Flexible endoscopes are commonly used diagnostic and therapeutic tools. Fiberoptic bronchoscopes, as one of them, use invasive procedures that may cause damage to human tissues. They are often used repeatedly in a short period of time in clinical practice. After use, they cannot withstand the damage of the human body due to their special materials, high precision, and complex structure.
Due to the characteristics of high temperature , the disinfection environment is special and the operation is difficult . When the cleaning and disinfection is not thorough , the conditional pathogens living on the endoscope and auxiliary equipment are very easy to spread between the examinees and staff , leading to the occurrence of hospital infection , the decline of medical quality , and the medical safety of patients . Therefore , it is particularly important to strengthen the standardized disinfection and management of fiber bronchoscopes . With the birth of fully automatic flexible endoscope cleaning and disinfection machines , the cleaning method of fiber bronchoscopes has gradually changed from manual cleaning to machine cleaning . Choosing an environmentally friendly , efficient and safe disinfectant has become the first choice. In recent years , hypochlorous acid disinfectant , as a new type of endoscope disinfectant , has a stable structure , does not require dilution, mixing, or addition, can be used directly , is easy to store , does not damage the endoscope and accessories , and has a low unit cost . It has begun to be used in manual disinfection of flexible endoscopes . The study by Xu Lihong et al. used hypochlorous acid disinfectant for machine washing and disinfection of fiber bronchoscopes , aiming to further explore its optimal compatibility with fully automatic flexible endoscope cleaning and disinfection machines by observing the disinfection effect of HOCL disinfectant.
The application of hypochlorous acid disinfectant in fully automatic soft endoscope cleaning and disinfection machines has shown good disinfection effects. According to research from Zhongshan Hospital Affiliated to Fudan University, using hypochlorous acid disinfectant for machine washing and disinfection for 5 minutes can quickly kill microorganisms without residual toxins. Compared with traditional glutaraldehyde disinfectants, its turnover efficiency is higher, and daily The number of endoscopes that can be processed has increased significantly.
Table 1 Stability test of hypochlorous acid disinfectant for 7 consecutive cycles
Specifically, after 7 days of continuous use of the hypochlorous acid disinfectant (Jiamba Medical Device Disinfectant) used in this study, although the effective chlorine concentration decreased, it still remained within the safe range (74~106 mg/ L), and the bacterial colony counts on the outer surface and inner cavity surface of the disinfected fiberoptic bronchoscope are both 0, which meets the disinfection requirements. In addition, the results of the ATP biofluorescence detection method also showed that the RLU value of the outer surface of the endoscope after treatment with hypochlorous acid disinfectant was significantly reduced, and the pass rate reached 100%.
Hypochlorous acid disinfectant not only has the advantages of high efficiency, non-toxicity and no residue, but also shows stability and reliability in its application in fully automatic flexible endoscope cleaning and disinfection machines. It is a safe, effective and environmentally friendly disinfection option in clinical applications .
The specific application steps and operation procedures of hypochlorous acid disinfectant in the fully automatic flexible endoscope cleaning and disinfection machine are as follows:
Initial cleaning:
Immediately wipe the dirt off the outer surface of the used flexible endoscope with wet gauze, and repeatedly supply air and water for at least 10 seconds.
Remove the endoscope and install the waterproof cover, place it in a suitable container and send it to the disinfection and sterilization room.
Multi-Enzyme Soak and Rinse:
Disassemble the endoscope into its smallest unit and scrub it under running water.
Soak the endoscope in multi-enzyme wash solution, follow the configuration and soaking time in the product manual, use a syringe to draw out the multi-enzyme wash solution, and flush the air and water supply pipes.
After the endoscope is soaked in the multi-enzyme cleaning solution, use a water gun or syringe to thoroughly flush all the channels to remove the multi-enzyme cleaning solution and loose dirt in the channels, and at the same time flush the outer surface of the endoscope.
Hypochlorous acid disinfection:
Move the cleaned endoscope together with the full pipeline perfusion device, buttons and valves into the disinfection tank and immerse them all in hypochlorous acid disinfectant.
Use a power pump or syringe to fill each pipe with hypochlorous acid disinfectant, change gloves, and inflate each pipe for at least 30 seconds.
The effective chlorine content of hypochlorous acid disinfectant should be between 50 and 210 mg/L, and the disinfection time can be set to 3 minutes or 5 minutes, depending on specific needs.
