Exchange Procedure Research Articles

Continuous Intracorneal Ring Implantation in Keratoconus: Efficacy, Predictive Factors, and Complications.

PurposeTo examine the clinical outcomes, predictors of visual improvement and complications of continuous intracorneal ring (ICCR) implantation in patients with keratoconus and confirmed contact-lens intolerance (CLI).MethodsThis nonrandomized, multi-centric, retrospective cohort study examined visual, keratometric and clinical outcomes evaluated after a minimum follow-up of 2 months. Among the inclusion criteria for the standard treatment group (STG) were corrected distance visual acuity (CDVA) <20/25 Snellen, no central corneal scars, minimum corneal thickness >350µm, and central mean keratometry reading (meanK) <55 diopters. All other eyes were classified as non-standard treatment group.ResultsA total of 118 eyes of 118 patients with aged 32 ± 11 years were included in this study. At a median follow-up of 161 days (interquartile range: 111–372 days) ICCR implantation improved the CDVA from a mean of 0.38 to 0.15 logMAR (p<0.0001). Our correlation analysis showed lower preoperative CDVA to be the single best predictor of CDVA improvement, with eyes of a CDVA of 20/80 or lower improving by 4.3 ± 2.0 lines on average. Eyes with a meanK >55 diopters gained 9.04±4.83 lines in UDVA and 2.86±3.09 lines in CDVA. However, postoperatively these eyes had a CDVA of 0.32±0.21 logMAR which is significantly inferior to the STG outcome (p=0.001372). Fifteen eyes (12.7%) had to undergo a ring exchange procedure because of refractive under- (9 eyes) or overcorrection (6 eyes). Two eyes (1.7%) experienced medical complications.ConclusionThis study confirms the inclusion criteria of ICCR implantation in KC eyes with CDVA <20/25 and CLI. Particularly in eyes with a preoperative CDVA <20/80 and a meanK <55 diopters, ICCR implantation should be considered due to its reversibility and low rates of serious complications. The main challenge remains in the low predictability of the magnitude of this improvement in eyes with CDVA >20/30.

Algorithm-based selection of automated red blood cell exchange procedure goals reduces blood utilization in chronically transfused adults with sickle cell disease.

Automated red cell exchange (RCE) is a common treatment for patients with sickle cell disease (SCD). Two key parameters are used to determine the volume of blood for RCE to reduce sickle hemoglobin (eg, HbS): fraction of cells remaining (FCR) and target hematocrit. We evaluated how the calculated FCR-using the manufacturer's algorithm-impacted blood utilization and incidence of acute care encounters. Retrospective chart review was conducted of 15 adults with SCD who underwent chronic RCE from July 1, 2015 to August 31, 2019. Blood utilization and acute care encounters were compared across three time periods: (a) when a fixed FCR of 30% was used (12 months); (b) transition period during which physicians made ad hoc changes to the FCR (25 months); (c) algorithm phase when a procedural FCR between 30% and 50% was selected using an algorithm generated by the manufacturer's built-in software to target a HbS fraction of 8% post-procedure (12 months). Wilcoxon signed rank test was used to determine statistical significance. Median blood utilization per procedure decreased from 2398 mL (interquartile range [IQR]: 2271-2759 mL) during the fixed FCR phase to 1887 mL (IQR: 1495-2241 mL) during the algorithm phase (P < 0.001). Similarly, median number of units transfused decreased from 10 (9-11) to 7 (5-9) during the respective phases (P < 0.001). Visits to the emergency department were 1 (0-4) in the fixed FCR phase and 0 (0-3) in the algorithm phase. Algorithm-based selection of a procedural FCR significantly reduced blood utilization (~21%) without appearing to increase acute care encounters.

A Method for Catastrophic Forgetting Prevention during Multitasking Reinforcement Learning

Reinforcement learning is based on a principle of an agent interacting with an environment in order to maximize the amount of reward. Reinforcement learning shows amazing results in solving various control problems. However, the attempts to train a multitasking agent suffer from the problem of so-called "catastrophic forgetting": the knowledge gained by the agent about one task is erased during developing the correct strategy to solve another task. One of the methods to fight catastrophic forgetting during multitask learning assumes storing previously encountered states in, the so-called, experience replay buffer. We developed the method allowing a student agent to exchange an experience with teacher agents using an experience replay buffer. The procedure of experience exchange allowed the student to behave effectively in several environments simultaneously. The experience exchange was based on knowledge distillation that allowed to reduce the off-policy reinforcement learning problem to the supervised learning task. We tested several combinations of loss functions and output transforming functions. Distillation of knowledge requires a massive experience replay buffer. Several solutions to the problems of optimizing the size of the experience replay buffer are suggested. The first approach is based on the use of a subset of the whole buffer; the second approach uses the autoencoder as a tool to convert states to the latent space. Although our methods can be applied to a wide range of problems, we use Atari games as a testing environment to demonstrate the methods.

