The Vicenza 'Short' peritoneal catheter: a twenty year experience

Dislocation of peritoneal dialysis catheters is one of the major causes of technique failure. We evaluated 701 Vicenza catheters, implanted since 1985 in 365 males, mean age 53 +/- 16 yrs, range 24 - 87, and 336 females, mean age 51 +/- 17 yrs, range 21 - 82. The Vicenza catheter is defined "short" since it consists of a classic straight double cuff PD catheter having however an inner segment (the portion located in the peritoneal cavity) much shorter than any other type of catheter. It is implanted in the lower abdomen, just a few centimeters above the pubis. The analysis of our results obtained in a large PD population displayed good device survival at 2 and 5 years (94.3% and 91.5% respectively), a low dislocation rate (4%) and an exit-site infection rate similar to other double cuffed catheters. There was no selection of patients receiving this catheter since from 1985 we have used this catheter in every incident patient. Due to its lower implantation site this catheter demonstrates excellent wearability and good body image acceptance.     

Macrophage activation induced by different carbon fiber-epoxy resin composites

The activation of cells by interaction with solid surfaces is important in many settings, including the response of tissue to implanted materials. However, few comprehensive studies of both cell migration and activation have been performed so that the connection between these events and immunological activation against foreign material is not well understood. In the present study, synthesis and expression of Ia antigens by peritoneal exudate macrophages after implantation of different carbon fiber composites in the rat peritoneal cavity have been investigated in order to determine whether the type of material implanted affected the composition of Ia-bearing cells of the exudate. The results have confirmed the low level of expression of Ia on resident peritoneal macrophages; while we have found that macrophages, harvested after implantation, express a different amount of Ia related to the different cure cycles of the composite material used.     

Chronic peritoneal dialysis catheters: challenges and design solutions

Although highly successful as transcutaneous access devices, today's peritoneal dialysis catheters still have imperfect hydraulic function, biocompatibility and resistance to infection. Success of Tenckhoff catheters is greatly improved by the proper positioning of deep and subcutaneous cuffs and intraperitoneal segment. Newer peritoneal catheter designs are intended to improve hydraulic function, avoid outflow failure, and diminish exit site infection. These catheter designs serve as excellent alternatives for patients with various types of failure of Tenckhoff catheters. Catheters have been designed for Continuous Flow Peritoneal Dialysis, and have generally been successful in providing high peritoneal dialysis flow rate, but not always successful in optimally distributing flow of peritoneal fluid. Improvements in catheter design may expand the use of peritoneal dialysis as a successful home dialysis therapy.     

Infective complications of central venous catheters in cardiac surgical patients

Prospective randomised study was conducted over a 24 months period in a cardiac surgical intensive care unit to determine the incidence of infection associated with multilumen venous catheters. The influence of various factors including fever, peripheral blood culture, catheter site, catheter usage for monitoring central venous pressure and/inotrope therapy on infection rates were statistically evaluated. A total of 100 catheters submitted to the Microbiology laboratory were bacteriologically examined. Forty-nine of these were inserted into upper body sites, and 51 were inserted into the femoral vein. Twenty-one were triple-lumen catheters. Catheters were removed when a central line was no longer necessary. Catheter tips were cultured by semiquantitative technique for aerobic and anaerobic bacteria. Bacteremia occurred in 3% of catheter insertions; (Enterococcus faecalis, one; Enterobacter spp. One; Acinetobacter spp., one); and catheter colonisation developed in 24%. Neither catheter colonisation nor catheter related infection were associated with any of the risk factors evaluated. Our data indicates that central venous catheters are safe to use in our patients. The inability to identify "risk factors" for catheter infection emphasise the need to maintain a high index of suspicion.     

Home infusion

Many medications for HIV-related infections are more effective when administered intravenously, and some can be safely and effectively administered at home. Generally, the patient has a catheter inserted, which may be either a superficial catheter (changed frequently and prone to infections) or a central catheter (permanently implanted under local anesthesia). Regardless of type, catheters require special care to reduce the likelihood of infection. Catheters allow a measured amount to be injected, and in some cases are used to administer nutritional supplements. Characteristics of several brands are described.     

