Regional blood flow and oxygen transport in septic shock

Abstract

Objective: To measure the blood flow distribution and regional oxygen transport in hyperdynamic septic shock during hypotension and after correction by vasopressor doses of dopamine or norepinephrine.

Design: Prospective, randomized, controlled trial.

Setting: Tertiary care center.

Patients: Ten patients with hyperdynamic septic shock (ages ranging from 45.1 +/- 16.6 yrs) and a control group of 11 postoperative cardiac surgery patients (ages ranging from 54.8 +/- 7.9 yrs).

Interventions: Systemic and regional hemodynamics and oxygen transport were measured in ten patients with hyperdynamic septic shock during hypotension and after vasopressor therapy (norepinephrine or dopamine). Oxygen consumption (VO2) was measured by indirect calorimetry and splanchnic and leg blood flow with indocyanine green infusion.

Measurements and main results: Splanchnic blood flow and VO2 (p < .05) were increased in septic shock during hypotension and during vasopressor therapy. Both dopamine and norepinephrine increased systemic blood flow and VO2 independently of the arterial lactate level. Despite the relatively small changes in systemic oxygen transport, major regional changes occurred in oxygen delivery and VO2, and these changes were unpredictable from systemic changes.

Conclusions: Regional changes in oxygen transport in septic shock cannot be predicted from the changes in the whole body. The increased oxygen demand in the splanchnic region is the main risk factor for splanchnic tissue hypoxia in septic shock.