Insufficient penetration of systemic vancomycin into the PermCath lumen

mycin, after which the catheters were sectioned at 4-cm intervals. Only the distal 4 cm of the catheters had Background. Catheter infection is a major cause of morbidity and catheter loss in chronic haemodialysis vancomycin concentrations of 2 and 5 mg/ml, the remaining segments had levels ∏0.5 mg/ml. patients. There has been a large discrepancy in the catheter salvage rate, after an episode of documented Conclusion. Our results indicate that diffusion of vancomycin from plasma into the haemodialysis catheter is bacteraemia, whether the patients receive systemic antibiotic alone or systemic antibiotics concomitant with negligible. Thus, haemodialysis patients with central venous catheter who have to be treated for bacteraemia ‘antibiotic-lock technique’ (20–30% vs 100%, respectively). To test the hypothesis that vancomycin may not with systemic antibiotic therapy must always receive ‘antibiotic-lock technique’ of the catheter after each adequately penetrate into the lumen of the catheter, despite therapeutic plasma levels, a series of in-vivo, haemodialysis session. ex-vivo, and in-vitro experiments were performed. Keywords: haemodialysis; vancomycin; sepsis; bacterMethods. We compared serum and intralumenal aemia; PermCath (0.3–0.5 ml aspirate from venous port of the catheter) vancomycin concentrations in 24 chronic haemodialysis patients, with documented bacteraemia, who had received prior systemic vancomycin therapy with 14 Introduction similar patients who had additionally received ‘vancomycin-lock technique’ (100 mg/ml of vancomycin in Dual-lumen tunnelled, cuffed catheters are increasingly heparin solution) after each haemodialysis session. used for permanent vascular access in patients with Results. Despite serum vancomycin concentration of limited access options for haemodialysis (HD). Infec~17 mg/ml in each group, the vancomycin concen- tion of these catheters remains the leading cause of tration in the venous hub of the catheter was only catheter loss, and constitutes a major source of morbid0.2±0.6 mg/ml in the former group, in sharp contrast ity and mortality in hospitalized patients. Since they to 125.6±13 mg/ml in the latter group. In the ex-vivo are used three times a week for HD, bacteraemia from experiment, four uninfected PermCaths which had any source would potentially lead to bacterial seeding been removed were immediately fixed and studied with inside the lumen of these catheters. Whether bacteraescanning electron microscopy. No cellular or fibrin mia is of catheter origin or is from other sources, e.g. barrier could be found at the terminal pore of the urinary tract infection, cellulitis, pneumonia, etc., the catheter interfering with the diffusion of vancomycin treatment of bacteraemia should also aim at sterilizafrom plasma into the catheter lumen. In the in-vitro tion of the catheter. experiments, three PermCaths filled with standard The incidence of bacteraemia associated with chronic heparin solution were incubated for 48 h in 100 ml HD catheters is from 2 to 8 bacteraemic episodes per of plasma containing 20 mg/ml of vancomycin. 1000 catheter days [1–3]. Gram-positive organisms are Vancomycin concentration was measured in 0.3–0.5 ml responsible for most of the catheter-related infections, solution aspirated from each port of the catheters. with Staphylococcal infection accounting for 40–80%, Vancomycin concentration was 0.2±0.1 mg/ml in the and enterococci and Gram-positive bacilli accounting aspirated samples. Finally, two PermCaths filled with for the remainder of the infections [2,3,6–8]. The the standard heparin solution were incubated for 48 h appropriate management of catheter-related bacterin 100 ml of plasma containing 20 mg/ml of vanco- aemia, in patients undergoing HD, has not been clearly defined. Although clinicians agree about the need for