Protective Sleeve Research Articles

Safety and efficacy of leadless pacemaker extraction using a novel retrieval tool: a multicenter analysis

Abstract Background Leadless pacemakers (LP) have emerged as a safe and effective alternative for cardiac pacing, increasingly adopted by the medical community. While rare, complications such as pacemaker syndrome or device dislodgment can occur. In such instances, the extraction of the leadless pacemaker and its replacement with a new device should be considered. Purpose This multicenter study aimed to describe the use of the Aveir retrieval sheath during Micra extraction procedure and to assess the success rates and potential complications associated with the procedure. Methods In this observational study, we analyzed prospectively collected data from 14 patients that underwent leadless pacemaker using Abbott retrieval catheter at three high volume centers for pacemaker extraction and leadless implant in United States. Thought femoral vein the Aveir steerable retrieval catheter is advanced to the right atrium and then across the tricuspid valve. Under TEE and fluoroscopy guidance the snare is advanced over the Micra, and the button is secured. A protective sleeve is advanced over the LP. With application of traction to snare and countertraction with the sleeve against the endocardium, the LP is free from the myocardium and removed via the sheath. (Fig. 1) The procedural duration should be intended as the combined total of the time taken for the extraction of the existing pacemaker and the implantation time of the new device. Extractions performed during the first year were described as early and thereafter as late. Procedural success was described as complete extraction of LP without procedural complication. Results The reason for early explant was LP dislodgment and for late explant was pacemaker syndrome. Median time to extraction was 4±2 months in early explant and 35±9 months in late explant. Procedural time in early and late groups was 68.7 and 72.3 min respectively (P=0.32). Fluoroscopy time in early and late groups was 12.2 and 16.4 respectively (P= 0.18). LP was then replaced with a transvenous pacemaker. Success was 100% in both groups. No complication occurred in both groups. Conclusion Micra pacemaker using Aveir retrieval catheter is an effective tool irrespective of dwell time.

Using an Innovative Protective Sleeve to Reduce Skin Compression Complications in Axillary Osmidrosis Surgery.

Osmidrosis is a condition characterized by malodorous sweat production in the armpits that often necessitates surgical intervention with tie-over bandages in the axillary area. Standard tie-over bandages may cause skin compression-related complications, such as bruising and skin erosion. To address this issue, we developed a novel technique using a modified protective sleeve. We conducted an observational study involving 60 patients undergoing axillary osmidrosis surgery and divided them into groups. In the experimental group we used a novel technique that included using a modified protective sleeve secured with 4-0 silk sutures. In the control group we used standard tie-over bandages. We created the protective sleeve from the tail of a 3mL syringe by drilling holes on both sides and securing it onto a 10 mm-wide Penrose drain. We threaded sutures through the holes and provided padding between the sutures and the skin. We assessed primary outcomes of bruising and skin breakdown at eight anchoring sites. We found that using the novel protective sleeve significantly reduced skin complications. Compared with standard bandages, the incidence of bruising was reduced by 83.33% (i.e., 16.7% vs 70%). The incidence of skin erosion was reduced by 75% (10% vs 40%). Notably, the control group exhibited delayed complications, such as hypertrophic scars.

PLANTAR STRUCTURES IN RELATION TO A STRAIGHT RETROGRADE HIND FOOT (RHF) NAIL INSERTED THROUGH A MIDLINE HEEL PAD APPROACH: A CADAVERIC STUDY

BackgroundRHF nail is an important tool for simultaneous ankle and subtalar joint stabilisation +/− fusion. Straight and curved RHF nails are available to use, but both seem to endanger plantar structures, especially the lateral plantar artery and nerve and Baxter's nerve.There is a paucity of literature on the structures at risk with a straight RHF nail inserted along a line bisecting the heel pad and the second toe (after Stephenson et al). In this study, plantar structures ‘at risk’ were studied in relation to a straight nail inserted as above.MethodsRe-creating real-life conditions and strictly following the recommended surgical technique with regards to the incision and guide-wire placement, we inserted an Orthosolutions Oxbridge nail into the tibia across the ankle and subtalar joints in 6 cadaveric specimens. Tissue flaps were then raised to expose the heel plantar structures and studied their relation to the inserted nail.ResultsThe medial plantar artery and nerve were always more than 10mm away from the medial edge of the nail, while the Baxter nerve was a mean 14mm behind. The lateral plantar nerve was a mean 7mm medial to the nail, while the artery was a mean 2.3mm away with macroscopic injury in one specimen. The other structures ‘at risk’ were the plantar fascia and small foot muscles.ConclusionLateral plantar artery and nerve are the most vulnerable structures during straight RHF nailing. The risk to heel plantar structures could be mitigated by making incisions longer, blunt dissection down to bone, meticulous retraction of soft tissues and placement of the protection sleeve down to bone to prevent the entrapment of plantar structures during guide-wire placement, reaming and nail insertion.

