The Dept of Anaesthesia & Intensive Care, CUHK
Most commonly accepted definitions are:
- catheter related infection: bacteraemia attributable exclusively related to catheter. Requires isolation of same organism from blood and catheter. Need not necessarily be associated with signs of sepsis
- catheter related bloodstream infection: bacteraemia, signs of sepsis, same organism isolated from catheter or puncture site, negative culture of infusate
- catheter related sepsis: signs of sepsis plus colonization of catheter
- common organisms: coagulase negative staph. (predominantly Staph. epidermidis) and Staph. aureus. Gram negatives (Klebsiella, Pseudomonas, Serratia, Acinetobacter, Stenotrophomonas maltophilia and other enterobacteria) and fungi isolated more frequently in recent years.
-catheter colonization results from exogenous contamination of patient’s skin, hubs or whole system. Occurs at time of insertion or re-insertion. Skin insertion site most common source of colonization and infection for catheters <10 days old. From the skin insertion site organisms migrate down the external surface of the catheter to colonize the distal tip and produce bloodstream infection. Hub contamination is more common in long term catheters and results in colonization of the lumenal surface of the catheter. Haematogenous colonization and contaminated infusates are the other routes of colonization.
- type and material of catheter: polyethylene catheters associated with highest risk of colonization, PVC intermediate and silicon least. Antibiotic bonded catheters associated with lower incidence of colonization but not infection. Triple lumen catheters associated with higher risk but this may simply reflect different uses
- site and mode of catheterization: higher incidence of colonization with internal jugular lines than subclavian. Also higher incidence if multiple attempts at cannulation required or if surgical cut-down required. Guidewire exchange of catheters is associated with a non-significant trend toward a higher rate of catheter exit site infection and catheter-related bacteraemia but fewer non-infective complications
- dressing: not clear whether transparent semi-occlusive dressing best or sterile dry gauze dressing
- duration of catheterization: significant increase in risk of catheter-related infection after 4th day but no benefit from routine changes of lines has been demonstrated
- patient factors: immunosuppression, infection, malignancy, tracheostomy, TPN, chronic haemodialysis
- strict use of barrier precautions (sterile gowns, gloves, masks etc) decreases infection risk
- may be difficult. Certain features point toward a vascular catheter as source of infection:
- semi-quantitative culture of catheter tip and a 5 cm section of catheter
taken from the part of the catheter distal to the insertion point is useful. The
presence of >15 colonies is associated with high risk of infection. Roll
plate method of culture less useful for detecting colonization of long term
silicone catheters where lumenal colonization is more common. In these patients
it may be more useful to take simultaneous cultures from central line and
peripheral site. Presence of 5-10 times more colonies in culture of blood taken
through the central line compared with peripheral blood diagnostic of catheter
related infection. When PA catheter tips are cultured the introducer should be
cultured as well.
- there is some data which suggest that this reduces the incidence of infection particularly with internal jugular catheters
Ionic silver cuff
- silver impregnated subcutaneous collagen cuffs have been shown to decrease the rate of infection in critically ill patients with central venous catheters placed for between 5.6 and 9.1 days. Does not prevent infection of long term catheters. Provides a physical barrier to migration of micro-organisms and the silver ions have an antimicrobial effect
- does not prevent migration from skin insertion site down the external surface of the catheter.
- catheters coated with chlorhexidine and silver sulphadiazine have been found to be nearly 50% less likely to be colonized and at least 4 times less likely to produce infection than uncoated catheters. Catheters coated with minocycline and rifampicin were associated with a 3-fold reduction in catheter colonization and prevented catheter-related septicaemia compared with uncoated catheters. No antibiotic resistant organisms were recovered from patients managed with coated central lines.
Heparin-bonded or addition of heparin to infusion
- associated with a significant reduction in bacterial colonization and strong but non-significant trend toward decreased catheter-related bloodstream infection
- simple removal of line may be sufficient but if signs of sepsis do not resolve antibiotic therapy should be started. Antibiotic therapy is recommended for catheter-related bloodstream infection.
- coagulase negative Staph.: 7 day course probably adequate if patient responds in 48-72 h
- Staph. aureus: in the absence of cardiac valvular disease and if patient responds within 3 days continue antibiotics for at least 2 weeks. Otherwise give 4 weeks.
- Candida: fluconazole for at least 14 days. Amphotericin for resistant Candida
- Gram +ve bacilli: vancomycin
- Gram –ve: usually non-aeruginosa Pseudomonas species or Stentrophomonas maltophilia. Give 1 week course
Central vein septic phlebitis
O'Grady, N.P., Barie, P.S., Bartlett, J.G., Bleck, T., Garvey, G., Jacobi, J., Linden, P., Maki, D.G., Nam, M., Pasculle, W., Pasquale, M.D., Tribett, D.L., and Masur, H. Practice guidelines for evaluating new fever in critically ill adult patients. Clinical Infectious Diseases 26:1042-1059, 1998.
Raad I. Intravascular-catheter-related infections. Lancet, 1998; 351:893-8
Randolph AG. Crit.Care Clinics, 1998; 14(3):411-21
© Charles Gomersall November 1998
April, 2014 unless
otherwise stated. The author, editor and The Chinese University of Hong Kong
take no responsibility for any adverse event resulting from the use of this