SOAP-II: Norepinephrine vs Dopamine in Shock

Dopamine = more arrhythmias + higher cardiogenic-shock mortality vs norepi.

Population

1,679 ICU adults requiring vasopressors for shock (62% septic, 17% cardiogenic, 16% hypovolemic).

Intervention

Dopamine titrated 5-20 mcg/kg/min.

Comparison

Norepinephrine 0.02-0.19 mcg/kg/min.

Outcome

28-day mortality; arrhythmic events.

Double-blind, multicenter RCT across 8 European ICUs. Open-label epi or vasopressin allowed for refractory shock. Cardiogenic, septic, and hypovolemic subgroups pre-specified.

• 28-day mortality overall: 52.5% dop vs 48.5% norepi (HR 1.17, P=0.10) — no significant overall difference.
• Arrhythmias: 24.1% dop vs 12.4% norepi (P<0.001) — most were AFib.
• Cardiogenic-shock subgroup mortality: 50.9% dop vs 39.4% norepi (P=0.03) — significant.
• Septic + hypovolemic subgroups: no mortality difference.

Norepinephrine is first-line vasopressor for septic shock (now codified in Surviving Sepsis 2021) and at minimum non-inferior in other shock types. Dopamine's higher arrhythmia rate + worse cardiogenic-shock mortality make it an obsolete first-line agent. Reserve dopamine for niche cases (some bradycardia where chronotropy is desired) and consider it superseded by norepi + low-dose epi in most shock states.

• Heterogeneous shock population — overall null result driven by septic majority.
• European-only; vasopressin use rates differ from US patterns.
• Did not compare norepi to vasopressin head-to-head (VASST did).

1. Why was dopamine ever first-line — what was the historical rationale (renal-dose dopamine, etc.) that turned out to be wrong?
2. When (if ever) do you still reach for dopamine in modern practice?
3. How do you decide between 'add vasopressin' vs 'climb the norepi dose' in refractory septic shock (see VASST)?