Pediatric Central Venous Catheter Research Articles

Development of an Anatomically Accurate Three-Dimensional Simulation Model for Pediatric Central Line Placement

Abstract Intensive care unit patients can require a central venous catheter (CVC) which medical trainees often place. The purpose of this study was to create a novel three-dimensional (3D) printed model, based on actual patient anatomy from a de-identified computed tomography (CT) scan, with improved anatomy, tactile properties, and realism beyond current task trainers for pediatric CVC placement simulation. Bakken Center researchers converted CT DICOM slices into a 3D model using multiple computer programs and multiple 3D printers. Faculty of various subspecialties at our institution attempted to place a CVC line into the model and then evaluated the model in 5 categories using an anonymous REDCap survey. Fifteen faculty participated and fourteen completed their survey. Feedback, based on a 0–10 scale with 10 being highest, was as follows: the model's size scored an average of 8.4, the model's tactile properties scored a 6.1, the model's anatomy received a 7.1, the model's perceived usefulness for practicing central line placement received a 7.6, and the model received a 7.6 in regard to whether it should be utilized in procedural training curriculums. Additional comments were collected in the survey and participants requested that the model's blood vessels be fully visible on ultrasound and that the model be firmer. In conclusion, creating a 3D simulation model for pediatric CVC placement is possible.

Ultrasound-Guided Insertion of Pediatric Central Venous Catheter

Ultrasound-Guided Insertion of Pediatric Central Venous Catheter

Peripheral Insertion of Pediatric Central Venous Catheters in Adults with Difficult I.V. Access

BackgroundDifficult intravenous access is a frequent occurrence in critical care and emergency medicine. Prior intravenous access, chemotherapy use, and obesity are a few factors associated with difficult access. Alternatives to peripheral access are often contraindicated, not feasible, or not readily available. ObjectivesTo describe the feasibility and safety of peripheral insertion of peripherally inserted pediatric central venous catheters (PIPCVC) in a cohort of adult critical care patients with difficult intravenous access. MethodsProspective observational study of adult patients with difficult intravenous access who underwent peripheral insertion of pediatric PIPCVCs at a large university hospital. ResultsDuring a 1-year period, 46 patients were evaluated for PIPCVC; 40 catheters were placed successfully. The median age of the patients was 59 years (range 19–95 years) and 20 (50%) were female. The median body mass index was 27.2 (range 17.1–41.8). The basilic vein was accessed in 25/40 (63%) patients, the cephalic in 10/40 (25%), and the accessed vessel was missing in 5/40 (13%) cases. The PIPCVCs were in place for a median of 8 days (range 1–32). One superficial thrombosis and one deep occurred; pulmonary embolism did not occur. ConclusionsPIPCVC placement seems to be a feasible option in patients in whom peripheral intravenous access is difficult. The safety of this technique needs to be evaluated in prospective studies.

A worldwide survey on the variability in checking the tip position of pediatric central venous catheter.

A worldwide survey on the variability in checking the tip position of pediatric central venous catheter.

Do not trust landmarks and your feelings while inserting pediatric central venous catheters

BackgroundCentral venous catheterization (CVC) is a commonly used procedure in pediatric surgery and intensive care units. For some reasons, catheterizations in children are technically more difficult in comparison to adult patients. The purpose of this study is to evaluate the CVC procedures performed with the aid of anatomic landmarks by experienced (35, 14, 4 years of experience) anesthesiologists and the associated complications. A total of 498 cases under the age of 18 who underwent CVC (temporary, port, or Hickman) between the years 2014 and 2017 were included in this retrospective study. All catheters were inserted with the aid of anatomic landmarks.ResultsThe mean age of the patients was 47.1 ± 59.2 months and 54.8% were male. By using anatomical landmarks, the average success rate in central venous catheterizations was calculated as 98.6%. Complications developed included arterial puncture in 8% (n 40), temporary arrhythmia in 6.2% (n 31) and pneumothorax in 1.4% (n 7) of the patients. Only using multiple punctures (p = 0.005) and catheterizations lasting more than 10 min (the time to blood return from the catheter, p = 0.017) were found to be associated with complications. The experience of the practitioner had no effect on the development of complications (p = 0.354).ConclusionsIn CVCs using anatomic landmarks, complications are seen more frequently in children. Even though a decrease in overall complication rates was detected in catheterizations performed by experienced hands, it is seen that experience does not eliminate complications in CVC insertions using anatomic landmarks.

