MHRA. Glucose solutions: false blood glucose readings when used to flush arterial lines (11 December 2014)

Summary

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.

There are several examples of glucose solutions being inadvertently and incorrectly used to flush arterial lines. 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.

Content

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.