Severe systemic infections (source unknown)

Separate guidance is available for:

If decompensated chronic liver disease with sepsis of unknown source, see poster for management.

Definition of Sepsis

  • Infection (includes system-related signs or symptoms and/or features of the Systemic Inflammatory Response Syndrome (SIRS)) with evidence of organ hypoperfusion (see figure 1 below).
  • SIRS is indicated by the presence of ≥2 of the following:
    • Temperature <36°C or >38°C
    • HR >90 bpm
    • Respiratory rate >20 breaths/minute
    • WCC <4 or >12 x 109/L.
  • Infection is suggested by localising symptoms (e.g. cough with green sputum or skin heat and erythema or urinary frequency and dysuria) or non-localising symptoms (e.g. fever, sweats, chills, rigors or malaise).

SIRS may indicate infection but is not specific; potentially being present in inflammation, ischaemia or trauma and so should be interpreted in the clinical context. CRP may be elevated in infection (and in other conditions) but cannot be used to judge severity of infection. CRP may also remain elevated even when infection is resolving and must not be used in isolation to assess the severity of infection (including the need for IV therapy).

N.B. Signs of sepsis (or SIRS) may be masked in: immunosuppression, the elderly and in the presence of anti-inflammatory drugs or beta-blockers.

Figure 1 – qSOFA scoring tool

A score of ≥2 of:

  • Confusion (<15 of Glasgow Coma Scale)
  • Respiratory rate ≥22/minute
  • Systolic blood pressure ≤100mmHg

Seymour CW et al. Assessment of Clinical Criteria for Sepsis - For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016; 315(8):762-774. Adapted with permission.

Mortality from sepsis increases with delay in initiating IV antibiotic therapy. In patients with sepsis, or severe infection, aim to complete the "Sepsis 6" within 1 hour.

Figure 2 – "Sepsis 6" - within 1 hour

  1. Blood cultures and any other relevant samples prior to administration of antibiotics. Consider source control.
  2. IV antibiotic administration according to GG&C infection management guidelines. For each hour’s delay in administering antibiotics in septic shock, mortality increases by 7.6%. Record first dose of antibiotic in the 'one-off' section of the kardex and communicate with the member of staff who is responsible for administration of IV antibiotic therapy to ensure it is administered immediately. N.B. administer the antibiotic in the clinical area where infection has been recognised and do not delay until arrival at destination ward. 
  3. Oxygen to maintain target saturation (>94% or 88%-92% in people at risk of hypercapnic respiratory failure)
  4. Measure lactate
  5. Start intravenous fluid resuscitation
  6. Monitor hourly urine output

Review empirical (best guess) antimicrobial therapy no later than 48 hours after initiation. Simplify and switch to narrow spectrum therapy when microbiology results become available.


Guideline reviewed: August 2023

Page updated: November 2023