Long-term surveillance of air quality in medical center operating rooms

doi:10.1016/j.ajic.2010.07.006

American Journal of Infection Control

Volume 39, Issue 4, May 2011, Pages 302-308

https://doi.org/10.1016/j.ajic.2010.07.006 Get rights and content

Background

Maintenance of adequate indoor air quality (IAQ) in operating rooms (ORs) is critical to the prevention of nosocomial infection in hospitalized patients. This study evaluated the characteristics of IAQ in various ORs in a medical center.

Methods

Air temperature, relative humidity, carbon dioxide (CO₂), particulate matter (PM), and bacterial concentrations were monitored in the ORs, and monthly variations were noted.

Results

The mean CO₂ concentrations in the ORs were lower than the suggested level (600 ppm average over 8 hours) set by Taiwan’s Environmental Protection Agency. Positive relationships were found among the number of persons, temperature (Spearman’s rho coefficient [r_s] = 0.19; P < .01), and CO₂ concentration (r_s = 0.34; P < .01) in the OR. Bacterial concentration was significantly associated with PM level when adjusted for OR category and the number of persons in the room. Gram-positive bacteria (eg, Bacillus spp, Micrococcus spp, Staphylococcus spp) were frequently found in the monitored ORs.

Conclusion

The IAQ in the ORs varied significantly from month to month. The number of persons in the OR affected IAQ, and a decreased PM level might indicate reduced microbial contamination in the OR.

Section snippets

ORs

IAQ was monitored in 8 ORs (a kidney transplantation room, a heart transplantation room, a liver transplantation room, a neurosurgery room, a trauma surgery room, a cardiovascular surgery room, a colon/rectal surgery room, and an orthopedic surgery room) at Chang Gung Memorial Hospital in northern Taiwan. During the sampling periods, the air in the ORs was conditioned in a no-heating mode. An airflow of 15 ACH was supplied to all ORs except the cardiovascular surgery room, which had an airflow

Air quality distribution in ORs

During the surveillance period, OR air temperature was 14.4-23.2°C, RH ranged from 52.1% to 80.9%, and the CO₂ concentration was 343-776 ppm (Table 1). The cardiovascular surgery room had the highest mean CO₂ concentration (558.6 ppm). Nineteen percent of the CO₂ samples obtained from the cardiovascular surgery room exceeded the IAQ level (600 ppm averaged over 8 hours) recommended by the Taiwan Environmental Protection Agency. In the other ORs (ie, transplantation rooms, orthopedic surgery

Discussion

This investigation is the first in Taiwan to measure air quality indices in various ORs in a medical center to document monthly variations in IAQ. The IAQ depends on the outdoor air quality, indoor environmental variables (concerning heating, ventilation, and air-conditioning systems; building materials; and cleaning products), and personnel-related factors (including the number of persons and human activities).24, 25 Long-term air monitoring results revealed that some CO₂ and bacterial samples

