To the Editor:
We read with great interest the article by Mears et al1 about door opening affecting operating room pressure during joint arthroplasty. The authors performed a retrospective study of 191 cases to investigate the number and duration of operating room door openings during hip and knee arthroplasty procedures and the effect of these door openings on operating room pressure. They found that the longer the duration of door opening, the greater the decrease in room pressure, reaching the conclusion that there is a significant relationship between operating room door openings and room pressure. Nevertheless, we have several queries related to this article.
It is basic knowledge that air temperature has an impact on air pressure and that the movement of air is in the direction from high to low pressure. Because the temperature of the operating room varies from that of the adjacent corridor, the direction of air flow may change once the difference in temperature between them reverses. Therefore, we think that patients should be divided into 2 subgroups: one group in the operating room where the temperature is higher than the adjacent corridor and the other in the operating room with lower temperature.
Detailed records of cut-to-close time, door openings, operating room pressure, and number of surgeons present in the operating room were obtained.1 We would like to know if the volume and pattern of room traffic influences room pressure. We raise this issue based on the knowledge that high room traffic disrupts the laminar air flow, and this may lead to a change in air pressure and the level of airborne bacterial contamination.2 Did more operating room traffic and more sophisticated traffic patterns exist in cases with decreasing positive room pressure? Could the volume and pattern of room traffic be the cause of decreasing positive room pressure?
In this study, each change in room pressure of 0.01 inch H2O was recorded as a pressure change. This is not the common recording mode. We think a mercury barometer would more accurately record the pressure change. We would like to know why the authors chose this recording pattern. Additionally, we think that the humidity of the operating room should be noted, as it has much impact on air pressure.3
We agree with the authors' declaration that the study has some limitations. For example, air quality was not monitored. Air quality should be taken into account, as different constituent parts of air affect air pressure. A larger sample must be evaluated before a definitive conclusion can be reached. Multicenter, controlled clinical studies would lead to more scientific and persuasive results and would reduce possible bias due to research sites' geographical differences.
Liang Xiong, MD
Jing Wang, MD
Tao Xiao, PhD
- Mears SC, Blanding R, Belkoff SM. Door opening affects operating room pressure during joint arthroplasty. Orthopedics. 2015; 38(11):e991–e994. doi:10.3928/01477447-20151020-07 [CrossRef]. doi:10.3928/01477447-20151020-07 [CrossRef]
- Bedard M, Pelletier-Roy R, Angers-Goulet M, Leblanc PA, Pelet S. Traffic in the operating room during joint replacement is a multidisciplinary problem. Can J Surg. 2015; 58(4):232–236. doi:10.1503/cjs.011914 [CrossRef]
- Zhou TJ, Yu RC. Atmospheric water vapor transport associated with typical anomalous summer rainfall patterns in China. J Geophys Res Atmos. 2005; 110(D08104):1–10. doi:10.1029/2004JD005413 [CrossRef]
The authors declined to comment on this letter.