Sterilizer Research Articles

Citicoline eluting hydrogels for therapeutic contact lenses intended to treat neurodegenerative diabetic ocular diseases

Ophthalmic neurodegenerative diseases related to diabetes, such as glaucoma and retinopathy, are among the major causes of blindness in the world. Citicoline (CIT) in the form of eye drops is currently used for the treatment/prevention of these diseases, which affect the posterior segment of the eye. To ensure the drug penetration into the back of the eye, frequent instillations of highly concentrated drug solutions are required with potential side effects. Drug-loaded soft contact lenses (SCLs) may be an effective alternative to the conventional eye drop treatment, since they may enable a sustained drug release during daily wear, ensuring a higher drug bioavailability, and avoiding drug waste. In this work, one 2-hydroxyethyl methacrylate (HEMA) based hydrogel was functionalised with N-(3-aminopropyl) methacrylamide hydrochloride (APMA), molecularly imprinted with CIT and loaded with the same drug. The material was extensively characterised, in terms of morphology, optical, mechanical, and physical–chemical properties, namely, equilibrium water content, wettability, oxygen and ionic permeability, Young’s modulus, shear deformation, transmittance and refractive index, before and after steam sterilisation. Additionally, the tendency of the material to adsorb proteins of the lachrymal fluid was evaluated and its biocompatibility was assessed by irritation and cytotoxicity assays. Comparison with the non-functionalised and non-imprinted hydrogel showed that the modified hydrogel led to a sustained in vitro release of a much higher amount of CIT than the original one, while keeping typical values for physical–chemical properties of SCLs. The drug-loaded material resisted steam sterilisation and proved to be biocompatible, demonstrating adequate properties to be used in therapeutic SCLs for the prophylaxis/treatment of neurodegenerative diabetic ocular diseases. The neuroprotective effect of the released drug was confirmed with tests using porcine retinal explants.

Assessing cytotoxicity: a comparative analysis of biodegradable and conventional 3D-printing materials post-steam sterilization for surgical guides

Abstract Introduction:
Ecological concerns and diminishing petroleum resources have prompted the exploration of biodegradable 3D-printing materials derived from bio-renewable sources, such as polylactide acid (PLA) or polyhydroxyalkanoates (PHA). This study aimed to compare the potential cytotoxic effects of a biodegradable PLA/PHA blend filament, a conventional photopolymer (MED610), and a combination of MED610 with a support material (SUP705) before and after steam sterilization in vitro.
Materials and Methods:
PLA/PHA, MED610, and SUP705 (both in their pure and steam-sterilized forms; n=6 per group) were assessed for their cytotoxic effects on human fibroblasts using the neutral red uptake assay. Positive controls included zinc diethyldithiocarbamate (ZDEC) and zinc dibutyldithiocarbamate (ZDBC), whereas high-density polyethylene served as a negative control. A stock solution of the extraction medium was used as the vehicle control.
Results:
Significant differences in cell viability were observed between pure PLA/PHA (1.2 ± 0.24) and MED610 (0.94 ± 0.08) (p=0.005). However, both materials exhibited non-cytotoxicity, with cell viability exceeding 70% compared to vehicle controls. SUP705 (0.58 ± 0.42) demonstrated significantly reduced cell viability compared to PLA/PHA (p=0.001) and MED610 (p=0.007). After steam sterilization, no significant difference in cell viability was noted between MED610 (1.0 ± 0.08) and PLA/PHA (1.2 ± 0.25) (p=0.111). While both materials remained non-cytotoxic after sterilization, SUP705 (0.60 ± 0.45) exhibited cytotoxic effects compared to MED610 (p=0.006) and PLA/PHA (p<0.001). Steam sterilization did not induce significant cytotoxic effects in the investigated materials (p=0.123).
Conclusion:
Pure and steam-sterilized PLA/PHA and MED610 were not cytotoxic. The observed cytotoxicity of SUP705 suggests caution in scenarios requiring sterile conditions, as the removal of support material from complex printed parts may be challenging. The consideration of PLA/PHA is recommended in such settings to ensure biocompatibility.

Influence of Material, Sterilization, and Disinfection on the Accuracy of Three-Dimensional Printed Surgical Templates: An InVitro Study.

