SIRS, Sepsis & Septic Shock Criteria
Systemic Inflammatory Response Syndrome (SIRS) criteria and Sepsis-3 definitions. SIRS ≥ 2 criteria; Sepsis = life-threatening organ dysfunction caused by dysregulated response to infection.
Score interpretation
Fewer than 2 SIRS criteria. Inflammatory response not meeting SIRS threshold.
→ Monitor clinical trajectory. If infection suspected, treat on clinical grounds. Consider alternative diagnosis for fever/tachycardia.
≥ 2 SIRS criteria. If infection suspected: possible sepsis. Assess for organ dysfunction (SOFA).
→ Calculate SOFA score. Blood cultures × 2 before antibiotics. IV access. Lactate. Broad-spectrum antibiotics within 1 hour if sepsis suspected. Sepsis-3 requires SOFA ≥ 2.
Suspected infection + organ dysfunction (SOFA ≥ 2). Sepsis-3 definition met. Life-threatening condition.
→ SEPSIS-6 within 1 hour: O₂, blood cultures, IV antibiotics, IV fluids (30 mL/kg crystalloid), lactate, urine output. Target MAP ≥ 65 mmHg. Noradrenaline if fluid-refractory. ICU referral if organ dysfunction not improving.
Septic shock: vasopressors required + lactate > 2 mmol/L despite adequate fluid resuscitation. Mortality > 40%.
→ IMMEDIATE ICU. Noradrenaline 0.01–3 mcg/kg/min titrate to MAP ≥ 65. Consider vasopressin 0.03 units/min as adjunct. Hydrocortisone 200mg/24h if vasopressor-refractory. Serial lactate 2-hourly. Source control. Consider early CRRT if AKI.
Interpretation bands for the SIRS / Sepsis. Apply clinical judgement and local guidance.
References
- Singer M et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016.
- NICE NG51. Sepsis: recognition, diagnosis and early management. 2016.
Related
Curated clinical cross-links plus same-class fallbacks.
- Hydrocortisone (ICU — Stress Dosing) · Corticosteroid (ICU/Septic Shock)
- Noradrenaline (Cardiogenic Shock / Vasopressor) · Vasopressor / Cardiogenic Shock
- Vasopressin / Terlipressin · Vasopressin Analogue — Vasodilatory Shock / Variceal Bleeding
- Ceftriaxone (Paediatric) · Third-Generation Cephalosporin — Meningitis / Sepsis / Community-Acquired Pneumonia
- Gentamicin (Paediatric) · Aminoglycoside — Neonatal Sepsis / Gram-Negative Infections in Children
- Flucloxacillin (Burns — Wound Infection) · Antibiotic — Penicillinase-Resistant Penicillin
- Difficult Airway Algorithm (DAS) · DAS 2015; Royal College of Anaesthetists
- Anaphylaxis Under Anaesthesia · AAGBI 2018; NAP6
- Malignant Hyperthermia · AAGBI 2011; MHAUS
- Local Anaesthetic Systemic Toxicity (LAST) · AAGBI 2010; ASRA 2017
- Spinal Anaesthesia Hypotension Management · AAGBI; ASA
- Postoperative Nausea & Vomiting · Society for Ambulatory Anesthesia 2020; AAGBI
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.