Abstract

The effectiveness of isoproterenol for treatment of ''irreversible'' hemorrhagic shock was tested in male Wistar rats. A total of 39 animals (weight 379 ± 23 g) were included in the experimental study. Femoral arteries were cannulated for bleeding into the reservoir which was maintained at 35 mm Hg pressure for 240 minutes. After reinfusioim of blood. isoproterenol (Isuprel) was infused intravenously to eight animals in amounts of 1.16 µg/min for 60 minutes. Arterial pressure was reduced to approximately 35 mm Hg, whereas arterial pressure was 87 mm Hg in eight hemorrhage control animals. Untreated animals survived for an average of 21 hours (range, 8-36 hours). All treated animals survived for more than 72 hours (P ≤ .001). A significant increase in O₂ uptake occurred in the 60 minutes after reinfusion of blood in those animals treated with isoproterenol when compared to the untreated controls (P < .001). Hypothermia observed after the reinfusion of blood was also reversed after infusion of isoproterenol. These observations provide additional evidence that blood pressure may be a totally invalid index of the effectiveness of circulation during shock and confirm the potential value of isoproterenol for treatment of irreversible hemorrhagic shock.