EFFECTIVENESS OF ASCORBIC ACID AND SALINE SOLUTION IN PEDIATRIC CENTRAL VENOUS ACCESS: RANDOMIZED CLINICAL TRIAL

Objective: to compare the effectiveness between the use of ascorbic acid and 0.9% saline solution in the prevention of pediatric central venous catheter obstruction. Method: randomized clinical trial conducted in a public hospital in Paraná, between the months of June 2018 to October 2019 with 152 participants, of which, 73 in the experimental group and 79, control group) who underwent central venous catheter insertion and randomized to receive the flush intervention with ascorbic acid or 0.9% saline solution. Results: Catheter obstruction occurred in 17 cases (11.2%), nine (11.4%) in the control group and eight (10.9%) in the experimental group. Thrombotic obstruction occurred in 15 cases, in a similar way, in both groups (p=0.88). Catheter removal occurred in 82 cases for elective reasons and in 63 cases for complications. Conclusion: the use of ascorbic acid is as efficient as 0.9% saline solution in preventing central venous catheter obstruction. The study expands the possibilities of interventions within the theme.

Manual Compression of External Iliac Vein to Increase the Size of Femoral Vein for Femoral Central Venous Catheter Insertion in Small Children: Pilot Experimental Study and Randomized Trial

Highlights Abstract Aim: Pediatric femoral central venous catheter insertion is sometimes difficult due to small vein size. External iliac vein (EIV) compression may provide a tourniquet effect to the femoral vein (FV) and may facilitate catheterization. This study was conducted to determine the effect of EIV compression on FV size and femoral venous catheterization success rates. Methods: This study had 2 parts. The first part was a single-arm experimental study. The second part was a randomized controlled trial. Children weighing 2.5–15.0 kg were included. First part: All patients received the same intervention and measurements. FV anteroposterior and medial-lateral diameters were measured by ultrasound without EIV compression, after which EIV was compressed using the assistant’s finger, and FV diameters were measured. Second part: Patients were randomized into compression and control groups. The compression group received EIV compression during femoral venous catheterization. The control group did not receive the compression. Results: A total of 30 patients (15 in each group) participated. EIV compression significantly increased FV anteroposterior diameter (3.36 ± 1.01 mm with compression, 2.39 ± 0.76 mm without compression, mean difference = 0.97 mm, 95% CI = 0.73, 1.21, P < 0.001) and medial-lateral diameter (4.58 ± 1.40 mm with compression, 3.86 ± 1.32 mm without compression, mean difference = 0.72 mm, 95% CI = 0.43, 1.01, P < 0.001). Catheterization success rates were not different between groups. Conclusions: EIV compression increased FV size, but the effect on femoral venous catheterization success rates was inconclusive due to a small sample size.

521 Maintaining Central Line Patency in Burned Children

IntroductionChildren with major burn injury frequently require prolonged central venous access to assure appropriate fluid management and pain control. Central venous catheters in children frequently develop clots that prevent drug administration, requiring administration of tissue plasminogen activator (TPA). The purpose of this study was to identify the frequency and efficacy of TPA use in burned children with central venous catheters (CVC).MethodsThis retrospective chart review evaluated all children requiring CVC admitted to our tertiary pediatric burn center from 2018-2019. Data collected included patient demographics (age, burn size, hospital length of stay (LOS)), catheter-related data (number of central lines, lines replaced due to clotting), TPA administration (number of times administered, successful TPA administrations, how often repeated), and line clotting data (time from insertion to clot, interval between TPA order and administration).ResultsIn 2018, 116 lines were place in 49 children with mean age of 8.4 years and mean burn size of 29%, intensive care unit LOS was 24 days. TPA was infused in 20% of lines to relieve obstruction and was successful in relieving the clot in 21% (5/23). The interval between identification of the obstructed line to TPA order was 191 minutes, with the administration of TPA 83 minutes after order placement. The average time from identification of obstruction to TPA administration was 257 minutes. In 2019, 150 lines were place in 65 children with mean age of 5.2 years and mean burn size of 25%, LOS was 13 days in the PICU. TPA was infused in 5% of lines to relieve obstruction and was successful in relieving the clot in 0 % (0/8). The interval between identification of the obstructed line to TPA order was 117 minutes, with the administration of TPA 49 minutes after order placement. The average time from identification of obstruction to TPA administration was 158 minutes.ConclusionsThe incidence of obstruction in pediatric central venous catheters in our unit decreased from 26% in 2018 to 3% in 2019. TPA was successful in clot resolution in only 5% (2018), and 0% (2019) . Based on our results, we targeted areas for improvement including: Standing order for TPA; staff education on TPA use; decreasing our average time to identify, order, and administer TPA; and standardizing the frequency of flushing unused central venous catheter lumens with heparinized saline flush.

