Nutritional status of patients undergoing valve replacement by open heart surgery.

In 10 patients undergoing heart-valve replacement with cardiopulmonary bypass total-body potassium was measured non-invasively with a whole-body monitor, and this measurement was used to derive the lean body mass as an index of the nutritional status. From measurements made before operation and on the 7th postoperative day, the metabolic response to surgery was found to be equivalent to a negative nitrogen balance of 10.8 g of nitrogen a day (50% greater than that calculated from conventional nitrogen-balance studies). 4 patients had a mean preoperative potassium depletion of 17.2%, and this was associated with increased morbidity. Well-nourished patients had a mean postoperative hospital stay of 16 days, whereas those in a depleted state before operation had an increased morbidity, as measured by their mean postoperative stay of 30 days. More attention needs to be given to the preoperative nutritional status of patients undergoing heart-valve replacement.