Post-pyloric enteral nutrition in septic patients: effects on hepato-splanchnic hemodynamics and energy status

Abstract

Objective: To evaluate the effects of post-pyloric enteral nutrition (EN) on hepato-splanchnic and systemic hemodynamics, metabolism and gastric mucosal energy balance in septic patients.

Design: Prospective clinical study.

Setting: Medical intensive care unit (ICU) in a university hospital.

Patients: Ten hemodynamically stable, mechanically ventilated patients with severe sepsis. Eight patients required norepinephrine.

Intervention: Low dose post-pyloric EN (Survimed, 40 ml bolus, 40 ml h(-1) continuously).

Measurements and results: Three data sets: F1 = baseline fasting, EN(120) = after 120 min of EN, F2=120 min after EN cessation. In addition to global hemodynamics and gastric mucosal PCO(2), we measured hepato-splanchnic blood flow (HSBF) using continuous primed indocyanine green dye infusion with hepatic venous sampling. The mean arterial pressure remained unchanged. During EN systemic vascular resistance decreased ( p<0.05), while cardiac index increased (p<0.001). Simultaneously, HSBF increased during EN and decreased again at F2 (1.54 [0.88; 1.66] l min(-1) m(-2 )at F1; 1.72 [1.18; 1.83] l min(-1) m(-2 )at EN and 1.38 [0.91; 1.63] l min(-1) m-(2 )at F2, p<0.001). Hepatic venous acid base status, lactate/pyruvate ratio and splanchnic lactate balance remained unchanged. There was also no change in splanchnic oxygen extraction ratio or in gastric mucosal to arterial PCO(2) difference.

Conclusion: The initiation of low dose post-pyloric EN in medical ICU patients with severe sepsis led to the parallel increase of systemic and hepato-splanchnic blood flow. Hepato-splanchnic energy metabolism, oxygen kinetics and gastric mucosal energy balance did not deteriorate during EN, suggesting that EN during sepsis may not be harmful even in patients requiring norepinephrine.