Particle and Carbon Dioxide Concentration Levels in a Surgical Room Conditioned with a Window/Wall Air-Conditioning System

Abstract

One of the most important functions of air conditioning systems in operating rooms is to protect occupants against pathogenic agents transported by air. This protection is done by simultaneously controlling the air distribution, temperature, humidity, filtration and infiltration from other areas etc. Due to their low price, simple installation, operation and maintenance, window/wall air conditioning system have largely been used in operating rooms in Brazil, even if these types of equipment only recirculate the air inside the room without appropriate filtration and renovation with outdoor air. In this context, this work aims to analyse the performance of the window/wall air conditioning systems on indoor air ventilation in operating rooms by measuring particle number concentrations and carbon dioxide concentrations during different surgical procedures, in a single surgical room and in the nearby areas (corridor) for two cases: single surgery and two subsequent surgeries. In addition, the efficiency of the analysed air conditioning system was evaluated by comparing the ventilation level calculated in the surgical room with the ventilation required in order to maintain the carbon dioxide concentration within acceptable levels. The results showed that this type of air conditioning system is not appropriate for use in operating rooms since it cannot provide an adequate level of ventilation. The CO2 concentrations during surgeries, in fact, significantly exceeded acceptable values and a simultaneous increase in particle number concentration was observed. The results also showed that there is a high risk of contamination between subsequent surgeries in the same surgical room, due to residues of contaminants transported by the particles emitted during the surgeries that were not removed from the operating room by the air conditioning system. The particle number concentration measured in the second surgery, in fact, was approximately six times higher than in the first surgery.

Monitors to improve indoor air carbon dioxide concentrations in the hospital: A randomized crossover trial

“…Our findings show that indoor air CO 2 concentrations in our hospital commonly peaked above recommended levels, providing a rationale for widespread use of CO 2 monitors in patient rooms and clinical areas. These results are in line with previous reports in the literature (Baures et al, 2018;Chang et al, 2013;Jung et al, 2015;Pereira et al, 2020;Tang et al, 2009;Zhou et al, 2015) and are thus likely widely generalizable to many acute hospital wards worldwide. Of course, there are also many modern hospital wards with superior HVAC systems and excellent overall ventilation (as seen in intensive care units for example) (Kenarkoohi et al, 2020;Vosoughi et al, 2021).…”

“…Few studies have reported indoor CO 2 concentrations in hospitals (Shajahan et al, 2019). Inappropriately high CO 2 concentrations were measured in hospitals without modern HVAC systems (Hwang and Park, 2020;Lee et al, 2020;Pereira et al, 2020;Zaman et al, 2021;Zhou et al, 2015). In contrast, excellent CO 2 values have been reported in COVID-19 wards without detectable airborne viral genomes (Vosoughi et al, 2021) and an Iranian intensive care unit (where viral genomes were still detected in N = 2/14 air samples) (Kenarkoohi et al, 2020).…”

Increasing Occupancy Levels in an Operating Room Environment Increases Detectable Ambient CO 2 Concentrations

“…In-door air quality is affected by a variety of factors including human occupation [1][2][3]. Developing and applying effective and non-invasive methods that monitor the amount of people in a room is particularly important in clinical settings where air quality is a major factor that can contribute to nosocomial infection including surgical site infections [4][5]. It has been reported that 2.0-2.4% of all total joint arthroplasties in the U.S. result in periprosthetic infection, [6] which imposes signi cant morbidity on patients and large nancial burdens on the healthcare system, [7] making the pursuit of improved air quality in operating rooms of high importance.…”

Development of a Wide-Range Non-Dispersive Infrared Analyzer for the Continuous Measurement of CO2 in Indoor Environments

“…Besides being a greenhouse gas in the atmosphere, carbon dioxide (CO 2 ) also plays an important role in indoor environments [1][2][3][4][5][6][7]. CO 2 is an indoor air quality indicator [8][9][10][11][12][13][14][15][16][17][18]. CO 2 is the principal product of the combustion of fossil fuels and biomass.…”