Sterilization Of Surgical Instruments Research Articles

Opening Sterile Surgical Packs

Welcome to our Basic Skills for the OR Series! Complete series includes: Scalpels Surgical Sutures Surgical Staplers Opening Sterile Surgical Packs Opening Sterile Surgical Instrument Containers Laparoscopic Instruments

Situation analysis of the quality of primary health care services in Pakistan.

Primary health care services to promote the mental and physical health of communities include preventive, promotive, curative, general hygiene, and nutritional elements. To assess the quality of service delivery at primary healthcare settings in Punjab, Pakistan. Quantitative surveys were conducted at 106 health facilities: 92 basic health units (BHUs) and 14 rural health centres (RHCs) across Punjab in 2020. Data from the survey were supplemented with information from observations by the researchers and all data were analysed using SPSS version 25. All the 7 district health authorities surveyed had monthly targets for number of normal deliveries and the outpatient department. Systems for safe transportation and storage of medicines were deficient except in 2 districts. Anti-venom and anti-rabies vaccines were either limited or not available at most of the health units visited. Some 14% of clinical equipment examined at the BHUs and RHCs were non-functional, and no BHU had ultrasonic machines to improve the quality of antenatal care. Sterilization of surgical instruments was unsatisfactory at most health units. Several key positions at BHU and RHC were vacant. Most health units did not have fence and their main buildings were in poor condition. Several gaps were identified at the primary healthcare level in Punjab that need to be addressed to improve the quality of service delivery.

Smart Sterilization Container Technology: Blue Wrap Innovation

Steam sterilization is the basis of modern surgical instrument sterilization. It is a highly effective, safe, cost-effective heat transfer method that is closely monitored and regulated. The autoclave time is typically 1 hour for sterilization and requires direct steam contact with surgical tray contents. A porous barrier, typically blue polypropylene wrap or filter, is required around or on the walls of the sterilized tray to allow steam to enter and escape. This barrier can require up to 2 hours of cooling without touching after autoclave sterilization to prevent moisture condensation and bacterial wicking. The porous barrier is fragile and can tear or develop holes which can lead to OR challenges. It is also moisture sensitive and may be an underappreciated source of surgical site infections. Porous barrier technologies create inherent inefficiencies in sterile processing and OR turnover. Electronic container technology may possibly forego the porous barrier limitations and inefficiencies by capturing a sterile vacuum seal in the autoclave. A verifiable vacuum sealed container may eliminate limited handling while cooling and may increase sterile department efficiency and reduce operating room turnover. If the technology is reliable and consistent, it may offer a safer and more durable, transportable, monitorable, sustainable sterile processing alternative than current porous barrier technologies.

Evaluation of the Impact of Refined Quality Control Management Model on the Qualified Rate of Disinfection and Sterilization of Surgical Instruments in the Sterilization Supply Center

Objective: To evaluate the application value of a refined quality control management model for a sterilization supply center. Methods: A retrospective analysis was conducted on the work situation of the sterilization supply center from January 2021 to January 2023. The work situation before January 31, 2022, was classified as the control group; a routine quality control management model was implemented, and the work situation after January 31, 2022, was classified as the observation group. The quality of medical device management and department satisfaction between the two groups were compared. Results: The timely recovery and supply rate, classification and cleaning pass rate, disinfection pass rate, packaging pass rate, sterilization pass rate, and department satisfaction score in the observation group were all higher than those of the control group (P < 0.05). Conclusion: Implementing a refined quality control management model in the sterilization supply center can improve the quality management level of medical devices and department satisfaction and is worthy of promotion.

A robust LP-based approach for a dynamic surgical case scheduling problem with sterilisation constraints

The purpose of this article is to investigate a practical scheduling problem in which a group of elective surgical cases are scheduled over time, while considering their unpredictable durations and potential delays in the sterilisation of surgical instruments. The primary objectives were to schedule the maximum number of surgeries and decrease overtime for the surgical staff, as well as limit the number of instruments requiring emergency sterilisation. The study was conducted in collaboration with the University Hospital of Angers in France, which also contributed historical data for the experiments. We propose two robust mixed integer linear programming models, which are then solved iteratively through a rolling horizon approach, in which the objective functions are taken into account in lexicographic order. Experiments on randomly generated instances indicated which of the two approaches had better performance. Comparison of the results for a real-world scenario involving actual planning at the hospital indicated a greater than 69% decrease in overtime, and a minimum of 92% fewer stressful situations in the sterilising unit.