Design and application of a new type of switchable semi-closed sputum suction device for transfer

Sputum suction is a necessary measure to remove respiratory secretions and collect sputum specimens, and the traditional sputum suction device includes open and closed methods. However, the open sputum suction device can easily cause sputum splashing during operation, polluting the operator and the surrounding environment. The closed sputum suction device is more expensive than the open sputum suction device. Although it can be used repeatedly, the friction between the protective sleeve and the wall of the suction tube increases after repeated uses, which in turn affects the operation. In addition, the two sputum suction methods need to be connected to a sputum collector when the sputum specimen is collected. This process can easily lead to leakage and contamination of specimens, and at the same time increase the infection risk for patients. In order to overcome the above problems, the medical staff from the department of critical care medicine of the First Affiliated Hospital of Dalian Medical University invented a new type of switchable semi-closed sputum suction device, and obtained the National Utility Model Patent of China (ZL 2020 2 1564712.3). The device is composed of a suction device connection port, a sliding negative pressure switch, an adapter interface, a pipe body, a transparent film protective sleeve, a clip-on connection joint, and a sputum collector. The sliding negative pressure switch at the connection port of the suction device can realize one-person one-handed operation. The sputum collector is connected with the sputum suction device to ensure that the specimen is not exposed. The transparent film protective sleeve covers the sputum suction tube body to ensure that the whole process of sputum suction operation is pollution-free. The clip-on connection joint is connected with the artificial airway interface to avoid sputum splashing during sputum suction, and it is clamped immediately after operation to reduce environmental pollution. Compared with the existing sputum suction device, the new switchable semi-closed sputum suction device has a more reasonable design and lower cost, which is worthy of clinical promotion.

Performance of a Shaft Protective Sleeve with an Elastic Damping Element

Performance of a Shaft Protective Sleeve with an Elastic Damping Element

Study of Wear Resistance of Cylindrical Parts by Electromechanical Surface Hardening

The work scientifically substantiates the use of an effective technology for increasing the wear resistance of cylindrical parts, using the example of protective sleeves of cantilever pumps, due to electromechanical surface hardening. A review of research was carried out and it was established that the achievement of the highest values of microhardness of the surface layer at a depth of up to 1.2 mm is possible during electromechanical processing of protective sleeves of cantilever pumps. The application of various modes and schemes of electromechanical surface hardening (EMSH) is accompanied by a change in structure and, as a result, an increase in the hardness of the surface layer of the bushings. The actual contact area of the tool roller with the processed surface and the depth of the temperature-deformation effect depend on the physical and mechanical properties of the materials and the pressing force. The formation of a temperature gradient in the hardened zone at a depth of up to 1.2 mm from the surface has been proven. Metallographic analysis of the surfaces of the sleeves treated by EMSH shows the formation of a white layer with reduced etchability and increased hardness in the hardening zones. The results of the X-ray structural analysis confirmed the formation of the martensite phase in the hardening zone. The microhardness of the hardened steel zone increased by 2.6...3.6 times compared to the initial values at a depth of up to 1 mm from the surface, depending on the materials. In the case of their overlap, the alternation of a fully hardened zone, a partially hardened zone, and a self-relief zone is observed. At the same time, the microhardness of steels along the surface depends on the hardening scheme.
 Wear tests under friction conditions of parts of cantilever pumps paired with stuffing boxes showed that the wear resistance of protective sleeves after EMSH increased by 3.1 times for 45 steel, 1.9 times for U8 steel, 2.5 times for SHKH15 steel, for cast iron by 1.9 times compared to the initial values. The use of U8 steel samples after EMSH, instead of serial bushings made of steel 45, allows to increase the wear resistance of parts by 6.1 times, which allows us to recommend U8 steel for use in the manufacture of protective bushings for console pumps. On the basis of the research, recommendations are given for the application of EMSH for the formation of a surface layer with increased wear resistance of protective sleeves during their production and during repair of console pumps in workshops or service centers of agribusiness companies.

