Calculators and Tools for Sepsis and Septic Shock

Sepsis-3 (2016) defines sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection. Organ dysfunction is identified by an acute SOFA score increase ≥2 points from baseline (assumed 0 in patients without known organ dysfunction). Septic shock = sepsis + vasopressor requirement to maintain MAP ≥65 mmHg AND serum lactate >2 mmol/L despite adequate fluid resuscitation (associated with >40% in-hospital mortality). SIRS-based definitions (Sepsis-1/2) are no longer recommended due to poor specificity.

qSOFA (Quick SOFA) flags high-risk patients outside the ICU using three bedside criteria: respiratory rate ≥22/min (1 point), altered mentation — GCS <15 (1 point), systolic BP ≤100 mmHg (1 point). A score ≥2 identifies patients at high risk of poor outcomes and should prompt full SOFA assessment, blood cultures, lactate measurement, and consideration of early antibiotics. qSOFA is a screening tool — not a diagnostic criterion. It has lower sensitivity than the full SOFA score and should not be used to exclude sepsis.

The SSC 2018 Hour-1 Bundle (to be initiated immediately): (1) Measure lactate — if >2 mmol/L, re-measure after resuscitation; (2) Obtain blood cultures before administering antibiotics; (3) Administer broad-spectrum antibiotics; (4) Begin IV crystalloid at 30 mL/kg for hypotension or lactate ≥4 mmol/L; (5) Apply vasopressors if MAP <65 mmHg during or after fluid resuscitation. Norepinephrine is the first-line vasopressor. Each hour of antibiotic delay in septic shock increases mortality by ~7%. Time to recognition and bundle completion are directly tied to outcomes.

The Surviving Sepsis Campaign recommends an initial MAP target of ≥65 mmHg in septic shock. The SEPSISPAM trial (2014) showed no overall mortality benefit of targeting MAP 80–85 vs 65–70 mmHg, though patients with chronic hypertension had less acute kidney injury at higher targets. Norepinephrine is the first-line vasopressor — titrate to MAP ≥65 mmHg. Add vasopressin 0.03 U/min to reduce norepinephrine dose. Dopamine is reserved for highly selected patients (bradycardia, low cardiac output). Avoid MAP >90 mmHg without clear indication.

SOFA (Sequential Organ Failure Assessment) scores six organ systems (0–4 each, total 0–24): respiratory (P/F ratio), coagulation (platelets), liver (bilirubin), cardiovascular (MAP/vasopressors), CNS (GCS), renal (creatinine/urine output). Higher scores predict ICU mortality: SOFA <9 ≈ <33% mortality; SOFA 9–11 ≈ 40–50%; SOFA >11 ≈ >95% mortality in some cohorts. Serial SOFA (trend over 48–72 hours) is more informative than a single score — declining SOFA predicts survival, while rising SOFA predicts worsening outcomes.

Lactate should be measured in all patients with suspected sepsis. Lactate >2 mmol/L meets the metabolic criterion for septic shock definition (even without hypotension). Lactate >4 mmol/L is associated with very high mortality (>40%) and mandates aggressive resuscitation regardless of blood pressure. Lactate clearance (>10% reduction at 2 hours) is a treatment goal — persistent elevation despite resuscitation suggests ongoing hypoperfusion or impaired lactate clearance (liver disease, severe ARDS). Serial lactate every 1–2 hours guides resuscitation adequacy.