A 58-year-old man with diabetes mellitus presents to the ICU with septic shock secondary to urosepsis. His lactate is 4.2 mmol/L and he requires noradrenaline infusion. Regarding the pathophysiology and management of septic shock, all of the following are true EXCEPT:

Question

Accepted Answer

D. Vasopressin is the first-line vasopressor agent and should be started before noradrenaline in septic shock. ## Septic Shock Management: Vasopressor Hierarchy

### Correct Answer: Vasopressin as First-Line Agent

**Key Point:** Noradrenaline (norepinephrine) is the FIRST-LINE vasopressor in septic shock, not vasopressin. The Surviving Sepsis Campaign guidelines (2021) recommend noradrenaline as the initial agent of choice.

### Vasopressor Selection in Septic Shock

| Agent | Role | Starting Dose | When to Use |
|-------|------|---------------|-------------|
| **Noradrenaline** | First-line | 0.01–0.05 μg/kg/min | Initial vasopressor; combined α and β activity |
| **Vasopressin** | Adjunctive | 0.03–0.04 U/min (fixed) | Add to noradrenaline if inadequate response; no dose titration |
| **Adrenaline** | Rescue | 0.05–0.5 μg/kg/min | If noradrenaline + vasopressin fails; higher mortality |
| **Phenylephrine** | Avoid | — | Pure α-agonist; reduces cardiac output; not recommended |

**High-Yield:** Noradrenaline combines α-adrenergic (vasoconstriction) and β-adrenergic (inotropic) effects, making it superior to pure vasoconstrictors in septic shock.

### Why the Other Options Are Correct

**Option 1 — EGDT Targets:** These are the classic Surviving Sepsis Campaign resuscitation endpoints [cite:Surviving Sepsis Campaign 2021]. ScvO₂ ≥70% reflects adequate tissue oxygenation.

**Option 2 — Procalcitonin:** Procalcitonin is a biomarker that rises in bacterial infections and correlates with severity. It is used to guide antibiotic de-escalation and discontinuation (PCT-guided protocols reduce antibiotic exposure) [cite:Harrison 21e Ch 297].

**Option 4 — Lactate Clearance:** Lactate clearance >10% in the first 6 hours is a marker of successful resuscitation and is associated with reduced mortality. It reflects improved tissue perfusion and microcirculation.

**Clinical Pearl:** The mnemonic for septic shock vasopressor escalation is **NAV**: **N**oradrenaline first → **A**dd vasopressin → escalate to **V**asodilators if needed (or switch to adrenaline if refractory).

Answer

A. Procalcitonin levels correlate with bacterial infection severity and can guide antibiotic discontinuation decisions

Answer

B. Early goal-directed therapy (EGDT) targets include MAP ≥65 mmHg, urine output ≥0.5 mL/kg/hr, and ScvO₂ ≥70%

Answer

C. Lactate clearance >10% in the first 6 hours is associated with improved outcomes and guides resuscitation adequacy

A 58-year-old man with diabetes mellitus presents to the ICU with septic shock secondary to urosepsis. His lactate is 4.2 mmol/L and he requires noradrenaline infusion. Regarding the pathophysiology and management of septic shock, all of the following are true EXCEPT:

Explanation

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