Best vasopressor for advanced vasodilatory shock: should vasopressin be part of the mix?

Since the publication of the Surviving Sepsis Campaign guidelines, a number of additional and highly relevant studies have been published addressing the issue of vasopressor use during septic shock. While these new results are provocative, none of the studies are definitive. In sum, they suggest that maybe we should not be thinking of one vasopressor versus another in a winner-takes-all sense. Rather, we should be looking for the best balance of vasopressor agents and, further, the choice likely depends on clinical context. Clinical context may drive the choice of adrenergic agonist; for example, norepinephrine may be superior to dopamine when the potential for arrhythmias is of concern. Norepinephrine may be superior to epinephrine if elevated lactate associated with epinephrine use confounds the clinical picture. The Vasopressin and Septic Shock Trial (VASST) identified an effective dose of arginine vasopressin (AVP) when adrenergic agonist doses are low, but higher doses of AVP may be appropriate in the context of very high adrenergic agonist doses. The effect may be a direct beneficial AVP effect or indirect sparing of adrenergic agonist use. The choice to add AVP may also be influenced by the clinical context, including renal function or the concomitant use of corticosteroids. These interim conclusions, in truth, are hypotheses warranting randomized controlled trials adequately powered to test for survival differences in these severely ill patients.