, pp. 138{147 (2005).
37. Humphreys, H. and Taylor, E.W. Operating theatre
ventilation standards and the risk of postoperative
infection", Journal of Hospital Infection, 50, pp. 85{90
38. Salvati, E.A. Infection rates after 3,175 total hip and
total knee replacements performed with and without
a horizontal unidirectional ltered air
ow system",
Journal of Bone and Joint Surgery, 64, pp. 525{535
39. Li, A., Ahmadi, G., Bayer, R.G., et al. Aerosol
particle deposition in an obstructed turbulent duct

ow", Journal of Aerosol Science, 25, pp. 91{112
40. Ahmadi, G. and Smith, D.H. Particle transport and
deposition in a hot-gas cleanup pilot plant", Aerosol
Science and Technology, 29, pp. 183{205 (1998).
41. Zhang, H. and Ahmadi, G. Aerosol particle transport
and deposition in vertical and horizontal turbulent
ows", Journal of Fluid Mechanics, 406, pp. 55{
88 (2000).
42. Memarzadeh, F. and Manning, A. Comparison of
operating room ventilation systems in the protection
of the surgical site", ASHRAE Transactions, 108, pp.
3{5 (2002).
43. Rui, Z., Guangnei, T., and Jihong, L. Study on
biological contaminant control strategies under di erent
ventilation models in hospital operating room",
Building and Environment, 43, pp. 793{803 (2008).
44. Sajadi, B., Saidi, M.H., and Ahmadi, G. Numerical
evaluation of the operating room ventilation performance:
Ultra-clean ventilation (UCV) systems",
Scientia Iranica, 26(4), pp. 2394{2406 (2019). DOI:
45. HVAC Design Manual for Hospitals and Clinics,
ASHRAE, Atlanta, GA (2003).
46. Guidelines for Design and Construction of Hospitals
and Health Care Facilities, AIA, Washington, DC
714 B. Sajadi et al./Scientia Iranica, Transactions B: Mechanical Engineering 27 (2020) 704{714
47. Chow, T.T., Lin, Z., and Bai, W. The integrated
e ect of medical lamp position and di user discharge
velocity on ultra-clean ventilation performance in an
operating theatre", Indoor and Built Environment, 15,
pp. 315{331 (2006).
48. Zoon, W.A.C., var der Heijden, M.G.M., Loomans,
M.G.L.C., et al. On the applicability of the laminar

ow index when selecting surgical lighting", Building
and Environment, 45, pp. 1976{1983 (2010).
49. MPROG 287: Healthcare facilities - Guidelines
for mechanical installations", MPROG, Tehran, Iran
50. DIN 4799: Heating, ventilation and air conditioning
- testing of air distribution systems serving operating
theatres", DIN, Berlin, Germany (1990).
51. Yakhot, V., Orszag, S.A., Thangam, S., et al. Development
of turbulence models for shear
ows by a
double expansion technique", Physics of Fluids A, 4,
pp. 1510{1520 (1992).
52. Launder, B.E. and Spalding, D.B. The numerical
computation of turbulent
ows", Computer Methods
in Applied Mechanics and Engineering, 3, pp. 269{289
53. Chen, Q. Comparison of di erent k􀀀" models for indoor
ow computations", Numerical Heat Transfer:
Part B, 28, pp. 353{369 (1995).
54. ANSYS FLUENT 12.1 User's Guide", ANSYS Inc.,
Canonsburg, PA (2009).
55. Patankar, S.V., Numerical Heat Transfer and Fluid
Flow, Hemisphere Publishing Corporation, New York:
NY (1980).
56. Davidson, L. and Fontaine, J.R. Calculation of the

ow in a ventilated room using di erent nite di erence
schemes and di erent treatments of the walls",
Proceeding of the 4th CLIMA 2000 Conference, Sarajevo,
Yugoslavia (1989).
57. ADMECO-LUX. Instructions for tting and use",
ADMECO AG, Hochdorf, Switzerland (2003).