Catheter-associated
urinary tract infection (CAUTI) presents a
significant health problem worldwide and is associated with increased
morbidity and mortality. Herein, a silver-polytetrafluoroethylene
(Ag-PTFE) nanocomposite coating for catheters was developed via a
facile wet chemistry method. Benefiting from the synergistic effect
of Ag and PTFE, the as-prepared Ag-PTFE-coated catheter exhibited
enhanced antibacterial and antiadhesive activities against two CAUTI-associated
strains: E. coli WT F1693 and S. aureus F1557. Compared to the uncoated commercial silicone catheters and
the Ag-coated catheters, the Ag-PTFE-coated catheters were able to
reduce bacterial adhesion by up to 60.3% and 55.2%, respectively.
The Ag-PTFE-coated catheters also exhibited strong antibiofilm activity,
reducing biofilm coverage by up to 97.4% compared with the commercial
silicone catheters. In an in vitro bladder model, the Ag-PTFE-coated
catheter displayed excellent anti-infection efficacy against bacteriuria,
extending the lifetime of silicone catheters from a mean of 6 days
to over 40 days. The Ag-PTFE coating also showed good biocompatibility
with fibroblast cells in culture, making it a prospective strategy
to overcome current challenges in CAUTI.
Thiel embalming is recommended as an alternative to formalin-based embalming because it preserves tissue elasticity, color, and flexibility in the long term, with low infection and toxicity risk. The degree to which Thiel embalming preserves elasticity has so far been assessed mainly by subjective scoring, with little quantitative verification. The aim of this study is to quantify the effect of Thiel embalming on the elastic properties of human ankle tendons and ligament. Biomechanical tensile tests were carried out on six Thiel-embalmed samples each of the peroneus longus, peroneus brevis, and calcaneal tendons, and the calcaneofibular ligament, with strain rates of 0.25%s(-1), 2%s(-1), and 8%s(-1). The stress-strain relationship was calculated from the force-extension response with cross-sectional area and gauge length. Young's modulus was determined from the stress-strain curve. The results showed that the tendon and ligament elasticity were lower after Thiel embalming than the literature values for fresh nonembalmed tendons and ligament. The biomechanical tensile test showed that the measured elasticity of Thiel-embalmed tendons and ligaments increased with the strain rate. The Thiel embalming method is useful for preserving human ankle tendons and ligaments for anatomy and surgery teaching and research, but users need to be aware of its softening effects. The method retains the mechanical strain rate effect on tendons and ligament.
Background: Catheter-associated urinary tract infections (CAUTIs) are among the most common hospital-acquired infections, leading to increased morbidity and mortality. A major reason for this is that urinary catheters are not yet capable of preventing CAUTIs. Aim: To develop an anti-infective urinary catheter. Methods: An efficient silver-polytetrafluoroethylene (Ag-PTFE) nanocomposite coating was deposited on whole silicone catheters, and two in-vitro bladder models were designed to test antibacterial (against Escherichia coli) and anti-encrustation (against Proteus mirabilis) performances. Each model was challenged with two different concentrations of bacterial suspension. Findings: Compared with uncoated catheters, coated catheters significantly inhibited bacterial migration and biofilm formation on the external catheter surfaces. The time to develop bacteriuria was an average of 1.8 days vs 4 days and 6 days vs 41 days when the urethral meatus was infected with 10 6 and 10 2 cells/mL, respectively. For antiencrustation tests, the coated catheter significantly resisted encrustation, although it did not strongly inhibit the increases in bacterial density and urinary pH. The time to blockage, which was found to be independent of the initial bacterial concentration in the bladder, was extended from 36.2AE1.1 h (uncoated) to 89.5AE3.54 h (coated) following bacterial contamination with 10 3 cells/mL in the bladder. Moreover, the coated catheter exhibited excellent biocompatibility with L929 fibroblast cells. Conclusion: Ag-PTFE coated Foley catheters should undergo further clinical trials to determine their ability to prevent CAUTIs during catheterization.
The soft-embalmed Thiel cadaver is a highly durable simulator that has excellent physical and functional properties that allow repeated injection for intensive ultrasound-guided regional anaesthesia training.
Working hours of UK trainee doctors have recently been reduced to 48 hours per week, reducing exposure to clinical cases. As such, there is widespread acceptance that trainees need to train in environments other than the ward or operating theatre in order to gain practical skills. Formalin-fixed cadavers demonstrate gross muscle and nerve anatomy but needle insertion under ultrasound guidance is poor. In contrast, a new development in medical simulation is the use of Thiel-embalmed cadavers, developed by Professor Thiel of the University of Graz, Austria, using a novel preservation technique that retains full flexibility of the limbs. Thiel cadavers have been used to successfully simulate laparoscopic surgery, neurosurgery and oral surgery. This paper investigates, for the first time, the application of ultrasound-based regional anaesthesia to the Thiel cadaver by tracing the course of peripheral nerves, injecting local anaesthetic around nerves, and reproducing inadvertent intraneural injection by injecting preservative directly into the nerve. The Thiel cadaver provides good conditions for anaesthetists to simulate regional anaesthetic block techniques using ultrasound.
Background: Our goal is to develop metrics that quantify the translation of performance from cadavers to patients. Our primary objective was to develop steps and error checklists from a Delphi questionnaire. Our second objective was to show that our test scores were valid and reliable. Methods: Sixteen UK experts identified 15 steps conducive to good performance and 15 errors to be avoided during interscalene block on the soft-embalmed cadaver and patients. Thereafter, six experts and six novices were trained, and then tested. Training consisted of psychometric assessment, an anatomy tutorial, volunteer scanning, and ultrasoundguided needle insertion on a pork phantom and on a soft-embalmed cadaver. For testing, participants conducted a single interscalene block on a dedicated soft-embalmed cadaver whilst wearing eye tracking glasses. Results: We developed a 15-step checklist and a 15-error checklist. The internal consistency of our steps measures were 0.83 (95% confidence interval [CI]: 0.78e0.89) and 0.90 (95% CI: 0.87e0.93) for our error measures. The experts completed more steps (mean difference: 3.2 [95% CI: 1.5e4.8]; P<0.001), had less errors (mean difference: 4.9 [95% CI: 3.5e6.3]; P<0.001), had better global rating scores (mean difference: 6.8 [95% CI: 3.6e10.0]; P<0.001), and more eye-gaze fixations (median of differences: 128 [95% CI: 0e288]; P¼0.048). Fixation count correlated negatively with steps (r¼e0.60; P¼0.04) and with errors (r¼0.64; P¼0.03). Conclusions: Our tests to quantify ultrasound-guided interscalene nerve block training and performance were valid and reliable.
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