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

Dear Editor,

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

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 0.8ml in a small (e.g 10 kg) child. If the line is locked with 5000 unit per ml heparin as the authors describe this means the line contains 4000 units of heparin or 400 units/kg bwt. This dosage of heparin, flushed into the child is more than five times the bolus dose for systemic heparinisation [3]. There are reported intances of children & adults comuing 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 units/ml). Alternatively a different drug should be used such as Urokinase or Alteplase, or Citrate, where the difference between line locking dose & 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.

References:

1.Polaschegg H, Shah C. Overspill of catheter locking solution: Safety & efficacy aspects. ASAIO Journal (2003) vol 49 (6); pp 713- 715.

2.Moritz M, Vats A, Ellis D. Systemic anticoagulation and bleeding in children with hemodialysis catheters. Pediatr Nephrol (2003). Vol 18; pp 68-70.