Clinical biodurability of aliphatic polyether based polyurethanes as peritoneal dialysis catheters

Thermoplastic polyurethane elastomers are the most important implantable grade polyurethanes in medical applications. An aliphatic polyether based polyurethane, Tecoflex (TF; Thermedics, Inc., Woburn, MA), is used in the construction of a proprietary peritoneal dialysis (PD) catheter. Information is limited regarding the biostability of the TF polymer in the clinical environment as a PD catheter. This report presents the clinical experience regarding the biodurability of 104 catheter implants. The extracorporeal tubing segments of all TF catheters eventually developed aesthetically offensive discoloration, opaqueness, and surface tackiness. Catheter breaks in the external segment occurred in 27% of devices that survived longer than 28 months. Mupirocin ointment at the catheter skin exit site caused swelling and deformity of the TF in one case. Three catheters extruded as a result of Dacron cuffs separating from the tubing wall. Catheters removed for other reasons were frequently found to have loose cuffs, especially if the devices were implanted for several years. Causes and possible mechanisms for observed failures are discussed. The durability of biomaterials used in construction of PD catheters is of vital importance for successful long-term functioning. The TF polymer embodied as a PD catheter represents a mismatch of the material and its mission. Fabrication of PD catheters from higher grade polyurethanes possessing greater biostability should be explored. Silicone rubber appears to remain the most durable material to date for PD catheter construction.     

Foreign body reaction to biomaterials

The foreign body reaction composed of macrophages and foreign body giant cells is the end-stage response of the inflammatory and wound healing responses following implantation of a medical device, prosthesis, or biomaterial. A brief, focused overview of events leading to the foreign body reaction is presented. The major focus of this review is on factors that modulate the interaction of macrophages and foreign body giant cells on synthetic surfaces where the chemical, physical, and morphological characteristics of the synthetic surface are considered to play a role in modulating cellular events. These events in the foreign body reaction include protein adsorption, monocyte/macrophage adhesion, macrophage fusion to form foreign body giant cells, consequences of the foreign body response on biomaterials, and cross-talk between macrophages/foreign body giant cells and inflammatory/wound healing cells. Biomaterial surface properties play an important role in modulating the foreign body reaction in the first two to four weeks following implantation of a medical device, even though the foreign body reaction at the tissue/material interface is present for the in vivo lifetime of the medical device. An understanding of the foreign body reaction is important as the foreign body reaction may impact the biocompatibility (safety) of the medical device, prosthesis, or implanted biomaterial and may significantly impact short- and long-term tissue responses with tissue-engineered constructs containing proteins, cells, and other biological components for use in tissue engineering and regenerative medicine. Our perspective has been on the inflammatory and wound healing response to implanted materials, devices, and tissue-engineered constructs. The incorporation of biological components of allogeneic or xenogeneic origin as well as stem cells into tissue-engineered or regenerative approaches opens up a myriad of other challenges. An in depth understanding of how the immune system interacts with these cells and how biomaterials or tissue-engineered constructs influence these interactions may prove pivotal to the safety, biocompatibility, and function of the device or system under consideration.     

Hemodynamic effects of gabapentin in rats

Gabapentin has been known to elicit the antinociceptive effect. However, little has been known about the effect of gabapentin on the cardiovascular system. The author's aim of this experiment was to examine the hemodynamic effects of gabapentin. Male Sprague-Dawley rats were used. Intrathecal or intracerebroventricular catheters were implanted and gabapentin was delivered through each catheter or directly into the peritoneal cavity. For hemodynamic measurements, catheters were inserted into the tail artery. Blood pressure and heart rate were measured over 60 min following administration of gabapentin. Intrathecal and intraperitoneal gabapentin did not induce significant changes of hemodynamics over the 60 min compared to the baseline value. Intracerebroventricular gabapentin increased systolic and diastolic blood pressure, but there is no statistically difference in blood pressure change according to the dose.     

