Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1994
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 Severe volume-controlled hemorrhage (40 mL/kg body weight (bw) withdrawn over 30 min followed by hypovolemia of 30 min duration) was induced in conscious rats.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). ⋯ 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)
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Anesthesia and analgesia · Nov 1994
Effect of ketamine on heterogeneity of cerebral microregional venous O2 saturation in the rat.
Heterogeneity of microregional O2 supply and consumption balance exists in the brain. Previous studies have shown that anesthetics such as pentobarbital and isoflurane, decrease the heterogeneity of O2 saturation in the small veins of the brain. This study was performed to determine whether ketamine, an anesthetic, would alter this heterogeneity. ⋯ The average regional O2 supply-to-consumption ratios were similar in the three brain regions in both of the groups. However, there was heterogeneity of the O2 saturation in small veins in all the brain regions that we studied. The coefficient of variation [CV = (SD/mean X 100] of venous O2 saturation of the ketamine group in the anterior cortex (19.8 +/- 7.2), in the posterior cortex (18.8 +/- 9.4), and in the pons (16.7 +/- 6.5) was not significantly different from that in the conscious animals (22.8 +/- 6.4, 23.1 +/- 5.3, and 15.7 +/- 6.4, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)