# The importance of measuring the levels of ionized magnesium in the blood in critically ill patients

## TL;DR

This paper highlights the importance of measuring ionized magnesium in critically ill patients to detect deficiencies that can impact survival and treatment outcomes.

## Contribution

The study emphasizes the need for measuring ionized magnesium rather than total magnesium in critical care settings.

## Key findings

- Abnormal magnesium levels are common in critically ill patients and can be life-threatening.
- Discrepancies between total and ionized magnesium levels are frequent in critical illness.
- Measuring ionized magnesium can improve detection and correction of magnesium imbalances.

## Abstract

Critical illnesses imply vital organ dysfunctions with high risk of imminent death. Magnesium is a bioessential element with multiple physiological effects relevant for vital body functions. It stabilizes excitable membranes contributing to proper neuromuscular, cardiovascular and respiratory functions. Ionized Mg2+ (iMg2+) is free bioactive form of Mg2+ in body fluids. Magnesium disorders in critically ill patients are often overlooked. Chronic Mg2+ deficiency is a condition of growing incidence in the general population and a significant factor in overall morbidity and mortality in critical illness. Main goal of this study was to investigate the existing literature related to determination of iMg2+ in the critically ill and to raise awareness of the problem of chronic Mg2+ deficiency in these patients.

Search was conducted across electronic PubMed library database from 1975 to November 2024 using keywords concerning iMg2+ and critical care patients, to identify studies investigating the measuring of blood concentration of iMg2+ fraction in patients with critical health conditions. Search was limited to English language. Selection criteria included only studies on human, and excluded studies on animal population.

We identified 95 relevant studies. Reviewed papers show that abnormalities of Mg2+ levels are prevalent in critical illnesses. Their severity can impose vital threat. Disconcordance between total Mg2+ (tMg2+) and iMg2+ blood levels is frequently present in critical patients.

Appropriate electrolyte analyzer assay is needed to promptly determine iMg2+ levels to assess Mg2+ status in critically ill patients, in order to help detect and correct Mg2+ imbalances and estimate the requirement for Mg2+ recompense in the case of deficiency, and thereby provide better outcome of the disease.