Safety and feasibility of single use cholecystoscopy for guiding laser or mechanical cholelithotripsy, and mechanical cholelithotomy.

PURPOSE Patients with acute calculus cholecystitis and contraindications to cholecystectomy receive cholecystostomy drainage catheters, many of which remain in place until end of life. This study aims to assess safety, feasibility, and early clinical outcomes of percutaneous cholecystoscopy using the LithoVue endoscope, laser/mechanical cholelithotripsy, and mechanical cholelithotomy for management of symptomatic cholelithiasis. METHODS This was a single-institute retrospective analysis of 17 patients with acute calculus cholecystitis who had contraindications to cholecystectomy, underwent cholecystostomy catheter placement between 2015 and 2017, and stone removal between 2017 and 2018. The LithoVue 7.7- 9.5 F endoscope was used in combination with laser/mechanical cholelithotripsy, mechanical retrograde, and balloon-assisted anterograde cholelithotomy to remove gallstones and common bile duct stones. Surgical contraindications ranged from cardiopulmonary disease to morbid obesity to neoplastic processes. Timing and number of interventions, as well as technical and clinical successes, were assessed. RESULTS The median time interval from cholecystostomy catheter placement to cholelithotripsy was 58 days, after an average of 2 tube exchange procedures. Technical and clinical success were achieved in all patients (stone-free gallbladder and cholecystostomy tube removal). On average, three sessions of cholecystoscopy and laser and mechanical cholelithotripsy were required for complete gallstone extraction. The mean interval time between the first cholelithotripsy session and removal of cholecystostomy was 71.8±60.8 days. There were neither major nor minor procedure-related complications. CONCLUSION Percutaneous cholecystoscopy using the LithoVue endoscope, in combination with laser/ mechanical cholelithotripsy and mechanical cholelithotomy, is feasible, safe, well-tolerated, and was able to remove the cholecystostomy tube in the patients with contraindication to cholecystectomy.

A comparison of adverse pregnancy events between ureteral stents and percutaneous nephrostomy tubes in the treatment of nephrolithiasis during pregnancy: A propensity score-matched analysis of a large multi-institutional research network.

To investigate rates of adverse pregnancy events associated with the use of percutaneous nephrostomy tubes (PCN) versus ureteral stents in the treatment of nephrolithiasis during pregnancy. We queried the TriNetX Diamond Network database to evaluate pregnant women (ICD-10 Z34, O09) with a history of nephrolithiasis (N20-23) who underwent a PCN (CPT 50432) or ureteral stent (52332) placement up to 6months before delivery (O80-82). We controlled for the following potentially confounding variables through propensity score matching: age, race, ethnicity, acute pyelonephritis (N10), infections of the genitourinary tract in pregnancy (O23.0), and other sepsis (A41) at the time of stent or PCN placement. We identified 2,999 pregnant women who underwent ureteral stent placement and 321 who underwent PCN. Following propensity score matching, we found there to be no significant difference in the rate of premature labor or delivery (aOR 1.08, 95% CI 0.735-1.588), premature rupture of membranes (0.889, 0.453-1.743), intrauterine infection (0.906, 0.379-2.165), or c-Sect.(0.825, 0.408-1.667). Within 6months of their initial procedure, women with a ureteral stent experienced a significantly decreased rate of subsequent urinary tract infection (UTI) or pyelonephritis (0.52, 0.38-0.71), inpatient hospital stay (0.40, 0.26-0.64), emergency department visit (0.65, 0.48-0.89), and repeat exchange procedure (0.70, 0.51-0.96). In the treatment of nephrolithiasis during pregnancy, PCN versus ureteral stent placement does not confer a significant difference in rates of adverse pregnancy events. However, ureteral stent placement was associated with a lower incidence of hospital admissions, emergency department visits, exchange procedures, and new UTIs or pyelonephritis.