Safety and efficacy of anticoagulant therapy in pediatric catheter-related venous thrombosis (EINSTEIN-Jr CVC-VTE)

AbstractAnticoagulant treatment of pediatric central venous catheter–related venous thromboembolism (CVC-VTE) has not been specifically evaluated. In EINSTEIN-Jr, 500 children with any VTE received rivaroxaban or standard anticoagulants. A predefined analysis of the CVC-VTE cohort was performed. Children with CVC-VTE (age, birth to 17 years) were administered rivaroxaban or standard anticoagulants during the 1-month (children <2 years) or 3-month (all other children) study period. Predefined outcomes were recurrent VTE, change in thrombotic burden on repeat imaging, and bleeding. Predictors for continuation of anticoagulant therapy beyond the study period were evaluated. One hundred twenty-six children with symptomatic (n = 76, 60%) or asymptomatic (n = 50, 40%) CVC-VTE received either rivaroxaban (n = 90) or standard anticoagulants (n = 36). There was no recurrent VTE (0%; 95% confidence interval [CI], 0.0%-2.8%). Three children had the principal safety outcome: none had major bleeding and 3 children had clinically relevant nonmajor bleeding (2.4%; 95% CI, 0.7%-6.5%), all in the rivaroxaban arm. Complete or partial vein recanalization occurred in 57 (55%) and 38 (37%) of 103 evaluable children, respectively. Results were similar for symptomatic and asymptomatic CVC-VTE. Continuation of anticoagulant therapy beyond the study period occurred in 61 (48%) of children and was associated with residual VTE but only in children <2 years (odds ratio [OR], 20.9; P = .003) and continued CVC use (OR, 6.7; P = .002). Anticoagulant therapy appeared safe and efficacious and was associated with reduced clot burden in most children with symptomatic or asymptomatic CVC-VTE. Residual VTE and continued CVC use were associated with extended anticoagulation. This trial was registered at www.clinicaltrials.gov as #NCT02234843.

Computer-assisted needle navigation for pediatric internal jugular central venous cannulation: A feasibility study.

Vascular access for central venous catheter placement is technically challenging in children. Ultrasound guidance is recommended for pediatric central venous catheter placement, yet many practitioners rely on imprecise anatomic landmark techniques risking procedure failure due to difficulty mastering ultrasound guidance. A novel navigation system provides a visual overlay on real-time ultrasound images to depict needle trajectory and tip location during cannulation. We report the first pediatric study assessing feasibility and preliminary safety of using a computer-assisted needle navigation system to aid in central venous access. A prospective, institutional review board-approved feasibility study was performed. All participants provided written informed consent. Ten patients (mean age: 11.4 years, five males) underwent central venous catheter placement with ultrasound and navigation system guidance. All procedures were performed by interventional radiologists expert in vascular access. Feasibility was measured through binary (yes/no) responses from participating users assessing device usability and feasibility. The number of needle passes and procedure time measures were also recorded. Internal jugular veins (seven right sided, three left sided) were cannulated in all patients with no complications. Users confirmed navigation system feasibility in all 10 participants. Mean vein diameter and depth was 13.3 × 9.8 ± 3.4 × 2.1 and 7.0 ± 1.7 mm, respectively. Successful cannulation occurred in all patients and required only a single needle pass in 9 of 10 patients. Mean device set-up and vascular access times were 5:31 ± 2:28 and 1:48 ± 2:35 min, respectively. This pilot study suggests that it is feasible to use a novel computer-assisted needle navigation system to safely obtain central venous access under ultrasound guidance in pediatric patients.

