Septic Shock
Also known as: Refractory sepsis
The most severe manifestation of the sepsis spectrum; sepsis with profound circulatory, cellular and metabolic derangement, associated with substantially higher mortality than sepsis alone.
Defined (Sepsis-3) as sepsis with persistent hypotension requiring vasopressor therapy to maintain mean arterial pressure ≥65mmHg AND serum lactate >2mmol/L despite adequate fluid resuscitation.
It is a distributive shock state driven by pathological vasodilation, capillary leak, and myocardial depression from the inflammatory cascade.
All features of sepsis, plus:
Persistent hypotension refractory to initial fluid resuscitation (SBP <90mmHg, MAP <65mmHg, or a drop >40mmHg from baseline)
Signs of hypoperfusion: cool, mottled, clammy skin : though paradoxically the skin may be warm and flushed in an early "warm shock" phase before progressing to cold, vasoconstricted shock; prolonged capillary refill (>3 seconds), reduced urine output (<0.5mL/kg/hr), altered mental status (agitation, confusion, obtundation)
Elevated lactate (>2mmol/L, often much higher; >4mmol/L indicates severe hypoperfusion) reflecting anaerobic metabolism
Multi-organ dysfunction developing: acute kidney injury, hepatic dysfunction, ARDS, DIC (bleeding, thrombocytopenia, prolonged clotting), myocardial depression
Clinical criteria per Sepsis-3 in the context of confirmed or suspected infection : largely a clinical and hemodynamic diagnosis built on the sepsis workup.
Serial lactate measurements: track clearance as a resuscitation target ; failure to clear despite treatment indicates ongoing hypoperfusion or inadequate source control
Invasive monitoring (arterial line for continuous BP, central venous access), typically in ICU ; allows vasopressor titration and assessment of dynamic fluid responsiveness
Echocardiography: assess cardiac function, differentiate septic cardiomyopathy from other shock etiologies, guide fluid versus inotrope decisions
Full sepsis source workup : identifying and controlling the source is as critical as hemodynamic support
Differentials: other shock states ; cardiogenic (poor response to fluids, signs of cardiac failure), hypovolemic (history of significant fluid or blood loss), obstructive (tension pneumothorax, tamponade, massive PE), anaphylactic ; which can coexist with or mimic septic shock, so careful assessment is needed if the response to sepsis-directed therapy is not as expected.
A time-critical ICU-level emergency requiring immediate, protocolized management.
Sepsis Six bundle applied urgently
Fluid resuscitation: initial crystalloid bolus 30mL/kg within the first 3 hours; further fluid guided by dynamic assessment of fluid responsiveness rather than fixed volumes ; avoid indiscriminate fluid loading once the initial deficit is corrected, given the risk of pulmonary edema and worse outcomes with overload
Vasopressor therapy ; if hypotension persists despite adequate fluid resuscitation (MAP <65mmHg):
Noradrenaline (norepinephrine) ; first-line, start 0.05-0.1 mcg/kg/min IV infusion via central line (peripheral administration is acceptable short-term via a large proximal vein with close monitoring for extravasation while central access is established), titrate to MAP ≥65mmHg
Vasopressin: add-on at fixed low dose (0.03 units/min) if the response to noradrenaline alone is inadequate ; allows noradrenaline dose reduction
Adrenaline: second-line add-on if MAP remains inadequate
Dobutamine: added if there is persistent hypoperfusion despite adequate fluid status and MAP target, particularly with myocardial dysfunction
Other management:
Corticosteroids: IV hydrocortisone 200mg/day (continuous infusion or divided doses) for septic shock with ongoing vasopressor requirement despite adequate fluid and vasopressor therapy
Source control: urgent ; drainage, device removal, surgical debridement, relief of obstruction. Cannot be deferred, and directly impacts survival
Ventilatory support: lung-protective ventilation (low tidal volume ~6mL/kg predicted body weight) if intubated
Renal replacement therapy for severe AKI with refractory hyperkalemia, fluid overload or acidosis
Glucose control: moderate glycemic targets, avoiding both severe hyperglycemia and hypoglycemia
Blood products: restrictive transfusion thresholds generally (Hb <7g/dL absent active bleeding or cardiac ischemia)
VTE and stress ulcer prophylaxis as standard ICU supportive care
Continuous reassessment ; mortality correlates strongly with time to appropriate intervention, with each hour of delayed antibiotic administration in septic shock associated with increased mortality
Disposition: ICU admission is mandatory ; vasopressor requirement and multi-organ dysfunction monitoring cannot be safely managed on a general ward.
