Hospital-acquired hyponatremia: Does the type of fluid therapy affect children admitted to intensive care?

Introduction: The objective of this study was to evaluate the association between the type of initial fluid therapy used (isotonic or hypotonic solutions) and the development of hyponatremia, the plasma chlorine values and the tolerance of venous access. Patients and Method: Retrospective cohort study in a Pediatric Intensive Care Unit (PICU) of a high complexity hospital. There were included children younger than 15 years old hospitalized during the first semester of 2010 and 2013 who received intravenous maintenance fluid therapy, excluding patients undergoing cardiac surgery, kidney transplant and admissions that lasted less than 24 hours. Epidemiological, comorbidity and admission-related data were collected, including type of solution received, sodium and chlorine values in the first 72 hours of hospitalization and the incidence of extravasation of peripheral intravenous lines. Results: 111 children were included; 68 children (61.3%) were treated with hypotonic solutions and 43 (38.7%) with isotonic solutions. There were no differences in pathology and severity, and also in the volume of fluid received. Among the patients who received hypotonic solutions, 28 (41.2%) developed hyponatremia, wich was moderate (Na <130 mEq/Kg) in 11 cases, compared with 8 children (18.6%) who received isotonic solutions, with only one case of moderate hyponatremia (p = 0.027). No cases of hypernatremia were recorded, and there were no differences in plasma chlorine values. There was also no increased frequency of venous access loss in patients treated with isotonic solutions (4.7% versus 7.4%, p = 0.704). Conclusion: Treatment with initial isotonic solutions in children hospitalized in PICU is associated with a lower incidence and severity of hyponatremia, without changes in the plasma chlorine values and it is well tolerated by peripheral intravenous lines.