Background & Aims: Hypophosphatemia is seen in very ill patients and can affect treatment outcomes. The aim of this study is the assessment of the prevalence and the effect of the hypophosphatemia in immediate outcome of open heart surgeries in children.

Materials & Methods: The patients were divided into two groups of normal and low serum phosphor level. In each group the duration of hospital and intensive care unit (ICU) stay, intubation and mechanical ventilation time and mortality ratio were studied. The data were assessed statistically.

Results: From 102 patients, 60 were male (58.8%); and 42 were female (41.2%). Mean patients age was 27.36+-27.07 months. The youngest was 16 days and the oldest was 6 years old. The most common diagnoses were ventricular septal defect (VSD), atrial septal defect (ASD), and VSD with ASD respectively. The change of phosphorus level after surgery was significant (P=0.015). There wasn’t significant difference about duration of hospital and intensive care unit (ICU) stay (P=0.153 and =0.660 respectively), intubation time (P=0.833) and mechanical ventilation time (P=0.389) between two groups.

Conclusion: Hypophosphatemia as a common complication of heart surgery can be affected by different factors. For accurate assessment of the effects of hypophosphatemia on patients' outcome, a wide study with more patients is required.