Should we rely on electrolyte values measured by venous blood gas analysis in children with critical illness?

Aim: In this study, we aimed to compare venous blood gas analysis and auto-analyzers for obtaining levels for sodium, potassium, and glucose in critically ill patients and to investigate the correlation between results. Material and Methods: Sodium, potassium, and glucose values obtained by two methods simultaneously were evaluated separately for three groups' pH status: acidosis, normal pH, and alkalosis. Results: A total of 198 paired measurements were recruited. A statistically significant difference was found between blood gas analyzer and auto-analyzer methods in terms of sodium (136.78 +/- 10.553 mmol/l; 136.78 +/- 6.686 mmol/l), potassium (4.307 +/- 0.881 mmol/l; 4.529 +/- 0.902 mmol/l), and glucose (182.89 +/- 83.39 mg/dl; 163.44 +/- 99.108 mg/dl) (p < 0.05). A Bland-Altman plot of difference suggested that all agreements between venous blood gas analysis and auto-analyzer were good (the latter measure was considered the standard). Discussion: Differences between electrolytes and glucose values obtained with both techniques vary according to the pH state.