## Septic Shock Management — Vasopressor Selection **Key Point:** In septic shock refractory to fluid resuscitation, noradrenaline (norepinephrine) is the first-line vasopressor agent per Surviving Sepsis Campaign guidelines and standard critical care protocols. ### Why Noradrenaline? **High-Yield:** Noradrenaline combines: - **α-adrenergic effects** → restores systemic vascular resistance and mean arterial pressure (MAP) - **β-adrenergic effects** → maintains cardiac output and renal perfusion - **Balanced action** → prevents the profound vasoconstriction and renal hypoperfusion seen with pure α-agonists ### Mechanism in Septic Shock Septic shock is characterized by: 1. Pathologic vasodilation (cytokine-mediated) 2. Myocardial depression (TNF-α, IL-1) 3. Distributive hypotension despite high cardiac output Noradrenaline restores perfusion pressure while maintaining organ blood flow better than alternatives. ### Comparison with Other Agents | Agent | Primary Effect | Role in Septic Shock | Limitation | | --- | --- | --- | --- | | **Noradrenaline** | α + β | First-line vasopressor | None (preferred) | | Dobutamine | β (inotrope) | Adjunct only if low CO | No vasoconstriction; worsens hypotension | | Phenylephrine | Pure α | Rescue only | Reflex bradycardia; renal/splanchnic vasoconstriction | | Hydrocortisone | Glucocorticoid | Adjunct in refractory shock | Not a vasopressor; supportive role | **Clinical Pearl:** Target MAP ≥65 mmHg with noradrenaline; add dobutamine only if cardiac output remains low despite adequate MAP. **Mnemonic:** **SNAP** for septic shock vasopressor choice = **S**epsis → **N**oradrenaline (+ fluids) → **A**djunct (dobutamine if low CO) → **P**erfusion restored [cite:Surviving Sepsis Campaign 2021]
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