Peri-operative effect of major gastrointestinal surgery on serum magnesium.

This study investigates the changes in serum magnesium levels after major gastrointestinal surgery and evaluates if Plasma-Lyte 148 used as maintenance fluid influences these changes in the peri-operative period. Thirty patients presenting for procedures ranging from anterior rectal resection to thoraco-abdominal cardio-oesophagectomy were randomly allocated into two groups, one of which received compound sodium lactate solution as the maintenance crystalloid during the intra- and postoperative period, and the other Plasma-Lyte 148, a magnesium-containing crystalloid solution. Serum magnesium levels were measured pre-operatively, in the immediate recovery period and 24 h postoperatively. The results showed a statistically significant (p < 0.05) reduction in the magnesium levels in both groups. The reduction was less marked in the Plasma-Lyte group but this did not achieve statistical significance (p > 0.05) compared with the compound sodium lactate group.