Objectives & Background Gaining intervenous access in children, especially those who are unwell, can be difficult. Blood samples are often taken from the cannula hub to avoid repeated venepuncture but leads to concerns about whether it is “free-flowing' and what effect it has on the accuracy of results. We postulated that this process should equally impact on all electrolytes and metabolites. In particular we wondered if there was a relationship between potassium and lactate which are both felt to be affected by procedures in which blood was difficult to obtain.

Methods A retrospective convenience sample of 101 children and young people (<16) who had had a blood gas performed were collated and analysed via microsoft excel.

Results 4 patients were excluded due to insufficient or inadequate data leaving 97 data sets available for analysis. A scatter graph of potassium and lactate results was plotted (figure 1). The correlation coeffecient was very weak (r=0.11). Mean potassium samples when lactates were seperated into values above and below 2.0 was not significantly different (4.4 vs 4.1)

Conclusion There appears to be no obvious relationship between lactate and potassium values. A procedure which results in a perceived haemolysed sample may therefore not affect all electrolytes or metabolites. Further data is needed to confirm the abence or precence of any relationship.⇓

• Download figure
• Open in new tab
• Download powerpoint

Figure 1

Scatter graph of potassium versus lactate in a convenience sample of 97 patients