To evaluate the influence of the three-dimensional (3D) printing technology, material, sterilization, and disinfection on the accuracy of guided surgical templates. Fifty printed resin surgical templates were designed and fabricated using a digital light processing 3D printer with a photopolymerizing resin, and 50 printed metal surgical templates were designed and fabricated using a selective laser melting 3D printer with a titanium alloy. Templates from both groups were randomly divided into five subgroups involving different sterilization and disinfection procedures. The group without any sterilization or disinfection procedure served as the control group, whereas the other groups were used as the study groups (hydrogen peroxide gas plasma sterilization, 5% povidone-iodine disinfection, 75% ethyl alcohol disinfection, and steam autoclave sterilization). Implant simulations were performed on the 3D-printed resin models, and postoperative impressions were acquired with scan bodies attached to the implants. All surgical templates were digitally scanned. The root mean square was used to determine and quantify fabrication accuracy and reproducibility, and the definitive and planned implant positions were compared. The printed resin templates exhibited lower fabrication accuracy and reproducibility, as well as higher 3D deviations, after steam autoclave sterilization (p < 0.001); however, the printed metal templates were not affected by the different sterilization or disinfection procedures (p > 0.05). Printed metal surgical templates are viable alternatives for guided implant surgery. Preoperative steam or gas plasma sterilization is recommended, especially for metal templates, as resin templates show deformation and decreased accuracy after steam sterilization. chictr.org.cn number: ChiCTR2400081334.

Diphenylacetylene‐Incorporating Octaphyrin: A Rigid Macrocycle with Readily Separable Conformational Isomers

AbstractAn expanded carbaporphyrinoid analogue, octaphyrin(2,1,1,1,2,1,1,1), containing two rigid diphenylacetylene moieties is reported. In contrast to traditional pyrrolic macrocycles where flexible conformers coexist in dynamic equilibrium, this macrocycle exists as two separable, conformationally stable stereoisomers, denoted as 1A and 1B. The conformational effect of both conformers, as well as their protonated forms, were thoroughly studied using NMR spectroscopy, UV/Vis, and single crystal X‐ray diffraction analyses. Importantly, heating conformer 1B leads to its irreversible conversion to 1A, whereas in its protonated form, 1A ⋅ 2MSA undergoes irreversible transformation to 1B ⋅ 2MSA at lower temperatures. These temperature‐dependent features establish a foundation for developing new accumulated heat sensors, as demonstrated by the use of the present octaphyrins as a customized thermochromic indicator in steam sterilization. The present study thus underscores how the conformational rigidity of these new polypyrrolic macrocycles imparts properties that are distinct from historically flexible expanded porphyrinoids.

Numerical and experimental investigation of the steam penetration in narrow channels during a dynamic steam sterilization cycle

The most challenging aspect of steam sterilization is the removal of all non-condensable gases (NCGs) from the autoclave. These gases prevent the effective killing of microorganisms, impairing the sterility of medical devices. Special cycles are performed to ensure the penetration of steam, even into the deepest passages. To better understand this process, numerical models were developed to determine the spatial distribution of steam within the chamber, including its penetration into narrow channels. These are the first models that can be used to accurately determine the flow within three-dimensional cavities during a dynamic sterilization cycle. To validate the model, an experiment was designed using direct tunable diode laser absorption spectroscopy at a wavelength of 1364 nm to measure the mole fraction of steam present at the end of an aluminum pipe at a temporal resolution of 1 s. This represents a pioneering application of this technique in the field of steam sterilization. This setup was designed for installation on any autoclave. Both simulation and experimental data exhibit good agreement over the entire pressure range (0.18–3.15 bar). The most interesting observation made during the study was the increase in the steam content at the end of the tube while a vacuum was generated. The numerical results show that the mole fraction of H2O increased from 0.53 to 0.63 over the course of a single vacuum phase. This phenomenon was attributed to a stronger diffusion effect combined with small pressure gradients during low pressures. This finding inspired the idea of taking the diffusion effect more into account when designing sterilization cycles in the future to make them more sustainable and effective. The presented methodologies and models represent an excellent basis for conducting more complex investigations in the future, such as those investigating the influence of condensation effects on steam penetration in cavities.

Biocompatibility Study of Purified and Low-Temperature-Sterilized Injectable Collagen for Soft Tissue Repair: Intramuscular Implantation in Rats.

