Hyponatraemia, harm reduction and the O’Hara report from Northern Ireland

Excerpt

The report on the ‘Inquiry into hyponatraemia-related deaths’ under the chairmanship of John O’Hara QC is an important anchor for the issue of teaching, assessment and practice in the field of electrolyte management [1]. The report outlined the systematic pathway instituted in Northern Ireland to improve fluid prescription in paediatrics. In parallel, the National Institute for Health and Care Excellence (NICE) published clinical guideline NG29 on the subject of ‘intravenous fluid therapy for children and young people in hospital’ [2]. This guideline directs at least hourly measurements of plasma sodium and intervention that restricts the change in sodium to <12 mmol/L in 24 h. In NG29, there is no reference to reference change value of sodium which in Beaumont hospital Dublin is 3.209%. At a sodium value of 121 mmol/L, two SDs either side of the mean delineates the 95% confidence interval and this is 118.78 to 123.5 mmol/L. This means that changes within these parameters may be random. Therefore over-interpretation of sodium values measured hourly is likely [3]. As laboratories will have different analytical equipment, the reference change value (RCV) for sodium can be calculated when the analytical precision is measured and known. An RCV for sodium in a paediatric population has been published with details of the biological variation included. That RCV value was 2.40%. The same paper listed an adult RCV for sodium of 2.90% [4]. The figure, which should be calculated locally, will have clear implications for treatment. …