Rinse and dry:
Move the disinfected endoscope together with the full-channel perfusion device, buttons and valves into the terminal rinse tank; use a power pump or pressure water gun to flush the channels of the endoscope with purified water or sterile water for at least 2 minutes.
Rinse the outer surfaces of the endoscope, buttons, and valves with purified or sterile water.
Place the endoscope on a dedicated drying table covered with sterile towels for subsequent processing.
Evaluation of disinfection effect:
After each disinfected fiber bronchoscope was dried, the disinfection effect was evaluated using the inner cavity sampling method and the outer surface sampling method.
Intracavity sampling method: Use a sterile syringe to draw a sampling liquid containing a neutralizer, inject it from the biopsy port of the endoscope to be inspected, collect it with a water sample membrane filter, send it to the laboratory in time, and use the membrane filter method to count bacterial colonies.
External surface sampling method: Apply the ATP water sample swab on the surface of the fiber bronchoscope in a clockwise rotation, place the collected swab in the fluorescence detector and press it to the bottom, and record the reading (RLU).
The comparative study of hypochlorous acid disinfectant and other disinfectants (such as glutaraldehyde) in terms of disinfection effect, safety and cost-effectiveness involves many aspects. The following is a detailed analysis based on the information I searched:
Disinfection effect
Hypochlorous acid disinfectant:
Sodium hypochlorite (NaClO) and hypochlorous acid (HOCl) have shown good disinfection effects in different studies. For example, in a study of two hospitals in Nigeria, hypochlorous acid showed better results at lower concentrations.
In the inactivation experiment of African swine fever virus (ASFV), sodium hypochlorite can effectively reduce the virus titer under low-contamination conditions and also shows a certain effect under high-level contamination conditions.
For the disinfection of fiber bronchoscopes, the new hypochlorous acid disinfectant can achieve good disinfection effects within 3 minutes, with a pass rate of 100%.
Glutaraldehyde:
Glutaraldehyde was effective against ASFV at a contact time of 30 minutes and a concentration of 1%.
The killing time of alkaline glutaraldehyde and enhanced acidic glutaraldehyde on Bacillus cereus spores was 7 minutes and 3.5 minutes, respectively, and the critical bactericidal concentrations were 5% and 1%, respectively.
Security
Hypochlorous acid disinfectant:
Sodium hypochlorite is highly corrosive and irritating, and has toxic side effects on mice.
However, hypochlorous acid offers an attractive alternative for low-income hospitals due to its improved safety profile, lack of environmental residues, and potential suitability for a variety of medical cleaning needs.
The new hypochlorous acid disinfectant has good safety and stability.
Glutaraldehyde:
Glutaraldehyde is highly toxic, especially alkaline glutaraldehyde, which is cytotoxic to cell culture.
Fortified acidic glutaraldehyde is more stable than alkaline glutaraldehyde, but its use still needs to be cautious.
Cost-effectiveness
Hypochlorous acid disinfectant:
Sodium hypochlorite and hypochlorous acid are inexpensive and quickly effective.
The new hypochlorous acid disinfectant has the characteristics of low cost and high stability.
Glutaraldehyde:
Although glutaraldehyde shows efficient disinfection effect in some cases, its high concentration and strong corrosiveness may increase the cost and risk of use.
Comprehensive evaluation
Overall, hypochlorous acid disinfectants have excellent disinfection effects, especially at low concentrations, and have good safety and cost-effectiveness. In contrast, although glutaraldehyde performs well in certain specific situations (such as inactivation of ASFV), due to its high toxicity and strong corrosiveness, it needs to be used with more caution and may increase the cost of use.
The specific mechanism of the decrease in effective chlorine concentration during the continuous use of hypochlorous acid disinfectant mainly includes the following aspects:
Decomposition reaction : Hypochlorous acid (HOCl) is unstable in water and easily decomposes into chlorine (Cl2), hypochlorite ions (OCl-) and other chlorine-containing compounds, resulting in a reduction in available chlorine concentration. This decomposition reaction is the main reason for the poor stability of hypochlorous acid disinfectants.
Temperature effect: Temperature has a significant impact on the attenuation of available chlorine in sodium hypochlorite solution. Studies have shown that the degradation rates of available chlorine are different at different temperatures. For example, in environments of 30°C and 37°C, the available chlorine content degrades quickly in the first five weeks, and then stabilizes in the next seven weeks, but there is still a certain degradation rate. The higher the storage temperature, the more obvious the decreasing trend of available chlorine concentration.
