Reprocessing of Catheters Used for Coronary Angiography and Changes in the Polymeric Structures
Bibliographic record
Abstract
BACKGROUND: Catheters are extensively used for coronary angiographies. These devices are long, thin, and flexible tubes of variable diameters that are made of the following polymer compounds: polyamide, polyurethane and Teflon. The objectives of this study are to identify changes that occur in the polymeric structure of the catheters, including an analysis of microcracks, fissures, cuts, perforations, roughness, and porosity in the internal and external layers after the first, second, third, and seventh reprocessing. METHODS: Five catheters of the same brand and manufacturer were selected for each analysis, except for the new and seventh catheters, which had only one sample. The catheters that we analyzed included new catheters, catheter reprocessed once (1st), catheters reprocessed twice (2nd), catheters reprocessed three times (3rd), and catheters reprocessed up to seven times (7th). Samples were cut into small pieces and the scanning electron microscope and infrared spectroscopy were used for analysis. RESULTS: Scanning electron microscopy (SEM) of reprocessed catheters revealed rougher surface with porosity, stainless steel wires, peeling of the inner layers, micropores, small holes, disordered cracks, cracks, grooves, microcracks, granular appearance, dots whitish, diffuse microcracks, desquamation, diffuse recesses, depressions, protrusions and deep crevices. Infrared spectroscopy suggested a possible change in the chemical structures of the polymer. There was a directly proportional relationship between the reprocessing number and the carbonyl ratio. CONCLUSIONS: The combined SEM and infrared analyses reveal that reprocessing damages the integrity of coronary angiography catheters. Therefore, the reprocessing of such catheters is not recommended.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".