Impact of oral or enteral nutritional support on clinical outcomes of patients subjected to cardiac surgery: A systematic review

Cardiovascular diseases represent the leading cause of death worldwide, in addition to having a direct negative impact on quality of life, functional capacity and nutritional status. Studies show high prevalence of malnutrition in patients undergoing cardiac surgery. It is known that cardiac surgery can also lead to changes in nutritional status, through surgical trauma, systemic inflammation and, often, delay in the initiation of nutritional support. On the other hand, the role of nutritional support as a driver of clinical outcomes in different surgical populations is well described in the literature.To review the literature in order to assess the effect of perioperative oral or enteral nutritional support on clinical outcomes of cardiac patients undergoing cardiac surgery.The search was conducted in February 2021 in the following databases: EMBASE, PubMed/MEDLINE, Scopus and Web of Science. Randomized clinical trials (RCT) and retrospective studies were selected, carried out with patients with heart disease, undergoing cardiac surgery and aged 18 years or over. The Outcomes of interest were: length of hospital stay, length of stay in the ICU, time on ventilatory support, mortality rate, clinical complications and use of vasoactive drugs in the postoperative period.Ten studies were included in this systematic review, of which 7 were RCTs and 3 were cohorts. The most prevalent surgery was myocardial revascularization. Six studies evaluated oral nutritional support, two enteral nutritional support and two analyzed both. Two studies found a significant reduction in the length of hospital and ICU staying associated with preoperative intake of carbohydrate-based beverages. Only one study observed a significant reduction in the requirement for ventilatory support after cardiac surgery, after preoperative carbohydrate-based drinks and early postoperative enteral nutrition. There was no influence of nutritional support on mechanical ventilation length and mortality.Most studies showed that nutritional support did not reduce hospital and ICU staying. Nutritional support benefits were demonstrated in studies that offered preoperative oral carbohydrate drinks. No association was observed between nutritional support and duration of mechanical ventilation or mortality rate. Most studies did not find any influence of nutritional support on the need and/or dosage of vasoactive drugs in the postoperative period of cardiac surgery.