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  airow", ASHRAE Technical Data Bulletin,  Hospital and Operating Room Ventilation, pp. 101-107  (1986).  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 airow 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 airow in comparison  with turbulent mixing and laminar airow 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  (2016).  20. Sadrizadeh, S. and Holmberg, S. E_ect of a portable  ultra-clean exponential airow 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  airow 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. Airow and pollutant  transport in street canyons", Journal of Wind Engineering  & Industrial Aerodynamics, 94, pp. 491{522  (2006).  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. Inuence of the shape of surgical lights  on the disturbance of the airow", 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 airow 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.  Inuence 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  (1989).  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  (2002).  38. Salvati, E.A. Infection rates after 3,175 total hip and  total knee replacements performed with and without  a horizontal unidirectional _ltered airow system",  Journal of Bone and Joint Surgery, 64, pp. 525{535  (1982).  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  (1994).  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  duct 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:  10.24200/SCI.2018.5431.1269  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  (2006).  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  (2006).  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  (1974).  53. Chen, Q. Comparison of di_erent kô€€€" models for indoor  airow 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).