The incisional infection rate after surgical procedures is positively correlated with the bacterial content of the operating room air, which not only directly affects the success or failure of the procedure, but also relates to the prognosis of the patient. At present, the air disinfection in the operating room mainly includes static and dynamic air disinfection. Static disinfection includes UV disinfection, triple oxygen machine disinfection, and various chemical disinfection methods; dynamic disinfection includes air laminar flow purification system disinfection, plasma air disinfection, and circulating wind UV air disinfection.

Some studies have shown that when the total number of planktonic bacteria in the operating room air reaches 700-1800 cfu/m³, the chance of postoperative infection of the patient increases significantly. The risk of postoperative infection was significantly reduced when the total number of planktonic bacteria was less than 180 cfu/m³. The general operating room is a Class II environment, and the bacterial content in the air cannot exceed 200 cfu/m³. In order to compare the effect of different disinfection methods on air disinfection in general operating rooms, a hospital compared the disinfection effect of three methods: air laminar flow purification system, plasma air disinfector, and UV disinfection from February 2020 to February 2021, and the results are reported below.

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1 Operating room selection

Three general operating rooms of similar size and adjacent location, with a temperature of 22~25℃ and The three general operating rooms with the relative humidity of 40%-60% were randomly divided into The three groups were randomly divided into three groups, and the air laminar flow purification system, plasma air purifier, and ultraviolet light were used for disinfection. The temperature, humidity, type of surgery, and a number of participants in the three operating rooms were different. There were no statistically significant differences in temperature, humidity, type of surgery, and a number of participants in the three operating rooms (all P >0.05).

2 Method

1) Operating room air disinfection

Plasma air disinfector group and air laminar flow purification system group operating room disinfection according to the method of the instructions on 120 min; ultraviolet group turn on ultraviolet lamp continuous irradiation 120 min.

Air Disinfection

2) Air sampling and bacterial culture

Air sampling in the operating room was carried out 10 min before and 60 min and 120 min after disinfection. Among them, 13 sampling points were set up in the operating room of the air laminar flow purification system group, including 5 in the operating area and 8 in the surrounding area. The plasma air disinfector group and the ultraviolet group were set up with 5 sampling points, including the middle and the four corners. The distance between the sampling points and the wall was 1 m and the height from the floor was 1.5 m. The exposure time was 0.5 h. The indoor bacteria were collected by the plate exposure method. The 9 cm diameter ordinary nutrient agar plate was placed at a distance of 1.5 m from the ground, and the number of monitoring points was placed according to the regulations; the plate cover was opened, and the sample was exposed for 30 min, and then placed in an ordinary incubator with the cover on, and the bacterial species and the number of colonies were observed, and the air quality qualification rate of each operating room was calculated and compared. The air quality of each operating room was calculated and compared. The air quality of the operating room was qualified if the bacterial colony count was ≤200 cfu/m³ and no pathogenic bacteria were detected. The indoor colony counts before 10 min after 60 min and 120 min of disinfection were compared.

3 Statistical analysis

The measurement data were expressed as mean±standard deviation (x±s), and the t-test was used to compare the groups with normal distribution, and the non-parametric test was used to compare the groups without normal distribution; the count data were expressed as a rate (%), and the χ² test was used. SPSS20.0 software was used for statistical treatment, and P < 0.05 was considered statistically significant.

3 Results

1) Comparison of air quality pass rate of 3 disinfection methods

Air laminar flow purification system, plasma air purification disinfector and ultraviolet light were used to disinfect the corresponding operating rooms after air sampling for bacterial culture, and the air quality qualification rate after disinfection was calculated. The air quality qualification rate of the operating room after disinfection with the plasma air disinfector was 92.00% (46/50), the air quality qualification rate of the operating room after disinfection with the air laminar flow purification system was 100.00% (50/50), and the air quality qualification rate of the operating room after disinfection with the ultraviolet ray was 92.00% (46/50). The air quality qualification rate of the operating room after disinfection with ultraviolet ray was 86.00% (43/50).

