POSTTRANSPLANT CARE OF THE CATHETER
For transplant patients who have a peritoneal catheter in situ, dressing changes should be performed weekly until the catheter is removed (commonly 4 – 12 weeks posttransplant). There is no need to obtain peritoneal cultures routinely; cultures should only be obtained when clinically indicated by infusing saline solution and culturing the effluent; in this setting cell counts may not be meaningful. At the time of transplantation, any infected catheters should be removed with appropriate antibiotic cover.
RECOMMENDATION FOR CATHETER OUTCOME EVALUATION
All centers should maintain data that, on subsequent analysis, would provide information on catheter survival, exit infection, and peritonitis. Outcome data are important and should denote whether a catheter is still functioning when removed and the reasons for removal.
The peritoneal catheter is the PD patient’s lifeline. Advances in catheter knowledge have made it possible to obtain access to the peritoneal cavity safely and to maintain access over an extended period of time. Catheter-related infections remain a major problem, solutions for which are being actively researched. Nevertheless, the successful outcome of a catheter is very much dependent on meticulous care and attention to detail. Adherence to the principles of catheter insertion and subsequent management and care remain the cornerstone of successful PD access. The guidelines provided in this publication represent a consensus view based on studies from the literature and opinions of experts in this field; it is hoped that implementation of these guidelines will improve catheter-related outcomes and, therefore, enhance patient care.
The committee is grateful to David Woodburn and Baxter Healthcare for their generous educational grant support for this venture, to Kerry Hulme for typing the manuscript, and secretarial support for the committee.
APPENDIX: GUIDELINES FOR PERITONEAL DIALYSIS CATHETERS FOR PEDIATRIC PATIENTS
Continuous ambulatory peritoneal dialysis has been the most frequently prescribed dialysis modality for pediatric patients under 15 years of age living in North America and in many European countries (Alexander and Honda, 1993; US Renal Data System 1996; Warady et al., 1997). For children, as for adults, a reliable peritoneal catheter is the cornerstone of successful peritoneal dialysis (PD). Unfortunately, there have been no controlled comparative studies of chronic peritoneal catheters in pediatric patients. Available information is entirely descriptive, although several large, multicenter, collaborative pediatric studies have made important observations on the relative merits of various catheter designs. The following recommendations rely heavily on those observational studies and should not be construed as truly “evidence-based” treatment guidelines. With the maturation of continuous PD as the primary maintenance dialysis therapy for children awaiting renal transplantation, controlled studies comparing available catheter configurations in pediatric patients should become a priority.
As with catheters designed for adult patients, the ideal pediatric catheter provides rapid dialysate inflow and outflow rates without leaks or infections. There is minimal catheter movement at the skin exit site, and the catheter is placed at a location that is both reachable and visible to the patient and/or caregivers. In addition, painful dialysate flow, in or out, is never acceptable when the patient is a child.
For most of the available adult catheters, there are comparable pediatric models that are generally shorter and smaller in internal and external diameters than their adult catheter counterparts. Pediatric and adult patients differ with respect to body size, underlying renal diseases, their associated anatomical and surgical features, and the routine performance of the dialysis procedures by alternate caregivers. However, no clearly superior pediatric catheter design has emerged, and the use of “adult”-sized and configured peritoneal catheters is commonly seen in all but the smallest pediatric patients (Alexander et al., 1985; Hymes et al., 1986; Watson et al., 1985).
Types of Catheters: Currently, most pediatric patients are treated with surgically placed, standard Tenckhoff catheters. For example, the most recent data available from the Dialysis Arm of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) identify catheter types used in 1126 independent courses of PD treatment in children reported from 65 pediatric dialysis centers in the United States, Canada, Mexico, and Costa Rica between 1992 and 1996 (Lerner et al., 1997). Tenckhoff catheters were used in 1078 (96%) courses of treatment, Toronto–Western Hospital catheters in only 8 (0.7%) courses, and a variety of other catheter types in 70 (6%) courses of PD treatment. The pediatric experience in Japan showed that 100% of 345 children followed for 10 years or longer were treated with a Tenckhoff catheter (Honda, 1997). An early report from the Italian Registry of Pediatric Chronic Peritoneal Dialysis noted the use of the Valli catheter in 27 of 188 (14%) courses of PD treatment performed between 1986 and 1991 (Verrina et al., 1993). A subsequent report from the Italian registry suggests that, as in North America and Japan, standard Tenckhoff catheters are now used in more than 95% of pediatric patients in Italy (Verrina et al., 1995).
