During sepsis, cardiac output often rises, with between 17% and 28% going to the splanchnic region. The oxygen extraction of the liver, however, increases dramatically to over 40% of total body oxygen consumption, compared to 30% in injured but nonseptic patients. With the high oxygen extraction required, the hepatocyte may be vulnerable to ischemic injury; higher flow would therefore be more appropriate to meet this demand. An improvement in effective splanchnic perfusion can normalize some of the metabolic derangements of critical illness.
Using labeled leucine and glucose, we measured baseline hepatic glucose production, leucine oxidation, and leucine first-pass effect in the livers of 8 patients; 5 had abdominal sepsis and 3 had necrotizing and hemorrhagic pancreatitis. After baseline readings, pulmonary wedge pressure was increased to 15 mm Hg by infusion of hydroxyethyl starch. After 3 h an infusion of dopamine, 6 M-g/kg, was begun. The results indicated a restoration of glucose production, leucine first-pass effect, and oxidation to more normal values (Fig 2). Fish oil feeding can raise the ratio of PGI to TXA, thus facilitating blood flow and tissue perfusion. In rats, using the microsphere technique, we have shown a fish oil infusion for 40 h prior to endotoxin challenge produced better hepatic blood flow than did infusion of safflower oil (see Table 1).
Figure 2. Effect of hydroxyethyl starch and dopamine infusion in 8 critically ill patients. Measurements were made 3 h after hydroxyethyl starch (HAES) infusion. Dopamine was then given at a dose of 6 jig/kg, and a further set of readings was taken 3 h later. Nfolues for normal volunteers are shown in the right panel. Error bars: +SEM.
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