The favorable outcome of subsequent pregnancy in a patient with a history of obstetric atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome (aHUS) is a severe life-threatening disease associated with uncontrolled activation of alternative complement pathway. Obstetric aHUS, which develops in pregnant women and puerperas, is characterized by a particularly severe course with multiple organ failure, high death risk and end-stage renal disease. The prognosis of patients with obstetric aHUS has changed dramatically after the introduction of eculizumab, a monoclonal antibody to C5 complement component, into clinical practice. With timely initiation of the complement blocking therapy, the patients would not only survive, but also completely restore the function of the affected organs. Naturally, the question arises on the possibility of repeated pregnancies in women with previous obstetric aHUS and on the strategy of pregnancy management.&#x0D; The paper describes a clinical case of successful treatment with eculizumab for obstetric aHUS in the third trimester of the first pregnancy in a young and previously healthy woman, and the management of her second pregnancy. A 23-year old woman at 35-36 weeks of her first pregnancy developed the clinical picture of obstetric thrombotic microangiopathy, which was interpreted as a manifestation of severe preeclampsia and HELLP syndrome. However, after an emergency surgical delivery, the patient's condition continued to deteriorate despite the plasma exchange procedure. After exclusion of the other causes of thrombotic microangiopathy, aHUS was diagnosed and treatment with eculizumab was started, which resulted in complete recovery. No aHUS-associated mutations were identified. The complement inhibitor treatment was discontinued after 12 months. Four years after the first birth, the patient had a second pregnancy after preconception planning. During pregnancy, the patient was closely monitored for a timely identification of potential complications and had prevention of placental complications with acetylsalicylic acid and low molecular weight heparin. No aHUS recurrence and/or other complications were observed, and the patient did not require treatment with eculizumab during pregnancy. Elective caesarean section was performed at 39 week of gestation. A healthy boy was born with a bodyweight of 3370 g, a height of 50 cm, and Apgar score 8-9.&#x0D; In women with obstetric aHUS history, a favorable outcome of repeated pregnancies is possible, in some cases even without any prophylactic use of complement-blocking therapy, provided that with complete remission of aHUS has been achieved, with close monitoring during gestation and prevention of placenta-associated complications.

Implementation of national blood conservation recommendations at an adult sickle cell center

Due to the national blood supply crisis caused by the COVID-19 pandemic, the American Society of Hematology proposed guidance to decrease blood utilization for sickle cell patients on chronic transfusion therapy (CTT). Little evidence exists to support the efficacy and safety of these blood conservation strategies. Through retrospective analysis, we sought to describe outcomes following implementation of these recommendations in 58 adult sickle cell patients on chronic exchange transfusions. The strategies employed included: relaxing the goal fraction of cells remaining (FCR) to 30%-50%, utilizing depletion exchanges in select patients, and transitioning select patients to monthly simple transfusions. We compared hemoglobin S%, hemoglobin values, and other laboratory parameters, acute care visits, and red blood cell usage during the first year of the COVID-19 pandemic to the year prior using Wilcoxon signed rank test. Of 53 patients who remained on chronic exchanges during the pandemic, use of depletion exchange increased (15%-23%) and FCR increased (34.9 [SD 4.7] vs. 37.6 [SD 4.5], p< .05). These changes resulted in 854 units conserved without clinically significant changes to pre-exchange laboratory parameters, including hemoglobin S%, or number of acute care presentations. In contrast, five patients who transitioned to predominantly simple transfusions, experienced difficulty maintaining hemoglobin S% less than 30 and worsening anemia. Our data suggest that in a blood shortage crisis, optimizing the exchange procedure itself may be the safest means of conserving blood in a population of adult patients with sickle cell disease.

Impact of therapeutic plasma exchange on meropenem pharmacokinetics.

The aim of this study was to investigate the impact of therapeutic plasma exchange (TPE) on the plasma concentrations and pharmacokinetic (PK) patterns of meropenem. Prospective, open-label, PK study. Academic tertiary care medical center. Eleven patients who underwent TPE. A single-center PK study was conducted on adult patients who underwent TPE. All patients received two phases of meropenem administration for research purposes. Meropenem PK studies were carried out after the administration of a single dose of 1g of meropenem in the patients during TPE (phase 1) and compared with meropenem 1g administration in the same patients without TPE (phase 2), which served as the control phase with an at least 72-h wash-out period separating the phases. The total clearance (CL) of meropenem during TPE was greater than the values obtained from the same patients without TPE (13.37 ± 6.23 L/h during TPE vs. 8.42 ± 2.84 L/h without TPE). The mean drug fraction eliminated during TPE was 14.22 ± 11.03%, and the mean amount of drug removed by the TPE was 142.23 ± 110.31 mg. These results indicate that the TPE had an impact on the elimination of meropenem in patients during the exchange procedure. The CL of meropenem during TPE was greater than the values obtained from the control phase without TPE.

