Safety of combined hemodilution and isoflurane-induced hypotension was assessed by studying their effects on splanchnic hemodynamics and oxygenation in nine anesthetized (ketamine/flunitrazepam) pigs. Acute normovolemic hemodilution (decrease in hematocrit from 29% to 15%) with 6% hydroxyethyl starch decreased (P < 0.05) 02 delivery despite increases in cardiac output and all splanchnic flows, as measured by electromagnetic flow probes. Superimposed isoflurane (1.45% end-tidal concentrations) caused marked decreases in arterial blood pressure, cardiac output, and splanchnic flows. Oxygen uptake of the liver became 02 supply dependent. A liver surface Po2 histogram (Clark-type electrode) showed 38% of Po2 values between 0 and 5 mm Hg. Hepatic lactate uptake decreased by 75%. These data suggest that depression of cardiovascular function during reduced 02-carrying capacity adversely affects hepatic perfusion, oxygenation, and function. Combined hemodilution and isoflurane-induced hypotension may not be appropriate in patients.
Address correspondence to Dr. Nöldge, Anaesthesiologische UniversitaUtsklinik, Hugstetter Strasse 55, 7800 Freiburg, Germany.
© 1992 International Anesthesia Research Society