Iatrogenic fluid overload comes as a potential side effect of intravenous fluid therapy in the hospital and sodium administration is not always evaluated as a separate cause of harm. A recent study substantiated the hypothesis that a considerable amount of fluid-induced harm is caused not only by fluid volume but also by the sodium that is administered to hospitalized patients.

This study showed how a regular dietary sodium intake is easily exceeded by the substantial amounts of sodium that are administered during typical hospital stays. The most noteworthy sodium burdens are due to isotonic maintenance fluid therapy and fluid creep described as the large volume unintentionally dispensed to patients in the form of dissolved medication. 

This study explained the limited renal handling of an acute sodium load and also demonstrated how the subsequent retention of water is an energy-demanding, catabolic process and how free water is required to excrete large burdens of sodium. This study also quantified the effect size of sodium-induced fluid retention and discussed its potential clinical impact. 

The highlights are as follows-

• The sodium burdens caused by isotonic maintenance fluids and fluid creep cause an added and avoidable derailment of fluid balance, with suspected clinical consequences.
• The handling of sodium overload is indicated by increased catabolism.
• Easy and effective measures for reducing sodium load and fluid retention could be selecting a hypotonic despite isotonic maintenance fluid strategy, or avoiding these fluids if adequate free water is delivered through other sources, and dissolving all the possible medications in glucose 5%.
• Adopting a maintenance fluid strategy that is low in sodium and provides enough free water, and avoiding NaCl 0.9% as the diluent for medication is recommended.
• Caution should be given regarding the development of hyponatremia and hypovolemia. 

SOURCE- Ann. Intensive Care, 2021;11(79). https://doi.org/10.1186/s13613-021-00851-3