Air Disinfection

2) 3 disinfection methods before and after disinfection of different time points of the operating room air

The number of colonies in the operating room air before and after disinfection by the three disinfection methods at different time points is shown in Table 1. The number of colonies in the operating room of the air laminar flow purification system group at 120 min was significantly lower than that of the plasma air disinfector group and the UV group at the same time point (all P < 0.01). The number of colonies in the operating room of the plasma air disinfector group at 60 min and 120 min after disinfection was significantly lower than that at 10 min before disinfection (P < 0.01), and the number of colonies at 120 min after disinfection was significantly higher than that at 60 min after disinfection (P < 0.01); the number of colonies in the operating room of the air laminar flow purification system group at 60 min and 120 min after disinfection was significantly lower (P < 0.01). The number of colonies in the operating room of the air laminar flow purification system group was significantly lower than the number of colonies 10 min before disinfection at 60 min and 120 min after disinfection (P < 0.01), and the difference between the number of colonies at 120 min after disinfection and 60 min after disinfection was not statistically significant (P > 0.05); the number of colonies in the operating room of the violet external line group was significantly lower than the number of colonies 10 min before disinfection at 60 min and 120 min after disinfection (P < 0.01).

Table 1 Comparison of the number of air colonies in the operating room at different time points before and after disinfection by three disinfection methods
TimePlasma air disinfector group colony count (x±s,cfu/m³)Air laminar flow purification system colony count(x±s,cfu/m³)UV group colony count(x±s,cfu/m³)FP
Before disinfection 10 min38.70±18.73a,d340.13±18.13b,e339.90±14.39c,f0.055>0.05
60 min after disinfection133.20±14.74g125.33±14.83130.43±11.60h2.506>0.05
120 min after disinfection146.43±18.10129.57±15.43138.70±13.988.429<0.01
Note: (1) Compared with 60 min after disinfection, at = 47.226, bt = 50.200, ct = 62.070, p < 0.01. (2) Compared with 120 min after disinfection, dt = 40.436, et = 48.4. 436, et = 48.419, ft = 54.924, gt = -3.105, ht = -2.493, all P < 0.05 or P < 0.01.

4 Discussions

Air disinfection of the operating room can effectively control and reduce the risk of infection in surgical incisions and is one of the important elements of quality management in the operating room. The “Sterilization Management Measures” formulated by the National Health and Welfare Commission clearly stipulates the air hygiene standards for various types of environments, in which the airborne bacteria content in general operating rooms and Class II environments is required to be controlled at 200 cfu/m³ and below, while the requirements for laminar flow clean operating rooms and Class I environments are significantly higher than the former, with the airborne bacteria content controlled at 10 cfu/m³ and below.

Air Disinfection

As a significant measure to reduce and prevent postoperative infections, hospitals at all levels often lack a precise basis for choosing air disinfection in the operating room. Currently, the common air disinfection methods are the air laminar flow purification system disinfection method, ultraviolet disinfection method, and air purification disinfector disinfection method. UV disinfection is a type of static disinfection and is a classic traditional air disinfection method, which is still used as a common disinfection method in the operating rooms of most primary hospitals. It can not only effectively sterilize and control the bacterial content in the air, but also is easy to use, simple to operate, and inexpensive. However, the disinfection effect of UV is affected by various factors such as room temperature and humidity as well as effective distance. In addition, its penetrating power is not strong, so there are typically dead spots for disinfection, and it can damage skin mucous membranes and impact human health, and it cannot be used in a human environment. The principle of disinfection by plasma air purifier is to use high-energy electron adsorption and decomposition of bacteria, resulting in the death of bacteria, thus playing a sterilization and high-intensity purification effect, with the advantages of easy and safe operation, simple maintenance, and low installation costs, etc. It is a safe, effective, and economical dynamic disinfection method, which is widely used in hospitals without laminar flow equipment or a large amount of surgery. The air laminar flow purification system is currently considered to be the ideal air disinfection treatment equipment, which can significantly reduce the number of bacteria in the operating room air, However, its cost is higher, and the maintenance requirements of the laminar flow purification device are also more with due to the complex structure.

References

[1] Comparative analysis of plasma air disinfector with laminar flow purification system and ultraviolet light for air disinfection in operating rooms[J]. Xie B, Ning Qun, Pang Xiuqing, Yang Dongxia, Luo Shanzhen, Peng Bodong. China Rural Health. 2018(06)

[2] Analysis of incisional infections associated with the operating room and countermeasures for prevention and control[J]. Tang Juan. Electronic Journal of Practical Clinical Nursing. 2018(05)

[3] Observation on the effect of plasma air disinfector for operating room air disinfection[J]. Ning Qun, Xie B, Pang Xiuqing, Yang Dongxia, Luo Shanzhen, Peng Bodong. Research on Women’s Health in China and Foreign Countries. 2018(01)