Macrophagic response to human mesenchymal stem cell and poly(epsilon-caprolactone) implantation in nonobese diabetic/severe combined immunodeficient mice

Nonobese diabetic, severe combined immunodeficient (NOD/SCID) mice are extensively used to assess in vivo potentials for human cellular differentiation, development, and neophysiology. They are not only deficient in T and B cells, but also exhibit macrophage dysfunction and an absence of circulating complement. However, the survival of engrafted human mesenchymal stem cells (hMSCs) is limited and minimal mature bone tissue develops from implanted hMSCs in this model. The aim of the present study was to investigate the response to such implants in NOD/SCID mice. To this end, hMSCs genetically marked with enhanced green fluorescent protein, a biodegradable polymer, poly(epsilon-caprolactone) (PCL), and a bioconstruct incorporating the enhanced green fluorescent protein-labeled hMSCs with PCL after culture together for 3 weeks in vitro, were implanted into NOD/SCID mice and followed for up to 10 weeks. Monocytes/macrophages appeared to be the major invading cell type in all the implants and remained in the materials regardless of whether or not hMSCs were present over the time periods studied. When the hMSCs were implanted without the PCL scaffold, host macrophage invasion was also observed with the majority of hMSCs being eliminated within 2 weeks. Multinuclear giant cells or foreign body giant cells were seen in the cases of PCL implantation. These cells slowly infiltrated into the central core of the materials over a 10-week period of implantation with neutrophils and mast cells also being observed. In conclusion, in NOD/SCID mice, monocytes/macrophages still effectively respond to the implantation of xenografts and biopolymers with functional migration, phagocytosis, adhesion, foreign body recognition and formation of multinuclear giant cells, or foreign body giant cells. Thus, these animals still retain a level of innate immune responsiveness to these implantations and in addition may provoke a physiological environment that is unsuitable for extensive intramembranous ossification by engrafted hMSCs.     

Connexin 43 expression of foreign body giant cells after implantation of nanoparticulate hydroxyapatite

In bone a role of connexin 43 has been implicated with the fusion of mononuclear precursors of the monocyte/macrophage lineage into multinucleated cells. In order to investigate the putative role of connexin 43 in formation of bone osteoclast-like foreign body giant cells which are formed in response to implantation of biomaterials, nanoparticulate hydroxyapatite had been implanted into defects of minipig femura. After 20 days the defect areas were harvested and connexin 43 expression and synthesis were investigated by using immunohistochemistry, Western Blot, and in situ hybridization within macrophages and osteoclast-like foreign body giant cells. Morphological analysis of gap junctions is performed ultrastructurally. As shown on protein and mRNA level numerous connexin 43 positive macrophages and foreign body giant cells (FBGC) were localized within the granulation tissue and along the surfaces of the implanted hydroxyapatite (HA). Besides, the formation of FBGC by fusion of macrophages could be shown ultrastructurally. Connexin 43 labeling observed on the protein and mRNA level could be attributed to gap junctions identified ultrastructurally between macrophages, between FBGC, and between FBGC and macrophages. Annular gap junctions in the cytoplasm of FBGC pointed to degradation of the channels, and the ubiquination that had occurred in the course of degradation was confirmed by Western blot analysis. All in all, the presently observed pattern of connexin 43 labeling refers to an functional role of gap junctional communication in the formation of osteoclast-like foreign body giant cells formed in response to implantation of the nanoparticulate HA.     

An in vivo method for the biological evaluation of metal implants

The peritoneal cavity of the rat was used as an implantation site in order to study the quantitative, cellular response and the qualitative, histopathological response to three metals (Ag, Sn, Cu). The effects of the metals on the cells were correlated with the cellular concentrations of the metal as determined by chemical analysis. Small variations in the cell population and a minimal foreign body reaction was observed with an implanted control material (silicone polymer). Large increases in the number of cells and an intense foreign body reaction was observed with Cu implants. Decreases in the number of cells were seen with Sn and Ag implants, but only Sn elicited a foreign body reaction. Implantation of Ag failed to elicit a foreign body reaction. Significant concentrations of all three metals were detected in the retrieved cells.     

