Significance of serum magnesium levels in critically ill-patients

BACKGROUND: 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. SETTINGS AND DESIGN: Single center prospective observational study of 2 years duration. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: Hypomagnesemia is a significant electrolyte abnormality in critically ill-patients. Critically ill hypomagnesemic patients have higher mortality than the normomagnesemic patients.