Nutrition Support After Cardiac Surgery: Lessons Learned From a Prospective Study

The importance of postoperative nutrition support (NS) has been poorly recognized in cardiac surgery. In this population, we aim to describe the delivery of NS, factors affecting calorie/protein delivery and NS-associated morbidity. From January 2015 to January 2017, we prospectively observed all cardiac surgery patients at a single institution who could not take nutrition orally, requiring postoperative NS, either enteral or parenteral, for the duration of NS up to 14 days. We compared outcomes to patients without NS and examined NS indications, factors affecting its delivery and its associated complications. Nine percent of patients (232/2603) required NS for a total of 1938 NS-days. The most common indication was mechanical ventilation. NS met 69% of daily caloric needs. On days when tube feeds (TFs) were held (mean of 13 hours), this decreased to 43%, compared to 96% when TFs were not held (p<0.001). The most common reason for holding TFs was procedures. When TFs were supplemented with parenteral nutrition (TFs+PN), 86% of daily caloric needs were met. Even on days when TFs were held, this only dropped to 77% (TFs+PN), compared to 36% (TFs-only). By multivariable logistic regression, elemental and semi-elemental formulas, TF volume and post-pyloric feeds increased the risk of diarrhea, occurring in 28% of patients and 18% of TF-days. In cardiac surgery patients given postoperative NS, mortality and morbidity were an order of magnitude higher than those able to be fed orally. Enteral feeding delivered approximately two-thirds of needs, but PN supplementation dramatically improved this. Diarrhea was common, associated with the post-pyloric route, increasing TF volume and non-intact formula.