Abstract
Critically ill children frequently encounter a most common and potentially life threatening electrolyte disturbances, i.e. hyponatremia. It is an independent risk factor for prolonged hospitalization in Intensive Care Unit (ICU) and increased in-hospital mortality. Hyponatremia occurs in up to 20-30% of admissions in Pediatric Intensive Care Unit (PICU). This observational study was conducted in pediatric intensive care unit (PICU) of a tertiary care hospital in a developing country from September 2018 to September 2019. Admission criteria in our PICU is; need of mechanical ventilation, fulminant hepatic failure, vasopressor support, respiratory failure and poorly controlled seizure. We studied 256 children, aged 1 month to 18 years, with normal serum sodium at admission. In our study seventy-two (28.1%) children developed hyponatremia. and about two third (n=48, 66.7%) of them developed within 72 hours of admission in PICU. Maximum children (n=46, 63.9%) in hyponatremic group were below 5 years. Wasted children (n=68, 26.6%) in hyponatremic and isonatremic group were 20 (27.8%) and 48 (26%) respectively. Most common etiology of hyponatremia was cerebral salt wasting syndrome (CSWS) (n=20, 27.8%) followed by drug induced cases (n=19, 26.4%). Drugs responsible were diuretics and antileptics. In our study, multi organ failure (OR=5.05, 95%CI=1.90-13.43; p=0.0001), shock (OR=7.38, 95%CI=3.56-12.28; p=0.0001), vasopressor use (OR=6.74, 95%CI=3.45-13.17; p=0.0001) and coagulopathy (OR=6.74, 95%CI=3.45-
2
13.17; p=0.0001) were the risk factors for the development of hyponatremia. Mortality among hyponatremic group (44.4%) was significantly higher than in isonatremic group (21.7%). Hyponatremia is a common electrolyte disturbance found in critically ill patients and is associated with prolonged hospitalization and increased mortality.

Key words: Hyponatremia; Intensive Care Unit; Pediatrics; Mortality; Pediatric Risk of Mortality (PRISM III); Risk factors.