Effect of pH: The pH of the water can also affect the effectiveness of hypochlorous acid. When the pH value is less than 7.0, most of the hypochlorous acid will decompose, and when the pH value is greater than 8.0, most of the hypochlorite ions will be formed, thereby reducing the disinfection ability.
Interfering substances: Interfering substances such as organic matter and ammonia in the water will react with hypochlorous acid, further reducing its effective chlorine concentration. For example, hypochlorous acid combines with ammonia to form chloramines, which consume freely available chloride.
What long-term follow-up studies are available after endoscope disinfection using hypochlorous acid disinfectants to evaluate its effects on endoscope materials?
At present, the long-term follow-up studies on the use of hypochlorous acid disinfectants for endoscope disinfection mainly focus on evaluating its impact on endoscope materials and disinfection effect. The following are relevant studies and evidence:
During June and July 2018, a study monitored 7 fiberoptic bronchoscopes (48 days in total) using sodium hypochlorite disinfectant for 5 minutes. The disinfection effect was evaluated by ATP fluorescence detection, filter membrane method, and backflow method. The results showed that the surface cleanliness and internal surface colony counts of all samples met the qualified standards, and the effective concentration of the disinfectant remained between 74-106 mg/L within a week.
The study explored the effect of continuous hypochlorous acid disinfection on the final rinse water of endoscopes. Although the study focused on the quality of rinse water, its results showed that continuous hypochlorous acid disinfection can effectively control the microbial contamination in the final rinse water of endoscopes, thus indirectly supporting the application effect of hypochlorous acid disinfectant in endoscope disinfection.
Another study evaluated the disinfection effect of hypochlorous acid disinfectant on clinical fiberoptic bronchoscopes. The study used SPSS software for statistical analysis and compared the results of different cleaning effect evaluation methods. Although the specific data and conclusions are not listed in detail, the study showed that hypochlorous acid disinfectant has a good disinfection effect in fiberoptic bronchoscope cleaning.
Current research mainly focuses on the evaluation of the disinfection effect of hypochlorous acid disinfectants on endoscopes, while there are few studies on its long-term effects on endoscope materials.
What is the environmental performance of hypochlorous acid disinfectant in fully automatic flexible endoscope cleaning and disinfection machines, and what advantages does it have compared to traditional disinfection methods?
BLUEWAV hypochlorous acid disinfectant is a new type of green and environmentally friendly chlorine-containing disinfectant that can produce an effective chlorine content of 90mg/L~110mg/L, 2000-15000ppm, and a pH value adjustable between 5.5~6.5 . It has no residue, no cumulative toxicity, and no pollution to the environment. Hypochlorous acid water can decompose into oxygen, water and chloride ions by itself. It is non-corrosive, safe and non-irritating. It is suitable for medical and health care, public places, educational institutions, food processing, families, animal husbandry and aquaculture and other high-hygiene occasions. BLUEWAV hypochlorous acid disinfectant production equipment adopts electrochemical activation technology. The production process is safe and harmless, low cost, low operating cost, small footprint, easy operation, low maintenance cost, the service life of the electrolytic cell is up to 30,000 hours, and the whole machine is guaranteed for 1 year.
Hypochlorous acid disinfectant has a short sterilization time, and the killing effect on bacteria such as Escherichia coli and Staphylococcus aureus is within 1min~2min. At 20°C, a hypochlorous acid solution with a concentration of 0.3ppm can be used. Hypochlorous acid disinfectant is a low-cost but powerful disinfectant suitable for a variety of disinfection scenarios.
Compared with traditional disinfectants, hypochlorous acid disinfectants have shown many advantages. Its efficiency in eliminating coronavirus OC43 is over 99.999%, and 50ppm concentration of hypochlorous acid can kill norovirus within 1 minute. Hypochlorous acid disinfectant is safe in acute oral toxicity tests, with an actual non-toxic level of 9. Its strong oxidizing properties decompose to form new ecological oxygen, effectively killing bacteria and viruses. Using sodium hypochlorite for flushing may produce chlorine odor, but hypochlorous acid does not have this problem.
In addition, hypochlorous acid disinfectant also has the function of removing odors. It is an oxidative decomposition of odors, which can instantly decompose malodorous gases such as ammonia and hydrogen sulfide, quickly decompose garbage odors, and remove formaldehyde, nicotine, etc. Hypochlorous acid disinfectant produces no residue, has no load on the environment, and has no pollution in emissions.
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