Ionized magnesium concentration during liver transplantation, resection of the liver and cardiac surgery.

In this study we investigated three groups of patients, the first undergoing liver transplantation (n = 9), the second resection of the liver (n = 7) and the third cardiac surgery (n = 10) with regard to changes of ionized and total magnesium concentration during operation. Liver transplantation: Ionized magnesium concentration decreased from 0.58 mmol/L to 0.34 mmol/L far below the reference interval (0.49-0.72 mmol/L), whereas total magnesium concentration changed only from 0.78 mmol/L to 0.67 mmol/L (reference interval: 0.65-1.05 mmol/L). Citrate concentration increased from 220 mumol/L to 1925 mumol/L (anhepatic stage) because of massive transfusion of blood products. It was inversely correlated to ionized magnesium concentration. Resection of the liver: There was a decline of ionized magnesium from 0.56 mmol/L to 0.43 mmol/L, which slightly exceeded the decline of total magnesium from 0.74 mmol/L to 0.64 mmol/L. Citrate concentration increased moderately even in cases, when no citrate was administered reflecting reduced hepatic function during operation. Cardiac surgery: Only in patients, to whom citrate but not magnesium was infused, ionized magnesium concentration fell slightly below the reference interval (0.45 mmol/L). In the other patients, to whom magnesium was administered, ionized magnesium concentration was within the reference interval or exceeded it. It is concluded that in patients with impaired hepatic function and/or high citrate load the monitoring of ionized magnesium concentration is mandatory.