MAGNESIUM-DEFICIENCY IN CRITICALLY ILL PATIENTS

A study was performed to assess the value of estimation of intracellular magnesium content. A magnesium loading test was used to diagnose magnesium depletion in critically ill patients. Patients were divided into magnesium depleted and non-depleted groups according to their response to the loading test. Pre-infusion plasma and intracellular (blood cell) magnesium levels were measured. There were no significant differences between the magnesium depleted (mean plasma magnesium 0.81 mmol.l(-1), red blood cell magnesium 2.34 mmol.l(-1), mononuclear blood cell magnesium 25.16 mmol.kg(-1) dry weight) and non-depleted groups (mean plasma magnesium 0.90 mmol.l(-1), red blood cell magnesium 2.18 mmol.l(-1), mononuclear blood cell magnesium 18.1 mmol.kg(-1) dry weight). We conclude that the diagnosis of magnesium depletion cannot be excluded in the face of normal plasma, red blood cell or mononuclear blood cell concentrations of magnesium.