More on sodium in “maintenance” fluids

Article Outline

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The rather spirited debate regarding the appropriate tonicity of intravenous maintenance fluids shows no sign of abating. Many have called for some sort of randomized trial to shed light on the controversy, although the logistics of designing such a trial are daunting.

An attempt at this is published in the current issue of The Journal by Neville et al in Sydney. Although this study is certainly not the final word on the topic—indeed, both sides are likely to find support in it—it represents a first substantive effort at such a trial.

The study merits careful reading. Children were grouped to receive either one-half isotonic or isotonic fluid, at 100% or 50% “maintenance” rates following surgery. Slight reductions in serum sodium were common 8 hours following surgery, and these reductions were more common in children receiving half isotonic fluid. By 24 hours, no significant differences were seen. Many children had evidence of elevations in plasma ADH, and there was no systematic fluid protocol followed prior to surgery. Not surprisingly, evidence of dehydration was seen in some children receiving “50% maintenance” fluid administration rates.

The careful reader will find a wealth of useful data in this paper and its accompanying online Table and Figures. These data can be used to inform future studies of this important topic.