Continuous flow peritoneal dialysis: a new double lumen catheter

Continuous flow peritoneal dialysis (CFPD) is a therapy originally utilized in the sixties. It was then abandoned because of technical reasons, but, today, a new interest in this technique is emerging, because of new technical solutions and new hardware capabilities. CFPD is a peritoneal dialysis technique in which a certain amount of fluid is maintained in the peritoneal cavity, while a continuous inflow and outflow is provided via twin catheters or through a double lumen catheter. In this paper a new double lumen catheter is presented. The catheter is characterized by the presence of a diffuser in the inflow lumen, while a standard coiled shape characterizes the outflow lumen. The diffuser allows the use of high dialysate flows without peritoneal damage and with an excellent distribution of the fluid. The other feature of the catheter is the removable hub which allows for an easy subcutaneous tunneling of the catheter with a subsequent connection to the y segment. The special shape also guarantees a minimum recirculation during treatment. Data obtained in the first implanted catheter showed a progressive increase in small solute clearances in relation to an increase of the flow and the tidal volume in the peritoneal cavity. In particular, urea clearances up to 48 ml/min and creatinine clearances up to 39 ml/min were obtained. No major complications were observed after one year of use of the catheter.     

Why bury the distal end of the peritoneal dialysis catheter

The first catheters for peritoneal dialysis were made in silicone with a Dacron cuff, which allowed tissue ingrowth, creating a barrier to the entrance of bacteria from the skin surface. However, the interruption of the skin envelope produces recurrent exit site and tunnel infections and peritonitis, which are the leading causes of discontinuing peritoneal dialysis. Experimental evidence suggests that the use of a double cuff silastic catheter and subcutaneous implantation of the distal catheter for 5-6 weeks before exposure reduces such infections, thus improving catheter life. Early preparation of peritoneal dialysis access with subcutaneous implantation allows healing of scar tissue into the cuffs and formation of an excellent bacteriological barrier.     

Lymphocytes and the foreign body response: lymphocyte enhancement of macrophage adhesion and fusion

The host foreign body response ensues immediately following implantation of medical devices and prostheses. We have previously identified the role of macrophages in adhering to biomaterial surfaces and guiding the foreign body response while fusing into foreign body giant cells (FBGCs) and concentrating degradative and phagocytic activities. Despite their early and transient presence around implanted biomaterials, few studies have focused on the role of lymphocytes in the foreign body response and biocompatibility. To address this, an in vitro human lymphocyte/macrophage coculture system has been developed. Using this system, it has been shown that when lymphocytes are present during the initial adhesion of monocytes, the rate of monocyte adhesion and fusion is significantly increased (1,500 cells/mm2 and 60%, respectively) when compared to either no lymphocytes present (500 cells/mm2 adhesion and 0% fusion). Although lymphocytes adhered to the tissue culture polystyrene surface, 90% of the lymphocytes were associated with adherent macrophages. However, these cell-cell direct interactions were not necessary to influence macrophage adhesion or fusion as separating the two cell types by a Transwell insert still resulted in significantly increased levels of macrophage adhesion (p < 0.05 when compared to macrophage only cultures). Conversely, the presence of macrophages in Transwell experiments increased lymphocyte proliferation rates at all time points tested. These studies begin to detail the interactions between lymphocytes and macrophages in the absence of known antigen that appropriately relates to the scenarios experienced upon implantation of biomedical devices and the initiation of the foreign body response.     

Cellular Plasticity of Inflammatory Myeloid Cells in the Peritoneal Foreign Body Response