Role of PSS-based assemblies in stabilization of Eu and Sm luminescent complexes and their thermoresponsive luminescence

The present work introduces self-assembled polystyrenesulfonate (PSS) molecules as soft nanocapsules for incorporation of Eu3+-Sm3+ complexes by the solvent exchange procedure. The high levels of Eu3+- and Sm3+-luminescence of the complexes derives from the ligand-to-metal energy transfer, in turn, resulted from the complex formation of Eu3+and Sm3+ ions with the three recently synthesized cyclophanic 1,3-diketones. The structural features of the ligands are optimized for the high thermal sensitivity of Eu3+- luminescence in DMF solutions. The PSS-nanocapsules (∼100 nm) provide both colloid and chemical stabilization of the ultrasmall (3–5 nm) nanoprecipitates of the complexes, although their luminescence spectra patterns and excited state lifetimes differ from the values measured for the complexes in DMF solutions. The specific concentration ratio of the Eu3+-Sm3+ complexes in the DMF solutions allows to tune the intensity ratio of the luminescence bands at 612 and 650 nm in the heterometallic Eu3+-Sm3+ colloids. The thermal sensitivity of the Eu3+- and Sm3+-luminescence of the complexes derives from the static quenching both in PSS-colloids and in DMF solutions, while the thermo-induced dynamic quenching of the luminescence is significant only in DMF solutions. The reversibility of thermo-induced luminescence changes of the Eu3+-Sm3+ colloids is demonstrated by six heating-cooling cycles. The DLS measurements before and after the six cycles reveal the invariance of the PSS-based capsule as the prerequisite for the recyclability of the temperature monitoring through the ratio of Eu3+-to- Sm3+ luminescence.

Monolithic Al2O3 Xerogels with Hierarchical Meso‐/Macropore System as Catalyst Supports for Methanation of CO2

AbstractCylindrical, cm‐sized monolithic Al2O3 xerogels with hierarchical meso‐/macropore system were prepared by sol‐gel synthesis. The influence of both solvent exchange and drying on monolith stability and the resulting pore system was studied following mass and volume of the monolith as well as by porosimetry and electron microscopy. Crack‐free drying of the monoliths requires a proper management of drying stress. This is achieved by adjusting the drying rate and solvent exchange procedure applied to the intermediate lyogels. Moreover, mainly through differences in capillary pressure, changing the pore fluid allows an adjustment of the mesopore width from 7.6 nm to 10.5 nm. Neither solvent exchange nor drying affect the macropores, the width of which stays at 1.5 μm. Finally, CO2 methanation over Ni‐impregnated Al2O3 monoliths reveals CO2 conversion and CH4 selectivity comparable to an industrial Ni/Al2O3 benchmark catalyst.

Influencing the coupling between network building blocks in CdSe/CdS dot/rod aerogels by partial cation exchange.

The assembly of CdSe/CdS dot/rod nanocrystals (NCs) with variable length of ZnS tips into aerogel networks is presented. To this end, a partial region selective cation exchange procedure is performed replacing Cd by Zn starting at the NC tip. The produced aerogel networks are investigated structurally and optically. The networks of tip-to-tip connected NCs have an intricate band structure with holes confined to the CdSe cores while electrons are delocalized within the CdS also within connected building blocks. However, the ZnS tips act as a barrier of variable length and strength between the NC building blocks partly confining the electrons. This results in NC based aerogel networks with tunable strength of coupling between building blocks.

