MBBS OSCE · Respiratory / General Medicine
OSCE — assessment of acute severe asthma
An 8-minute OSCE station assessing the candidate's structured ABCDE assessment, BTS/SIGN severity banding, first-hour drug doses, and escalation of an acute severe asthma attack. Marks for recognising the life-threatening PaCO2 and giving IV magnesium.
8 min stationVerification in progress
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Exam tags
NEET-PGINICETUSMLEPLAB
Brief (to candidate)
A 26-year-old man with known asthma presents with worsening wheeze over 2 days despite frequent salbutamol (two canisters this week). He cannot complete sentences, RR 30, SpO2 91% on air, HR 124, PEF 40% of his best, marked accessory-muscle use; ABG on air shows PaCO2 44 mmHg (normal) and pH 7.36. You have 8 minutes to assess him, grade severity, and outline immediate management.
Candidate instructions
- Take a focused, structured history and examine using an ABCDE approach.
- Grade severity using the BTS/SIGN acute asthma bands.
- Outline the immediate management, including investigations and drug therapy with doses, routes and timing.
- State your disposition (ward vs ICU) and the discharge / safety-net / follow-up advice.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| ABCDE / resuscitation | Airway; high-flow O2 to target SpO2 93–95%; IV access; do not wait for tests to treat |
| Severity — BTS/SIGN | Reproduces bands; identifies acute severe + a life-threatening feature (normal PaCO2, SpO2 91%); states pre-arrest / ICU[1] |
| First-hour bronchodilators | Nebulised salbutamol 5 mg repeated q20 min/continuous; nebulised ipratropium 500 mcg in the first hour |
| Corticosteroid + magnesium | Prednisolone 40–50 mg (or IV hydrocortisone 100 mg q6h) for 5 days; IV magnesium sulphate 2 g over 20 min for severe attack (3Mg evidence)[4] |
| Escalation / ICU | Life-threatening + normal PaCO2 → ICU now; consider IV salbutamol/aminophylline; prepare for ventilation; never sedate |
| Investigations | ABG (interpret PaCO2), CXR (exclude pneumothorax/pneumomediastinum), bloods; identify trigger |
| Prevention / safety-net | MART controller, written action plan, switch from SABA-only reliever (unsafe — SMART); early follow-up[2] |
Model key actions
- Oxygen target 93–95% with rationale; treat immediately on recognition.
- Recognises the normal PaCO2 as life-threatening / pre-arrest — the discriminating observation.
- Salbutamol 5 mg neb + ipratropium 500 mcg neb + prednisolone 40–50 mg + IV magnesium 2 g over 20 min; ICU referral.[1][4]
- Never use a SABA-only reliever — optimise to ICS-formoterol MART; written action plan; review adherence/trigger.[2]
- Examines for and manages complications (pneumothorax, mucus plugging).
Common errors
- Treating the normal PaCO2 as reassuring rather than a pre-arrest sign.
- Omitting ipratropium or IV magnesium in a severe attack.
- Using a SABA-only reliever on discharge (unsafe — SMART).
- Sedating the anxious patient (respiratory depression).
- Delayed ICU referral; not examining for pneumothorax.
References3ShowHide
- [1]Global Initiative for Asthma (GINA) Global Strategy for Asthma Management and Prevention (2024 update). GINA, 2024.Source
- [2]Nelson HS, et al. The Salmeterol Multicenter Asthma Research Trial (SMART). Chest, 2006.PMID 16424409
- [4]Goodacre S, et al. Intravenous or nebulised magnesium sulphate versus standard therapy for severe acute asthma (3Mg trial): a double-blind, randomised controlled trial. Lancet Respir Med, 2013.PMID 24429154