Implantation of sterile foreign objects in the peritoneal cavity of an animal initiates an inflammatory response and results in encapsulation of the objects by bone marrow-derived cells. Over time, a multilayered tissue capsule develops with abundant myofibroblasts embedded in extracellular matrix. The present study used the transgenic MacGreen mouse to characterize the time-dependent accumulation of monocyte subsets and neutrophilic granulocytes in the inflammatory infiltrate and within the tissue capsule by their differential expression of the csf1r-EGFP transgene, F4/80, and Ly6C. As the tissue capsule developed, enhanced green fluorescent protein-positive cells changed from rounded to spindle-shaped morphology and began to co-express the myofibroblast marker α-smooth muscle actin. Expression increased with time: at day 14, 11.13 ± 0.67% of tissue capsule cells co-expressed these markers, compared with 50.77 ± 12.85% of cells at day 28. The importance of monocyte/macrophages in tissue capsule development was confirmed by clodronate-encapsulated liposome removal, which resulted in almost complete abrogation of capsule development. These results confirm the importance of monocyte/macrophages in the tissue response to sterile foreign objects implanted in the peritoneal cavity. In addition, the in vivo plasticity of peritoneal macrophages and their ability to transdifferentiate from a myeloid to mesenchymal phenotype is demonstrated.The tissue response to foreign materials including biomaterials and medical devices is known as the foreign body response and is universally characterized by inflammatory cell recruitment and subsequent encapsulation of the foreign material by fibrotic tissue.¹ At the site of implantation an array of inflammatory mediators (and signaling molecules) including cytokines, growth factors, extracellular matrix proteins, and matrix-degrading enzymes create a dynamic microenvironment that mediates a defined sequence of events.² In the initial acute inflammatory phase, neutrophils are recruited to the surface of the implanted materials, followed by lymphocyte and mononuclear cell involvement and foreign body giant cell formation (chronic inflammation). If the foreign material cannot be removed, resolution of these inflammatory responses occurs when a fibrous capsule has formed around it.³ Although the purpose of fibrous encapsulation is to isolate foreign material from the surrounding tissue, this fibrotic tissue, along with foreign body giant cells at the tissue/material interface, can significantly compromise the efficiency of medical devices or prostheses and frequently leads to device failure.Our laboratory has observed a similar response to foreign material implanted in the peritoneal cavity. Within the first 3 to 5 days after implantation, the object is covered by rounded cells, many of which have a macrophage-like morphology and express the common leukocyte antigen Ly-5 (CD45).⁴ After 2 to 3 weeks, a tissue capsule comprising multiple layers of myofibroblasts and extracellular matrix and covered by a continuous layer of mesothelial cells surrounds the object.⁵ In contrast with the tissue surrounding foreign material at other anatomical sites, the tissue encapsulating free-floating foreign objects in the peritoneal cavity is avascular. On harvest, the tissue has been used as an autologous graft for replacement/repair of hollow smooth muscle organs including blood vessels, bladder, vas deferens, and uterus.^5–7 Over the ensuing 2 to 3 months, the grafted tissue undergoes further cell differentiation and tissue remodeling to assume the morphology and function of the host organ.⁸In addition to providing a sterile location to develop myofibroblast-rich tissue for engineering purposes, the peritoneal cavity is a convenient site to investigate the involvement of myeloid cells in the inflammatory response. The mononuclear phagocyte system encompasses bone marrow precursors, peripheral blood monocytes, tissue macrophages, and dendritic cells, all of which express the macrophage colony-stimulating factor receptor (csf1r).^9–11 Macrophages also express F4/80^12,13 and exhibit phenotypic and functional heterogeneity (reviewed in ¹⁴). Recently, blood monocytes have also been shown to exhibit heterogeneity in terms of expression of surface molecules such as Gr1 (Ly6C), chemokine receptors (CX3CR1), and migratory predisposition.^15–17Understanding the cellular processes involved in the foreign body response is central to the development of tissue engineering strategies using the resultant myofibroblast-rich tissue. It is also the key to maintaining the integrity and function of biomedical implants such as orthopedic implants, dental or breast implants, artificial organs, vascular grafts, heart valves, renal dialyzers, and controlled drug delivery systems. Thus, the aims of the current study were to characterize the cells involved in the inflammatory response to foreign objects implanted in the peritoneal cavity and to determine whether monocyte/macrophages are the source of peritoneum-derived tissue capsule myofibroblasts. We have previously demonstrated that myofibroblasts within the tissue capsule are of bone marrow (hematopoietic) origin using sex-mismatched bone marrow transplant experiments.⁴ Others have demonstrated that labeled peripheral blood mononuclear cells, injected into the peritoneal cavity at the same time as foreign object implantation, contribute to tissue capsule formation.¹⁸ However, it is not clear whether monocyte/macrophages are a cellular source of tissue capsule myofibroblasts. Thus, we investigated the hypothesis that in the peritoneal foreign body response, monocyte/macrophages can transdifferentiate to myofibroblasts.For these investigations we used the transgenic MacGreen mouse in which a promotor region of the c-fms (csf1r) proto-oncogene directs myeloid-specific expression of the reporter gene, enhanced green fluorescent protein (EGFP).^19,20 The c-fms gene encodes the receptor for the cytokine CSF-1, which is essential for macrophage survival, proliferation, and differentiation. Our results demonstrate that the inflammatory myeloid cells recruited into the peritoneal cavity exhibit differential (bimodal) expression of csf1r-EGFP; when used in conjunction with markers F4/80 and Ly6C, the csf1r-EGFP reporter provides a unique marker of monocyte/macrophage subsets and neutrophilic granulocytes. We also show that monocyte/macrophages within the tissue capsule are capable of differentiating to a mesenchymal phenotype, evidenced by co-expression of myeloid (EGFP) and myofibroblast (α-smooth muscle [SM] actin) markers. These results provide evidence of the capacity for fully differentiated macrophages to transdifferentiate and suggest a greater potential for cellular plasticity than recognized previously.     