The clinical application of collagen-based biomaterials is expanding rapidly, especially in tissue engineering and cosmetics. While oral supplements and injectable skin boosters are popular for enhancing skin health, clinical evidence supporting their effectiveness remains limited. Injectable products show potential in revitalizing skin, but safety concerns persist due to challenges in sterilization and the risk of biological contamination. Traditional methods of sterilization (heat and irradiation) can denature collagen. This study addresses these issues by introducing a novel technique: the double filtration and low-temperature steam sterilization of a collagen gel. In vitro tests documented the sterility and confirmed that the collagen did not show cytotoxicity, degradation, integrity, and viscosity characteristics changes after the processing and sterilization. The collagen gel induced new collagen expression and the proliferation of human dermal fibroblasts when the cells were cultured with the collagen gel. An in vivo study found no adverse effects in rats or significant lesions at the implantation site over 13 weeks. These results suggest that this novel method to process collagen gels is a safe and effective skin booster. Advanced processing methods are likely to mitigate the safety risks associated with injectable collagen products, though further research is needed to validate their biological effectiveness and clinical benefits.

Short-Cycle Autoclave Sterilization of Instruments in Same-Day Ophthalmic Surgeries

What Is the Issue? The volume of ophthalmic surgeries is increasingly high, with cataract surgery being 1 of the most performed surgeries in Canada. Infections following ophthalmic surgeries, while rare, can cause severe complications that may lead to irreversible vision loss. Reducing postsurgery infections is a high priority in clinical practice. Running a full wrapped, terminal steam sterilization cycle for ophthalmic instruments in autoclaves may be inefficient for ophthalmic surgeries and may cause unnecessary heavy economic and environmental burdens due to high surgical volumes. Using instruments sterilized on a short cycle between sequential same-day ophthalmic surgeries may help improve efficiency and reduce resources used. These instruments are generally processed using autoclaves (i.e., steam sterilizers); the effectiveness of a shorter-cycle method of sterilization is unclear. What Did We Do? To inform decisions regarding the use of autoclaves for short-cycle sterilization for sequential same-day instrument use in ophthalmic surgery, we sought to identify and summarize evidence comparing this method to full-cycle sterilization of wrapped instruments and identify any relevant recommendations. We searched key resources, including journal citation databases, and conducted a focused internet search for relevant evidence published since 2012. One reviewer screened articles for inclusion based on predefined criteria. What Did We Find? In a laboratory setting to simulate sequential same-day procedures, short-cycle sterilization with interrupted dry time for unwrapped ophthalmic instruments is feasibly as effective as full-cycle sterilization for wrapped instruments using the STATIM autoclave. Similarly, short-cycle sterilization with interrupted dry time for contained ophthalmic instruments is feasibly as effective as full-cycle sterilization for contained instruments using the AMSCO autoclave. For sequential same-day ophthalmic procedures, wet instruments sterilized by a short-cycle process with an interrupted dry time can remain sterile for at least 3 minutes if kept in a covered sterilizer containment device. One guideline recommends that wrapped or unwrapped ophthalmic instruments sterilized by a short-cycle process without full drying should be stored in a covered containment device until retrieved by staff wearing sterile gloves and gowns in the operating room for the subsequent surgery after a short delay. Phaco handpieces should be immediately primed with a balanced salt solution and remain wet as they sit on the sterile instrument table. We did not identify any clinical setting evidence from studies or autoclave manufacturers. It is unclear if clinical outcomes differ between patients undergoing sequential same-day ophthalmic surgeries using short-cycle sterilized instruments and those undergoing surgery using full-cycle sterilized instruments. What Does This Mean? Preliminary laboratory evidence and guideline recommendations supporting the use of autoclaves for short-cycle sterilization of instruments for sequential same-day ophthalmic surgeries are available. However, there is no clinical effectiveness evidence available on this process in patient settings. Future research is necessary to understand the clinical safety of using instruments sterilized by short cycles for sequential same-day use for patients undergoing ophthalmic surgeries. In addition to the evidence and recommendations identified, other factors, such as environmental influence, may be useful considerations when making decisions about short-cycle sterilization for sequential same-day instrument use for ophthalmic surgery.

