Central venous catheters for maintenance hemodialysis: a cautionary approach

There is an increasing trend toward the use of indwelling central venous catheters (CVC) for maintenance hemodialysis. Although such devices are necessary in some problematic cases, the general use of CVC is worrisome. Not only may CVC prejudice the ultimate success of future permanent vascular access, but CVC also may be associated with reduced dialysis delivery and with several important complications. This review summarizes recent developments in catheter design, placement techniques, maintenance of the indwelling catheter, and complications of CVC use. Based on cumulated experience, a judicious position is taken that recognizes the place of CVC among the various access options but that favors permanent vascular access whenever feasible.

Clinical considerations in hemodialysis access infection

Hemoaccess infections remain a substantial cause of morbidity in patients on hemodialysis, especially with the increasing reliance on prosthetic devices as the average age of the hemodialysis population increases. Access manipulation, either through needle puncture or secondary surgical procedures, is the primary etiology of infection. Other conditions such as access location, patient hygiene, and intravenous drug use can cause contamination. Local evidence of inflammation or infection, especially pain and purulence, are the most reliable signs of infection; however, the access can be infected and there may be minimal systemic symptoms. Medical therapy must be directed primarily against Staphylococcus aureus, with vancomycin being used most frequently. There are distinct conditions in which infection with gram-negative bacilli is also common. A coordinated effort between medical management and surgical intervention is essential to optimize therapy. Several situations, such as loss of vascular integrity or infection at anastomosis sites, mandate full excision of the graft. However, the access or at least the access site, can be preserved through creative surgical intervention along with aggressive medical treatment. Approaches to the diagnosis and treatment of infection in autologous arteriovenous fistulae, polytetrafluoroethylene arteriovenous conduits, and cuffed dual-lumen venous hemodialysis catheters are discussed.

Bacteremia in a pediatric hemodialysis unit secondary to Enterococcus fecalis

Bacteremia is often a serious and recurring problem in children with hemodialysis catheters. We report an outbreak of Enterococcus bacteremia in a pediatric hemodialysis unit occurring from June 1992 to June 1993. During this period, 18 episodes of bacteremia occurred in eight children; 11 infections were polymicrobial. Enterococcus fecalis was associated with 13 infections in five patients (8 polymicrobial). Other pathogens included Enterobacter cloacae (5 infections), Staphylococcus (3), Staphylococcus epidermidis (2), and Klebsiella pneumoniae (2). All Enterococcus infections occurred in patients with dual-lumen subclavian venous catheters. Skin and catheter sites were culture negative, except in one patient. Rectal swabs were positive for Enterococcus in five patients. Enterococcus was not isolated from any source within the unit. Serotypes of all Enterococcus isolates were different, except for 2 isolates in the same patient. Starting in June 1993, catheters were flushed after dialysis with vancomycin or ampicillin. Since initiating this procedure, further episodes of Enterococcus bacteremia have not occurred. A questionnaire sent to other pediatric hemodialysis units failed to identify Enterococcus among 26 cases of bacteremia.

IN CONCLUSION

(1) Enterococcus is an unusual pathogen for hemodialysis-related bacteremia in children; (2) patients with dialysis catheters were predisposed to this infection; (3) a common source for Enterococcus could not be identified by either culture or by serotyping; (4) flushing catheters with antibiotics after dialysis was effective prevention.

Use of a silicone dual-lumen catheter with a Dacron cuff as a long-term vascular access for hemodialysis patients

We evaluated our experience over a 4-year period with a silicone dual-lumen catheter with a Dacron cuff (SDLCDC) to determine if the catheter represents an alternative to the polytetrafluoroethylene graft for long-term vascular access for hemodialysis patients. Records of 131 patients who used 168 catheters were reviewed for catheter function, duration of use, and occurrence and response to treatment of complications. Eighty-five percent of catheters functioned adequately until their use was no longer required or the end of the study. One-year catheter survival estimate was 65% and median survival estimate was 18.5 months. Mean blood flow rate achieved was 243 mL/min and recirculation was 7.5%. Exit-site infection occurred in 21% of patients and bacteremia in 12%. There were significantly more exit-site infections in diabetics than nondiabetics (33% v 11%, P less than 0.02). Exit-site infections resolved with parenteral antibiotic therapy in 90% and bacteremia in 25% of cases without catheter removal. Unresolved bacteremia was the most common cause of catheter removal and led to the loss of 7% of catheters. Thrombotic complications occurred in 46% of catheters. Urokinase instillation successfully treated catheter occlusion in 81% of cases. When urokinase instillation failed, streptokinase infusion restored catheter patency 97% of the time. The literature on the polytetrafluoroethylene (PTFE) graft was reviewed, and the SDLCDC was found to be similar to the graft in function, duration of use, and frequency of infectious and thrombotic complications. We conclude that the catheter represents an alternative to the graft for long-term vascular access in hemodialysis patients. Because of the frequent complications with both accesses, neither should be considered optimal. Further research is required to improve vascular access for patients in whom placement of an arteriovenous fistula is not possible.