IM R4 박미나 Management of infected Central venous catheters used for hemodialysis

Introduction Patients undergoing HD - Increased risk of infection - various defects in immune function, uremic state, dialysis procedure itself Catheter-related infections - significant cause of morbidity and mortality

Central venous catheters - Cuffed, double lumen silastic catheters -Single lumen temporary catheters -Double lumen non-cuffed catheters

Incidence of bacteremia Noncuffed, temporary HD catheter bacteremia per 1000 catheter-days Tunneled, cuffed catheters bacteremias per 1000 catheter-days Exit site infection per 1000 catheter-days Metastatic complications (osteomyelitis, endocarditis, septic arthritis) - 25%

Risk factors Prolonged duration of usage History of previous catheter-related bacteremia Diabetes mellitus Iron overload Microbiology Gram-positive organism - staphylococcal infection : 40-81% Enterococcus, Gram negative rods

Pathogenesis Extraluminal colonization of catheter, which orginates from skin and less commonly from hematogenous seeding of catheter tip Intraluminal colonization of hub and lumen of CVC

Catheter-related infections Catheter colonization -  15 CFU in semiquantitative culture Exit site infection - exudate at catheter exit site yields micro-organisms - erythema, tenderness within 2cm of catheter exit site Tunnel infection - erythema, induration, tenderness > 2cm from exit site, along the subcutaneous tract Catheter-related bloodstream infection

Clinical evaluation Microbiologic confirmation ( documenting presence of bloodstream infection + demonstrating that infection is related to catheter) Catheter-related bloodstream infection

Inflammation of purulence at insertion or exit site Absence of alternative source of infection Isolation of CNS, Corynebacterium, fungus Dysfunction of catheter resulting from intraluminal clot Clinical signs of sepsis start abruptly after infusion of IV fluid or medications Rapid clinical improvement of following removal of catheter

Cultures of IV catheter (tip or tunneled segment) - positive result of semiquantitative (>10 5 CFU) growth same as pph culture Paired cultures of blood (through the IV catheter and percutaneously) - same organisms isolated Quantitative cultures of CVC and peripheral blood - a ratio of  5:1 (CVC vs. peripheral) Differential time to positivity for CVC vs. pph cultures - positive result of culture from a CVC is obtained at least 2 hours earlier than a positive result of pph blood

Treatment Vancomycin 20mg/kg weekly + gentamicin 1-2mg/kg after each HD session Cefazolin (20mg/kg after each HD session) Penicillinase-resistant PC or 1st or 2nd generation cephalosporin for sensitive S. aureus Optimal duration of therapy? - 3 weeks and reculture on week after completion of antibiotics therapy

Necessity of catheter removal ? Only 25-32% of catheter being salvaged with antibiotics alone Significant number of catheters can be salvaged if catheter is functioning properly, exit site and tunnel tract are not infected and hemodynamically stable.

Low success rate of antibiotic salvage only Bacteria adherent to catheter: failure of antibiotics Criteria of catheter exchange - afebrile after 48 hours of antibiotics - clinically stable - no evidence of tunnel tract infection Less successful in highly adherent species (S.aureus, Enterococcus)

Treatment recommendations Catheter-associated bacteremia - whenever possible, catheter should be removed (all non-cuffed catheter) Candida or infected clot – should be removed

If alternate site for vascular access is not avilable - trial of catheter salvage - cultures from both catheter and peripheral site - two day trial of antimicrobial Tx and observation - removal if hemodynamically unstable or if fever persists or cultures remain positive after two days Febrile or positive cultures after catheter removal - exam for metastatic complication (endocarditis and vertebral osteomyelitis)

Prevention General consideration - Hand hygiene & Aseptic technique - Maximal sterile barrier precaution during insertion (cap, mask, sterile gown & gloves, large sterile drape) Catheter dressing regimens - Transparent, semipermeable polyurethane  gauze - Change at least weekly

Elimination of S.aureus nasal carriage - antibiotic prophylaxis to decrease nasal carriage of S.aureus -> fewer access related infection - emergence of resistance with chronic antibiotic use Topical exit site application - topical use of povidone-iodine, polysporin, mupirocin at catheter entrance site - resistance to topical or intraluminal antimicrobial agents

Catheter with a lower infection rate - non cuffed -> tunneled, cuffed catheter - antibiotic bonded catheter : much lower rate of infection : not yet in HD population Lock solutions - filling of catheter with antibiotics - heparin gentamicin+heparin (0.4 vs 0.03)

Heparin 5000IU/mL + Gentamicin 1-5mg/mL Vancomycin 1-5mg/mL Cefa 5-10mg/mL

Hand hygiene & Aseptic technique Elimination of S.aureus nasal carriage Topical exit site application Antibiotics lock therapy

Nephrol Dial Transplant (2004)