High Performance Organic Mixed Ionic‐electronic Polymeric Conductor with Stability to Autoclave Sterilization

We present a series of newly developed donor‐acceptor (D‐A) polymers designed specifically for organic electrochemical transistors (OECTs) synthesized by a straightforward route. All polymers exhibited accumulation mode behavior in OECT devices, and tuning of the donor comonomer resulted in a three‐order‐of‐magnitude increase in transconductance. The best polymer gFBT‐g2T, exhibited normalized peak transconductance (gm,norm) of 298±10.4 S cm‐1 with a corresponding product of charge‐carrier mobility and volumetric capacitance, μC*, of 847 F V‐1 cm‐1 s‐1 and a μ of 5.76 cm2 V‐1 s‐1, amongst the highest reported to date. Furthermore, gFBT‐g2T exhibited exceptional temperature stability, maintaining the outstanding electrochemical performance even after undergoing a standard (autoclave) high pressure steam sterilization procedure. Steam treatment was also found to promote film porosity, with the formation of circular 200 – 400 nm voids. These results demonstrate the potential of gFBT‐g2T in p‐type accumulation mode OECTs, and pave the way for the use in implantable bioelectronics for medical applications.

High Performance Organic Mixed Ionic-Electronic Polymeric Conductor with Stability to Autoclave Sterilization.

We present a series of newly developed donor-acceptor (D-A) polymers designed specifically for organic electrochemical transistors (OECTs) synthesized by a straightforward route. All polymers exhibited accumulation mode behavior in OECT devices, and tuning of the donor comonomer resulted in a three-order-of-magnitude increase in transconductance. The best polymer gFBT-g2T, exhibited normalized peak transconductance (gm,norm) of 298±10.4 S cm-1 with a corresponding product of charge-carrier mobility and volumetric capacitance, μC*, of 847 F V-1 cm-1 s-1 and a μ of 5.76 cm2 V-1 s-1, amongst the highest reported to date. Furthermore, gFBT-g2T exhibited exceptional temperature stability, maintaining the outstanding electrochemical performance even after undergoing a standard (autoclave) high pressure steam sterilization procedure. Steam treatment was also found to promote film porosity, with the formation of circular 200-400 nm voids. These results demonstrate the potential of gFBT-g2T in p-type accumulation mode OECTs, and pave the way for the use in implantable bioelectronics for medical applications.

Effect of thermal treatment and secondary bonds on the storage stability of ready-to-eat sea cucumbers

Ready-to-eat sea cucumbers (RSC) are highly sensitive to quality deterioration during storage at room temperature. The study investigated the anti-deterioration effects of high-pressure steam sterilization (HPSS) and high-temperature boiling (HTB) on RSC, as well as the impact of secondary bonds on HTB-treated RSC. The results indicated that there were no significant changes in the secondary structure following thermal treatment. Compared to day 0, the maximum thermal denaturation temperature of collagen in the control (CT) group decreased by 24.49℃, while decreases in the HPSS and HTB groups were 8.53℃ and 9.8℃, respectively. This confirmed that the stabilization of RSC could be enhanced through HPSS and HTB treatment during storage. When hydrogen bonds are destroyed, the texture properties of HTB-treated RSC significantly decrease, with hardness values dropping to 3.65±0.514 N and 2.41±0.615 N, springiness to 7.52±1.342 mm and 7.69±0.066 mm, and chewiness to 19.7±1.211 mj and 16.6±1.837 mj, respectively. Furthermore, the degradation of collagen fibers due to the breaking of hydrogen bonds prior to storage was more pronounced. These findings indicate that hydrogen bonds play a crucial role in maintaining the storage stability of RSC. These results offer a theoretical foundation and technical assistance for the processing and storage of RSC.

Analisis Penambahan Lini Produksi pada PT XYZ pada Proses Pembuatan Alat Steam Sterilizer Menggunakan Metode Incremental Cost Analysis

PT XYZ manufactures medical equipment, including the Steam Sterilizer Autoclave MD 25L. With the increasing demand for healthcare products, particularly the Autoclave MD 25L, production capacity reached its maximum by 2024, causing excessive strain on the workforce. Consequently, alternatives are needed to enhance production capacity without overburdening employees. The decision analysis for expanding the production line was conducted using the incremental cost analysis method, resulting in three alternatives: the existing design, adding one grinding machine and employees, and adding one bending machine and employees. The feasibility analysis confirmed that all three alternatives are viable. Alternative 3 has the highest investment cost, followed by alternative 2, while alternative 1 has the lowest. Initial iterations focused on alternatives 3 and 2, showing a ΔROR of 89.06% with a MARR of 18.36%. Since ΔROR &gt; MARR, alternative 3 was chosen. In the second iteration, comparing alternative 3 with alternative 1 yielded a ΔROR of 77.51%, confirming that alternative 3 remains the best option.

