During the first months of the pandemic, elective surgical procedures were cancelled in many operating rooms (OR) due to COVID-19 pandemic containment efforts, and earlier this year began to reopen. This reopening process has been guided by a multidisciplinary joint position statement recommending measures to prevent ongoing transmission of SARS-CoV-2, an additional airborne risk in ORs around the globe.1,2 Some of the recommended measures serve not only to prevent transmission of SARS-CoV-2 and other respiratory viruses, but also will reduce the risk of contaminated particulates which can cause surgical site infections (SSI).
OR air quality and surgical infection risk
A number of professional organizations provide guidance regarding air quality in the United States (U.S.). These organizations recommend engineering controls for ORs which provide specific dilution of air (20 air changes per hour), specific filtration of air (Minimum Efficiency Reporting Value filtration rating between 13 and 14), and pressurization of air (positive to surrounding areas).3,4 Since these organizations are not regulatory, they cannot mandate the engineering controls, but their guidance is voluntarily followed by the majority of ORs. In addition, AORN and CDC recommend certain surgical team practices that can further reduce airborne contaminants and the associated surgical infection risk, including minimizing foot traffic during cases, long sleeves, full head hair coverage, minimizing door openings during surgical cases, and removal of patient hair from the surgical site before the patient enters the OR in order to prevent the dispersal of bacteria-laden clipped hair in the OR environment.5 These prevention measures are necessary given that skin scales and hair are continually being shed from the body surface, many of which are laden with bacteria including Staphylococcus aureus and methicillin-resistant Staphylococcus aureus, both causative pathogens in SSI. As many as 10 million skin particles can be shed in a 24-hour period, detached by body movement as well as friction between skin and clothing.5,6
Surgical procedures involving an implant have the greatest risk of infection from airborne contaminants.7 Because these implants are foreign bodies, very few organisms are necessary to trigger the formation of biofilm, leading to infection.8 Implant procedures of many types are becoming ever more common, including hip and knee replacement with prosthetic implants, hernia repair with mesh, breast implants and many more. Bacteria circulating in OR air can come not only from skin cells, and hair strands, but also respiratory aerosols shed by members of the surgical team, since masks are not 100 percent effective. When dispersed in the OR on air currents these bacteria laden particles can settle in the open incision or adhere to the implant, resulting in post-operative SSI.9-12 Airborne contamination has been reported to account for between 20 percent and 24 percent of SSI.13
Despite these prevention measures and controls, sustained zero preventable SSI remains an elusive goal for most ORs. On average, SSIs occur in 2 percent to 4 percent of all patients undergoing surgical procedures, resulting in significant morbidity and mortality.14 These infections additionally create an economic burden, with an infected joint replacement estimated to be associated with costs as high as $400,000 per case.15 This estimate combines the cost of prolonged hospitalization, treatment and reoperation, however, doesn’t address the significant impact on the quality of life of the patient and family.
Surprisingly, given the risks and costs associated, there are no requirements for assessing and ensuring high quality air in U.S. ORs, though this is mandated in U.S. compounding pharmacies as well as European ORs.16 Instead, the engineering controls described previously are considered sufficient in U.S. ORs to ensure safe air quality for patients and surgical teams. Unfortunately, these engineering controls (positive air pressure, increased air changes, temperature and humidity control) can be compromised by door openings and room traffic during cases.17
Surgical smoke plume and employee health risk
Surgical smoke plume poses a risk to patients as well as to surgical team members, resulting in not only upper respiratory irritation, but reports of human papilloma virus infection, and squamous cell carcinoma.18 Surgical smoke plume is generated when a surgeon uses an electrosurgical unit or a laser for thermal destruction of tissue. This smoke can contain carbon monoxide, viral fragments, bacterial fragments, carcinogenic and mutagenic particles.19,20 According to one study, exposure to surgical smoke generated by cautery/burning of one gram of tissue is comparable to the mutagenic effect of smoking three cigarettes for lasers, and six cigarettes for electrocautery.21 Because surgical masks do not provide adequate protection from smoke plume, smoke evacuation devices are recommended.22 Unfortunately, smoke evacuation devices are not consistently used in all ORs.23
Technology designed to improve the quality of OR air
There are now numerous devices with claims related to improving air quality in ORs, though not all are supported by peer reviewed clinical studies. However, a novel device combining HEPA and UV-C disinfection of air has been demonstrated in published peer reviewed studies to be effective in reducing airborne particles, circulating pathogens, and most importantly, reducing surgical infection rates.15, 24-30 In hospital studies, after this device was employed in two different orthopedic O.R.s, it reduced the circulating airborne bacterial level by 80 percent, while in a general surgery O.R. the airborne bacterial level was reduced by 67 percent.26,29 In a March 2018 cross-sectional study this same device was positioned with the intake close to the main door and the output directed towards the center of the O.R. Particle counts were measured during three consecutive periods during a bariatric surgical case where the O.R. door was opened eight, nine and four times, respectively (the device was on for the second period only). There was a statistically significant reduction (p < 0.05) in the number of particles from ≥0.3 µm to ≥10 µm when the device was on. This outcome was achieved despite the presence of 10 O.R. staff and the door openings as described.30 It is effective in eliminating airborne viruses as well. Independent laboratory testing of this portable HEPA plus UV-C device has demonstrated 100 percent inactivation efficiency in viral single-pass testing, using Key issues for perioperative leaders regarding the COVID-19 pandemic Sue Barnes, RN, CIC, FAPIC, Independent IP Consultant 44 Executive Briefing the surrogate for SARS-CoV-2 (MS2 virus) at 450 cubic feet of air per minute. This testing was reviewed by the FDA in 2018. SARS[1]CoV-2 is larger than MS2, making it potentially more vulnerable to this HEPA plus UV-C device than the MS2 test organism. During a more recent study, testing of this device demonstrated 100 percent elimination of SARS-CoV-2 virus during 15 trials when compared to 40 percent reduction by two control devices, one inactive and one with UV-C only.31
The primary differences between this novel HEPA plus UV-C device and other technologies on the market is the small size, the portability, the fact that it does not disrupt the air flow pattern, requires no installation and includes two filter banks. This ensures both inactivating circulating microorganisms using UV-C, and filtering out the particles, some of which can be hazardous, such as by-products of surgical smoke. Additionally, it has a built-in particle counter, which can be used to validate the efficacy of air cleaning before, during and after surgical cases.16
Introduction of new technology in O.R.s often involves a perioperative executive champion who can shepherd the business case through all required committees and approval processes. To further support successful introduction, the vendor can often provide assistance with flexible funding strategies. Avoiding capital level expense can serve to reduce much of the required approvals.
The most successful infection prevention programs include early adopters of new technology with proven efficacy. Looking beyond standard engineering controls is critical given the increasing airborne risks to patients and surgical teams, including the newest, COVID-19. As we continue the journey towards sustained zero preventable surgical infections, ongoing study in this area of risk will help to determine the best method(s) for optimizing air quality in O.R.s.
References
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