Microbial Transfer by Intermittent Catheters: An In Vitro Evaluation of Microbial Transfer in Catheter With Variable Protective Features.

The purpose of this study was to evaluate the effects of various protective features (eg, catheter cap, introducer tip, and catheter sleeve) of hydrophilic intermittent catheters against contamination with urinary tract infection-associated microorganisms using an in vitro model. An in vitro study of microbial transfer. Gloves were contaminated with uropathogenic microorganisms and used to simulate intermittent catheterization of male anatomical models with and without the protective features present in 5 commercially available hydrophilic catheters. Using this contaminated touch transfer method, both the meatus of the sterile male anatomical models and sterile surgical gloves of an operator were inoculated with a high level of microorganisms (107 and 109 colony-forming units [CFU], respectively). The operator then performed catheterization of the anatomical model. The most relevant segments of the catheter were sampled, and the level of microbial transfer and catheter contamination was quantified. Results from experimental and sample replicates from the 3 microbial species and 5 catheters (sleeved and unsleeved) were analyzed by pair-wise t tests and analysis of variance. Of the 5 commercially available sleeved intermittent catheters evaluated in this study, use of catheters with multiple protective components (ring cap, introducer tip, and catheter sleeve) resulted in significant improvement in protection against contamination with a 25- to 2500-fold lower level of microbial contamination (C1 segment) across all species as compared to catheters protected with only sleeves or un-sleeved catheters. The combination of a ring cap, protective introducer tip, and protective sleeve provides additional protection when compared to sleeve alone from transferring microbial contamination from the meatus to the advancing catheter. Additional research is needed to determine whether these design features result in fewer urinary tract infections among intermittent catheter users.

The addition of a leaded arm sleeve to leaded aprons further decreases operator upper outer quadrant chest wall radiation dose during fluoroscopically guided interventions

ObjectiveBreast cancer most commonly occurs in the upper outer quadrant (UOQ) chest wall (CW). The effectiveness of routine leaded aprons to protect this region of the body in interventionalists during fluoroscopically guided interventions (FGIs) is unknown. Given the high lifetime attributable risks of prolonged occupational exposure to ionizing radiation and the increasing number of practicing female vascular surgeons and interventionalists, we sought to determine if the use of a leaded arm shield would offer additional protection to the lateral CW and axilla in operators compared with routine leaded aprons. MethodsEffectiveness of leaded sleeves in attenuating radiation dose to the axilla and UOQ was evaluated in clinical practice and simulated scenarios. In the clinical setting, optically stimulated luminescence nanoDot detectors were placed at the UOQ lateral CW position, both over and under a standard leaded apron vest with and without the addition of an antimony/bismuth Enviro-Lite sleeve on two vascular surgeons performing FGIs. In the simulation, nanoDots were similarly placed on an anthropomorphic phantom positioned to represent a primary operator performing right femoral access. Fluorography was performed on 12-inch-thick acrylic scatter phantom at 80 kVp for an exposure of 3 Gy reference air kerma. Experiments were done with and without the sleeve. Paired Wilcoxon and χ2 tests were performed to identify the statistical significance of radiation attenuation. ResultsOperator UOQ CW dose was measured during 61 FGIs: 33 cases (54%) with and 28 cases (46%) without the sleeve. Median procedure reference air kerma and fluoroscopy time was 180 mGy (interquartile range [IQR], 85-447 mGy) and 21 minutes (IQR, 11-39 minutes) when the sleeve was worn vs 100 mGy (IQR, 67-270 mGy) and 11 minutes (IQR, 6.3-25 minutes) without the sleeve. Radiation dose to the operator’s UOQ was reduced by 96% (IQR, 85%-96%) when the sleeve was present and by 62% (IQR, 44%-82%; P < .001) without the sleeve. In the simulated setting, the sleeve reduced the radiation dose to the UOQ compared with the apron alone (96% vs 67%; P < .001). ConclusionsRoutine leaded aprons do attenuate the majority of UOQ chest wall radiation dose; however, the addition of a lead-equivalent sleeve further significantly reduces this dose. Because this area of the body has a high incidence of cancer formation, additional protection, especially to female interventionalists, seems prudent. Vascular surgeons should consider using a protective sleeve with their personal protective equipment when performing complex fluoroscopically guided procedures.

