Impregnated central venous catheters should be readily used to reduce risk of bloodstream infection

I note with some concern the letter by Gilbert, Harron, Mok and Gamble on the subject of Impregnated central venous catheters published on 4th December 2013 [1]. Here they conclude that such devices should be used readily to reduce the risk of bloodstream infection.

The evidence cited in the letter by Smith and Nolan [2] outlines that in the 56 trials they studied, the risk of bloodstream infection was reduced by the use of antiseptic or antimicrobial impregnated Central venous catheters. However the Cochrane Database systematic review [3] referenced in the letter suggested that there was no significant reduction in all cause mortality or clinically diagnosed sepsis. Indeed central venous catheter colonisation was only significant when the patient study was limited to Intensive Care Units. There was no benefit for those requiring central lines for haematological or oncological reasons. This comes as little surprise since the most acutely unwell patients requiring ICU admission are the most likely to have the marked physiological compromise and impaired immunological function to allow bacterial colonisation [4]. Other antibiotic stewardship options involving intermittent and heterogenous prescribing may be more successful [5, 6].

I am also concerned about the side effects that routine use of such devices would have upon patients. My main areas of concern are threefold:

Firstly routine use of antibiotic impregnated catheters must surely act as a perfect bacterial selection trait to ensure widespread resistance to that strain of antibiotic since the bacteria will have exposure to low levels of the antibiotic. Locations where patients needing central lines localise such as ICU for the reasons outlined above are the perfect location for bacterial spread to occur.

Secondly is the risk of exposure of patients to potential antigens for anaphylaxis [7]. Although anaphylaxis is a rare event, antibiotics are the most common source of iatrogenic anaphylaxis [8]. I am concerned that an already ill patient with a superimposed anaphylactic reaction would surely be fatal.

Thirdly the cost of using such catheters. Such devices may decrease bacterial colonisation compared to non-impregnated but would this represent an efficiency saving when compared with regular central catheter checks for phlebitis by nurses and treatment with IV antibiotics if indicated. I feel that more evidence is required to substantiate whether impregnated central catheters are financially viable.

Overall I would urge doctors to be sceptical of the concept that impregnated central line catheters may be beneficial and that such devices may actually cause more harm than good in the long term.

References
[1]Gilbert R, Harron K, Mok Q and Gamble C. Impregnated central venous catheters should be readily used to reduce risk of bloodstream infection. BMJ 2013;347:f7169
[2] Smith RN, Nolan JP. Central venous catheters. BMJ2013;347:f6570. (11 November.2013)
[3] Lai NM, Chaiyakunapruk N, Lai NA, O’Riordan E, Pau WSC, Saint S. Catheter impregnation, coating or bonding for reducing central venous catheter-related infections in adults. Cochrane Database Syst Rev2013;6:CD007878
[4] Timsit JF, Laupland KB. Update on bloodstream infections in ICUs. Curr Opin Crit Care. 2012 Oct;18(5):479-86.
[5] Shiu J, Wang E, Tejani AM, Wasdell M Continuous versus intermittent infusions of antibiotics for the treatment of severe acute infections. Cochrane Database Syst Rev. 2013 Mar 28;3:CD008481.
[6] Piper GL, Kaplan LJ. Antibiotic heterogeneity optimizes antimicrobial prescription and enables resistant pathogen control in the intensive care unit. Surg Infect (Larchmt). 2012 Aug;13(4):194-202.
[7] Worth A, Sheikh A. Prevention of anaphylaxis in healthcare settings. Expert Rev Clin Immunol. 2013 Sep;9(9):855-69.
[8] Richter AG, Nasser SM, Krishna MT. A UK national survey of investigations for beta-lactam hypersensitivity - heterogeneity in practice and a need for national guidelines - on behalf of British Society for Allergy and Clinical Immunology (BSACI). Clin Exp Allergy. 2013 Aug;43(8):941-9.