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

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.