Evaluation of patients with hyponatremia in the pediatric intensive care unit

Evaluation of patients with hyponatremia in the pediatric intensive care unit Introduction and Purpose: Hyponatraemia, defined as a serum sodium (Na) level <135 mEq/L, is the most common electrolyte imbalance in children and is usually a problem that develops in hospital. Approximately 25% of hospitalised children are affected by this condition and it is mostly encountered in patients receiving hypotonic intravenous fluid administration. In this study, it was aimed to clinically evaluate the patients hospitalised in the Pediatric Intensive Care Unit of Dicle University Faculty of Medicine due to hyponatremia and to investigate the underlying etiological causes. Materials and Methods: A total of 99 patients, including 55 boys and 44 girls, who were diagnosed with hyponatremia between 01 January 2019 and 30 April 2024 in the Pediatric Intensive Care Unit of Dicle University Faculty of Medicine, Children's Hospital, were included in the study. Patients were grouped according to sodium levels and clinical and laboratory characteristics of the two groups were compared. Results: Patients were classified into two groups based on their sodium levels: the group with sodium levels of 130–135 mEq/L was defined as Mild Hyponatremia (n=64), and the group with sodium levels ≤129 mEq/L was defined as Severe Hyponatremia (n=35). The most common reasons for hospitalization in both groups were identified as neurological, respiratory, and hematological causes. In the mild hyponatremia group, the mean sodium level, normal blood pressure at admission, the proportion of normovolemic patients, the proportion of patients with normal urine output, and the proportion of patients with normal blood pressure during the hyponatremic period were statistically significantly higher compared to the severe hyponatremia group. Conversely, the proportion of patients with low blood pressure, hypovolemia, decreased or increased urine output, the duration of hyponatremia development, the rate of patients with low blood pressure, the amount of intravenous sodium received (mEq/kg/day), and the proportion of patients receiving >3 mEq/kg/day intravenous sodium were statistically significantly lower (p<0.05). In the deceased group, compared to the surviving group, the hospitalization cause being related to hematological issues, higher blood pressure during the hyponatremic period, the use of 3% hypertonic saline and Ringer's lactate solutions, and a lower average fluid intake were found to be statistically significant factors for mortality (p<0.05). Conclusion: In cases of hyponatremia, it was observed that as sodium levels decreased, the rates of normovolemia, normal blood pressure, and normal urine output declined, while the rates of hypovolemia, low blood pressure, and either increased or decreased urine output rose. Additionally, the amount of intravenous sodium administered and the use of hypertonic saline became more pronounced. Hospitalization due to hematological causes, elevated blood pressure during the hyponatremic period, and reduced fluid intake were identified as factors that significantly increased the risk of mortality. These findings highlight that as the severity of hyponatremia increases, patients' clinical conditions deteriorate, underscoring the importance of appropriate treatment strategies.