Eulmesekianet al, conducted a prospective observational study on postoperative patients admitted in paediatric intensive care unit to establish incidence and factors associated with hospital acquired hyponatremia. A total of 81 patients having serum sodium in normal range (136-146 mmol/l) and requiring IV fluid in the post-operative period were included in the study. The incidence of hospital-acquired hyponatremia at 12 hrs was 21% [95% CI (3.7-38.3)], at 24 hrs it was 31% [95% Confidence interval (CI)(11.4-50.6)]. At 12 hrs, relative risk of developing hyponatremia was 11.55 (95% CI [ 2.99-44.63]; p =0.0004) for Na loss of >0.5 mmol/kg/hr, RR=10 (95% CI, 2.55-39.15; p=0.0009) for a negative Na balance of >0.3 mmol/kg/hr, and RR=4.25 (95% CI,1.99-9.08; p=0.0002) for a urine output >3.4 mL/kg/hr. At 24 hrs, relative risk for hyponatremia was 3.25 (95% CI [1.2-8.77]; p =0.0201) for a positive fluid balance of > 0.2 mL/kg/hr.