A prospective observational study to identify the effectiveness of intravenous magnesium replacement in an intensive care setting.

Background And Aims: To estimate the incidence of hypomagnesemia and identify the effectiveness of a calculated dose of intravenous magnesium sulfate (MgSO) in correction of hypomagnesemia and its relationship with renal function in critically ill patients.

Material And Methods: All patients admitted in the adult intensive care unit were enrolled in the study and magnesium levels were monitored. Patients with serum magnesium levels <1.7 mg/dL received calculated doses of Intravenous MgSO. The average rise in serum magnesium levels per gram of MgSO administered was calculated and relationship with estimated glomerular filtration rate (eGFR) was identified.

Results: In total, 27.27% of patients admitted in our intensive care unit had an incidence of hypomagnesemia. The average rise of serum magnesium levels in patients with hypomagnesemia was 0.13 (±0.05) mg/dl. The average rise of serum magnesium levels was 0.10 (±0.04) mg/dL in patients with eGFR ≥ 90 mL/min/1.73 m and 0.15 (± 0.05) mg/dL in patients with eGFR < 90 mL/min/1.73 m. This difference between the two groups (-value = 0.002) and the trend of increasing average rise in serum magnesium levels with declining eGFR values (-value = 0.013) were both statistically significant.

Conclusion: Incidence of hypomagnesemia in the critically ill population is around 27.27%. Intravenous administration of 1 g of MgSO results in a rise of serum magnesium levels by 0.1 mg/dL in patients with normal eGFR and around 0.15 mg/dL in patients with eGFR values between 30 and 89 mL/min/1.73 m.