CE Article: A Quality Improvement Approach in Standardizing Pediatric Central Venous Catheter Dressings and Its Impact on the Reduction of Central Line-Associated Bloodstream Infections and Costs

Highlights A CVC dressing inventory is beneficial to pediatric patients. Dressing standardization reduced unplanned dressing changes and costs. In our study, the new dressing inventory helped reduce the CLABSI rate.

Vascular Access Choice, Complications, and Outcomes in Children on Maintenance Hemodialysis: Findings From the International Pediatric Hemodialysis Network (IPHN) Registry

Arteriovenous fistulas (AVFs) have been recommended as the preferred vascular access for pediatric patients on maintenance hemodialysis (HD), but data comparing AVFs with other access types are scant. We studied vascular access choice, placement, complications, and outcomes in children. Prospective observational cohort study. 552 children and adolescents from 27 countries on maintenance HD followed up prospectively by the International Pediatric HD Network (IPHN) Registry between 2012 and2017. Type of vascular access: AVF, central venous catheter (CVC), or arteriovenous graft. Infectious and noninfectious vascular access complication rates, dialysis performance, biochemical and hematologic parameters, and clinical outcomes. Univariate and multivariable linear mixed models, generalized linear mixed models, and proportional hazards models; cumulative incidence functions. During 314 cumulative patient-years, 628 CVCs, 225 AVFs, and 17 arteriovenous grafts were placed. One-third of the children with an AVF required a temporary CVC until fistula maturation. Vascular access choice was associated with age and expectations for early transplantation. There was a 3-fold higher living related transplantation rate and lower median time to transplantation of 14 (IQR, 6-23) versus 20 (IQR, 14-36) months with CVCs compared with AVFs. Higher blood flow rates and Kt/Vurea were achieved with AVFs than with CVCs. Infectious complications were reported only with CVCs (1.3/1,000 catheter-days) and required vascular access replacement in 47%. CVC dysfunction rates were 2.5/1,000 catheter-days compared to 1.2/1,000 fistula-days. CVCs required 82% more revisions and almost 3-fold more vascular access replacements to a different site than AVFs (P<0.001). Clinical rather than population-based data. CVCs are the predominant vascular access choice in children receiving HD within the IPHN. Age-related anatomical limitations and expected early living related transplantation were associated with CVC use. CVCs were associated with poorer dialysis efficacy, higher complication rates, and more frequent need for vascular access replacement. Such findings call for a re-evaluation of pediatric CVC use and practices.

Central venous catheters: Indications, techniques, and complications

Central venous catheters (CVC) are commonplace in the management of critically ill patients and serve a variety of purposes. Venous access is important for the administration of fluid and medications as well as blood procurement needed for lab analyses. However, not every critically ill patient requires a CVC. This article highlights the key considerations, pitfalls and evidence-based practices regarding the use pediatric central venous catheters.

Fractured pediatric central venous catheters — Repair or replace?

IntroductionCentral venous catheter (CVC) fracture is a common complication. The aim of this study is to examine risk factors resulting in CVC fracture and compare outcomes of children undergoing CVC repair versus replacement. MethodsA retrospective chart review was conducted from 2000 to 2016 for children with tunneled CVCs. Children with CVC fractures were compared to those without to identify risk factors resulting in fracture. Children with fractured CVCs were divided into repair or replacement treatment groups and outcomes compared. A logistic regression model determined independent predictors of CVC-associated bloodstream infections (CLABSI) after fracture. ResultsIn the 236 children with CVCs, the fracture rate was 29.2%. Fractured CVCs were more common with double lumen CVC (p = 0.040) and children whose indication was total parenteral nutrition (p = 0.003). Given children often underwent multiple repairs or replacements. 98 CVC repairs and 41 replacements were analyzed. CVC replacements had longer durability than repair (181.98 vs. 98.9 days, p = 0.038). There were no differences in CLABSI incidence for repair vs. replacement (OR 0.5 CI 0.05–4.97) after controlling for other factors. ConclusionsCVC fracture is a frequent complication in children with tunneled CVCs. CVC repair has no increased incidence of CLABSI but eliminates the intraoperative and anesthetic risks of CVC replacement. Type of studyRetrospective cohort study. Level of evidenceLevel III.

Cost-Effectiveness of Pediatric Central Venous Catheters in the UK: A Secondary Publication from the CATCH Clinical Trial.

