Blood poisoning

Septicaemia is a systemic disease associated with the presence and persistence of pathogenic organisms or their toxins in the blood:

• sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection (1)
• guidance in NICE NG253 provides updated recommendations on risk evaluation, initial fluid resuscitation, procalcitonin testing, and antimicrobial stewardship timelines (2)

Definitions and Diagnostic Frameworks

Sepsis-3 Definitions

• organ dysfunction is clinically identified by an increase in Sequential Organ Failure Assessment (SOFA) score >= 2 points, associated with in-hospital mortality > 10% (1)
• Systemic Inflammatory Response Syndrome (SIRS) criteria no longer form part of the formal diagnostic criteria for sepsis (3)

Septic Shock

• defined as a subset of sepsis with profound circulatory, cellular, and metabolic abnormalities substantially increasing mortality (1)
• clinically identified by vasopressor requirement to maintain mean arterial pressure (MAP) >= 65 mmHg and serum lactate > 2 mmol/L despite fluid resuscitation
• in general practice and urgent care, persistent hypotension with presumed infection is an appropriate surrogate for presumed septic shock (3)

QuickSOFA (qSOFA)

• adult patients with suspected infection outside the ICU are at higher risk of poor outcomes if meeting >= 2 of the following:
  • respiratory rate >= 22 breaths/min
  • altered mentation
  • systolic blood pressure <= 100 mmHg

Risk Stratification in Secondary and Acute Settings in acute hospital settings, ambulances, and mental health facilities, risk evaluation for patients aged 16 and over uses National Early Warning Score 2 (NEWS2) (4):

• high risk: NEWS2 score >= 7, or NEWS2 5–6 with a single parameter red flag (2)
• moderate risk: NEWS2 score 5–6, or NEWS2 3–4 with a single parameter red flag
• low risk: NEWS2 score 1–4
• very low risk: NEWS2 score 0

Single Parameter Red Flag Rule: a score of 3 in any single NEWS2 parameter requires urgent review by an FY2+ clinician to determine if sepsis risk tier should be escalated (3).

Initial Management and Antibiotic Timelines (2)

High Risk

• administer broad-spectrum IV antibiotics within 1 hour of NEWS2 calculation
• initiate IV fluid resuscitation immediately
• send blood gas (with lactate), blood cultures, FBC, CRP, U&Es, LFTs, and clotting
• recalculate NEWS2 every 30 minutes; escalate to senior/critical care if no improvement within 1 hour

Moderate Risk

• review by FY2+ clinician within 1 hour
• antibiotics may be deferred up to 3 hours to gather diagnostics and target therapy
• consider procalcitonin (PCT) testing alongside routine bloods

Low Risk

• review by registered health practitioner
• antibiotics may be deferred up to 6 hours for diagnostic workup

Fluid Resuscitation Protocol

• use isotonic crystalloids (balanced solutions preferred over 0.9% sodium chloride)
• administer in 250 ml boluses over 10–15 minutes
• reassess clinical response and lactate after each 250 ml bolus
• max total 1,000 ml before mandatory senior clinical decision-maker and critical care review

Vasopressors

• discuss early with senior decision-maker or critical care
• peripheral vasopressor administration may be initiated early if central access is unavailable

References

1. Singer M et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016 Feb 23;315(8):801-10.
2. National Institute for Health and Care Excellence (NICE). Suspected sepsis in people aged 16 or over: recognition, assessment and early management (NG253). Published Nov 2025, updated Sep 2026 (supersedes NICE NG51).
3. UK Sepsis Trust. The Sepsis Manual. General Practice recognition & management of Sepsis in adults and children and young people over 12 years. 7th edition. 2024.
4. Royal College of Physicians. National Early Warning Score (NEWS) 2: Standardising the assessment of acute-illness severity in the NHS. RCP London.