The glucose error in arterial sampling: assessing staff awareness and the effect of sampling technique

Using a dextrose-containing solution, instead of normal saline, to maintain the patency of an arterial cannula results in the admixture of glucose in line samples. This can misguide the clinician down an inappropriate treatment pathway for hyperglycaemia.

Following a near-miss and subsequent educational and training efforts at our institution, we conducted two simulations: (1) to observe whether 20 staff would identify a 5% dextrose/0.9% saline flush solution as the cause for a patient's refractory hyperglycaemia, and (2) to compare different arterial line sampling techniques for glucose contamination.

(1) Only 2/20 participants identified the incorrect dextrose-containing flush solution, with the remainder choosing to escalate insulin therapy to levels likely to risk fatality, and (2) glucose contamination occurred regardless of sampling technique.

Despite national guidance and local educational efforts, this is still an under-recognised error. Operator-focussed preventative strategies have not been effective and an engineered solution is needed.