Effects of polyvinyl chloride film and oxygen-blocking gel on irradiance and depth of cure.

This study aimed to analyze the effects of polyvinyl chloride (PVC) film and oxygen-blocking gel (OBG) on the irradiance from an LED source and the depth of cure of a composite resin. Irradiance was measured with a curing radiometer, and curing depth was evaluated according to the methods described by the International Organization for Standardization (ISO 4049). Twelve experimental conditions were investigated in a 3 × 4 factorial design (n = 5 specimens per condition): no PVC film at the tip of the device, fitted PVC film, or misfit PVC film; and no OBG or a 1-, 2-, or 3-mm-thick layer of OBG. The data were analyzed using analysis of variance and Tukey tests (P < 0.05), and a linear regression test was performed between the variables (P < 0.05). The analyses showed that the variables under study influenced the irradiance (P < 0.05) but not the curing depth (P > 0.05). The 3 groups that did not have the PVC film and either did not have the OBG or had the OBG in a thickness of 1 or 2 mm were not significantly different from each other (P > 0.05) but presented the highest irradiance values among all the groups (P < 0.05). The use of the misfit PVC film with a 3-mm layer of OBG led to the lowest irradiance values (P < 0.05). The variables did not influence each other (P > 0.05). The results of this study indicated that the presence of PVC film, especially misfit film, reduced the irradiance. In addition, the greater the thickness of the OBG, the lower the irradiance. None of the PVC film barrier conditions or OBG thicknesses had an effect on the depth of cure.

Microscopic and chemical characterization of PVC tube used for dialysis lines: A new approach.

Polyvinylchloride is universally agreed upon to be the material of choice for tubings and for containers for medical application. Many alterations of the chemical/physical surface conditions, mainly due to an altered extrusion process, could influence its biocompatibility by promoting platelet aggregation. Biocompatibility and safety of the medical device must be preserved, also monitoring the migration of additives within polyvinylchloride during the diffusion process. A large variety of methods are used to verify the correct composition and extrusion of polyvinylchloride but, generally, they need long experimental time and are expensive. The aim of the study is to propose a simple, economic and rapid approach based on Fourier transform-infrared spectroscopy and Coomassie Blue staining. The method has been used to detect chemical and morphological defects caused by an altered extrusion process on 20/75 polyvinylchloride tubings in a blind test. This approach positively identified altered samples in 80% of the cases. The suggested approach represents a reliable and versatile method to detect and monitor surface defects by an easy, inexpensive and reproducible method.

Capacity of Infusion Lines for Insulin Adsorption: Effect of Flow Rate on Total Adsorption.

BACKGROUND: Insulin adsorption to clinical materials has been well observed, but not well quantified. Insulin adsorption reduces expected and actual insulin delivery and is unaccounted for in insulin therapy or glycemic control. It may thus contribute to poor control and high glycemic variability. This research quantifies the problem in the context of clinical use. METHOD: Experimental insulin adsorption data from literature is used to calculate insulin delivery and total insulin adsorption capacities for polyethylene (PE) and polyvinal chloride (PVC) lines at clinically relevant flow rates and concentrations. RESULTS: Insulin adsorption capacity decreased hyperbolically with flow rate for both PE and PVC, where low flow scenarios result in greater insulin adherence to infusion lines. When the infusion flow rate was halved from 1 to 0.5 mL/h, twice as much insulin adsorbed to the line. Insulin loss to adsorption resulted in up to ~50% of intended insulin not delivered over 24 hours in a low flow and low concentration context. CONCLUSION: Material capacity for insulin adsorption is not constant, but increases with decreasing flow. Different materials have different adsorption capacities. In low flow and low concentration contexts, such as in neonatal or pediatric intensive care, insulin loss to adsorption represents a significant proportion of daily insulin delivery, which needs to be accounted for.

Exposure of patients to di(2-ethylhexy)phthalate (DEHP) and its metabolite MEHP during extracorporeal membrane oxygenation (ECMO) therapy.