Background: Antibiotic-impregnated central venous catheters (CVCs) reduce the risk of bloodstream infections (BSIs) in patients treated in pediatric intensive care units (PICUs). However, it is unclear if they are cost-effective from the perspective of the National Health Service (NHS) in the UK.Methods: Economic evaluation alongside the CATCH trial (ISRCTN34884569) to estimate the incremental cost effectiveness ratio (ICER) of antibiotic-impregnated (rifampicin and minocycline), heparin-bonded and standard polyurethane CVCs. The 6-month costs of CVCs and hospital admissions and visits were determined from administrative hospital data and case report forms.Results: BSIs were detected in 3.59% (18/502) of patients randomized to standard, 1.44% (7/486) to antibiotic and 3.42% (17/497) to heparin CVCs. Lengths of hospital stay did not differ between intervention groups. Total mean costs (95% confidence interval) were: £45,663 (£41,647–£50,009) for antibiotic, £42,065 (£38,322–£46,110) for heparin, and £44,503 (£40,619–£48,666) for standard CVCs. As heparin CVCs were not clinically effective at reducing BSI rate compared to standard CVCs, they were considered not to be cost-effective. The ICER for antibiotic vs. standard CVCs, of £54,057 per BSI avoided, was sensitive to the analytical time horizon.Conclusions: Substituting standard CVCs for antibiotic CVCs in PICUs will result in reduced occurrence of BSI but there is uncertainty as to whether this would be a cost-effective strategy for the NHS.

Central venous access in children: indications, devices, and risks.

Central venous catheters (CVCs) have a prominent role in the diagnostic and therapy of neonates and children. Herein, we describe the multiple indications for CVC use and the different devices available for central venous access. Given the prevalent use of CVCs, healthcare systems are focused on reducing complications from their use, particularly central line-associated bloodstream infections (CLABSIs). The most up-to-date information available sheds light on best practices and future areas of investigation. Large systematic reviews of randomized trials suggest that ultrasound guidance for placement of CVCs in children is safer than using blind technique, at least for internal jugular vein access. Appropriate catheter tip placement is associated with decreased complications. Furthermore, the prophylactic use of ethanol lock between cycles of parenteral nutrition administration has reduced the rates of CLABSI. A recent randomized trial in pediatric CVCs showed a benefit with antibiotic-coated CVCs. Based on the available evidence, multiple techniques for CVC placement are still valid, including the landmark technique based on practitioner experience, but ultrasound guidance has been shown to decrease complications from line placement. Adherence to CVC care protocols is essential in reducing infectious complications.

Study of in vivo catheter biofilm infections using pediatric central venous catheter implanted in rat.

Venous access catheters used in clinics are prone to biofilm contamination, contributing to chronic and nosocomial infections. Although several animal models for studying device-associated biofilms were previously described, only a few detailed protocols are currently available. Here we provide a protocol using totally implantable venous access ports (TIVAPs) implanted in rats. This model recapitulates all phenomena observed in the clinic, and it allows bacterial biofilm development and physiology to be studied. After TIVAP implantation and inoculation with luminescent pathogens, in vivo biofilm formation can be monitored in situ, and biofilm biomass can be recovered from contaminated TIVAP and organs. We used this protocol to study host responses to biofilm infection, to evaluate preventive and curative antibiofilm strategies and to study fundamental biofilm properties. For this procedure, one should expect ∼3 h of hands-on time, including the implantation in one rat followed by in situ luminescence monitoring and bacterial load estimation.

Engaging Frontline Staff in Central Line–Associated Bloodstream Infection Prevention Practice in the Wake of Superstorm Sandy

