Abstract
Neonates in critical care constitute a vulnerable group, and vitamin D status in this group is the subject of extensive research. Studies suggest that critically ill neonates and children have lower mean vitamin D levels than healthy ones, and there is evidence linking vitamin D deficiency to an increased risk of mortality, illness severity, and complications in these patients. Vitamin D deficiency in neonates and children with congenital heart disease (CHD) undergoing corrective surgical treatment has attracted particular attention. Overall, studies show high prevalence rates of vitamin D deficiency in this group. Moreover, several studies report significant associations between low vitamin D levels and unfavorable findings, such as increased requirements for vasoactive support and mechanical ventilation and prolonged ICU stays. Available data suggest vitamin D deficiency as a risk factor in neonatal and pediatric critical illness, specifically in CHD patients undergoing surgical treatment. Clinical trials have been proposed to examine the beneficial effect of preoperational vitamin D supplementation on the outcome in this group. However, for now, vitamin D supplementation should be considered in critically ill neonates, particularly those undergoing surgery for CHD, aiming to maintain vitamin D at safe levels over the threshold of vitamin D deficiency.