Low-dose vasopressin in the treatment of vasodilatory septic shock

Background: Despite appropriate therapy, refractory hypotension often occur s in septic shock, A double-blinded placebo controlled clinical trial was p erformed to assess the role of low-dose vasopressin (VP) as a pressor agent in septic shock. Methods: Patients admitted to a trauma intensive care unit with vasodilator y septic shock were randomized to receive either VP at 0.04 U/min (n = 5) o r placebo (n = 5), Vasodilatory septic shock was defined as a need for cate cholamine agents to maintain a mean arterial pressure more than or equal to 70 mm Hg, despite a cardiac index more than 2.5 L/min and a minimal pulmon ary artery wedge pressure more than 12 mm Hg, After 1 hour of initiation of the study drug, attempts to discontinue norepinephrine, phenylephrine, and /or dopamine, in respective order, were undertaken provided that the mean a rterial pressure remained more than or equal to 70 mm Hg. Results: A vasopressin infusion increased systolic arterial pressure (98 +/ - 5 to 125 +/- 8 mm Hg, p < 0.008) because of peripheral vasoconstriction ( systemic vascular resistance increased from 878 +/- 218 to 1,190 +/- 213 dv nes/s per cm(-5), p < 0.05), Arterial pressure and systemic vascular resist ance were statistically unaffected in the placebo group, Before study termi nation, measured at 24 hours after drug initiation, two patients in the pla cebo group died of refractory hypotension, However, all patients receiving VP survived the 24-hour study period and had all other catecholamine presso rs withdrawn and blood pressure maintained solely with a low-dose VP infusi on. Conclusion: A VP infusion improved arterial pressure and permitted the with drawal of catecholamine vasopressors, VP is a useful agent in the treatment of refractory septic shock.