Lower incidence of hypo-magnesemia in surgical intensive care unit patients in 2011 versus 2001

Hypo-magnesemia is described to occur in as many as 65% of intensive care unit (ICU) patients. Magnesium (Mg) is a cofactor in over 300 enzymatic reactions involving energy metabolism, protein, and nucleic acid synthesis. The membrane pump that creates the electrical gradient across the cell membrane is dependent on Mg, and it is important in the activity of electrically excitable tissues. Since Mg regulates the movement of calcium in smooth muscle cells, it is also important in peripheral vascular tone and blood pressure. Studies have linked hypo-magnesemia to multiple chronic diseases and to a higher mortality rate. To explore trends within our own tertiary care surgical ICU, we sampled our patients' laboratory records in 2001 and in 2011. Hypo-magnesemia in our ICU is defined as an Mg less than 2.0 mg/dL. This retrospective review of all SICU patients from October to December revealed that there was a significant increase (P < 0.01) in the patients with their serum Mg level measured between 2001 (89%) and 2011 (95%). There was a significant decrease (P < 0.001) in patients with hypomagnesemia (< 2 mg/dL) between 2001 (47.5%) and 2011 (33.0%). On the other hand, there was a significant increase (P < 0.001) in patients with normal serum Mg level (> 2 mg/dL) between 2001 (52.5%) and 2011 (67.0%). There was not only more monitoring of Mg in 2011, but a lower incidence of hypo-Mg compared to 2001. Possible explanations include changing patterns of antibiotic and diuretic use, less amphotericin use, more frequent laboratory surveillance, and better trained ICU practitioners.