Prevention of hypomagnesemia and hypocalcemia in open-heart surgery

We have studied the behavior of calcium and magnesium in the serum in dogs subjects to cardiopulmonary bypass with total hemodilution (Ringer's lactate). 5 mEq/l of calcium and magnesium was added to the filling solution. Serum levels of Ca++ and Mg++ were determined, by atomic absorption spectrophotometry, in the basal state, every thirty minutes during the perfusion, and one hour after stopping the bypass. We observed that the calcium and magnesium levels were higher than be baseline throughout the perfusion, and even 60 minutes after stopping the bypass they were still noticeably higher. Since this type of perfusion yields normal final calcium and magnesium levels, the advantages of this method become obvious, especially considering the adverse phenomena that are caused by defiencies of these cations.