The Veterinary clinics of North America
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Vasoactive agents may have vasoconstrictor, vasodilator, cardiac stimulatory, or combined effects on the cardiovascular system. The intensity or degree of therapeutic effect differs with each agent. Table 1 provides a relative ranking of each discussed compound's effect regarding its ability to produce one or more of the listed effects. ⋯ The increased excitability of the heart caused by many of the drugs is a drawback, but compounds such as dopamine seem to have less excitatory effect than does isoproterenol. It may be that vasoconstriction, vasodilation, and cardiac stimulation are all contributory to the alleviation of shock. However, it is important to remember that the use of vasoactive agents must be reserved for those deteriorating shock states in which primary and secondary factors responsible for the initial state have been adequately controlled and only when appropriate methods for judging hemodynamic performance have been instituted.