The Surgical Instrument Sterilization Process: What Every Surgeon Should Know.

» The phases of the sterilization process for surgical equipment are cleaning, disinfection, and sterilization.» Following manufacturer and regulatory guidelines will minimize contamination throughout the sterilization process.» Immediate use steam sterilization, when used appropriately, is a reasonably safe option to be used at the discretion of the operating surgeon.

Instrument Sterilization and Surgical Site Infections in Low and Middle Income Countries

With the recent surge in oftentimes fatal bacterial resistance, surgical site infections (SSI) are now a prominent topic of scholarly discussion. These infections occur due to unsterile surgical practices infiltrating the operating room, and deadly pathogens with it. The developed world has lowered rates of SSI through scrupulous enforcement of CDC sterilization guidelines while low and middle income countries (LMICs) continue to fall victim to inefficient sterilization. LMICs often don't have the resources to reach these CDC guidelines and as a result endure surgical instrument contamination. Currently, there is a gap in funding and research related to the state of surgical instrument sterilization. This study aims to reveal first hand data regarding the gap in adherence to CDC sterilization guidelines for a variety of LMICs. Data was collected through virtual interviews with surgeons or surgical technologists globally. Interview responses were later scored for adherence to the CDC guidelines and correlated with rates of SSI per country. Results showed that the adequacy of surgical instrument sterilization processes (SP) in hospitals is directly correlated to SSI rates in LMICs. A one tailed test with a flow of SP adherence to SSI prevalence rendered the following strong correlation of R squared=0.772. This relationship demonstrates that investments to improve surgical sterilization processing will likely render lower rates of SSI. Lower SSI rates in LMICs could give rise to an increase in surgical tourism, a decrease in expensive treatments for highly resistant bacteria, and ultimately a decrease in surgical morbidity and mortality.

Six Sigma can significantly reduce costs of poor quality of the surgical instruments sterilization process and improve surgeon and operating room personnel satisfaction

Operating room (OR) management is a complex multidimensional activity combining clinical and managerial aspects. This longitudinal observational study aimed to assess the impact of Six-Sigma methodology to optimize surgical instrument sterilization processes. The project was conducted at the operating theatre of our tertiary regional hospital during the period from July 2021 to December 2022. The project was based on the surgical instrument supply chain analysis. We applied the Six Sigma lean methodology by conducting workshops and practical exercises and by improving the surgical instrument process chain, as well as checking stakeholders’ satisfaction. The primary outcome was the analysis of Sigma improvement. Through this supply chain passed 314,552 instruments in 2022 and 22 OR processes were regularly assessed. The initial Sigma value was 4.79 ± 1.02σ, and the final one was 5.04 ± 0.85σ (SMD 0.60, 95%CI 0.16–1.04, p = 0.010). The observed improvement was estimated in approximately $19,729 of cost savings. Regarding personnel satisfaction, 150 questionnaires were answered, and the overall score improved from 6.6 ± 2.2 pts to 7.0 ± 1.9 pts (p = 0.013). In our experience the application of the Lean Six Sigma methodology to the process of handling the surgical instruments from/to the OR was cost-effective, significantly decreased the costs of poor quality and increased internal stakeholder satisfaction.

Effect of far-infrared radiation on inhibition of colonies on packaging during storage of sterilised surgical instruments

The sterilisation of surgical instruments is a major factor in infection control in the operating room (OR). All items used in the OR must be sterile for patient safety. Therefore, the present study evaluated the effect of far-infrared radiation (FIR) on the inhibition of colonies on packaging surface during the long-term storage of sterilised surgical instruments. From September 2021 to July 2022, 68.2% of 85 packages without FIR treatment showed microbial growth after incubation at 35 °C for 30 days and at room temperature for 5 days. A total of 34 bacterial species were identified, with the number of colonies increasing over time. In total, 130 colony-forming units were observed. The main microorganisms detected were Staphylococcus spp. (35%) and Bacillus spp. (21%) , Kocuria marina and Lactobacillus spp. (14%), and mould (5%). No colonies were found in 72 packages treated with FIR in the OR. Even after sterilisation, microbial growth can occur due to movement of the packages by staff, sweeping of floors, lack of high-efficiency particulate air filtration, high humidity, and inadequate hand hygiene. Thus, safe and simple far-infrared devices that allow continuous disinfection for storage spaces, as well as temperature and humidity control, help to reduce microorganisms in the OR.

