Pentoxifylline but not saralasin restores hepatic blood flow after resuscitation from hemorrhagic shock.

After determining that hepatic blood flow remains impaired after resuscitation from hemorrhagic shock, we used the angiotensin II receptor antagonist saralasin and pentoxifylline to investigate their respective effects on hepatic blood flow responses after resuscitation from hemorrhagic shock. Rats were bled to 50% of baseline blood pressure for 60 min and resuscitated with shed blood and an equal volume of lactated Ringer's solution. Saralasin [10 micrograms/kg per min (n = 6)], pentoxifylline [25 mg/kg bolus and 12.5 mg/kg per hr (n = 7)], or saline (n = 11) were started with the onset of resuscitation. Total hepatic blood flow measured by ultrasonic transit time flow meter, effective nutrient hepatic blood flow measured by galactose clearance, mean arterial pressure, and cardiac output were recorded at 15-min intervals for 2 hr after resuscitation. Hemorrhage decreased cardiac output 57% below baseline and decreased total hepatic blood flow 64% below baseline. Resuscitation restored cardiac output to baseline levels in all three groups. Despite restoration of cardiac output, total hepatic and effective hepatic blood flow remained significantly below baseline in the saline control and saralasin groups but was restored to baseline levels in the pentoxifylline group. These data indicate that angiotensin II does not contribute significantly to the hepatic blood flow impairment after resuscitation from hemorrhagic shock. Improvement in flow with pentoxifylline implies that hemorrhage and resuscitation impair hepatic microvascular hemorrheology and that addition of pentoxifylline to standard resuscitation corrects the impairment.