Despite this apparent worldwide consensus favoring Tenckhoff catheters for pediatric patients, controversy exists over the optimum configuration of the intraperitoneal segment (straight or coiled), shape of subcutaneous tunnel (straight or permanent bend), and the orientation of the catheter skin exit site (up, down, or lateral).
Coiled or Straight Tenckhoff Catheters: Early in the development of continuous PD for children, the use of Tenckhoff catheters with straight intraperitoneal segments was routinely reported. Concerns about dialysate inflow pain and other mechanical catheter problems, such as complete or partial obstruction, may have subsequently led pediatric centers to favor Tenckhoff catheters with curled intraperitoneal segments. In a recent report from 18 pediatric PD treatment centers in the United States and Canada, the curled Tenckhoff design was noted to be the first choice of 88% of the centers reporting (Neu et al., 1995). NAPRTCS data on over 1000 courses of PD treatment in children confirm the use of coiled Tenckhoff catheters in the majority of pediatric patients (59%), nearly twice as many as used straight Tenckhoff catheters (34%) (Lerner et al., 1997).
Available data do not establish the superiority of the coiled over the straight Tenckhoff design in children, although mechanical failures may be seen less frequently with coiled catheters. In a review of 1383 courses of PD treatment in pediatric patients, peritonitis rates were found to be identical to straight and coiled Tenckhoff catheters (one episode per 13.4 months) (Warady et al., 1996). In a subsequent report, catheter revision rates for all reasons were also very similar between the two catheter types. Revision rates were reported as the “access revision ratio” (number of revisions/number of catheters at risk). Straight Tenckhoff catheters had a revision ratio of 0.26 (108 revisions/415 catheters at risk), compared to 0.19 (138/741) for coiled Tenckhoff catheters (Lerner et al., 1997). However, mechanical malfunction as a cause for catheter revision was more frequently seen among straight catheters. Forty-nine of 415 straight catheters (12%) failed due to mechanical malfunction (primarily obstruction) compared to 45 or 741 (6%) coiled catheters (Lerner et al., 1997).
The incidence of inflow pain has never been studied systematically in children.
One or Two Subcutaneous Cuffs: Early pediatric experience with double-cuff Tenckhoff catheters was unsatisfactory (Alexander and Tank, 1982; Watson et al., 1985). The superficial cuff was large and tended to migrate to the skin exit site, leading to skin erosion and eventual exit-site/tunnel infection. Superficial cuff erosion seemed to occur frequently in children, perhaps because most pediatric patients have less abdominal wall adipose and muscle tissue than adults. The adoption of single-cuff Tenckhoff catheters resulted in avoidance of superficial cuff erosion, but subsequent observations have suggested that the use of a single cuff is associated with higher peritonitis rates in children. NAPRTCS found a significantly higher peritonitis rate of one episode per 12.6 months in children with single-cuff catheters, compared to a rate of one episode per 15.1 months when two cuffs were present (p = 0.01) (Warady et al., 1996). In addition, the time to the first episode of peritonitis was significantly delayed when two cuffs were used (p = 0.02).
Straight or Permanent Bend Tunnel Configuration: The use of the permanent bend (Swan neck) tunnel configuration in pediatric patients has increased from 16% reported by the NAPRTCS in 1994 (Kohaut and Tejani, 1996) to 21% in the most recent data (Lerner et al., 1997). At first, some pediatric catheter surgeons may have been reluctant to create the large subcutaneous Swan neck tunnel track, with its attendant local tissue trauma; now there are smaller versions of the Swan neck catheter available for children. For the smallest patients, the Swan neck tunnel can be placed in the center of the abdomen curving over the umbilicus like an inverted horseshoe.
Recent observations have shown no significant differences in overall outcomes between catheters with Swan neck and straight tunnel configurations. In one study, peritonitis rates were lower with Swan neck catheters although this difference was not significant (Warady et al., 1996). Subsequent analysis showed that more Swan neck catheters required revision due to exit-site/tunnel infections (5% compared to 1% of straight catheters) (Lerner et al., 1997).
Exit-Site Orientation: The clear superiority of a downward (caudad) pointing exit site has been demonstrated in a large cohort of pediatric patients. Peritonitis rates were one episode per 18.8 months when the exit site pointed down, compared to one episode per 10.6 months when the exit site pointed upward (p = 0.010) (Warady et al., 1996).
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