Estimation formulas for ionized magnesium in critically ill children

Area of Science:

• Clinical Chemistry
• Pediatric Intensive Care
• Acid-Base Balance

Background:

• Ionized magnesium (iMg) measurement is crucial for assessing magnesium homeostasis but requires specialized equipment.
• Total magnesium (tMg) is often used as a surrogate, but it lacks precision.
• Developing accurate estimation methods for iMg is clinically significant.

Purpose of the Study:

• To develop predictive formulas for estimating ionized magnesium (iMg) levels.
• To utilize routinely measured clinical parameters, particularly those involved in acid-base regulation.
• To provide a more accessible method for assessing magnesium status.

Main Methods:

• Prospective study in a pediatric intensive care unit with 200 patients.
• Serum iMg levels measured using a Stat Profile Prime analyzer.
• Multiple regression analysis and Bland-Altman analysis were employed to develop and validate estimation equations.

Main Results:

• A strong correlation (0.915) was found between iMg and tMg.
• Three predictive equations for estimating iMg were successfully developed using multivariate analysis.
• Validation on additional samples showed minimal error and high concordance between measured and estimated iMg values.

Conclusions:

• An effective iMg estimation model was developed using standard clinical parameters.
• This model can aid in assessing magnesium homeostasis when direct iMg measurement is not feasible.
• The findings support the use of predictive formulas for improved clinical decision-making.