Diphenylacetylene-Incorporating Octaphyrin: A Rigid Macrocycle with Readily Separable Conformational Isomers.

An expanded carbaporphyrinoid analogue, octaphyrin(2,1,1,1,2,1,1,1), containing two rigid diphenylacetylene moieties is reported. In contrast to traditional pyrrolic macrocycles where flexible conformers coexist in dynamic equilibrium, this macrocycle exists as two separable, conformationally stable stereoisomers, denoted as 1A and 1B. The conformational effect of both conformers, as well as their protonated forms, were thoroughly studied using NMR spectroscopy, UV-Vis, and single crystal X-ray diffraction analyses. Importantly, heating conformer 1B leads to its irreversible conversion to 1A, whereas in its protonated form, 1A·2MSA undergoes irreversible transformation to 1B·2MSA at lower temperatures. These temperature-dependent features establish a foundation for developing new accumulated heat sensors, as demonstrated by the use of the present octaphyrins as a customized thermochromic indicator in steam sterilization. The present study thus underscores how the conformational rigidity of these new polypyrrolic macrocycles imparts properties that are distinct from historically flexible expanded porphyrinoids.

Effect of repeated steam sterilizations on insertional torque, torque to failure, and axial pullout strength of 3.5-mm and 2.0-mm cortical bone screws.

The objective of this study was to determine the effects of repeated steam sterilization cycles on the biomechanical properties of surgical screws. 42 3.5-mm and 42 2.0-mm self-tapping, cortical screws were divided into 3 groups per size and underwent autoclave sterilization for 1 (G1), 50 (G50), or 100 (G100) cycles and testing from August 2018 through June 2021. Sixty screws were then inserted into canine cadaver femurs, and biomechanical properties were measured, including peak insertional torque, torque to failure, and pullout strength, each normalized to cortical thickness. Scanning electron micrographs were taken from 24 screws, and images were blindly analyzed by 5 trained examiners. The mean normalized insertion torque for 3.5-mm screws was significantly different between G1 and both G50 and G100. The mean normalized torque to failure for 3.5-mm screws was significantly different between G1 and both G50 and G100. Axial pullout testing was found to be significantly different for 2.0-mm screws between G1 and G100. Scanning electron micrographs surface scoring identified a significant difference in 3.5-mm screws at the screw tip. The results indicate that biomechanical changes occur with repeated steam sterilizations. Specifically, peak insertional torque and torque to failure are decreased with increased sterilizations for 3.5-mm screws, whereas 2.0-mm screws were altered in pullout testing after 100 sterilizations. It is suspected that numerous sterilizations negatively alter the physical-mechanical properties of certain screw sizes. The biomechanical properties of the bone-implant interface could negatively be affected by multiple steam sterilizations during clinical setting.

Effect of Sterilization Methods on Chemical and Physical-Mechanical Properties of Cotton Compresses.

The aim of this work was to determine the changes in the chemical and physical-mechanical properties of gauze compresses under the influence of various sterilizations. Gauze compresses are made of cotton; therefore, all methods used focused on cotton. The methods used to test possible damage to cotton materials (pH value (pH paper, KI starch paper), yellowing test, Fehling reaction, reaction to the formation of Turnbull blue (Berlin blue), microscopic staining with methylene blue and swelling reaction with Na-zincate) did not show that the sterilizations affected the cotton compresses. The morphological characteristics were examined with a scanning electron microscope (SEM). The SEM images showed that there were no morphological changes in the cotton fibers. FTIR-ATR spectroscopy revealed that the sterilization processes did not alter the characteristic bands of the cotton. The length of the macromolecules was increased (DP), showing that the sterilization processes had affected the cotton. The results of the wet strength test followed. The samples showed values below 100%, with the exception of two samples. It is known from theory that the relative wet strength is less than 100% when the material is damaged. The t-test performed on the strength results showed that the p-value was greater than 0.05 for all samples tested, with the exception of one sample. The degree of swelling capacity was determined, with non-sterilized samples having the highest capacity, followed by samples sterilized with ethylene oxide and then samples sterilized by steam sterilization. The results obtained are a contribution to the innovation of the topic of this work and a scientific confirmation for manufacturers and anyone interested in the influence of the sterilization process on natural fibers (cotton).

