Intensive Care Medicine

, Volume 31, Issue 1, pp 151–156 | Cite as

Total and ionized serum magnesium in critically ill patients

  • Maria Paz Escuela
  • Manuel Guerra
  • José M. Añón
  • Vicente Martínez-Vizcaíno
  • María Dolores Zapatero
  • Angel García-Jalón
  • Sebastian Celaya
Brief Report



To assess the alterations in total serum magnesium (tsMg) and ionized serum magnesium (Mg2+) and their association with prognosis in critically ill patients.

Design and setting

Prospective, cohort study in the intensive care unit (ICU) of a university teaching hospital.


Adult patients admitted to the ICU without previous factors influencing magnesium homeostasis were included during a 6-month period.

Measurements and results

One hundred forty four patients were included. Mean age was 60.6±15.4 years; mean APACHE II score was 12.6±6.9. Blood samples were collected in the first 24 h after ICU admission and again on the second, third, and last days of stay in the ICU. At ICU admission 52.5% had total hypomagnesemia and 13.5% total hypermagnesemia; with respect to the Mg2+ 9.7% showed ionized hypomagnesemia and 23.6% ionized hypermagnesemia. Patients who developed ionized hypermagnesemia had higher mortality than patients without ionized hypermagnesemia development (P=0.04). A moderate correlation between tsMg and Mg2+ concentrations was found; however, a number of patients with total hypomagnesemia (69–85% during the study) had ionized normomagnesemia. The measure of agreement between tsMg and Mg2+ levels was poor.


Magnesium alterations are frequently found in critically ill patients. The usually determined tsMg levels are not a reflection of Mg2+ levels. Development of ionized hypermagnesemia is associated with prognosis.


Magnesium Magnesium deficiency Prognosis Electrolytes 


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Maria Paz Escuela
    • 1
    • 2
  • Manuel Guerra
    • 3
  • José M. Añón
    • 2
  • Vicente Martínez-Vizcaíno
    • 4
  • María Dolores Zapatero
    • 5
  • Angel García-Jalón
    • 5
  • Sebastian Celaya
    • 1
  1. 1.Intensive Care UnitHospital Clínico UniversitarioZaragozaSpain
  2. 2.Intensive Care UnitHospital Virgen de la LuzCuencaSpain
  3. 3.Physiology DepartmentUniversity of ZaragozaSpain
  4. 4.Epidemiology and Public Health DepartmentUniversity of Castilla-La ManchaSpain
  5. 5.Biochemistry DepartmentHospital Universitario Miguel ServetZaragozaSpain

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