Should we use hypotonic or isotonic maintenance intravenous fluids in sick patients? Why a study in healthy volunteers will not provide the answer Response to: Effect of isotonic versus hypotonic maintenance fluid therapy on urine output, fluid balance, and electrolyte homeostasis: a crossover study in fasting adult volunteers

Editor —Sick patients who are unable to ingest oral fluids usually receive i.v. maintenance fluid therapy (IVMFT). The main goal of IVMFT is to temporarily meet water, electrolyte and glucose needs pending a more sustainable (par)enteral solution for feeding and hydration. Despite routine application, IV MFT is often based on dogmatic principles rather than high quality empirical research.1 Furthermore, macro- and micronutrient deficiencies, fluid overload, hyperchloraemic acidosis and hyponatraemia have all been reported as potentially detrimental complications. Fortunately, well-designed high quality studies performed over the last decade have substantially improved our insights into safe and effective IVMFT. Recently, Van Regenmortel and colleagues2 contributed additional data to this growing body of evidence by comparing the effects of isotonic and hypotonic IVMFT in healthy adult volunteers. They conclude that a hypotonic IVMFT (NaCl 0.32%) increased diuresis and resulted in significantly less intravascular fluid retention compared with isotonic IVMFT (NaCl 0.9%). In line with a previous report by this group, the authors argue that IVMFT should be hypotonic in order to avoid fluid overload.3
Source: British Journal of Anaesthesia - Category: Anesthesiology Source Type: research