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14,519 operations were analyzed with 179 SSIs (1.2%). The lower/upper 10th percentiles for temperature and RH were 64.4/71.4 °F and 33.5/55.5% respectively. Low or high temperature carried no significant increased risk for SSI (Low ⁰F OR = 0.95, 95% CI 0.51–1.77, P = 0.86; High ⁰F OR = 1.13, 95% CI = 0.69–1.86, P = 0.63). This was also true for low and high RH (Low RH OR = 0.96, 95% CI 0.58–1.61, p = 0.88; High RH OR = 0.61, 95% CI = 0.33–1.14, P = 0.12). Analysis of combined temperature/humidity showed no increased risk for SSI.
Significant deviations in intraoperative temperature/humidity are not associated with increased risk of SSI.
Can particle counting replace conventional surveillance for airborne bacterial contamination assessments? A systematic review using narrative synthesis
2023, American Journal of Infection Control
Bacterial airborne contamination in the operating room during surgery indicates an increased risk for surgical site infection. The conventional surveillance method for bacteria in the air is by air sampling, plating, and counting of colony-forming units (CFU). Particle counting measures particles in the air, typically in sizes of 1-20 µm, and has been suggested as an alternative to CFU measurements. The primary aim was to investigate the correlation between the number of airborne CFU and particles during surgery. The secondary aim was to explore whether different ventilation settings influence the correlation between CFU and particles.
The databases Cochrane, Embase, and Medline were searched for relevant publications. Due to the heterogeneity of the data, meta-analysis was not possible and a narrative analysis was performed instead.
The review included 11 studies. Two of the studies (n = 2) reported strong correlation between particles and CFU (R_p = 0.76 and R_c = 0.74). The remaining studies observed moderate correlation (n = 3), low correlation (n = 3), or no correlation (n = 3). Based on the primary results from this study, ventilation attribution to distinguish the correlation between particles and CFU had no or little contribution.
Due to the lack of convincing evidence of correlation and lack of high-quality studies performing measurements in a standardized way, the studies could not provide the necessary evidence that show that particle counting could be used as a substitution for conventional air bacterial assessment. Further studies are warranted to strengthen the conclusion.
Experimental analysis of airborne contaminant distribution in an operating room with different ventilation schemes
2023, Building and Environment
Experimental and numerical investigations were performed in a research operating room to compare laminar air flow and turbulent mixing ventilation systems in reducing the concentrations of airborne germs and surgical smoke in operating room air. In addition, measurements at scattered positions were conducted to find positions that are suited best for airborne monitoring in real-time during surgeries. In the experiments, particle counters were used to sample tracer aerosols originating from the wound area and the facial area of the thermal manikins representing surgical staff. The results showed that it is important to perform monitoring close to the areas with high hygiene requirements. Increasing the air change rate with turbulent mixing ventilation significantly reduced the number of airborne particles, however, not in the surgical microenvironment. Our findings show varying results considering the particle concentration using laminar air flow compared to turbulent mixing ventilation. With laminar air flow, higher contaminant levels are obtained in the areas with a high demand for contamination reduction. In contrast, laminar air flow was more effective in reducing the concentration of surgical smoke in the facial areas of the surgical staff. Regarding airborne germs, monitoring should be performed at the instrument tables and close to the wound area to evaluate the risk for surgical side infections. These results can support the development of guidelines and best practices for operating room ventilation design and maintenance to improve patient safety and reduce the risk of healthcare-associated infections.
Inhalation exposure assessment techniques on ventilation dilution of infectious respiratory particles in a retrofitted hospital lung function room
2023, Building and Environment
Controlling the spread of respiratory infections in healthcare settings is important to prevent nosocomial infections. To assess the effectiveness of commonly used techniques in the hospital for evaluating the performance of building retrofit to reduce the risk of nosocomial infection, we employed computational fluid dynamics (CFD) simulation, real-time carbon dioxide (CO₂) monitoring, microorganism culturing, and microorganism sequencing. These techniques can quantitatively assess the direct and indirect inhalation exposure risk of healthcare workers (HCWs) to infectious respiratory particles (IRPs) exhaled by patients in a hospital lung function room under two ventilation configurations. Originally, the ventilation system provided 2 air changes per hour (ACH) for clean air and 2 ACH for recirculated air. After retrofitting, the ventilation system was modified to increase clean air to 6 ACH and remove recirculated air. However, the assessment techniques yielded conflicting results regarding the percentage differences in exposure risk before and after the retrofit. The findings indicated that the retrofit system reduced indirect inhalation exposure risk, as estimated by real-time CO₂ monitoring and microorganism culture, by over 50.00%. However, the CFD simulation indicated an increase in inhalation exposure risk when 6 ACH of clean air was supplied. These results suggest that removing recirculated air and increasing the air change rate are effective in reducing long-range indirect inhalation exposure in the lung function room. However, they are insufficient to minimize the direct inhalation exposure of patients exhaling IRPs in close proximity. Given the conflicting results obtained from the commonly accepted techniques used in our study, it is necessary to provide a better understanding of infection control associated with the ventilation dilution of IRPs for hospital architects, hospital healthcare workers, and built-environment researchers.
Investigating particulate production in the operating suite following the use of waterless alcohol based dry scrub versus traditional hand washing and drying with commonly used surgical towels: An experimental study
2023, American Journal of Infection Control
An often-overlooked item that could cause contamination in the operating suite are the towels used for hand drying following surgical scrub. The purpose of this current study was to determine if there was a difference in the particulate count from different hand drying methods following surgical hand preparation.
Three simulated hand drying groups were established: disposable sterilized surgical towels, reusable sterilized surgical towels, and a waterless alcohol-based dry rub. Particle size measurements of 0.3 µm, 5.0 µm, and 10.0 µm were collected at time zero and repeated every minute for 5 minutes for a total of 10 trials each.
Both the reusable and disposable towels produced significantly more particle matter in all size groups compared to the alcohol scrub control group. A comparison analysis and ANOVA testing demonstrated that alcohol dry scrub produced significantly fewer particles compared to both the disposable blue towels (P < .01) and the reusable green towels (P < 0.01). Disposable towels produced significantly more particles in the 0.3 µm count compared to reusable towels (P < .05).
An alcohol-based dry rub without using a towel yielded the lowest amount of particulate formation in this experimental model, while reusable surgical towels produced the highest number of particles.
Level II Experimental Study.
Many Common Pathogens are Present in the Operative Room Air During Surgery
2022, Journal of Arthroplasty
The main objective of this study was to assess the sanitary measures of operating theaters using next-generation sequencing.
Air was sampled from the operating room for the whole duration of 10 surgical days of “clean” (no infection cases) procedures (6 hip/knee arthroplasty and 4 spine cases). Controls consisted of samples at the beginning of the day (1 hour before the surgery started) and at the end of the day after terminal cleaning. One additional control sample, consisting of a culture swab that was opened and exposed to the air for 5 seconds, was collected at each time point. All samples were sent for next-generation sequencing analysis (16S rRNA sequencing) for bacterial identification.
Overall, 306 samples were collected (159 controls and 147 experimental). Microbial DNA was detected in only 1 control sample, while 18 (12.2%) experimental samples were positive for microbial DNA. The most common organisms retrieved were Escherichia coli (6/18, 30%), Cutibacterium acnes (3/18, 15%), and Pseudomonas aeruginosa (2/18, 11.1%). There was no difference in positive samples between arthroplasty and spine cases (P > .05).
Microbial organisms are not uncommonly present in the operating room air during hip and knee arthroplasties and spine procedures.

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Major articleLong-term surveillance of air quality in medical center operating rooms

Background

Methods

Results

Conclusion

Section snippets

ORs

Air quality distribution in ORs

Discussion

J Hosp Infect

Sci Total Environ

J Hosp Infect

Energy Build

J Hosp Infect

J Hosp Infect

J Hosp Infect

J Hosp Infect

J Hosp Infect

J Hosp Infect

J Hosp Infect

J Hosp Infect

Indoor environmental quality in hospitals

Occlusive scrub suits in operating theaters during cataract surgery: effect on airborne contamination

Infect Control Hosp Epidemiol

Environmental air pollution in an intensive care unit for nephrology and dialysis

J Nephrology

Airborne particulates in the OR environment

AORN J

Droplet fate in indoor environments, or can we prevent the spread of infection?

Indoor Air

Indoor particulate matter measurement as a tool in the process of the implementation of smoke-free hospitals

Monaldi Arch Chest Dis

Major article
Long-term surveillance of air quality in medical center operating rooms