[Oxygen delivery and tissue extraction in septic shock]

Hemodynamic and oxygen transport variables were evaluated in 34 patients with septic shock during fluid repletion and infusion of vasoconstricting and inotropic catecholamines (dopamine, dobutamine). Hypovolemia, increased cardiac output (CO), low pulmonary and systemic vascular resistance dominated in initial hypotensive status. Oxygen consumption (VO2) decreased despite increased oxygen delivery (DO2). Hypotension and hypovolemia were successfully corrected by therapeutic intervention and significantly higher values of CO and DO2 were obtained. However, VO2 remained low and oxygen extraction index declined from the initial level.

The underlying pathophysiological defect in septic shock is not altered hemodynamics or low DO2 but impaired tissue oxygen extraction. The usual hemodynamic resuscitation does not improve tissue oxygen utilization and the results in the treatment of septic shock remain poor.