Clinical application of a novel stent-assisted in situ intestinal bypass in preventing postoperative anastomotic leakage for low-mid rectal cancer: A retrospective study.

This study aimed to investigate the safety and feasibility of a novel stent-assisted in situ intestinal bypass for low-mid rectal cancer patients. Patients who were diagnosed with rectal cancer and received laparoscopic low anterior rectal resection plus a novel stent-assisted in situ intestinal bypass were respectively included from March 2022 to June 2022. Biofragmentable intestinal stent with a protective sleeve was placed in the proximal colon before anastomosis, and feces could be discharged through the protective sleeve without touching the anastomosis, which achieved an in situ bypass of feces. Perioperative characteristics and short-term outcomes were collected. Rectal imaging was performed each week after surgery for the first 3 weeks to surveil the stent and feces delivery. Follow-ups were conducted for more than 3 months. Thirty patients who successfully received surgery were included in this study. There were 18 (60.0%) males and 12 (40.0%) females. As for perioperative characteristics, operation time was 213.8 ± 43.0 minutes, blood loss was 53.3 ± 24.6 mL, time to first flatus via protective sleeve after surgery was 3.2 ± 1.1 days, postoperative hospital stay was 11.8 ± 1.6 days, and time to discharge stent was 22.4 ± 3.2 days. As for short-term outcomes, 6 patients suffered from pneumonia, urinary tract infection or incision infection. During the follow-up, there was no anastomotic leakage or mortality. This novel stent-assisted in situ intestinal bypass is safe and feasible, it might be an applicable way to prevent postoperative anastomotic leakage for patients with low-mid rectal cancer.

Enhancing the integrity of a buried gas pipelines: Investigating ruptures, explosions, and strengthening solutions

The present paper presents findings from a case study of a buried gas pipeline that ruptured, causing a gas cloud explosion and subsequent fire. The study aimed to identify the incident's cause and improve the pipeline's strength under specific conditions. The study measured the pipe's actual wall thickness and conducted stress analysis using analytical and finite element methods to assess its integrity under corrosion. It evaluated if the 20-inch pipeline near road crossings could withstand external forces.In conclusion, the research underscores the importance of accurately assessing the structural integrity of buried pipelines, especially under conditions of corrosion. It highlights the utility of finite element analysis in providing a more precise understanding of stress distribution and can aid in designing pipelines that are better equipped to withstand various external pressures.The investigation illustrates the importance of increasing the strength of buried natural gas pipelines, in the crossing road area and, for this purpose, it was proposed (in terms of novelty associated with the study) a solution consisting in introduction of the pipeline in protective sleeves fitted with spacer rings.

The effect of the backfill on the integrity of a buried pipeline upon heavy-duty vehicle crossings

The aim of this work was to determine stresses in the wall of a buried empty gas pipeline caused by the weight of backfill as well as by heavy-duty vehicles crossing the pipeline, and, on their basis to assess the applicability of protective sleeves. A buried pipeline with zero internal pressure of transported medium (empty pipeline) differs from an unburied pipeline by the vertical load due to the weight of the backfill which causes an ovalness of the circular cross section of the pipeline. This leads to the rise of through-wall bending stresses with the tensile stress at the outside surface at the 3 and 9 o´clock positions and compressive stress at the inside surface. At the 6 and 12 o´clock positions the stresses are tensile at the inside surface and compressive at the outside surface. The current depth of soil cover above gas pipelines is 0.5 m. For pipes DN500, t ~ 6.5 mm the through-wall bending stress is found to be σb ≈ ±10 MPa. In comparison with the yield stress of pipeline material, this stress is negligible. The situation is changed when heavy-duty vehicles cross the pipeline. For example, when a MAN truck with the mass load 3270 kg acting on a single wheel of the front axle crosses this pipeline, the pressure transmitted to the pipe will cause the through-wall bending stress σb ≈ ±76 MPa. This stress is superimposed to that of the backfill to give the total value ±86 MPa. When dead loads, imposed by backfill cover, together with live loads, caused by truck-wheel loads, are excessive a crushing of side walls of the pipeline and/or ring buckling of the pipe cross section can happen.

