Individual free fatty acids and lactate uptake in the human heart during severe sepsis

Coronary haemodynamics and myocardial metabolism of nonesterified fatty acids (NEFA) and lactate were studied in 11 patients with severe sepsis, and compared to 10 control subjects. Coronary sinus blood flow was evaluated by thermodilution. Arterial and coronary sinus blood samples were collected for the measurement of lactate and total and individual NEFA concentrations both in septic and control patients. There was an increase in lactate and total NEFA arterial concentrations with a marked increase in palmitic and linolenic acids. The uptake of the main NEFA (C14:0 to C18:2) was significantly decreased. In the control group, individual NEFA uptake was proportional to their arterial concentrations. This relationship was not observed in patients with sepsis: there was no preferential extraction of any particular NEFA. Furthermore, in patients with sepsis, myocardial oxygen consumption did not correlate with NEFA, but only with lactate uptake. Alterations in NEFA uptake were found to be constant during severe sepsis and are consistent with major disturbances in myocardial metabolism.