The plasticizer di(2-ethylhexyl)phthalate (DEHP) is often used for PVC medical devices, that are also largely used for intensive care medical treatments, like extracorporeal membrane oxygenation (ECMO) therapy. Due to the toxicological potential of DEHP, the inner exposure of patients with this plasticizer is a strong matter of concern as many studies have shown a high leaching potential of DEHP into blood. In this study, the inner DEHP exposure of patients undergoing ECMO treatment was investigated. The determined DEHP blood levels of ECMO patients and the patients of the control group ranged from 31.5 to 1009 µg/L (median 156.0 µg/L) and from 19.4 to 75.3 µg/L (median 36.4 µg/L), respectively. MEHP blood levels were determined to range from < LOD to 475 µg/L (median 15.9 µg/L) in ECMO patients and from < LOD to 9.9 µg/L (median 3.7 µg/L) in the control group patients, respectively. Increased DEHP exposure was associated with the number of cannulas and membranes of the ECMO setting, whereas residual diuresis decreased the exposure. Due to the suspected toxicological potential of DEHP, its use in medical devices should be further investigated, in particular for ICU patients with long-term exposure to PVC, like in ECMO therapy.

Advanced Drug-Eluting Poly (Vinyl Chloride) Surfaces Deposited by Spin Coating.

Background and objectives: Medical devices such as catheters are used on a large scale to treat heart and cardiovascular diseases. Unfortunately, they present some important drawbacks (structure failure, calcifications, infections, thrombosis, etc.), with the main side effects occurring due to adhesion and proliferation of bacteria and living cells on the surface of the implanted devices. The aim of this work is to modify the surface of polyvinyl chloride (PVC), an affordable biocompatible material, in order to reduce these aforementioned side effects. Materials and Methods: The surface of PVC was modified by depositing a thin layer also of PVC that incorporates an active substance, dicoumarol (a well-known anticoagulant), by spin coating process. The modified surfaces were analyzed by Fourier-transform infrared (FT-IR) microscopy, Fourier-transform infrared (FT-IR) spectroscopy, Ultraviolet-visible spectroscopy (UV-VIS), and Scanning electron microscopy (SEM) in order to determine the surface morphology and behavior. The samples were tested for Gram-positive (S. aureus ATCC 25923) and Gram-negative (P. aeruginosa ATCC 27853) standard strains from American Type Culture Collection (ATCC). Results: The material obtained had a smooth surface with a uniform distribution of dicoumarol, which is released depending on the deposition parameters. The concentration of dicoumarol at the surface of the material and also the release rate is important for the applications for which the surface modification was designed. PVC modified using the proposed method showed a good ability to prevent salt deposition and decreased the protein adhesion, and the resistance to bacterial adherence was improved compared with standard PVC.

Síndrome de la bolsa de orina púrpura / Purple urine bag syndrome

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Diseño y elaboración de una férula tipo tenodesis fabricada en termoplástico de alta resistencia policloruro de vinilo PVC para la promoción de agarre de pinza trípode en personas con secuelas de trauma raquimedular / Design and development of a kind tenodesis splint made in high resistance thermoplastic polyvinyl chloride PVC to promote tripod clamp grip in people with spinal cord trauma aftermath

El presente documento es una propuesta teórica, que tiene como finalidad presentar un protocolo de elaboración de una férula dinámica tipo tenodesis a partir de un material termoplástico de alta temperatura, de fácil consecución en el mercado llamado policloruro de vinilo; Este tipo de férula se clasifica dentro de las denominadas férulas dinámicas y su objetivo final es la promoción de agarre de pinza trípode en personas que por lesiones a nivel de C5-C6, presentan ausencia de movilidad en los dedos de la mano pero conservan movimientos de muñeca. Cuando el usuario extiende la muñeca, la férula activa una serie de mecanismos que producen flexión pasiva de articulaciones metacarpofalangicas de los dedos II y III y simultáneamente hay una abducción y una relativa oposición del pulgar; estos movimientos formarán una pinza que proveerá al usuario la posibilidad de realizar actividades básicas con sus manos.

