Shock Patients and Enteral Nutrition?

Shock is a life-threatening condition characterized by microcirculatory disturbances and inadequate tissue perfusion. In hemodynamically unstable individuals, arterial pressure is maintained with vasoactive agents. Enteral nutrition (EN) is crucial for the intensive treatment of critically ill patients, facilitating intestinal recovery and improving clinical outcomes such as reducing infections, shortening hospital stays, and lowering costs. The impact of vasoactive agents on gastrointestinal blood flow varies, depending on the drug, dose, body size, and individual sensitivity. EN is categorized into early and delayed, and multiple guidelines recommend delayed EN due to the risks in the early stage, which may lead to EFI, non-obstructive mesenteric ischemia and necrosis. Guidelines for early EN in shock patients are still evolving, exploring the optimal timing and safety thresholds. Studies have shown that early EN can be safely implemented in hemodynamically stable patients maintaining a mean arterial pressure of 70 mmHg with stable doses of antihypertensives. This review summarizes the optimal and safe timing of initiating EN in shock patients to guide clinical practice. The pathophysiology of shock, EN selection, considerations, nutritional regimens, effects of antihypertensive agents, and feeding regimens are further discussed.