SAN FRANCISCO — Added to norepinephrine, low-dose vasopressin decreased mortality in one group of patients with septic shock, Dr. James Russell reported at the International Conference of the American Thoracic Society.
In a multicenter, randomized controlled trial, vasopressin at a dose of 0.03 U/min decreased mortality at 28 days and at 90 days in patients with less severe septic shock, but not in patients with more severe septic shock.
The reduction in mortality did not come at the expense of additional serious adverse events, said Dr. Russell of the University of British Columbia, Vancouver.
For the purposes of the trial, patients with more severe septic shock were defined as those needing more than 15 mcg/min of norepinephrine in the hour before randomization. Patients needing 5–15 mcg/min of norepinephrine formed the less severe group.
A total of 779 patients participated in the trial, all of whom were very ill, with Acute Physiology and Chronic Health Evaluation II (APACHE II) scores averaging 27. About half of the patients were in the less severe subgroup.
The less severe patients receiving vasopressin in addition to norepinephrine had a 9% absolute reduction in the risk of death at 28 days (36% to 27%), and a 10% absolute reduction in the risk of death at 90 days (46% to 36%), when compared with patients taking norepinephrine alone.
In the patients in the more severe subgroup, vasopressin was not associated with significant decreases in mortality at either 28 days or 90 days.
Physicians conducting the study were blinded as to whether they were administering vasopressin or norepinephrine. Patients were started at a steady infusion rate of 5 mL/min, corresponding to 0.01 U/min of vasopressin or 5 mcg/min of norepinephrine. The study drug was titrated from 5 to 15 mL/min over the course of 40 minutes in order to reach a mean arterial pressure of 65–75 mm Hg.
Once the patients were stable for 8 hours and receiving open-label vasopressors, they were weaned off the study drug.