Serum Magnesium Levels in Critically Ill Patients on Admission in ICU and its Correlation with Outcome

Many studies found that only hypomagnesemia, but not hypermagnesemia is linked with increased mortality. However, reports of mortality due to magnesium dysregulation in the critical care setting are controversial.

To study serum magnesium levels in critically ill patients on admission in intensive care unit (ICU) and its correlation with patient's need and duration for ventilator support, duration of ICU stay, incidence of cardiac arrhythmias and mortality Methods: Two hundred forty six critically ill patients admitted in ICU with Acute Physiology and Chronic Health Evaluation (APACHE) II scores>10, were included for this prospective observational study. Serum total magnesium level was measured at the time of admission to ICU. Primary outcome measure was ICU mortality whereas, secondary outcome measures were patient's need and duration for ventilator support, duration of ICU stay, and incidence of cardiac arrhythmias. Categorical and continuous variables were tested using Chi-square/Fisher's exact test and analysis of variance respectively. Multivariate logistic regression analysis was carried out to determine association of serum magnesium levels with ICU mortality.

Incidence of ICU mortality was significantly higher in group of patients with hypomagnesemia compared to those with normal magnesium levels. Hypomagnesemia was associated with need and longer duration of ventilator support, longer duration of ICU stay, higher APACHE II score, QTc prolongation, higher incidence of cardiac arrhythmias compared to patients with normal magnesium levels. Hypomagnesemia was an independent and statistically significant determinant of ICU mortality.

Hypomagnesemia was associated with higher mortality rate, longer duration of ventilator support and ICU stay, and higher APACHE II score in critically ill patients.