Significance of serum magnesium levels in critically ill-patients

Magnesium is one of the major electrolytes, deficiency of which is frequently overlooked in critical illness, leading to an adverse clinical outcome if not monitored regularly.

Single center prospective observational study of 2 years duration.

The subjects studied were monitored for serum magnesium levels 2 times: Day 1 and day 4 of intensive care unit (ICU) admission. Patients were divided into normomagnesemic and hypomagnesemic groups and compared for various parameters.

Out of 70 critically ill-patients, 50 patients (71.43%) were normomagnesemic, 17 patients (24.29%) were hypomagnesemic and three patients were hypermagnesemic. The stay of the patients in ICU (P > 0.05), Acute Physiology and Chronic Health Evaluation-II (APACHE-II) scoring (P = 0.34) and co-morbidity (P = 0.360) showed an insignificant variation between the two groups. Associated electrolyte abnormalities in hypomagnesemic patients were hypokalemia (58.82%), hyponatremia (47.05%), hypocalcemia (70.58%) and hypophosphatemia (29.41%). About 76.47% of hypomagnesemic population was on magnesium lowering drugs while as 46% of normomagnesemic population was on magnesium lowering drugs (P = 0.030). Mortality of hypomagnesemic group was 74.47% while that of normomagnesemic group was 36% (P = 0.004).

Hypomagnesemia is a significant electrolyte abnormality in critically ill-patients. Critically ill hypomagnesemic patients have higher mortality than the normomagnesemic patients.