Simulation of acute respiratory viral infections pathogen spread in dentists

Aim. To study the airborne transmission of acute respiratory viral infections (ARVIs) in medical care workers of dental clinics.Materials and Methods. We developed a simulation model in which the bacteriophage E. coli, which is a part of the drug "Intesti-bacteriophage", was used as a model of the virus. The host bacterium was Escherichia coli strain M-17, which is part of the Kolibakterin drug. The phage titer according to Appelman was 10-5 plaque-forming units per mL. The experiment was conducted in outpatient care dental office with the participation of medical care workers and implied the contamination of the dental dummy oral cavity by the bacteriophage (A-Dec Simulator REF: 4820) during the treatment of tooth decay by means of aerosol-generating technologies and further detection of the bacteriophage in the environment. Bacteriophage spread was evaluated in 5 series of experiments by collecting the samples from dental office air (n = 50), surfaces of equipment (n = 90), and personal protective equipment of a dentist (n = 80).Results. We found an intensive contamination by bacteriophages during the treatment of tooth decay with the use of aerosol-generating technologies. Phage was isolated in all air samples in the treatment area (100.00% [95% CI 47.82-134.48]) and in 20% of samples at a distance of 160 cm (near the exit). Bacteriophages spread by air currents contaminated the personal protective equipment: protective glasses, gloves, and sleeves of a robe in 100.00% [95% CI 47.82-134.48]) of samples. We have also found a frequent contamination of the inner surface of glasses (40.00% [95% CI 5.27-85.34]) and a medical mask (80.00% [95% CI 28.36-99.49]).Conclusion. We developed a model to study the airborne transmission of ARVI pathogens spread during dental care. Intensive phage contamination of the dental office air and personal protective equipment has been established. A detailed study of the airborne transmission of ARVIs is necessary to improve their prevention in dental workers.

Research on Rotor Sleeve Winding Techniques for High-Speed Permanent Magnet Motors via NOL Ring Testing

Surface-mounted high-speed permanent magnet motors are known for their small size, high power factor, and reliable control and operation. However, these motors may have low mechanical strength and weak tensile strength in their rotor magnet, which necessitates the adoption of an external sleeve for protection. Currently, carbon fiber composite sleeves are garnering increasing attention for their durable and reliable protective capabilities. Despite the apparent benefits of carbon fiber composite protective sleeves, systematic research on the relevant parameters such as winding angle, fiber type, resin type, winding tension, and curing method is currently lacking in the literature for high-speed permanent magnet motors. In this context, this paper employs an innovative approach, utilizing the Taguchi method, the National Ordnance Laboratories (NOL) ring failure test, and a resin content test, to investigate the winding process parameters of carbon fiber composite protective sleeves for high-speed permanent magnet motors. The results indicate that the tensile strength of the composite sleeve with a winding angle of 45 and 30° is reduced by 20~25% compared with the sleeve with a pure hoop winding angle. The loss of strength caused by the manufacturing process accounts for 30%. When the wet winding tension is 130 N, the tensile and shear strength of the sleeve decreases by 13 and 12%, respectively, compared with that of 70 N. When the dry winding temperature rise rate is 3 min/°C, the strength of the sleeve decreases by 16% compared with that of 1 min/°C. For a small-thickness sleeve with a thickness of 1.5 mm, two-layer curing can increase the tensile strength of the sleeve, while three-layer curing or more can decrease the strength. By studying the process parameters of the sleeve, this article prepared a composite sleeve for a high-speed permanent magnet motor with a line speed of 200 m/s. This study provides a comprehensive analysis of the manufacturing process parameters of the rotor sleeve, which is helpful for the design and performance optimization of high-speed permanent magnet motors.

Drill Bone with Both Hands: Plunge Depth and Accuracy with 4 Bracing Positions.

