The mortality of
septic shock remains high in newborns. Although the effectiveness of
adrenergic drug therapy continues to be controversial,
adrenergic drugs have been used for the treatment of newborn endotoxic
shock. To elucidate the effects of beta-
adrenergic drugs on the fulminant hemodynamic deterioration of newborn endotoxic
shock, newborn dogs (2-10-day-old, 264-800 g) were given Escherichia coli
lipopolysaccharide (LPS; 10 mg/kg iv) and treated with
isoproterenol (0.1 micrograms/kg/min) or
dopamine (5 micrograms/kg/min) infusion from 5 to 120 min after LPS injection.
Isoproterenol attenuated the effects of LPS by increasing the mean arterial pressure (32 +/- 2 vs. 13 +/- 1 mmHg at 120 min), cardiac output (183 +/- 29 vs. 118 +/- 23 ml/min/kg at 120 min), and the survival time (5.3 vs 2.9 hr). However,
dopamine did not improve the hemodynamic deterioration. As
dopamine-beta-hydroxylase activity in the blood was significantly lower in newborn dogs than in adult dogs, inadequate response of newborn dogs to
dopamine was thought to be in part due to enzymatic immaturity.