Flow cell for operando X-ray photon-in-photon-out studies on photo-electrochemical thin film devices

Background: Photo-electro-chemical (PEC) water splitting represents a promising technology towards an artificial photosynthetic device but many fundamental electronic processes, which govern long-term stability and energetics, are not yet fully understood. X-ray absorption spectroscopy (XAS), and particularly its high energy resolution fluorescence-detected (HERFD) mode, emerges as a powerful tool to study photo-excited charge carrier behavior under operating conditions. The established thin film device architecture of PEC cells provides a well-defined measurement geometry, but it puts many constraints on conducting operando XAS experiments. It remains a challenge to establish a standardized thin film exchange procedure and concurrently record high-quality photoelectrochemical and X‑ray absorption spectroscopy data that is unperturbed by bubble formation. Here we address and overcome these instrumental limitations for photoelectrochemical operando HERFD-XAS. Methods: We constructed a novel operando photo-electro-chemical cell by computer numerical control milling, guided by the materials’ X‑ray and visible light absorption properties to optimize signal detection. To test the cell’s functionality, semiconducting thin film photoelectrodes have been fabricated via solution deposition and their photoelectrochemical responses under simulated solar light were studied using a commercial potentiostat in a three-electrode configuration during HERFD-XAS experiments at a synchrotron. Results: We demonstrate the cell’s capabilities to measure and control potentiostatically and in open‑circuit, to detect X‑ray signals unperturbed by bubbles and to fluently exchange different thin film samples by collecting high-resolution Fe K-edge spectra of hematite (α -Fe2O3) and ferrite thin film (MFe2O4, M= Zn, Ni) photoelectrodes during water oxidation. Conclusions: Our cell establishes a measurement routine that will provide experimental access of photo-electro-chemical operando HERFD-XAS experiments to a broader scientific community, particularly due to the ease of sample exchange. We believe to enable a broad range of experiments which acquired fundamental insights will spur further photoelectrochemical research and commercialization of water splitting technologies

Geochemical and isotopic study of phreatic aquifer in an arid area, case study of El Golea region (Algerian Sahara)

Shallow groundwater is a major reservoir of water in arid areas. This water is characterized by strong mineralization which represents a major quality problem for human consumption and even for its use in agriculture. For this reason, geochemical, statistical and isotopic studies were conducted to obtain an overview of the processes that control water mineralization in the oasis of El Golea (Algerian Sahara). Spatial distributions of EC in this area show that the highest concentrations are situated close to the El Golea Lake formed by evaporitic rock. Geochemical and statistical analysis and data from 28 water points in the phreatic aquifer of the El Golea oasis show a strong correlation between electrical conductivity and the majority of chemical elements, indicating the influence of the interaction between fresh water and bed rock on this mineralization. The results obtained indicate that Carbonate minerals (calcite) are oversaturated in all groundwater samples. The ionic ratios demonstrate the role of weathering, dissolving, ion exchange, and evaporation procedures in mineralization acquisition. The scatter plot of that relates δ 2 H = f (δ 18 O) reveals that all of the samples were founds to be below both the GMWL of Craig (1961) and the Sfax local meteoric boundaries (South Tunisia) indicating that groundwater samples have an old origin. This isotopic composition depletion can be explained by the presence of mixes of phreatic groundwater and Continental Intercalaire (CI) (W2).

Comparative evaluation of efficacy and safety of automated versus manual red cell exchange in sickle cell disease: A systematic review and meta-analysis.

Exchange transfusion is a valuable treatment option in sickle cell disease (SCD) and is preferred over simple transfusion as it removes abnormal haemoglobin S (HbS) levels and reduces complications. This meta-analysis aims to evaluate the efficacy and safety profile of automated red cell exchange (aRBX) procedure over manual red cell exchange transfusion (MET) in SCD patients. A standard meta-analysis protocol was developed, and after performing a comprehensive literature search in PubMed/MEDLINE, Cochrane and International Clinical Trial Registry Platform (ICTRP), reviewers assessed eligibility and extracted data from nine relevant studies. A random effects model was used to estimate the pooled effect size calculated from the mean difference in HbS percentage, serum ferritin level and risk ratio for the adverse events. Quality assessment was done using the risk-of-bias assessment tool, and a summary of observations was prepared using standard Cochrane methodology with GradePro GDT. The random-model analysis revealed a mean difference of 4.10 (95% CI: -3.29-11.49;Z= 1.09;p= 0.28) for HbS percentage, mean difference of 435.29 (95% CI: -73.74-944.32;Z= 1.68;p= 0.09) for serum ferritin and pooled risk ratio of 1.35 (95% CI: 0.63-2.87; Z=0.77;p= 0.44) for adverse events. This meta-analysis did not reveal any significant benefit of aRBX in reducing HbS percentage and attenuating the serum ferritin level when compared with MET. There was also no significant increased risk of adverse events detected in association with aRBX.