A prospective study with randomized crossover was conducted to assess the effect of 4 bracing positions on orthopaedic surgical trainee performance in a simulated bone drilling task. Linear mixed effects models considering participant training level, preferred bracing position, height, weight, and drill hole number were used to estimate pairwise and overall comparisons of the effect of each bracing position on 2 primary outcomes of drilling depth and accuracy. A total of 42 trainees were screened and 19 were randomized and completed the study. Drill plunge depth with a 1-handed drilling position was significantly greater by pairwise comparison to any of the 3 double handed positions tested: a soft tissue protection sleeve in the other hand (0.41 mm, 95% confidence interval [CI] 0.80-0.03, p = 0.031), a 2-handed position with the contralateral small finger on bone and the thumb on the drill (0.42 mm, 95% CI 0.06-0.79, p = 0.018), and a 2-handed position with the contralateral elbow braced against the table (0.40 mm, 95% CI 0.02-0.78, p = 0.038). No position afforded a significant accuracy advantage (p = 0.227). Interactions of participant height with plunge depth and accuracy as well between drill hole number and plunge depth were observed. Orthopaedic surgical educators should discourage trainees from operating a bone drill using only 1 hand to reduce the risk of iatrogenic injury due to drill plunging. Therapeutic Level II.

Structure, design, and test of 13 kA HTS current lead

The 13 kA High Temperature Superconducting Current Leads (HTSCL) were designed and manufactured by the Institute of plasma physics, Chinese Academy of Sciences (ASIPP). This lead differs from former HTS current leads, in that it features an integrated heat exchanger (HEX) structure, a HTS magnetic shield and protective sleeve, and a Low Temperature Superconducting (LTS) module with a through cold conduction channel. The HTS and LTS module is cooled by SHe. In November 2020, the 13 kA steady-state test, Loss Of Flow Accident (LOFA) test, joint resistance test, pulse current test, insulation voltage test and other low-temperature electrical test items of the leads were completed. The test results indicate that all parameters meet the design requirements.

Effect of Protective Padding in Pneumatic Tourniquet Applications on the Prevention of Skin Complications.

The use of pneumatic tourniquets in orthopaedic surgery has become essential as they create a bloodless surgical field in lower and upper limb applications and allow the anatomical structures to be better visualized. This aim of this study, which was conducted on 60 patients, was to determine the effect of protective padding on preventing skin complications in pneumatic tourniquet applications. Patients were divided into 3 groups of cotton-cast padding, protection sleeve, or no/without protective padding underneath the tourniquet cuff. Mean values were as follows: age: 27.7 ± 6.9 years, tourniquet pressure: 307.5 ± 31.7 mmHg, and tourniquet duration: 87.8 ± 15.3 minutes. There was a significant difference between the groups in terms of the rate of skin complications (p < .05) immediately after survey, 30 minutes after surgery, and 180 minutes after surgery. Protective padding underneath pneumatic tourniquet cuff can be recommended during anterior cruciate ligament reconstruction.

Dr. Thakur innovative technique of suprapatellar nailing of tibia

Intramedullary nailing is treatment of choice for diaphyseal fractures of tibia in adults. Infrapatellar medullary nailing usually done for diaphyseal tibial fractures but in metaphyseal fractures reduction become a challenge due to anterior deformity due to pull of patellar tendon. Suprapatellar nailing is becoming popular and route of choice for metaphyseal fractures because it is done in semiextended position which helps in good reduction and fixation. But the major disadvantage of this approach is the specific instrument sets and implants are very costly. In this study we used an innovative technique of suprapatellar nailing of fracture tibia which is very cost effective. No special instrument sets used, no jig used, protective sleeve and trocar are used from PFNA2 set and colour coded infrapatellar nail extractor used to introduce the nail in proper position.

Using Six Sigma DMAIC Cycle to Improve Workplace Safety in the Company from Automotive Branch: A Case Study

The article presents the results of the use Six Sigma DMAIC cycle to improve workplace safety and decrease the cost associated with work accidents in the company from the automotive branch. Selected tools of the DMAIC cycle were used at each stage: the project card and the Pareto-Lorenz diagram at the define (D) stage, the matrix diagram at the measure (M) stage, the Ishikawa diagram with the verification of causes at the analysis (A) stage, the 5WHY method at the improve (I) stage and the c control chart at the control (C) stage. Each of the successive stages was based on the results of the previous one in order to achieve a lasting solution for the analysed problem by the implementation of remedial measures. Because of the implementation of remedial measures, the level of work safety in the examined company was improved. The DMAIC analysis made it possible to identify the main causes (Xn) of accidents at work and to objectively evaluate them in order to discover the root cause (Xn!) of the problem. The root cause turned out to be inadequate protection of the lathe due to the protective cover installed too far away from the lathe chuck, which resulted in the catching of protective sleeves or gloves of the lathe operators and accident events in the form of upper limb damage. The solution to this problem was to reduce the gap between the guard and the lathe chuck by adjusting the guard so that no more items of workers' clothing were caught while the machine was running. The article proves the effectiveness of using the Six Sigma DMAIC cycle in analyzing and improving the state of occupational safety and is an incentive to use this cycle and a specific set of tools to analyze similar problems.

