Materials and Methods: This prospective observational study was conducted on 8 beds of PICU for two years. In parallel with the routine treatment protocol, the levels of magnesium (Mg), phosphate (P), and calcium (Ca) on the admission day were measured in 240 hospitalized patients with pneumonia. Based on clinical outcomes, patients were categorized into three groups. Finally, the demographic data and electrolyte imbalances were analyzed based on the aim of the study.

Results: There were no significant differences regarding age and gender, as well as the percentages of patients with mechanical ventilation and dopamine administration. In addition, no differences were observed in the lengths of mechanical ventilation and dopamine administration among the three groups. Furthermore, the length of PICU and hospital stays was significantly longer in patients either as discharged with the sequel or dead ones. The results further revealed that the scores of the pediatric risk of mortality and sequential organ failure assessment were significantly higher in patients that passed away. Moreover, Ca and Mg deficiencies were significant in patients either as discharge with the sequel or dead ones. Additionally, 16.2% and 25% of patients who discharged with the sequel and passed away showed P deficiency, respectively. Finally, Ca deficiency by 12.39 times increased patients" poor prognostic clinical outcomes.

Conclusions: Among primary electrolyte deficiencies, hypocalcaemia can be considered as a prominently poor prognostic factor for clinical outcomes in PICU patients with pneumonia but hypomagnesaemia and hypophosphatemia do not predict clinical outcomes.