Earlier vasopressin in septic shock was linked to lower mortality

Design

Target trial emulation using two ICU databases

Population

3,810 adults with septic shock on norepinephrine at 0.25 µg/kg/min or more

Primary outcome

28-day mortality

Effect

48.1% vs 53.0%; risk difference −5.0 points (95% CI −6.8 to −3.2)

Using two US ICU databases, investigators emulated a trial in 3,810 adults with septic shock whose norepinephrine dose reached 0.25 µg/kg/min before any vasopressin. They compared starting vasopressin within three hours of that point with starting at three to six hours.

The weighted 28-day mortality was 48.1% with ultra-early initiation and 53.0% with early initiation (risk difference −5.0 points, 95% CI −6.8 to −3.2; HR 0.82). Ultra-early initiation was also associated with less renal replacement therapy (HR 0.68) and slightly fewer treated arrhythmias, though not with less acute kidney injury.

Current practice often adds vasopressin when norepinephrine reaches roughly this range. These data suggest not waiting once the threshold is crossed. They are observational, and residual confounding is likely.

• Consider adding vasopressin promptly once norepinephrine reaches about 0.25 µg/kg/min.
• Avoid waiting several hours at high norepinephrine doses before adding a second agent.
• Monitor for digital and mesenteric ischaemia after starting vasopressin.
• Treat this as supportive evidence for timing, not proof.

Why it matters

The timing of the second vasopressor may matter as much as the choice.

Don't overread it

This is observational; it cannot prove that earlier vasopressin saves lives.

The statistics, in plain English

A 5-point absolute difference in mortality is large, but this is a target-trial emulation: it imitates a trial using records and statistical weighting. Sicker or less sick patients may still differ between groups in ways the data do not capture.

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