Glucose solutions: false blood glucose readings when used to flush arterial lines

False blood glucose readings when used to flush arterial lines leading to incorrect insulin administration and potentially fatal hypoglycaemia.

Article date: July 2012

Arterial lines are routinely fitted for severely ill patients in critical care and are flushed with a solution to maintain patency, and ensure that blood does not clot in the line. Saline is recommended as the flush solution for arterial lines.

Case reports of fatal hypoglycaemia

There are several examples of glucose solutions being inadvertently and incorrectly used to flush arterial lines[footnote 1] [footnote 2] [footnote 3]. This has lead to inaccuracies in blood glucose measurements, which resulted in unnecessary administration of insulin and subsequent cases of hypoglycaemia, some of which have been fatal.

It is important to note that even a fraction of a millilitre of glucose-containing solution is likely to raise the measured plasma glucose to extremely high levels (5% glucose infusate has approximately 280 mmol/L of glucose).

Care should be taken when selecting the flush solution for arterial lines – saline infusions are recommended.

Advice for healthcare professionals

  • do not use glucose-containing solutions as infusates for maintaining arterial line patency, unless there are no suitable alternatives
  • saline infusions are recommended as the flush solution for arterial lines, to minimise the risk of incorrect blood glucose estimation and inappropriate insulin administration
  • if samples are drawn from arterial lines for estimation of biochemistry, a minimum volume of three times the dead space of the cannula system should be discarded first to avoid contamination[^4]
  • remain vigilant when selecting a solution for arterial line infusate. Similarities between glucose and saline solution bags means that confusion may occur
  • ensure that the arterial infusion line length is kept to the minimum necessary

Article citation: Drug Safety Update July 2012, vol 5 issue 12: A2

  1. Sinha S, Jayaram R, Hargreaves CG. Anaesthesia 2007; 62(6): 615 620 

  2. Panchagnula U, Thomas AN. Anaesthesia 2007; 62(10):1077 1078 

  3. National Patient Safety Agency, 2008. New guidance issued following problems with infusions and sampling from arterial lines 

Published 11 December 2014