Fast, Sensitive, and Highly Selective Room-Temperature Hydrogen Sensing of Defect-Rich Orthorhombic Nb2O5-x Nanobelts with an Abnormal p-Type Sensor Response.

The research and development of low-power-consumption and room-temperature hydrogen sensors are of great significance for the safe application of hydrogen energy. Herein, orthorhombic Nb2O5-x nanobelts are prepared through a combined procedure of hydrothermal, ion exchange, and annealing treatment in Ar. The topological transformation process results in the formation of abundant surface defects including chemical defects such as Nb4+, oxygen vacancies, and disordered microregions, which lead to the abnormal p-type conducting and hydrogen sensing behavior. Moreover, the orthorhombic Nb2O5-x nanobelts exhibit fast and sensitive room-temperature hydrogen sensing performance, which shows greater advancement than the monoclinic, tetragonal, and hexagonal Nb2O5 one-dimensional (1D) nanostructures. The response time and lowest limit of detection of the as-fabricated room-temperature sensor decrease to 28 s and 3.5 ppm, respectively. The sensor also exhibits a highly selective hydrogen response against CO, CH4, ethanol, H2S, and NH3. The hydrogen response of the Nb2O5-x nanobelts can be attributed to the redox reaction between hydrogen and preadsorbed oxygens. The defective surface structure and the prolonged dimension of the nanobelts give rise to the highly reactive surface and the suppression of the negative nanojunction effect, which greatly improves the sensing performance. The orthorhombic lattice structure can also promote gas adsorption and diffusion behavior due to its specific catalytic and pathway effect. The results of this work can be helpful for the rational design and defect engineering of the Nb2O5-based 1D nanostructures for room-temperature hydrogen sensing applications.

Therapeutic Plasma Exchange in Pediatric Patients With Sinusoidal Obstruction Syndrome/Veno-Occlusive Disease After Hematopoietic Stem Cell Transplantation: A Single-Center Experience.

Sinusoidal obstruction syndrome/venoocclusive disease is a significant complication of hematopoietic stem cell transplantation. Due to high mortality rates, new treatment strategies have been investigated. Here, we have presented outcomes of therapeutic plasma exchange performed on patients with sinusoidal obstruction syndrome/veno-occlusive disease. Our study included 70 pediatric patients diagnosed with sinusoidal obstruction syndrome/veno-occlusive disease. Therapeutic plasma exchange procedures in patients were evaluated retrospectively. There were 9 mild (12.9%), 9 moderate (12.9%), 21 severe (30%), and 31 very severe (44.2%) cases of sinusoidal obstruction syndrome/venoocclusive disease. Therapeutic plasma exchange was performed in 31 of the 70 study patients (59.6%). Moreover, 10/21 patients with severe (47.6%) and 21/31 patients with very severe (67.7%) disease underwent plasma exchange. Mean time from diagnosis of sinusoidal obstruction syndrome/venoocclusive disease to therapeutic plasma exchange initiation was 2.3 days. The 31 patients who received therapeutic plasma exchange had a total of 146 sessions. Overall survival rates at 100 days were 87.1% and 92.3% for patients who did and did not undergo therapeutic plasma exchange, respectively. When patients with mild and moderate disease who were not expected to undergo plasma exchange were excluded (n = 52), 100-day overall survival rates were 87.1% and 90.5% for those who did and did not undergo plasma exchange, respectively. When we compared severe versus very severe groups, no significant difference was found. Plasmapheresis had no positive effect on survival. However, overall survival in all groups was higher than that in the literature, despite the high number of patients with severe and very severe disease. Interpretation of the results is limited by the retrospective nature of the study. Thus, prospective, randomized controlled trials with larger numbers of patients are necessary to investigate the role of therapeutic plasma exchange in patients with sinusoidal obstruction syndrome/veno-occlusive disease.

An Ultrasensitive and Selective Determination of Cadmium Ions at ppt Level Using an Enzymic Membrane with Colorimetric and Electrochemical Detection.

