Shock Recognition: Perfusion, Phenotype and Immediate Priorities

Shock is inadequate tissue perfusion and may be hypovolaemic, distributive, cardiogenic, obstructive or mixed. Hypotension can be late, and normal blood pressure does not guarantee adequate perfusion.

Clinical ID: LIB-000000121 Version: 1.0 Evidence: Evidence-informed Reading time: 2 minutes

Clinical overview

Shock is inadequate tissue perfusion and may be hypovolaemic, distributive, cardiogenic, obstructive or mixed. Hypotension can be late, and normal blood pressure does not guarantee adequate perfusion.

Clinical significance

Use an ABCDE approach, identify reversible causes, assess response to treatment and escalate early. Point-of-care ultrasound can support phenotype assessment when performed by trained clinicians.

Immediate assessment

Use an ABCDE approach, identify time-critical threats, review observations and trends, and establish what treatment has already been given. Confirm relevant medicines, comorbidity, allergies, treatment ceilings and the need for senior or specialist support.


Sponsored


Structured interpretation

Combine bedside findings with laboratory data, imaging and response to treatment. Do not allow a single score, biomarker or apparently reassuring result to override physiological deterioration. Reassess after each meaningful intervention and document the trajectory.

Clinical pearls

  • Trend and rate of change often carry more information than a single value.
  • Use validated pathways within the population in which they were developed.
  • Make the escalation plan explicit before deterioration occurs.

Common mistakes

  • Delaying treatment while waiting for every investigation.
  • Using a calculator without checking inclusion criteria and limitations.
  • Failing to repeat observations after treatment.
  • Assuming that normal blood pressure or oxygen saturation excludes serious disease.

Escalation triggers

Escalate urgently for threatened airway, increasing work of breathing, worsening gas exchange, shock, altered consciousness, rapidly changing physiology, refractory biochemical disturbance or concern that ward-level monitoring is insufficient.

Related MediCalc clinical tools

Related Clinical References

Frequently asked questions

Can this reference replace a local emergency pathway?

No. Use the current local protocol, formulary and escalation policy.

When should a specialist be contacted?

Contact the relevant specialist early when the patient is unstable, the diagnosis is uncertain, initial treatment fails or an advanced intervention may be required.

Key practice points

  • Recognise deterioration early.
  • Treat reversible threats while investigating.
  • Use calculators to support, not replace, clinical judgement.
  • Reassess and document response.
  • Escalate before physiological reserve is exhausted.

References and further reading

  1. Resuscitation Council UK ABCDE approach
  2. NICE CG174 intravenous fluids
Reviewed by: MedicalC Clinical Editorial Team Last reviewed: 2026-08-06 Next review: 2028-08-06
This professional reference supports education and clinical decision-making. It does not replace local policy, specialist advice or individual clinical judgement.