This document is a methodological contribution, which is to present a protocol for developing a tenodesis type dynamic splint from a high temperature thermoplastic material, easy to achieve on the market called polyvinyl chloride, this type of splint is classified within the so-called dynamic splints and its purpose is to promote tripod pincer grip in people with injuries at C5-C6, present lack of mobility in the fingers but retain wrist movements. When the user extends the wrist, splint activates a series of mechanisms that produce passive flexion of metacarpophalangeal joints of fingers II and III and simultaneously there is a relative abduction and thumb opposition, these movements form a clamp that will provide the user the ability to perform basic activities with their hands.

New developments in PVC.

Some hospitals in Europe still recommend medical devices that are not made from poly(vinyl chloride) (PVC) mainly because of environmental concerns. Yet, a brand new life cycle analysis that compares a medical device made from PVC with two devices made from alternative plastic materials shows that deselection of PVC is not advisable. This article reports on the latest scientific opinion on the possible risks related to the use of di(2-ethylhexyl) phthalate in medical devices and addresses some of the conclusions of the life cycle analysis.

Treatment of dural arteriovenous fistula using ethylene vinyl alcohol (onyx) arterial embolization as the primary modality: short-term results.

OBJECT: A dural arteriovenous fistula (DAVF) typically involves meningeal feeding arteries and can cause clinical symptoms ranging from tinnitus to rupture of draining cortical or parenchymal veins. Surgical treatment may be technically demanding. Ethylene vinyl alcohol (Onyx, ev3 Neurovascular) has several properties that make it potentially useful as a primary treatment agent for DAVF. Onyx is expected to be a permanent embolic agent. It should have a decreased risk of catheter retention when compared with other permanent embolic materials. METHODS: The authors report a series of six patients with symptomatic DAVF who were treated initially with transarterial Onyx embolization and other endovascular techniques. RESULTS: Five patients had complete occlusion of their DAVF noted on the follow-up angiogram obtained between 2 and 4 months. One patient had residual filling via a small arterial branch that was stable on follow-up angiography. None of the patients had worsening of neurological function. One case was complicated by a retained catheter fragment. CONCLUSIONS: Transarterial Onyx embolization and other endovascular methods can angiographically obliterate DAVF. In some cases, embolization allowed occlusion of multiple arterial feeding arteries from a single arterial injection. Technically, the embolization was optimized when a microcatheter position immediately adjacent to the point(s) of fistulization was achieved.

Resultados de la aplicación de mitomicina en la dacriocistorrinostomía endonasal y endocanalicular con láser diodo / Results the application of mitomicyn during endonasal and endocanalicular dacryocystorhinostomy by diode laser

Objetivo: Valorar el beneficio, efectos secundarios y seguridad de la aplicación de mitomicina C (MMC) de forma intraoperatoria, durante la realización de una dacriocistorrinostomía endonasal y endocanalicular con láser diodo (TLA-ELA DCR). Métodos: Se realizó un estudio prospectivo randomizado, intervencional y doble ciego. Se estudiaron 200 pacientes a 150 pacientes se les aplicó MMC intraoperatoria (0,4 mg/0,2 ml) durante un tiempo de 5 minutos, mediante un apósito de acetato de polivinilo que se coloca sobre la osteotomía. En el resto de pacientes fueron revisados a las 24 horas, 10 días, 1, 3 y 6 meses postcirugía. Se estudió el aspecto endoscópico y las posibles complicaciones. Los resultados se comparan mediante el test de Chi-cuadrado con la corrección de Yates. Se estudió la presencia o ausencia de efectos secundarios por la aplicación de MMC. Resultados: El seguimiento medio fue 15,25 meses (rango= 6-21 meses). El porcentaje de alteraciones por cicatrización excesiva fue del 21,77% y del 8,03%, en los pacientes sin y con MMC respectivamente. La diferencia fue estadísticamente significativa (p=0,02). No hubo efectos secundarios por la aplicación de MMC. Conclusiones: La aplicación de MMC intraoperatoria tópica durante TLA-ELA DCR disminuye los hallazgos patológicos por cicatrización del área periférica al nuevo drenaje sin producir efectos secundarios

