Effects of a perfluorocarbon emulsion on regional cerebral blood flow and metabolism after fluid resuscitation from hemorrhage in conscious rats.

Regional cerebral blood flow and metabolism were investigated after addition of a small volume of perfluorocarbon (PFC) emulsion to the resuscitation fluid after hemorrhage. Severe volume-controlled hemorrhage (40 mL/kg body weight (bw) withdrawn over 30 min followed by hypovolemia of 30 min duration) was induced in conscious rats. While breathing 100% oxygen, the intravascular volume was repleted by the infusion of either 6% hydroxyethyl starch (mean mol wt 200,000/0.5; HES) or 6% hydroxyethyl starch plus perflubron (90% wt/vol emulsion of perfluoroctylbromide, 3 mL/kg bw; HES-PFOB). Two hours after fluid resuscitation either iodo[14C]antipyrine or 2[14C]deoxy-D-glucose were infused. Local cerebral blood flow (LCBF) or local cerebral glucose utilization (LCGU) were determined in 34 brain structures using quantitative autoradiography. Local cerebral metabolism was not disturbed in the HES and the HES-PFOB groups after fluid resuscitation, although slight reductions (mean -14%) were measured (HES-PFOB vs HES; P < 0.05). The HES-PFOB group showed LCBF values that were higher in the different brain structures than those of the HES group (mean +30%). A close correlation was found between LCGU and LCBF of the 34 brain structures in both groups (HES: r = 0.96, P < 0.01; HES-PFOB: r = 0.98, P < 0.01), whereas the LCBF-to-LCGU ratio was reset from 2.2 mL/mumol in the HES group to 3.4 mL/mumol in the HES-PFOB group (P < 0.05). The higher blood flows in the HES-PFOB group were sufficient to restore cerebral oxygen delivery to normal levels at a reduced arterial oxygen content.(ABSTRACT TRUNCATED AT 250 WORDS)