TREATING SEPSIS

Stage C: re-establishing the circulation

Vasoactive Drugs

Vasoactive therapy is commenced after other measures have failed. The patient must be volume resuscitated first. Vasoactive medication must be aimed at restoring tissue perfusion without causing ischemia.

Vasoactive therapeutics in sepsis is an ever changing picture: it must be said, that if you assume that the cardiovascular system is simple, and that the pharmacology of vasoactive drugs and their effects on multiple

tissues is easily predictable, then you will lose organs. Vasoactive drugs may be essential, to help resuscitation, but they are almost certainly harmful. You must ask yourself when starting one of these agents: 1. What am I trying to achieve with this drug? 2. What effects will it have elsewhere in the body? Remember that “sepsis” is a complex disorder of macro- and micro-circulation: some tissues are overperfused, some underperfused, the ability to extract oxygen is variable. Thus, the concept of using a pure vasoconstrictor to treat “low SVR” is no longer appropriate. Current pharmacological management of sepsis is to maintain blood pressure and tissue perfusion, whilst minimizing unwanted systemic/metabolic effect. As a result it may be necessary to combine multiple agents with differing pharmacologic profiles.

Individual Agents

The modern use of vasoactive agents emphasizes organ perfusion along the continuum: first brain, then heart, then splanchnic (gut, liver and kidneys) then all else. The gut had previously been the forgotten organ. It has acquired a level of importance due to the emergence of the “gut origin” theory of sepsis. So if we are going to choose a vasoactive agent to maintain blood pressure, we would prefer to use one that not only maintains brain and heart perfusion, but renal, liver and gut mucosal perfusion also (1).

References

(1)   Bellomo R, Cole L, Ronco C. Hemodynamic support and the role of dopamine. Kidney Int Suppl 1998; 66:S71-S74.

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