SG-APSIC1206: Effectiveness of sterilization practice in reprocessing medical devices among different multidisciplinary tertiary-care hospitals in Dhaka City

Objectives: Sterilization failure is one of the main causes of surgical-site infections. We assessed the effectiveness of the sterilization process of surgical instruments to determine the reasons for sterilization failure. Methods: In total, 100 sterilization cycles were observed from February 4, 2022, to September 5, 2022, in hospitals in Dhaka City. We used sterilization quality assurance monitoring tools (ie, biological indicators) for rapid steam and ethylene oxide sterilization methods. Tests were performed using an automatic reading machine, chemical indicator strips, and indicator tape for both steam and ethylene oxide methods. For laboratory testing and data collection, APSIC guidelines were followed. All samples were incubated for 48 hours to cross check the accuracy of the auto-reader result. Results: All ethylene oxide sterilization cycles were 100% successful, as shown by the rapid biological indicator (auto-reader), chemical indicator strips, and indicator tape. However, 22% sterilization failure occurred with steam sterilization, which was confirmed by the auto-reader, chemical indicator strips, and indicator tape. All biological samples showed no growth after 48 hours of incubation, except the sample from steam sterilization, which did show growth after 48 hours of incubation. Conclusions: We detected 22% steam sterilization failure, and serious harm to patients could occur if these surgical instruments were used for surgery. Process recall would not have been not possible if rapid biological indicator tests had not been performed and other chemical monitoring tools had not been used. The regular use of monitoring tools according to guidelines can be a reliable solution to reduce surgical site infections caused by inappropriate sterilization of surgical instruments.

Physical mechanism of aluminum contamination presented in H2O2 plasma sterilization

In this paper, it is first demonstrated that Aluminum (Al) contamination is present; H2O2 plasma sterilization is widely used for sterilization of surgical instruments. The contamination amount of Al can reach as high as 7.9 × 1012 atoms/cm2. Aluminum is well known as a harmful element to human health, which may damage bones and the brain. During the use of the surgical instruments after H2O2 plasma sterilization in surgery, the contaminated Al may enter and reside in the human body and threaten the health and even life safety. Therefore, it is necessary to study the Al contamination present in H2O2 plasma sterilization to arouse public attention and take countermeasures. The physical mechanism of the Al contamination presented in H2O2 plasma sterilization is diffusion. In our previous study, we developed two physical models for calculating the diffusion coefficient. In this study, both models are used to calculate the diffusion coefficient of the contaminated Al in sterilized Si samples. From the calculation results, it is inferred that the contamination mechanism of Al presented in H2O2 plasma sterilization is closer to the model, where the diffusion coefficient value is a function of the plasma treatment time.

The safety of a novel single-drape cover for sterile back tables in the operating room compared to the standard two-drape method: an experimental study

BackgroundCovering the prepared sterile back tables (PSBTs) during periods of nonuse and during active surgeries may decrease contamination of sterile surgical instruments that have direct contact to surgical wound. The Association of periOperative Registered Nurses (AORN) declared that an easy method for covering and removing the drape will ultimately be most effective (e.g. standard two-drape method). Hence, this study was designed to test the hypothesis that using a novel single-drape cover had more efficiency and safety in decreasing airborne bacteria-carrying particles (ABCPs) settling on the PSBTs during static and dynamic periods than the standard two-drape method.MethodsThis experimental study was conducted with using 918 agar plates to detect contamination of the PSBTs with ABCPs on two conditions (static and dynamic) at an academic medical center in Kashan, Iran, from September 25, 2021, to January 20, 2022. The contamination of PSBTs was evaluated by 6 agar settle plates (n = 918 in total) on each PSBT in static and dynamic operating room (OR) conditions. At each time-point, this set-up was repeated on two occasions else during data collection, establishing 81 PSBTs in total. Tested groups included the PSBTs covered with the standard two-drape method, the novel single-drape cover, or no cover. The plates were collected after 15, 30, 45, 60, 120, 180, 240 min and 24 h. The primary outcome measured was comparison of mean bioburden of ABCPs settling on covered PSBTs on two conditions by using agar settle plates. The secondary outcomes measured were to determine the role of covering in decreasing contamination of PSBTs and the estimation of time-dependent surgical instrument contamination in the uncovered PSBTs on two conditions by using agar settle plates.ResultsCovering the PSBTs during static and dynamic OR conditions lead to a significantly decreased bioburden of ABCPs on them (P < 0.05). No differences were seen between the standard two-drape method and the novel single-drape cover (P > 0.05).ConclusionsWe found that there is no preference for using the novel single-drape cover than the standard two-drape method. Our results showed a significant decrease in bioburden of ABCPs on the PSBTs when those were covered during static and dynamic OR conditions, indicating the efficiency for covering the PSBTs during periods of nonuse and during active surgery.