Cadmium ions (Cd2+) are extremely toxic heavy metal pollutants found in the environment, and which endanger human health. Therefore, it is critical to develop a sensitive and simple method for rapidly detecting Cd2+ in water samples. Herein, an enzymic membrane was developed based on an easy and rapid immobilization method of horseradish peroxidase (HRP), for determination of Cd2+ in drinking water. Hence, for the first time, an enzymic membrane was applied for the detection of Cd2+ without being pretreated. In the first format, the inhibition of horseradish peroxidase was performed using a colorimetric microplate reader. Under optimal conditions, the achieved limit of detection was 20 ppt. In addition, an electrochemical biosensor was developed, by combining the enzymic membrane with screen printed electrodes, which showed a linear calibration range between 0.02–100 ppb (R2 = 0.990) and a detection limit of 50 ppt. The use of this enzymic membrane proved to be advantageous when reversible inhibitors such as the copper ion (Cu2+) were present in water samples, as Cu2+ can interfere with Cd2+ and cause erroneous results. In order to alleviate this problem, a medium exchange procedure was used to eliminate Cu2+, by washing and leaving only cadmium ions as an irreversible inhibitor for identification. The use of this membrane proved to be a simple and rapid method of immobilizing HRP with a covalent bond.

THE METHOD FOR Cu AND Zn ISOTOPE RATIO DETERMINATION BY MC ICP-MS USING THE AG MP-1 RESIN

The isotopic composition of copper is of great interest for researchers in various fields of science, geochemistry and hydrology in particular, wherein the consideration is being given to the variations in the isotopic composition of the Earth’s crust, extraterrestrial matter, and water basins, as well as to the origin and transfer of matter. Zn isotopes appear to be promising for identifying the sources and pathways of the environmental pollution. The aim of this study involves the refinement and validation of the zinc and copper isotopic ratio determination methodology covering the whole process from sample digestion to MC ICP-MS measurements. For this reason, as well as to assess the suitability of the methodology for the analysis of environmental samples, Zn and Cu isotopic analysis of the BHVO-2, BCR-2 and AGV-2 USGS certified reference materials has been performed. The method for determination of Cu and Zn stable isotope ratios by multi-collector inductively coupled plasma mass spectrometry in environmental samples is developed. The application of the AG MP-1 resin with optimized layer parameters (resin bed height 3.5 cm, diameter 1 cm) provides the high-purity Cu and Zn fractions. The method is characterized by high throughput and adequate analytical figures of merit when using the standard-sample bracketing technique for mass bias correction. The procedural blanks related to chemical dissolution and ion exchange procedures are lower than 1 and 3 ng for Cu and Zn, respectively, assuring no blank effect on the isotopic composition of samples. The accuracy and precision obtained for Cu and Zn isotope measurements in the BHVO-2, BCR-2 and AGV-2 geological certified reference materials demonstrate good agreement with the reference values published.

MO1051: Standardized Simulation Education Program with Summative Assessment on Exchange Procedure of Ultrabag System for Peritoneal Dialysis: Innovations in Practical Recommendations

Abstract BACKGROUND AND AIMS Inexperience in practicing peritoneal dialysis (PD) and lack of standard education program under the instruction of qualified renal nurses are known causes of peritonitis in patients with chronic renal failure [1]. Thus far, the standardized and validated curriculum for Continuous Ambulatory Peritoneal Dialysis (CAPD) training has not been well-established under simulation-based education model [2]. We aimed i) to develop a well-structured and standardized educational training program on exchange procedure of Ultrabag system and ii) to evaluate the degree of acquisition in domains of cognitive (knowledge) and psychomotor (skills) by summative assessment using valid and reliable knowledge evaluation index and performance checklist. METHOD Following an invention of 3D-printed CAPD device, ‘Helping Hands’ in closed system operation, the Renal Unit in the Department of Medicine and Multi-Disciplinary Simulation and Skills Centre (MDSSC) in Queen Elizabeth Hospital (QEH) formulated a standard 5-day CAPD training to equip PD patients with knowledge and skills for safe Ultrabag exchange. In order to optimize training effectiveness and assessment standards, the program was designed with ‘6 (+2 additional) guiding questions’ from the International Society for Peritoneal Dialysis (ISPD) document [3]. Scoring Checklist with specific and relevant items, such as fixation of the connecting catheter, parallel point-to-point connection and procedures in placing disinfection cap, could strengthen internal validity. RESULTS In 2021, 17 CAPD patients with partial impairment in vision (12, 71%) or eye-hand coordination (13, 77%) attended this education program. Post-training assessment showed that participants had improved cognitive knowledge (M = 71%; A Grade (&amp;gt;80 marks) = 5, 29% B Grade (60–80 marks) = 9, 53%; C Grade (&amp;lt;60 marks) = 3, 18%) and psychomotor skills (100% achievement in simulation task). Except for 1 participant who required additional training session and re-assessment, 94% of them passed the simulation examination by completing all procedures without any assistance in one-take. A validated educator-guided scheme of psychomotor skills in proper use of CAPD is recommended with six operational phases: CONCLUSION Repetitive performance in task-specific procedure of bag exchange, coupled with constructive feedback from experienced renal nurse educators and well-validated assessment (with a standardized scoring sheet and checklist), resulted in improved skill performance. The training program, correspondent with traditional concept of Miller's pyramid (1990), demonstrated how CAPD novice turns skillful user by developing competence in cognition with factual knowledge of dialysis (‘Knows’) and verbalization of rationale and flows of PD (‘Knows How’); and competence in behavior with simulation practice with CAPD device (‘Shows’) and summative assessment demonstrating mastery of safe bag exchange skills to be integrated into everyday practice (‘Does’). Further studies may be warranted to investigate whether knowledge and skills acquired before use of CAPD could be carried over time and on how education program accounts for risk minimization of CAPD-related peritonitis and survival rate.

