Hypomagnesemia in critically ill cancer patients: a prospective study of predictive factors

Abstract

Hypomagnesemia is the most common electrolyte disturbance seen upon admission to the intensive care unit (ICU). Reliable predictors of its occurrence are not described. The objective of this prospective study was to determine factors predictive of hypomagnesemia upon admission to the ICU. In a single tertiary cancer center, 226 patients with different diagnoses upon entering were studied. Hypomagnesemia was defined by serum levels <1.5 mg/dl. Demographic data, type of cancer, cause of admission, previous history of arrhythmia, cardiovascular disease, renal failure, drug administration (particularly diuretics, antiarrhythmics, chemotherapy and platinum compounds), previous nutrition intake and presence of hypovolemia were recorded for each patient. Blood was collected for determination of serum magnesium, potassium, sodium, calcium, phosphorus, blood urea nitrogen and creatinine levels. Upon admission, 103 (45.6%) patients had hypomagnesemia and 123 (54.4%) had normomagnesemia. A normal dietary habit prior to ICU admission was associated with normal Mg levels (P = 0.007) and higher average levels of serum Mg (P = 0.002). Postoperative patients (N = 182) had lower levels of serum Mg (0.60 ± 0.14 mmol/l compared with 0.66 ± 0.17 mmol/l, P = 0.006). A stepwise multiple linear regression disclosed that only normal dietary habits (OR = 0.45; CI = 0.26-0.79) and the fact of being a postoperative patient (OR = 2.42; CI = 1.17-4.98) were significantly correlated with serum Mg levels (overall model probability = 0.001). These findings should be used to identify patients at risk for such disturbance, even in other critically ill populations.

Relationship between serum total magnesium and serum potassium in emergency surgical patients in a tertiary hospital in Ghana

“…7,12 Some studies have, however, found no correlation between serum magnesium levels and serum potassium levels. 13,14 Whang et al described the phenomenon of "refractory potassium repletion" which is the inability to correct hypokalaemia in the presence of unrecognized and continuing magnesium deficiency. 12 Hypomagnesaemia like hypokalaemia may result in muscular weakness and lethal cardiac dysrhythmias.…”

Clinical Consequences and Management of Hypomagnesemia

“…Mg 2ϩ deficiency has also been reported in 20 to 60% of patients in intensive care units (ICU). [3][4][5] Mg 2ϩ homeostasis involves the kidney, small bowel, and bone. In the gastrointestinal tract, Mg 2ϩ absorption occurs primarily in the jejunum and ileum by both a passive paracellular mechanism and an active transport process 8,9 ; however, most evidence suggests that Mg 2ϩ is absorbed mainly by ionic diffusion and "solvent drag" resulting from the bulk flow of water.…”

Prevalence of Hypomagnesemia and Its Predictive Prognostic Value in Critically Ill Medical Patients

“…Various studies evaluated hypomagnesemia in critically ill patients previously ranging from 14% -70%. [12][13][14][15][16][17][18] In our study a relatively higher mortality was observed among patients with hypomagnesemia compared to normomagnesemic patients. The relation between hypomagnesemia and mortality varies from study to study.…”