[Plasma and erythrocyte magnesium concentration in the postoperative period. Relations between calcium and magnesium].

Transient hypomagnesiaemia was noted postoperatively, particularly on the 1st day in patients submitted to intestinal procedures. Slight hypocalcaemia was also observed; this was often related to a low plasma Mg value. A hormonal mechanism is presumed to be the cause of this stress-linked fall in blood magnesium.