Two devils: hypernatremia and hyponatremia can show faces to the same patient in the intensive care unit

In this large study, the patients were divided into three groups of acquired hyponatremia, always normal sodium, and acquired hypernatremia according to their first episode of SD after arrival in the ICU. The categorization of the patients based on the first episode of SD, although simple and informative, we think oversimplifies a complex and common disorder in the ICU. Critically ill patients in the ICU may experience multiple episodes of SD, hypernatremia or hyponatremia. A significant hypernatremic episode and its impact on final outcome could therefore easily be missed in a final analysis of patients who experienced a transient hyponatremia as the first episode of SD or vice versa. In other words, examining the impact of SD on the final outcome of patients in the ICU should take into consideration the spectrum of SD in a given patient in the ICU rather than an episode of hyponatremia or hypernatremia in isolation. It is not clear in their paper whether the investigators examined the effects of mixed SD happening in the same patient during their ICU stay.