Central venous catheters are crucial devices in the care of hospitalized children, both in and out of critical care units, but the concomitant risk of central line-associated bloodstream infection (CLABSI) affects 15,000 Americans annually. In 2012, CLABSI rates varied among units from 6.8/1,000 to 1.0/1,000 in a 109-bed children's service within NYU Langone Medical Center (NYULMC; New York City), a 1,069-bed tertiary care academic medical center. In response to variation in central line-related practices and infection prevention rates, a CLABSI Prevention Core Team began an effort to standardize central venous catheter (CVC) care across all pediatric units (ICU and non-ICU). Momentum in this quality improvement (QI) work was interrupted when Superstorm Sandy shuttered the flagship hospital, but the relatively decreased clinical load provided a "downtime" opportunity to address CLABSI prevention. The first phase of the collaborative effort, Booster 1, Planning/Initial Phase: Development of a Pediatric Central Venous Catheter Working Group, was followed by Booster 2, Maintenance/Sustaining Phase: Transitioning for Sustainability and Adopting Model for Improvement. Data in the subsequent 21 months after the temporary closure of the facility (January 2013-September 2014) showed an increase in maintenance bundle reliability. The inpatient CLABSI rate for patients<18 years decreased from an annual rate of 2.7/1,000 line days (2012) to 0.6/1,000 line days (2013) to 0.5/1,000 line days as of August 2014. There was a decrease in pediatric CLABSI events and no significant change in line days. Key elements contributing to initial success with evolving QI capacity and resources were likely multi-factorial, including staff and leadership engagement, culture change, consistent guidelines, and accountability by individuals and by our multidisciplinary core team.

Factors affecting survival in pediatric cardiac tamponade caused by central venous catheters.

Pediatric central venous catheter (CVC) placement is useful but associated with complications such as cardiac tamponade. We aimed to identify risk factors for death in cardiac tamponade. Published articles on pediatric CVC-associated cardiac tamponade were obtained by searching PubMed and Google and retrospectively reviewed to analyze risk factors for death. Factors examined for their effect on mortality risk included patient age, weight, CVC size, days from CVC insertion to tamponade occurrence, substances administered, insertion site, treatment, CVC material, and initial CVC tip position. Of 110 patients reported in 62 articles, 69 survived and 41 died. Among survivors, 55 of 69 patients were treated; among deaths, only 7 of 38 (OR 537.9, 95% CI 29.3-9,877, p < 0.0001). Multiple regression analysis in 44 cases showed that treatment (p < 0.0001) and initial CVC tip position (p = 0.020) were independent predictive factors related to improved cardiac tamponade survival. Past studies have mainly discussed how to avoid pediatric cardiac tamponade; by contrast, the present study focused on how to avoid deaths. The findings of this review suggest that cardiac tamponade survival is better when tamponade is detected early and treated promptly and might be affected by initial CVC tip position.

Simulation Training for Pediatric Residents on Central Venous Catheter Placement

To assess the effect of simulation training on pediatric residents' acquisition and retention of central venous catheter insertion skills. A secondary objective was to assess the effect of simulation training on self-confidence to perform the procedure. Prospective observational pilot study. Single university clinical simulation center. Pediatric residents, postgraduate years 1-3. Residents participated in a 60- to 90-minute ultrasound-guided central venous catheter simulation training session. Video recordings of residents performing simulated femoral central venous catheter insertions were made before (baseline), after, and at 3-month following training. Three blinded expert raters independently scored the performances using a 24-item checklist and 100-mm global rating scale. At each time point, residents rated their confidence to perform the procedure on a 100-mm scale. Twenty-six residents completed the study. Compared with baseline, immediately following training, median checklist score (54.2% [interquartile range, 40.8-68.8%] vs 83.3% [interquartile range, 70.0-91.7%]), global rating score (8.0 mm [interquartile range, 0.0-64.3 mm] vs 79.5 mm [interquartile range, 16.3-91.7 mm]), success rate (38.5% vs 80.8%), and self-confidence (8.0 mm [interquartile range, 3.8-19.0 mm] vs 52.0 mm [interquartile range, 43.5-66.5 mm]) all improved (p < 0.05 for all variables). Compared with baseline, median checklist score (54.2% [interquartile range, 40.8-68.8%] vs 54.2% [interquartile range, 45.8-80.4%], p = 0.47), global rating score (8.0 mm [interquartile range, 0.0-64.3 mm] vs 35.5 mm [interquartile range, 5.3-77.0], p = 0.62), and success rate (38.5% vs 65.4%, p = 0.35) were similar at 3-month follow-up. Self-confidence, however, remained above baseline at 3-month follow-up (8.0 mm [interquartile range, 3.8-19.0 mm] vs 61.0 mm [interquartile range, 31.5-71.8 mm], p < 0.01). Simulation training improved pediatric residents' central venous catheter insertion procedural skills. Decay in skills was found at 3-month follow-up. This suggests that simulation training for this procedure should occur in close temporal proximity to times when these skills would most likely be used clinically and that frequent refresher training might be beneficial to prevent skills decay.