Earlier vasopressin shows no clear survival benefit in septic shock

Clinical takeaway: Individualize vasopressin initiation in septic shock; this trial does not support routinely lowering the vasopressor-dose threshold solely to improve survival.

Vasopressin is commonly added when norepinephrine requirements rise, but the optimal threshold remains uncertain. Earlier initiation could reduce catecholamine exposure, yet potential adverse effects and costs also warrant consideration.

The VASSPR trial enrolled 3,959 adults with septic shock at 13 hospitals in Utah and Idaho. Hospitals alternated monthly between 2 vasopressin initiation strategies: a lower-threshold strategy, which recommended starting vasopressin when the total vasopressor dose reached the equivalent of norepinephrine 0.1 mcg/kg/min, and a higher-threshold strategy, which delayed vasopressin until the dose reached 0.4 mcg/kg/min. Both strategies recommended a fixed vasopressin dose of 0.03 units/min.

Vasopressin use was more common in the lower-threshold group, at 52.4% versus 32.9% in the higher-threshold group. However, 28-day mortality was 31.8% versus 33.0%, respectively, with no significant difference after adjustment.

The groups also had similar kidney replacement therapy-free days, hospital-free days, and ICU-free days. New or persistent cardiogenic shock occurred in 7.4% of patients in the lower-threshold group versus 6.3% in the higher-threshold group, but this exploratory safety finding requires confirmation.

Clinicians could override the assigned strategy, and adherence was imperfect; the findings therefore reflect how these strategies performed in routine care. The trial could not rule out a small survival advantage for either strategy.

“Our study suggests that hospitals can take a more conservative approach, helping deliver effective care while using resources wisely,” said lead investigator Ithan D. Peltan, MD, of Intermountain Health.

Source: Peltan ID, et al. (2026 Oct 14) JAMA. Effect of Vasopressin Initiation Threshold on Septic Shock Mortality: The VASSPR Cluster Crossover Randomized Strategy Trial