septic shock with low cardiac output — FFICM MCQ

Correct answer: B — Add dobutamine

B, add dobutamine, is correct because this patient has persistent tissue hypoperfusion (raised lactate, oliguria) and echocardiographic evidence of low cardiac output despite an adequate mean arterial pressure (68 mmHg) and ongoing fluid resuscitation with norepinephrine. This pattern indicates a perfusion problem driven by inadequate cardiac output rather than inadequate vascular tone, so the correct intervention is an inotrope, not further vasoconstriction. Dobutamine, a predominantly beta-1 agonist, increases myocardial contractility and cardiac output, directly addressing the low-output state identified on bedside echo. Current sepsis guidance used in UK critical care specifically recommends adding dobutamine to norepinephrine in this exact scenario of septic shock with cardiac dysfunction and persistent hypoperfusion despite adequate volume status and blood pressure. Why the other options are wrong: A. Increase norepinephrine only: MAP is already at target (68 mmHg); further vasoconstriction increases afterload and can worsen an already low cardiac output without correcting the underlying perfusion deficit. C. Start dopamine: Dopamine is no longer recommended as a routine second agent in septic shock because of a higher incidence of tachyarrhythmias and less favourable outcome data compared with norepinephrine-based regimens; it is not the guideline-preferred inotropic strategy here. D. Add phenylephrine: This is a pure alpha-1 agonist with no inotropic effect, and by raising afterload alone it would further depress an already compromised cardiac output. E. Stop vasopressors: MAP is only just at target and stopping norepinephrine risks immediate hypotension and worsening organ hypoperfusion; there is no indication to withdraw vasopressor support. Key point: When septic shock persists with adequate MAP but echo-confirmed low cardiac output and ongoing hypoperfusion markers, add an inotrope (dobutamine) rather than escalating or removing vasopressor therapy.

Reference: Surviving Sepsis Campaign International Guidelines for Management of Sepsis and Septic Shock 2021 (Evans et al., Crit Care Med 2021), recommendation on adding dobutamine to norepinephrine for septic shock with cardiac dysfunction and persistent hypoperfusion; https://www.sccm.org/clinical-resources/guidelines/guidelines/surviving-sepsis-guidelines-2021