Sepsis Red Flags: The UK Screening Standard

Sepsis is the leading cause of preventable death in UK hospitals. Early recognition and prompt action change outcomes substantially.

This chapter summarises the recognition framework. The binding source is NICE NG51 and the UK Sepsis Trust screening tools (both publicly available and updated periodically). Local sepsis pathways at your trust take precedence over generic guidance.

The red flags

The UK Sepsis Trust’s adult red flag criteria (always verify against the current tool):

• New altered mental state (confusion, drowsiness, agitation).
• Systolic blood pressure ≤ 90 mmHg or > 40 mmHg below normal baseline.
• Heart rate raised beyond certain thresholds.
• Respiratory rate elevated beyond certain thresholds.
• SpO2 < 92% (or < 88% in known COPD).
• Need for oxygen to maintain SpO2 above target.
• Not passing urine in past 18 hours (or < 0.5 mL/kg/hr if catheterised).
• Mottled/ashen/cyanotic appearance.
• Non-blanching rash.
• Lactate ≥ 2 mmol/L.
• Recent chemotherapy (in past 6 weeks).

Any single red flag in a patient with suspected or confirmed infection should trigger sepsis pathway action.

The Sepsis Six

The UK Sepsis Trust’s intervention bundle, to be delivered within one hour of sepsis recognition:

1. Give oxygen to maintain target SpO2.
2. Take blood cultures (before antibiotics where possible without delaying them).
3. Give IV antibiotics within one hour of recognition.
4. Give IV fluids if hypotension or lactate raised.
5. Measure lactate by venous or arterial blood gas.
6. Measure urine output (catheterise if needed).

The “hour” is the target. Earlier is better.

The nursing role

The first nurse to suspect sepsis is the one most likely to change outcomes.

Recognition:

• NEWS2 score rising (often the first sign before specific red flags appear).
• New confusion or behavioural change.
• Fever or unusually low temperature.
• Tachypnoea.
• Tachycardia.
• Hypotension below baseline.

Initial action:

• Escalate immediately to medical team.
• Initiate the Sepsis Six in parallel where authorised.
• Set up for IV access and blood work.
• Continuous monitoring (NEWS2 frequent re-checks).

Documentation:

• Time of recognition.
• Each element of the Sepsis Six and time delivered.
• Clinical response.
• Communication with medical team and outcome.

Common recognition gaps

Pattern-matching to other diagnoses. A patient with sepsis can present as a “UTI” or “chest infection” without anyone naming sepsis. The infection is recognised but the systemic response isn’t.

Anchoring on baseline. A patient whose baseline is unusual (chronic illness, ITU readmission) may have abnormal observations that look “their normal” but are actually deteriorating from their current state.

Confusing dementia patient. New confusion in a patient with dementia is sepsis until proven otherwise. The baseline confusion makes new acute confusion harder to detect.

Atypical elderly presentations. Elderly patients with sepsis may present with falls, reduced mobility, or vague unwellness rather than classic fever and tachycardia.

When suspected but not confirmed

If you suspect sepsis but the red flags aren’t clearly there:

• Document the concern in the notes.
• Increase observation frequency to at least hourly NEWS2.
• Escalate verbally to the medical team for review.
• Watch the trajectory. A patient whose NEWS2 is rising hour-on-hour needs reassessment whether or not red flags are present.

Sepsis can develop hour by hour. Continuous reassessment is the safety net.

Sepsis in the OSCE

An OSCE scenario with sepsis features may include:

• Assessment station: recognise the red flags in vital signs and presentation.
• Planning station: initiate the Sepsis Six bundle.
• Implementation station: perform IV access, blood cultures, fluid administration.
• Silent station: questions on the time targets and bundle components.

Knowing the Sepsis Six bundle by name is helpful. Knowing the red flags is essential.

Maternal and paediatric sepsis

This chapter focuses on adult sepsis. Maternal sepsis uses different criteria reflecting pregnancy physiology, and the UK Sepsis Trust publishes a separate maternity screening tool. Paediatric sepsis has its own framework with age-adjusted parameters and the Paediatric Sepsis Six.

If you work in maternity or paediatrics, use the specialty-specific tools, not the adult ones.

The next chapter, the last in Part 7, covers the top 20 drugs UK nurses administer most often, with the key nursing considerations for each.