Vasoactive substances and their effects on nutrition in the critically ill patient

Critically ill patients often require specialized nutrition via the enteral route. The benefits of enteral feeding, particularly early in the care of the critically ill patient, are well documented. Controversy exists regarding the provision of enteral nutrition (EN) in critically ill patients with hemodynamic instability who require vasopressors or inotropes. Concerns center on the potential for gut ischemia that may develop in the face of an imbalance between oxygen supply and demand. Current guidelines offer some guidance as to when to it is safe to initiate enteral feeding in patients on vasopressors, but the decision on when to start EN in hemodynamically unstable patients requiring vasoactive substances remains a clinical dilemma for most critical care practitioners. This review focuses on the effects of vasoactive substances such as pressors and inotropes on the gastrointestinal tract, as well as their use in combination with EN.