Arginine vasopressin in septic shock: supplement or substitute for norepinephrine?

In the current issue of Critical Care, Simon and coworkers investigated the effects of first-line arginine vasopressin (AVP) on organ function and systemic metabolism compared with norepinephrine in a pig model of fecal peritonitis. AVP was titrated according to the mean arterial pressure suggesting a vasopressor rather than a hormone replacement therapy. The study provides some evidence for the safety of this therapeutic approach. It needs to be determined whether AVP is most beneficial as a constant low-dose infusion to supplement norepinephrine or in higher doses than currently recommended to substitute norepinephrine. In addition, future studies are warranted to evaluate whether a first-line therapy of AVP is superior to a last-resort administration.