Effectiveness of the Glass Bead Sterilizer for Sterilizing Surgical Instruments.

Survival rodent surgery requires the use of sterile instruments for each animal, which can be challenging when performing multiple surgeries on batches of animals. Glass bead sterilizers (GBS) are widely considered to facilitate this practice by sterilizing the tips of the instruments between animals. However, other disciplines have raised questions about the efficacy of the GBS, especially when used with surgical tools that have grooves or ridges that may contain organic debris. In this study, we evaluated the efficacy of the GBS to sterilize instruments commonly used in rodent surgery by intentionally contaminating a selection of instruments with a standardized bacterial broth inoculated with Staphylococcus aureus and Escherichia coli. As expected, a simple ethanol wipe was ineffective in sterilizing instruments in all treatment groups. An ethanol wipe followed by GBS was effective in sterilizing 82.5% (99 of 120) of the instruments. Our study suggests that the GBS may not be effective for consistent sterilization of surgical instruments.

Effect of Nursing in Operating Room Combined with Intraoperative Heat Preservation Intervention on Prevention of Incision Infection and Improvement of Hemodynamics in Patients with Anterior Cruciate Ligament Injury and Reconstruction under Knee Arthroscopy.

Objective To explore the effect of nursing in operating room combined with intraoperative heat preservation intervention on preventing incision infection and improving hemodynamics in patients with anterior cruciate ligament (ACL) injury and reconstruction under knee arthroscopy. Methods About 200 patients with knee arthroscopic ACL reconstruction in our hospital from January 2019 to July 2021 were enrolled. The patients were randomly assigned into two groups: the control group and the study group. The former group received nursing care in the operating room operating room and the latter group received nursing care in operating room combined with intraoperative heat preservation intervention. Nursing satisfaction, incidence of incision infection, knee joint VAS score, knee joint range of motion, knee joint Lysholm score, and hemodynamic indexes were compared. Results First of all, we compared the nursing satisfaction, the study group was very satisfied in 78 cases, satisfactory in 20 cases, and general in 2 cases, and the satisfaction rate was 100.00%, while in the control group, 445 cases were very satisfied, 20 cases were satisfied, 15 cases were general, and 8 cases were dissatisfied. The satisfaction rate was 82.00%. The nursing satisfaction of the study group was higher compared to the control group (P < 0.05). Secondly, we compared the incidence of incision infection. The incidence of incision infection in the study group was lower compared to the control group (P < 0.05). With regard to the knee joint VAS score, the knee joint VAS score of the study group was lower compared to the control group at 2 weeks, 4 weeks, 8 weeks, and 12 weeks after operation (P < 0.05). In terms of the range of motion of the knee joint, the range of motion of the knee joint in the study group was higher compared to the control group at 2 weeks, 4 weeks, 8 weeks, and 12 weeks after operation (P < 0.05). Regarding the knee joint Lysholm score, the knee joint Lysholm score of the study group was higher compared to the control group at 2 weeks, 4 weeks, 8 weeks, and 12 weeks after operation (P < 0.05). Finally, we compared the hemodynamic indexes. Before nursing, there exhibited no significant difference (P > 0.05). During and after nursing, the indexes of HR and MAP in the study group fluctuated little (P < 0.05). Conclusion During the perioperative period of patients with ACL injury and reconstruction under knee arthroscopy, standardized and necessary operating room combined with intraoperative thermal insulation intervention measures should be given, attention should be paid to the management of operating room, and intraoperative thermal insulation intervention should be strengthened. It includes preoperative visit, psychological nursing of patients, strict application of antibiotics before operation, monitoring of air quality in operating room, disinfection and sterilization of surgical instruments, shortening operation time, maintaining body temperature during operation, and paying attention to hand hygiene of medical staff. It plays a supervisory role in promoting the attention of medical staff to the prevention of wound infection, which is beneficial to the healing of surgical wounds of patients. It plays a positive role in enhancing hemodynamic indexes. Comprehensive nursing intervention on the risk factors of each link can effectively prevent postoperative wound infection and strengthen the prognosis and quality of life of patients.

Clean and Confident: Impact of Sterile Instrument Processing Workshops on Knowledge and Confidence in Five Low- and Middle-Income Countries.