History of peritoneal access development

The first peritoneal accesses were devices that had been used in other fields (general surgery, urology, or gynecology): trocars, rubber catheters, and sump drains. In the period after World War II, numerous papers were published with various modifications of peritoneal dialysis. The majority of cases were treated with the continuous flow technique; rubber catheters for inflow and sump drains for outflow were commonly used. At the end of the 1940s, intermittent peritoneal dialysis started to be more frequently used. Severe complications of peritoneal accesses created incentive to design accesses specifically for peritoneal dialysis. The initial three, in the late 1940s, were modified sump drains; however, Ferris and Odel for the first time designed a soft, polyvinyl intraperitoneal tube with metal weights to keep the catheter tip in the pelvic gutter where the conditions for drain are the best. In the 1950s, intermittent peritoneal dialysis was established as the preferred technique; polyethylene and nylon catheters became commercially available and peritoneal dialysis was established as a valuable method for treatment of acute renal failure. The major breakthrough came in the 1960s. First of all, it was discovered that the silicone rubber was less irritating to the peritoneal membrane than other plastics. Then, it was found that polyester velour allowed an excellent tissue ingrowth creating a firm bond with the tissue. When a polyester cuff was glued to the catheter, it restricted catheter movement and created a closed tunnel between the integument and the peritoneal cavity. In 1968, Tenckhoff and Schechter combined these two features and designed a silicone rubber catheter with a polyester cuff for treatment of acute renal failure and two cuffs for treatment of chronic renal failure. This was the most important development in peritoneal access. Technological evolution never ends. Multiple attempts have been made to eliminate remaining complications of the Tenckhoff catheter such as exit/tunnel infection, external cuff extrusion, migration leading to obstruction, dialysate leaks, recurrent peritonitis, and infusion or pressure pain. New designs combined the best features of the previous ones or incorporated new elements. Not all attempts have been successful, but many have. To prevent catheter migration, Di Paolo and his colleagues applied the old idea of providing weights at the catheter tips to Tenckhoff catheters. In another modification, Twardowski and his collaborators created a permanent bend to the intra-tunnel portion of the silicone catheter to eliminate cuff extrusions. The Tenckhoff catheter continues to be widely used for chronic peritoneal dialysis, although its use is decreasing in favor of swan-neck catheters. Soft, silicone rubber instead of rigid tubing virtually eliminated such early complications as bowel perforation or massive bleeding. Other complications, such as obstruction, pericatheter leaks, and superficial cuff extrusions have been markedly reduced in recent years, particularly with the use of swan-neck catheters and insertion through the rectus muscle instead of the midline. However, these complications still occur, so new designs are being tried.     