Self-tuning control of steam sterilizer temperature based on fuzzy PID and IPSO algorithm

Self-tuning control of steam sterilizer temperature based on fuzzy PID and IPSO algorithm

Salmonella Prevalence in Raw Cocoa Beans and a Microbiological Risk Assessment to Evaluate the Impact of Cocoa Liquor Processing on the Reduction of Salmonella

Salmonella in raw cocoa beans (n = 870) from main sourcing areas over nine months was analyzed. It was detected in 71 (ca. 8.2%) samples, with a contamination level of 0.3–46 MPN/g except for one sample (4.1 × 104 CFU/g). Using prevalence and concentration data as input, the impact of thermal treatment in cocoa processing on the risk estimate of acquiring salmonellosis by a random Belgian chocolate consumer was calculated by a quantitative microbiological risk assessment (QMRA) approach. A modular process risk model from raw cocoa beans to cocoa liquor up to a hypothetical final product (70–90% dark chocolate tablet) was set up to understand changes in Salmonella concentrations following the production process. Different thermal treatments during bean or nib steam, nib roasting, or liquor sterilization (achieving a 0–6 log reduction of Salmonella) were simulated. Based on the generic FAO/WHO Salmonella dose–response model and the chocolate consumption data in Belgium, salmonellosis risk per serving and cases per year at population level were estimated. When a 5 log reduction of Salmonella was achieved, the estimated mean risk per serving was 3.35 × 10−8 (95% CI: 3.27 × 10−10–1.59 × 10−7), and estimated salmonellosis cases per year (11.7 million population) was 88 (95% CI: <1–418). The estimated mean risk per serving was 3.35 × 10−9 (95% CI: 3.27 × 10−11–1.59 × 10−8), and the estimated salmonellosis cases per year was 9 (95% CI: <1–42), for a 6 log reduction. The current QMRA model solely considered Salmonella reduction in a single-step thermal treatment in the cocoa process. Inactivation obtained during other process steps (e.g. grinding) might occur but was not considered. As the purpose was to use QMRA as a tool to evaluate the log reduction in the cocoa processing, no postcontamination from the processing environment and ingredients was included. A minimum of 5 log reduction of Salmonella in the single-step thermal treatment of cocoa process was considered to be adequate.

Energy, economic, and environmental analysis of a novel combined cooling, heating, and power (CCHP) from infectious medical waste

The outbreak of coronavirus disease 2019 (COVID-19) has led to an increase in infectious medical waste (IMW). Waste-to-energy (WtE) technologies are considered to manage IMW in the context of the COVID-19 situation and to reduce illegal dumping and landfill problems. This study focuses on managing IMW by using WtE technology. Energy, economic, and environmental (3E) impacts are considered as a single implication value of WtE technology. Combined cooling, heating, and power (CCHP) is a novel system for generating energy from a treated IMW by using a steam sterilization system. The moisture from sterilization waste is extracted by a drying process to create refuse-derived fuel type 3 (RDF-3). An RDF-3 of 81.98 kg/h at a low heating value of 26.29 MJ/kg is used for a combustion–incineration process of 236.56 kW. A net power from an organic Rankine cycle of 15.80 kWe, an absorption cooling capacity of 4.62 kW, and a drying room unit of 13.21 kW are found from the combined CCHP system. The energy index is calculated at an overall energy efficiency of approximately 13.40 %. The energy–environmental impact is summarized by a single score of 5.63E-04 Pt. The energy–economic impact is summarized by a levelized energy cost of 0.35 USD/kWh. The economic-environmental perspective is an energy costing per life cycle assessment of 0.73 USD/kg emission-eq. The 3E analysis reveals a single indicator of 1.95E-04 USD·Pt/kWh2, which is used in the decision to compare with other energy systems. The CCHP system shows advantages in terms of sustainability, quality, and efficiency. Consequently, a novel in this study promotes the sustainability of energy, avoiding environmental impact, and IMW management.