PO-693-05 REMOVAL OF A CHRONICALLY-IMPLANTED LEADLESS VENTRICULAR PACEMAKER AFTER 9-YEARS USING A HIGHLY TORQUE RETRIEVAL CATHETER A CASE REPORT

Leadless cardiac pacemakers (LPs) are an effective and safe alternative to transvenous pacemakers for single-chamber ventricular pacing. However, the feasibility of retrieving and replacing chronically implanted LPs is not well understood. We report a case of LP retrieval and replacement of a 9-year chronically implanted Nanostim LP. N/A An 84 year old woman had a Nanostim LP (St Jude Medical Inc) implanted in December 2012, with good pacing parameters: threshold 0.5 V at 0.4 ms, impedance 500 Ohm, R-wave amplitude 7.5 mV. The parameters remained stable over time until the most recent clinic visit (early November 2021), when interrogation failed - indicating battery end-of-life. One month later, she underwent LP retrieval. Fluoroscopy revealed significant swinging movement of the LP docking button - suggestive that success of retrieval was likely. After femoral venous access, with fluoroscopy + ICE guidance, we used a tri-loop snare LP retrieval catheter (Abbott Inc) designed to be engage the LP in a highly torque-responsive manner. After confirming coaxial alignment between the snare and the docking button, the snare was closed, and locked around the docking button on the proximal end of the LP. After closing the snare, the retrieval catheter was docked with the LP. The protective sleeve was then advanced over the LP to assist with the coaxial alignment between the retrieval catheter docking cap and the LP. Thereafter, the retrieval catheter was rotated counterclockwise to allow the LP to unscrew from the myocardium. After less than 2 minutes, the tri-Loop retrieval catheter snared the docking cap, and the soft protective sleeve was easily advanced over the LP. After two full rotations, and in less then 2 minutes, the LP was released from the RV wall. The explanted LP device had limited adherent tissue ingrowth. During the same procedure, a new LP (Aveir VR; Abbott Inc.) was implanted: acute threshold 1 V/0.4, Impedance 630 ohm and R wave amplitude 9 mV. This case report demonstrates the feasibility of retrieval of even long-term chronically-implanted LPs after 9 years duration. Successful retrieval seems to be related to the combination of i) identifying swinging motion of the LP with fluoroscopy, plus ii) the high torque-responsiveness of the retrieval catheter.

Investigation of ice and snow accumulations on the bogie areas of high-speed trains using ice wind tunnel experiments

Accumulated snow and ice will severely influence the safe operation of high-speed trains in snowy weather, where the snow and ice in the bogie region are the main concerned problems that contribute to such issues. The work presented in this paper initiated experimental studied snow and ice accumulation on the running bogies of the high-speed trains to clarify the snow and ice accumulation process and causes. Two original and two optimized cases with protective schemes combined with electoral heating and an air-flow deflector under the customized train body were adopted to carry out the snow and ice wind tunnel experiments in the Icing-snowing Wind Tunnel (ISWT) of Central South University (CSU). The distributions and mass of the snow and ice were analysed, and the preliminary conclusions were drawn: the leeward side and the depressions of the bogies accumulated a layer of snow, and the melt water sprayed by the rotating brake discs flew everywhere, which contributed to rapidly growing icicles on the bogies and train body during the experiments. Deflectors, protective sleeves and different kinds of heating methods were adopted according to the original cases to optimized where they should be placed, they were capable of reducing the snow and ice mass by 62.9% and 50.4% from the original trailer and motor bogie, respectively. Thus, the optimized schemes were confirmed to be effective to show great application potential to reduce mass and increase running safety for high-speed trains in winter in cold regions.