Background: Proper sterilization of surgical instruments is essential for safe surgery, yet re-processing methods in low-resource settings can fall short of standards. Training of Trainers (TOT) workshops in Ethiopia and El Salvador instructed participants in sterile processing concepts and prepared participants to teach others. This study examines participants' knowledge and confidence post-TOT workshop, and moreover discusses subsequent non-TOT workshops and observed sterile processing practices. Methods: Five TOT workshops were conducted between 2018 and 2020 in Ethiopia and Central America. Participant trainers then led nine non-TOT workshops in El Salvador, Guatemala, Honduras, and Nicaragua. Interactive sessions covered instrument cleaning, packaging, disinfection, sterilization, and transportation. Participants completed pre- and post-tests, demonstrated skill competencies, and shared feedback. Peri-operative sterile processing metrics were also observed in Ethiopian hospitals pre- and post-workshops. Results: Ninety-five trainees participated in TOT workshops, whereas 169 participated in non-TOT workshops. Knowledge on a 10-point scale increased substantially after all training sessions (+2.3 ± 2.8, +2.9 ± 1.7, and 2.7 ± 2.5 after Ethiopian, Central American, and non-TOT workshops, respectively; all p < 0.05). Scores on tests of sterile processing theory also increased (Ethiopian TOT, +68% ± 92%; Central American TOT, +26% ± 20%; p < 0.01). Most respondents felt "very confident" about teaching (Ethiopian TOT, 72%; Central American TOT, 83%; non-TOT, 70%), whereas fewer participants felt "very confident" enacting change (Ethiopian TOT, 36%; Central American TOT, 58%; non-TOT, 38%). Reasons included resource scarcity and inadequate support. Nonetheless, observed instrument compliance improved after Ethiopian TOT workshops (odds ratio [OR], 1.47; 95% confidence interval [CI], 1.21-1.78; p < 0.01). Conclusions: Sterile processing workshops can improve knowledge, confidence, and sterility compliance in selected low- and middle-income countries. Training of Trainers models empower participants to adapt programs locally, enhancing sterile processing knowledge in different communities. However, national guidelines, physical and administrative resources, and long-term follow-up must improve to ensure effective sterile processing.

Reducing the Environmental Impact of Sterilization Packaging for Surgical Instruments in the Operating Room: A Comparative Life Cycle Assessment of Disposable versus Reusable Systems

The widespread use of single-use polypropylene packaging for sterilization of surgical instruments (blue wrap) results in enormous environmental pollution and plastic waste, estimated at 115 million kilograms on a yearly basis in the United States alone. Rigid sterilization containers (RSCs) are a well-known alternative in terms of quality and price. This paper deals with two research questions investigating the following aspects: (A) the environmental advantage of RCS for high volumes (5000 use cycles) in big hospitals, and (B) the environmental break-even point of use-cycles for small hospitals. An in-depth life cycle assessment was used to benchmark the two systems. As such a benchmark is influenced by the indicator system, three indicator systems were applied: (a) carbon footprint, (b) ReCiPe, and (c) eco-costs. The results are as follows: (1) the analyzed RSC has 85% less environmental impact in carbon footprint, 52% in ReCiPe, and 84.5% in eco-costs; and (2) an ecological advantage already occurs after 98, 228, and 67 out of 5000 use cycles, respectively. Given these two alternative packaging systems with comparable costs and quality, our results show that there are potentially large environmental gains to be made when RSC is preferred to blue wrap as a packaging system for sterile surgical instruments on a global scale.

Application of Rapid Biological Indicators Coupled With Auto-Reader for the Quality Assurance of Surgical Instruments After Sterilization at a Cardiac Hospital in Bangladesh.

BackgroundSterilization failure is one of the main reasons for surgical site infections (SSIs). The biological indicator (BI) test is the most reliable test to check sterilization efficiencies. But 48 hours BI test result makes the monitoring process time-consuming. Rapid BI testing can be time demanding in this regard. Therefore, the objective is to determine the importance of rapid BI monitoring for the quality assurance of sterile surgical instruments.MethodsThis study was conducted in the Labaid Cardiac Hospital, Bangladesh from April 1, 2021, to July 8, 2021. A total of 100 steam and 100 ethylene oxide (EO) rapid BIs and an auto reader incubator were used to conduct this research. Quick BI of steam and EO were used once per day and tested by the auto reader. Later, all the tested BIs were incubated for 48 hours by a conventional incubator to confirm the auto reader's rapid BI test results.ResultAll the EO BI results were found negative, but the BI was found positive twice in steam sterilization. Surgical items of those two loads were re-sterilized. Again, after checking the BI result, the items were released. All BIs except positive steam rapid BIs were found with no growth after 48 hours of incubation for cross-checking of auto reader results. In positive rapid BI of steam, growth was found after 48 hours of incubation.ConclusionWhen sterilization failure occurred, process recall could not be possible at that time if rapid BI tests were not performed. So, integration of a rapid BI test with an auto reader can save the patient from critical SSI.

