In this interesting trial by Lima and colleagues, with findings published recently in the Journal of Neurosurgical Anesthesiology, the authors compare normal saline (NS) with a balanced crystalloid as a maintenance fluid for elective tumour resection in paediatric patients. Their main endpoint was change in serum chloride from baseline to end of surgery. Perhaps unsurprisingly the greatest elevation was noticed in the NS-group. Among the other endpoints, such as other serum electrolytes and Base Excess, changes from baseline were also less pronounced in the balanced fluid cohort. This would indicate that balanced solutions are more physiologically sound and induce less metabolic derangement than NS. It is not quite clear how much clinical relevance this has in terms of more patient-important outcomes, as this study was underpowered for that. However, the trial does add to the compelling physiological rationale for choosing a solution with balanced constituents, especially as both fluids achieved comparable surgical conditions as judged by degree of brain relaxation.