Hypocalcemia, measured through ionized calcium, is a common derangement in critically ill patients. Hypocalcemia is corrected as a routine procedure in intensive care units; however, no clear guidelines exist for its management.

This narrative review aims to provide an overview of hypocalcemia in critical care settings. This includes its association with important clinical outcomes and the assessment of the need for its correction in critically ill patients in general and in two subgroups: those with trauma and sepsis.

An extensive article search on hypocalcemia in critically ill patients was performed using PubMed, Web of Science, Cochrane Library, and Google Scholar.

Several studies showed an association between hypocalcemia and high mortality and disease severity in critically ill patients. However, the scientific evidence concerning its correction remains conflicting. Most studies showed that calcium supplementation did not improve clinical outcomes, such as mortality, and in some cases, ionized calcium levels normalized without supplementation. Patients with trauma and sepsis are subgroups, with special characteristics that should be considered when treating hypocalcemia.

We concluded that hypocalcemia is associated with several important clinical outcomes. Treating severe hypocalcemia is generally recommended, whereas treating moderate or mild hypocalcemia can lead to higher mortality and organ dysfunction, outweighing the potential clinical benefits, particularly in patients with sepsis. Hence, multicenter clinical trials are needed to assess the efficacy and safety of hypocalcemia treatment in these patients.