Aim of the study: To study the effects, secondary effects and security of the intrasurgical application of mitomicyn C during endonasal and endocanalicular dacryocystorhinostomy with diode laser (TLA-ELA DCR). Methods: We carried out a randomized, prospective, interventional and double blind study in 200 patients: intrasurgical mitomicyn C was applied in 150 of then (0.4 mgr/0.2 ml) for 5 minutes by means of a polivinil acetate dressing over the osteotomy. In other 50 patients MMC was not used we followed up at 24 hours, 10 days and 1, 3 and 6 months after surgery. Endoscopic aspects and possible complications were valued. The results were compared using the Chi-squared test with the Yates correction. We looked for the presence or abscense of secondary effects in the application of mitomicyn C. Results: The average follow up was 15.25 months (range 6 to 21 months). The percentages of alterations for excesive scarring were 21.77% in patients without and MAC 8.03% in the ones MMC. The difference was statisticaly significant (p= 0.02). We did not find secondary effects due to application of mitomcyn. Conclusions: Intrasurgical application of topical MMC during TLA-ENL DCR reduces the number of pathological findings due to scarring of the surrouding area of the new drainage without secondary effects

[Experimental validation of the method of autografts creation for arteries].

Experimental studies on rats have demonstrated possibility of connective-tissue grafts formation on polyvinylchloride base introduced subcutaneously. Dynamics of autograft formation is characterized by gradual thinning of wall, regulation of collagen fibers, decreased number of cells with fibrocytes predominance. Autografts in carotid position retain its patency during 3 months, and endotheliocytes appear on their internal surface.

Comparison among Op-site, polyvinyl chloride film and tulle gauze in the treatment of skin graft donor sitet.

A prospective analytic study was performed at the Division of Plastic and Reconstructive Surgery, Department of Surgery, King Chulalongkorn Memorial University Hospital and the Department of Surgery, Chiang Mai University Hospital to compare among Polyvinyl chloride film (PVC film), Op-site and tulle gauze in the treatment of skin graft donor site. From October 1998 to January 2000, 81 donor sites in the same number of patients were treated by three different methods; tulle gauze (26 patients), Op-site (27 patients) and PVC film (28 patients). Each wound was followed until it was completely healed and visual analogue scale was used for pain evaluation. Donor site dressed with PVC film had a healing time of 10.44 days which was not different from Op-site (10.54 days) but significantly faster (p<0.001) than tulle gauze (17.84 days). Pain as measured with visual analogue scale in the group of PVC film (1.48) was not different from Op-site (1.34) but significantly less than (p<0.001) tulle gauze (5.45). There was no difference in the rate of infection between each group. In conclusion, the authors found no difference between Op-site and PVC film in healing time and pain. Both of them were better than tulle gauze. The results demonstrate the usefulness of PVC film as a donor site dressing as it promises relatively rapid healing, less pain and is inexpensive.

Emprego da bolsa plástica de transferência de hemoderivados no tratamento da gastrosquise / Utilization of a hemoderivates plastic bag for the treatment of gastroschisis

Os autores apresentam a sua experiência com a utilizaçäo da bolsa plástica de PVC (cloreto de polivinila), usada na transferência de hemoderivados, como prótese na confecçäo do silo para o tratamento cirúrgico da gastrosquise, em quatro recém-nascidos. Essa bolsa plástica é estéril, impermeável aos microorganismos, transparente, flexível, resistente, lisa internamente e näo aderente às alças, de fácil aquisiçäo e de baixo custo; características que a tornam excelente alternativa como prótese para o tratamento cirúrgico estadiado das anomalias congênitas da parede abdominal, como gastrosquise e a onfalocele. Os autores ressaltam ainda a importância da equipe multidisciplinar no atendimento a recém-nascidos com gastrosquise, para que haja bom exito pós-operatório.