Advancing Plasmon-Induced Selectivity in Chemical Transformations with Optically Coupled Transmission Electron Microscopy

Nanoparticle photocatalysts are essential to processes ranging from chemical production and water purification to air filtration and surgical instrument sterilization. Photochemical reactions are generally mediated by the illumination of metallic and/or semiconducting nanomaterials, which provide the necessary optical absorption, electronic band structure, and surface faceting to drive molecular reactions. However, with reaction efficiency and selectivity dictated by atomic and molecular interactions, imaging and controlling photochemistry at the atomic scale are necessary to both understand reaction mechanisms and to improve nanomaterials for next-generation catalysts. Here, we describe how advances in plasmonics, combined with advances in electron microscopy, particularly optically coupled transmission electron microscopy (OTEM), can be used to image and control light-induced chemical transformations at the nanoscale. We focus on our group's research investigating the interaction between hydrogen gas and Pd nanoparticles, which presents an important model system for understanding both hydrogenation catalysis and hydrogen storage. The studies described in this Account primarily rely on an environmental transmission electron microscope, a tool capable of circumventing traditional TEM's high-vacuum requirements, outfitted with optical sources and detectors to couple light into and out of the microscope. First, we describe the H2 loading kinetics of individual Pd nanoparticles. When confined to sizes of less than ∼100 nm, single-crystalline Pd nanoparticles exhibit coherent phase transformations between the hydrogen-poor α-phase and hydrogen-rich β-phase, as revealed through monitoring the bulk plasmon resonance with electron energy loss spectroscopy. Next, we describe how contrast imaging techniques, such as phase contrast STEM and displaced-aperture dark field, can be employed as real-time techniques to image phase transformations with 100 ms temporal resolution. Studies of multiply twinned Pd nanoparticles and high aspect ratio Pd nanorods demonstrate that internal strain and grain boundaries can lead to partial hydrogenation within individual nanoparticles. Finally, we describe how OTEM can be used to locally probe nanoparticle dynamics under optical excitation and in reactive chemical environments. Under illumination, multicomponent plasmonic photocatalysts consisting of a gold nanoparticle "antenna" and a Pd "reactor" show clear α-phase nucleation in regions close to electromagnetic "hot spots" when near plasmonic antennas. Importantly, these hot spots need not correspond to the traditionally active, energetically preferred sites of catalytic nanoparticles. Nonthermal effects imparted by plasmonic nanoparticles, including electromagnetic field enhancement and plasmon-derived hot carriers, are crucial to explaining the site selectivity observed in PdHx phase transformations under illumination. This Account demonstrates how light can contribute to selective chemical phenomena in plasmonic heterostructures, en route to sustainable, solar-driven chemical production.

Pediatric Extracorporeal Cardiopulmonary Resuscitation ELSO Guidelines.

Pediatric Extracorporeal Cardiopulmonary Resuscitation ELSO Guidelines.

Numerical prediction of the chemical indicator response used in steam sterilisers

Steam sterilisation is a commonly used method in the sterilisation of surgical instruments. To ensure the sterility of the sterilised goods an evaluation of the sterilisation process is required. This might be achieved either through physical measurements or indicators. Optimal sterilisation results are achieved by removing the air from the sterilisation chamber. In this paper a new computational fluid dynamics (CFD) based approach is presented, which allows to calculate the steam distribution within a sterilisation chamber with focusing on hollow loads. Additional measurements were performed using a self-developed measurement chamber to validate the CFD model. A modified process challenge device (PCD) with different tube lengths in combination with a chemical indicator (CI) was tested, to identify the volumetric influence of the lumen on the resulting air-steam mixture therein. A numerically efficient model was developed to determine a steam volume fraction threshold leading to a response of the CI. This study aims to predict the volumetric amount of steam which is necessary in order to pass a PCD test fitted with a CI. Both the CFD model and the measurements showed that often an insufficient steam penetration is indicated by PCDs which can lead to an insufficient sterilisation of hollow loads.