OSCE — Respiratory Failure

Brief (to candidate)

You will assess a patient with a presentation consistent with Respiratory Failure.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.

Clinical context

Respiratory failure is the failure of the respiratory system to maintain adequate gas exchange, defined by the arterial blood gas: PaO2 below 8 kPa (60 mmHg) at room air, with or without a raised PaCO2. Type 1 (hypoxaemic) is low oxygen with normal or low CO2, caused by ventilation-perfusion mismatch or shunt — pneumonia, pulmonary embolism, pulmonary oedema, ARDS, asthma. Type 2 (hypercapnic) is low oxygen AND high CO2 (PaCO2 above 6 kPa / 45 mmHg), caused by alveolar hypoventilation — COPD, neuromuscular disease, opiates, obesity hypoventilation, brainstem depression. The ABG diagnoses it and the type drives treatment. Management is oxygen (target SpO2 94–98% for type 1; 88–92% for COPD/ty

Candidate tasks

1. Clarify onset, severity, associated features, and red-flag symptoms.
2. State focused examination priorities.
3. List first-line investigations and any named score/criteria.
4. Give immediate resuscitation steps.
5. Outline definitive management with doses/routes where standard.
6. Name complications and disposition (ward / HDU / theatre / discharge safety-net).
7. Mention one special-population modifier (pregnancy, child, elderly, CKD).

Examiner checklist

Model outline

Lead with the working diagnosis and life threats. Resuscitate before definitive tests when unstable. Use guideline-standard therapy with named agents and doses. Document escalation criteria and follow-up. A safe candidate is specific, structured, and never delays critical care for non-urgent imaging.