Cytokine generation in rabbits during extracorporeal lung assist with a mini hollow fiber lung.

To examine host responses to extracorporeal lung assist (ECLA) in small animals, we developed a mini hollow fiber lung of nonmicroporous polyolefin and an extracorporeal bypass circuit with a priming volume of 25 ml. This circuit allowed ECLA of up to 72 h without blood transfusion in 20 rabbits. The ECLA procedure induced the appearance of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) receptor antagonist (IL-1Ra) in plasma, but not IL-1 beta. However, these changes were observed only at the initial stage of ECLA, and the levels returned to pre-ECLA levels within 24 h. Although leukocytes adhering to the hollow fibers were immunohisto-chemically positive for IL-1 beta and IL-Ra, the plasma levels of these cytokines in response to ECLA were not different from those observed in rabbits given anesthesia and subjected to minor surgery but without ECLA. Thus, ECLA itself is a minor factor in the production of these cytokines.

Thermographic assessment of burns using a nonpermeable membrane as wound covering.

Infrared thermography is a useful technique for the investigation of disorders which affect skin blood flow. The damage to skin blood vessels caused by thermal injury is a major determinant of the capacity of the wound to heal. Thermographic assessment of this damage has been found to correlate with the healing time of burn wounds. However, the application of thermography to the assessment of burns for early surgery has been limited because of the difficulties involved in correcting for cooling artefacts resulting from the effect of evaporative water loss (EWL) at the wound surface. A water impermeable polyvinylchloride film (sold in the USA as Saran Wrap, in Australia as Glad Wrap and in the UK as Clingfilm (CF)) was investigated as a wound covering to avoid this cooling effect. It was found that the CF abolished the cooling effect of EWL and did not significantly interfere with the measurement of surface temperature. This material provides a solution to the problems of thermographic examination of wounds such as burns where damage to the skin surface allows exudation or EWL to occur.

Measurement of surface temperature as an aid to the diagnosis of burn depth.

In 60 burned patients, the depth of injury was assessed clinically, and then surface temperature measurements were taken of the burn and of nearby unburned skin. The final diagnosis of burn depth was determined by the time taken to heal or by the findings at excision of the burn. The temperature difference between burned and unburned skin correlated with the depth of the injury. Overall diagnosis of burn depth was 60 per cent accurate by clinical assessment and 78 per cent accurate by measurement of surface temperature. Accuracy was greater when burns of the hand, face and feet, and burns seen late, were excluded.

Polyvinyl chloride work boots in the management of shoe dermatitis in industrial workers.

A sugar refinery worker developed allergic contact dermatitis of his feet secondary to rubber accelerators in his work boots. The dermatitis resolved when polyvinyl chloride work boots were substituted. The importance of controlling hyperhidrosis in the management of foot dermatitis in workers is discussed.

The Swan-Ganz catheter: a review.

Right heart catheterization, first reported in 1905, is now used for bedside assessment and management of the critically ill patient. A Swan-Ganz catheter and pulmonary artery pressure monitoring are the tools employed. In spite of the complications cited, the occurrence of hazard to the patient is infrequent. The catheter is particularly valuable in the hemodynamic evaluation of cardiac function. Right and left heart pump performance can be assessed by pressure measurements. The ability of the left heart to provide an adequate cardiac output can be numerically calculated, and its adequacy at a cellular level can be evaluated by determining arterial-venous oxygen saturation difference. One of the more important and newest uses of the Swan-Ganz catheter is the preventive function it plays in anesthesia administration. Implications of the Swan-Ganz catheter for nursing practice are: (1) explanation and support to patient and family; (2) technical understanding and knowledge of set-up; (3) care and maintenance of the catheter after insertion; (4) the understanding of physiologic principles underlying the use of the catheter; and, most important, (5) ability to correlate clinical observations and physiologic changes occurring in the patient with pressure measurements.