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T R Cuadrado

Publications and source records attributed to T R Cuadrado.

2 recordsLinked to original sources

Assessment of parameters associated to the risk of PVC catheter reuse.

The practice of single use devices (SUD) recycling raises public health concerns, primarily with regard to the potential risks of infection and device malfunction. These concerns have led to a Food and Drug Administration (FDA) revision of the present regulations. The purpose of our work is to identify different material parameters that could contribute to the health risks associated with the practice of reprocessing PVC catheters for use in other patients. Ethylene oxide hospital-reprocessed central venous catheter samples were obtained from the stock of a health-care institution. One device trademark was selected, and samples that had been used 8 and 24 times were compared with new ones. In order to determine the total percentage of extractables, supercritical fluid extraction (SFE) was used, and off-line gas-chromatography-flame-ionization detection (GC-FID) was employed for identification and quantitation of bis-(2-ethyl hexil)phthalate (DEHP). Storage modulus (E') and dissipation factor (tan delta curves were obtained by dynamic mechanical analysis (DMA). Successive catheter recycles produced increased plasticizer loss, increased glass transition temperature (T(g)) and E', widening of tan delta curve with a simultaneous shift to higher temperature, small decrease of weight average molecular weight (M(w)), increased surface roughness, and increased appearance of surface grooves (severe damage). The magnitude of biomaterial parameter changes measured suggests that reuse could alter the original device performance. Examples of possible adverse clinical events include leaching of toxic agents, device rigidization or breakage, increased catheter protein retention, or the promotion of bacterial adhesion by device topography modification.

Biocompatible Materials↗

Polymethylmethacrylate-based bone cement modified with hydroxyapatite.

A commercial acrylic bone cement was modified by the incorporation of different weight fractions of polycrystalline hydroxyapatite (HA), and the modified formulation was investigated. The influence of the filler proportion on the flow characteristics and the mechanical behavior of the resultant composite was evaluated. The residual monomer present in the cured materials was measured by gas chromatography. The comparison of the residual monomer present in the cements with and without reinforcement demonstrated that the degree of polymerization was not affected by the addition of HA. Porosity morphology was analyzed by optical and scanning electron microscopy. Image examination revealed that the porosity and the pore size of the hardened cement increased with an increasing amount of particulate filler. Flexural, compressive, and fracture properties of the cement with varying amounts of HA reinforcement were measured. It was found that up to 15 wt% HA could be added for increases in flexural modulus and fracture toughness. HA acts as a rigid filler that enhances fracture resistance and flexural modulus. Our results show that the workability of the modified formulation limited the incorporation of the ceramic filler to a maximum value of 15 wt%.

Biocompatible Materials↗