MO707: Efficacy and Safety of ‘Helping Hands’: A 3D-Printed Device of Peritoneal Dialysis Adopted in Continuous Ambulatory Peritoneal Dialysis: A Randomized Controlled Trial

Abstract BACKGROUND AND AIMS Touch contamination during bag exchange in continuous ambulatory peritoneal dialysis (CAPD) is a common cause of peritonitis, especially for renal failure patients with fair eye–hand coordination plus and minus poor vision who fail to do the aseptic technique in connecting tubing (Hsieh et al. The negative impact of early peritonitis on continuous ambulatory peritoneal dialysis patients. Perit Dial Int. 2014;34(6):627–35; Woten and Cabrera. Peritonitis: prevention of peritoneal dialysis-induced peritonitis in adults. CINAHL Nursing Guide EBSCO Publishing, 16 November 2018). Those who are unable to execute CAPD by themselves resulted in high restriction in independent living where support from helper or institutional care is required. Up till now, no commercially available CAPD device could be utilized to solve this issue. ‘Helping Hands’ is a device designed with distinctive features including tunnel container for catheter fixation and comfortable handle and clips for parallel point-to-point movement with embedded magnets, and the use of this device might enable those CAPD patients with poor vision and/or eye–hand coordination to perform bag exchange procedure safely and independently. In this study, we hypothesized the use of ‘Helping Hands’ device could reduce the risk of CAPD related peritonitis by allowing CAPD users to work through a safer connection process without direct touch on tubing during bag exchange procedures. METHOD This is a randomized, paralleled, controlled pilot trial in public hospital setting. An interdisciplinary collaboration workgroup was established at Queen Elizabeth Hospital in May 2019. The Renal Unit of Department of Medicine together with the Multi-disciplinary Simulation and Skill Centre designed, prototyped, and then fabricated a CAPD device named ‘Helping Hands’ using 3D-printing technology. All new CAPD patients using ultra-bag peritoneal dialysis (PD) system and attaining ‘high to moderate readiness’ in assessment with occupational therapists were invited to participate in this program. All consented participants were randomly assigned to either intervention group (training + ‘Helping Hands’ provided for CAPD bag exchange) or control group (training alone + CAPD bag exchange without ‘Helping Hands’) using computer-generated numbers. RESULTS From December 2020 to November 2021, 17 patients, with their demographic shown in Fig. 1 were recruited into the study. Nine (53%) and eight (47%) were assigned to intervention group and control group, respectively. Within comparable study period (41 patient-month for both groups), peritonitis rate of intervention group was significantly lower than that of control group, 0.29 versus 1.18/patient-year (P &amp;lt; .01). The peritonitis rate in the intervention group was also lower than the overall peritonitis rate in the Queen Elizabeth Hospital within the same study period, which was 0.31/patient-year (4193 patient-month; peritonitis episode = 108). Investigation report found that the episode of peritonitis identified in intervention group was due to patient not clamping the transfer set before disconnection in performing the bag exchange as opposed to device safety issues. CONCLUSION The use of ‘Helping Hands’ device is safe and can significantly reduce the risk of CAPD-related peritonitis by no direct touching on tubing during bag exchange procedures. The distinctive features of ‘Helping Hands’ might enable those PD patients with poor vision and/or eye–hand coordination to perform bag exchange procedure safely and independently.