Tissue reaction to intraperitoneal polymer implants: species difference and effects of corticoid and doxorubicin

The peritoneal cavity is a convenient site for implantation of encapsulated hormone-secreting tissue. However, host tissue organization around such implants may affect solute exchange and viability of the encapsulated tissue. The reaction to polyvinyl chloride acrylic copolymer capsules implanted in the peritoneal cavity of rats and mice was therefore studied. Some animals received a slow release dexamethasone pellet, others were pretreated with doxorubicin, in an attempt to minimize the tissue reaction. The tissue reaction was significantly thicker in rats than in mice at both 2 and 6 weeks after implantation. In rats, corticoids decreased significantly the thickness of the reactive layer as compared to control at all time points studied, but doxorubicin had no effect. The tissue reaction in mice was not significantly affected by corticoid treatment. In both species the thickness of the tissue reaction did not increase significantly between 2 and 6 weeks. At 3 days the tissue reaction consisted of an interrupted single layer of macrophages in mice, whereas in rats the reaction consisted of two or three layers of macrophages and polymorphonuclear cells. At both 2 and 6 weeks, several cell layers surrounded the implants: a single layer of macrophages lying along the polymer, a variable number of layers of fibroblasts interspersed with collagen fibrils (fewer in mice than in rats, and fewer in corticoid treated rats than control rats) and an outer monolayer of mesothelial cells. We conclude that the intensity of tissue reaction to polymer implants in the peritoneal cavity is species dependent and can be decreased by the administration of corticoids but not doxorubicin.     

The self-locating catheter: review and cost analysis

The self-locating catheter invented by Nicola Di Paolo has been increasingly used in Italy and elsewhere since 1994, with about a thousand patients currently implanted every year. Twelve grams of tungsten inserted in the tip of the conventional Tenckhoff catheter during extrusion do not significantly change its form, but suffice to keep the tip firmly in the Douglas cavity. The validity of the new catheter is confirmed by a multicentric controlled study in a large population of peritoneal dialysis patients. This trial showed that patients with the new catheter have fewer episodes of peritonitis, tunnel infection, cuff extrusion, catheter malfunction, obstruction and leakage. This paper outlines the present situation and reports a comparative analysis of the costs of Tenckhoff and self-locating catheters.     

Microbiological diagnosis of bacteremia from a catheter: a simple method? Results of a retrospective study

Diagnosing catheter-related bloodstream infections is important but not always easy and a failure to make the diagnosis may have serious consequences. A high rate of unnecessary catheter removal is noted. We retrospectively compared the clinical and usual methods of microbiological diagnoses of catheter-related sepsis to the speed of detection of the catheter versus peripheral blood cultures using the Bact-Alert system. We analyzed 50 files of patients with central indwelling devices: 16 single lumen catheters and 34 implanted ports. Twenty-one catheters were classified as infected, and we observed an earlier positivity of catheter versus peripheral blood in all cases, but significant for 19 patients. According to standard diagnosis methods, 29 catheters were estimated non-infected, a more rapid detection of peripheral culture was reported for 17 specimens and, for another eight patients, the time of detection was equal to blood culture drawn from the catheter. In this group, four discrepancies were recorded with a differential time in favor of sepsis related to catheters ranging from 0.5 to 2 hours. Because of its simplicity and low cost, we believed that this method could be the first step of a diagnosis of catheter-related sepsis and could, therefore, avoid unjustified removal, in particular for the implanted ports for which the diagnostic methods are less codified than for catheters. A prospective study is ongoing; the design of the study focuses only on implanted ports.     

持续质量改进降低腹膜透析的漂管、堵管发生率

目的:通过持续质量改进措施,降低腹膜透析患者的漂管、堵管致腹透管功能障碍的发生率。方法:观察持续质量改进(continous quality improvement,CQI)前2002年至2007年的腹膜透析植管患者共226例,持续质量改进后2008年至2011年的腹膜透析植管患者共302例,分析、总结发生漂管、堵管的可能原因;运用PDCA四步法[设计(plan)—实施(do)—检验(check)—应用(act)]设计,并实施减少漂管、堵管发生率的流程。结果:CQI后我中心的腹透植管的漂管、堵管所致腹透管功能障碍的发生率明显降低,由CQI前的5.9%降至2.3%。结论:通过CQI改进措施,降低了腹膜透析的漂管、堵管的发生率。