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Arch Dis Child. 2007 October; 92(10): 937.
PMCID: PMC2083226

Response to: Should paediatric central lines be aspirated before use?

Drs Coulthard and Skinner are correct to highlight the potential dangers of clot embolisation from paediatric central lines.1 There is, however, an equally strong argument for aspirating the lines to remove heparin and prevent inadvertent systemic anticoagulation.2,3

Haemodialysis lines in particular have relatively large volumes in comparison to patient size and it is not uncommon to have a line with a lumen volume of 0.8 ml in a small (eg, 10‐kg) child. If the line is locked with 5000 U per ml heparin as the authors describe, this means the line contains 4000 U of heparin or 400 U/kg bodyweight. This dosage of heparin flushed into the child is more than five times the bolus dose for systemic heparinisation.4 There are reported instances of children and adults coming to harm from the flushing of central lines containing heparin.

Central lines should certainly be aspirated before use and, in addition, the concentration of heparin reduced to the minimum necessary to prevent clotting (in our unit we now use 100 U/ml). Alternatively, a different drug should be used such as urokinase or alteplase, or citrate, where the difference between line locking dose and systemic dose is far greater.

Perhaps most importantly, paediatricians should recognise that the drugs we use to flush and lock vascular access are indeed drugs capable of inducing harm.


Competing interests: None declared.


1. Coulthard M G, Skinner R. Should paediatric central lines be aspirated before use? Arch Dis Child 2007. 92517–518.518 [PMC free article] [PubMed]
2. Polaschegg H, Shah C. Overspill of catheter locking solution: safety and efficacy aspects. ASAIO J 2003. 49(6)713–715.715 [PubMed]
3. Moritz M, Vats A, Ellis D. Systemic anticoagulation and bleeding in children with hemodialysis catheters. Pediatr Nephrol 2003. 1868–70.70 [PubMed]
4. BNF for children Heparin. = 6&q = heparin (accessed 27 June 2007)

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