Immediate Use Steam Sterilization and the Effect on Surgical Site Infections in an Acute Care Facility

Background: Immediate use steam sterilization (IUSS) shortens the time from sterilization to the aseptic transfer onto the surgical sterile field. Published data incompletely defines the extent to which IUSS increases risk of surgical site infection (SSI), compared to standard sterile reprocessing methods. We aimed to measure the association between IUSS use for surgical instrument reprocessing and SSI risk in a facility where IUSS use increased due to staffing constraints and case volumes. Methods: In this retrospective observational study at a tertiary care hospital with a diverse mix of surgery types, we used sterile reprocessing logs and SSI outcomes defined using National Health and Safety Network definitions to compare SSI rates among surgeries using surgical devices sterilized using IUSS compared to standard terminal sterilization methods. We calculated a risk ratio (RR) and 95% confidence interval (95%CI), including stratification by eleven high-volume service lines. Results: Among 23,919 surgical procedures, 416 (1.74%) developed SSIs. IUSS was used to sterilize instruments prior to 1,524 (6.37%) surgical procedures, and of these procedures 39 (2.56%) developed an SSI, compared to 1.68% of non-IUSS procedures (377 SSI in 22,395 procedures; risk ratio [RR] 1.52, 95% confidence interval [95%CI] 1.10-2.11). Two surgical services had statistically significant RRs for SSI development after IUSS: transplant surgery (RR 2.47, 95%CI 1.32-4.60] and plastic surgery (RR 3.64, 95%CI 1.13-11.74; Figure). Conclusion: IUSS is associated with a significant increase in SSIs, including among varied surgery types. IUSS utilization should be minimized.

Reduction in IUSS (Immediate Use Steam Sterilization) Associated with Reduction in Surgical Site Infections

Background: Immediate use steam sterilization (IUSS) is a potential risk factor for surgical site infection (SSI). During a regulatory survey, it was discovered that IUSS rates for a 767-bed hospital exceeded what had been reported to Infection Prevention (IP) and surgery leaders (estimated at an average of 60 instances per month, with approximately 40 of those in orthopedic cases). A Quality Improvement (QI) project to reduce IUSS was implemented. Methods: The QI project started with the requirement of three signatures for every cycle of IUSS (surgery management, sterilization management, and IP). Additional trays were ordered to provide an ample supply for cases. Surgery personnel were no longer allowed to perform IUSS, and the number of sterilizers available for IUSS was reduced from 8 to 1. The project was fully implemented as of December 2019. To evaluate the impact, SSI rates for hip and knee prothesis were compared using chi square analysis (Epi Info, CDC); before QI project rates were measured from 2017-2019 and after QI project rates were measured for 2020-2022. No other changes were made that were anticipated to impact orthopedic SSI rates. Results: There were no instruments or implants processed by IUSS after December 2019. Prior to the project, there were 9 hip SSI (rate = 0.54 per 100 procedures) and 14 knee SSI (rate = 0.49 per 100 procedures). After the project, hip SSI decreased by 76% (2 SSI, rate = 0.13 per 100 procedures, p = &lt; 0 .05) and knee SSI decreased by 18% (7 SSI, rate = 0.41 per 100 procedures, p=0.67). Conclusion: A multidisciplinary QI project was successful at drastically reducing the use of IUSS, and a correlating statistically significant decrease in hip SSI and clinically significant decrease in knee SSI was seen for 3 years after the project was completed.Disclosure: Kathleen McMullen: Speaker - 3M

Comparing the impact of various sterilization methods on the cyclic fatigue resistance, bending strength, and torsional fatigue properties of NiTi rotary files

This study aimed to evaluate the influence of various sterilization techniques on the cyclic fatigue resistance, bending strength, and torsional fatigue resistance of Tornado Blue and Race Evo rotary endodontic file systems. Both the file systems underwent a series of 15 cycles of sterilization according to the following study groups: control group (G1; i.e., without treatment), chemical sterilization with 5.25% sodium hypochlorite (G2), dry heat sterilization (G3), glass beads sterilization (G4), and steam autoclaving (G5). Each group consisted of 8 samples (n = 8/group). Statistical analysis was performed using a two-way ANOVA and Tukey’s tests (p ≤ 0.05). Mean values for the number of cycles between both files were 1291 ± 52.79 rpm and 2095 ± 52.91 rpm for Tornado Blue and Race Evo, respectively. The torsional fatigue resistance was 8.00 ± 0.85 NCF and 10.70 ± 0.85 NCF and the bending strength was 486.94 ± 20.97 gf and 564.17 ± 20.97 gf for Tornado Blue and Race Evo, respectively. The results showed no significant difference in the mechanical properties followed by different sterilization protocols. However, a significant difference was observed in tested properties between the two file systems (p ≤ 0.05). The outcome is reassuring for clinicians that the essential process of routine sterilization at clinics seems safe with regards to mechanical integrity of the endodontic files.