Asthma & COPD Exacerbations: FRCEM SBA Cases & Guidelines

Here's something most FRCEM candidates get wrong: they revise asthma and COPD together, treating them as two versions of the same "wheeze in the ED" problem. They're not. The pathophysiology is different, the oxygen targets are different, the severity thresholds are different, and the treatment escalation steps are completely different.

Get them mixed up under exam pressure, and you lose marks on questions that should have been straightforward.

This guide covers both conditions the way FRCEM actually tests them — severity classification, step-by-step ED management, the specific numbers that appear in SBA options, and the updated guideline changes you need to know. Follow this alongside your overall FRCEM SLO 1 preparation and these become some of the most reliable marks in the paper.

Part 1: Acute Asthma Exacerbations

Asthma appears in 4–6 FRCEM SBA questions. Most test severity classification, the correct escalation sequence, and the clinical scenarios where you'd give magnesium sulphate. Get the severity thresholds memorised exactly — the numbers are what distinguish the right answer from the wrong one.

Severity Classification (BTS/SIGN, Acute Asthma Pathway)

This is the most tested section. FRCEM will give you clinical observations and ask which severity category fits — or give you a severity and ask what treatment comes next.

Moderate acute asthma:

• PEF 50–75% best or predicted

• No features of acute severe or life-threatening asthma

• Speaking in sentences

Acute severe asthma — any one of:

• PEF 33–50% best or predicted

• Respiratory rate ≥25/min

• Heart rate ≥110 bpm

• Can't complete sentences in one breath

Life-threatening asthma — any one of:

• PEF <33% best or predicted

• SpO₂ <92%

• PaO₂ <8 kPa

• Silent chest, cyanosis, feeble respiratory effort

• Bradycardia, arrhythmia, or hypotension

• Exhaustion, altered consciousness

• Normal or rising PaCO₂ (≥4.6 kPa) — this is an ominous sign, not reassuring

Near-fatal asthma:

• Raised PaCO₂

• Requiring mechanical ventilation

The single most common FRCEM trap: a "normal" CO₂ in a deteriorating asthma patient. Students assume this is reassuring. It is not — a normal or rising PaCO₂ in acute severe asthma signals fatigue and impending respiratory failure. This is a life-threatening feature.

[Image Needed] -- Clean severity classification table with PEF percentages and clinical features across moderate, severe, life-threatening, and near-fatal columns

ED Management: Step by Step

Immediate Actions (All Acute Asthma)

1. Oxygen — titrate to maintain SpO₂ 94–98%. Do not use high-flow oxygen indiscriminately; this is asthma, not COPD, but targeted oxygen is still the standard.

2. Salbutamol 5 mg nebulised — oxygen-driven, not air-driven. Repeat every 15–30 minutes in severe/life-threatening, every 4 hours if responding.

3. Prednisolone 40–50 mg orally (or IV hydrocortisone 100 mg if oral not possible) — give immediately, benefits appear within 3–4 hours. Continue for at least 5 days.

4. Ipratropium bromide 0.5 mg — add to nebuliser for acute severe or life-threatening asthma, or if poor initial response to salbutamol. Combined nebulisation produces greater bronchodilation than salbutamol alone. Give 4–6 hourly until improving.

If Life-Threatening Features Present

5. IV magnesium sulphate 1.2–2 g over 20 minutes — smooth muscle relaxant with bronchodilatory effect. Safe and effective when the patient hasn't responded sufficiently to initial bronchodilators and steroids. Give as a single dose; seek senior review.

6. Senior clinician and ICU input immediately — do not manage life-threatening asthma alone.

7. Consider continuous salbutamol nebulisation — 5–10 mg/hour if appropriate nebuliser available.

8. ABG — if any life-threatening feature is present. A rising PaCO₂ or falling pH signals impending respiratory failure.

What FRCEM Tests About Escalation

The exam frequently presents a patient who has received oxygen, salbutamol, and steroids but hasn't improved after 15–30 minutes. The correct next step is ipratropium if not yet given, then reassess, then magnesium if still life-threatening features persist. IV aminophylline is now reserved for senior/critical care decision-making only — it's no longer a routine step in the acute algorithm and carries significant arrhythmia risk.

[Image Needed] -- Escalation flowchart: moderate → severe → life-threatening, with treatment steps at each tier

Key Numbers to Lock In

Discharge and Follow-Up Criteria

Before discharging any acute asthma patient, they need:

• PEF >75% best or predicted after treatment

• Symptoms adequately controlled

• Inhaler technique checked and optimised

• Written personalised asthma action plan

• Oral prednisolone course to complete (if given)

• GP notified within 24 hours of ED discharge

FRCEM tests the 24-hour GP notification requirement specifically — it appears in questions about safe discharge planning.

Part 2: COPD Exacerbations

COPD exacerbations account for a similar question volume to asthma in FRCEM, but the approach is fundamentally different. The two areas where candidates most often lose marks: oxygen targets and NIV criteria.

What Is a COPD Exacerbation?

An acute event — typically worsening over a few days — characterised by increased dyspnoea, cough, and/or sputum production beyond the patient's normal day-to-day variation. Most are triggered by respiratory infection (viral or bacterial) or environmental pollutants.

FRCEM tests the three cardinal symptoms associated with bacterial exacerbations:

1. Increased dyspnoea

2. Increased sputum volume

3. Increased sputum purulence

Antibiotics are indicated when all three are present, or when two are present and one is purulent sputum, or when the patient requires mechanical ventilation (per latest GOLD guidelines).

Oxygen Therapy in COPD: The Most Tested Topic

This is the number one area where FRCEM catches candidates out — and the correct answer is the opposite of what instinct says.

Target SpO₂ in COPD exacerbation: 88–92%

Not 94–98%. Not "as high as possible." 88–92%.

Why? Many patients with severe COPD have chronic hypercapnia and rely on hypoxic drive to maintain respiratory stimulus. Aggressive oxygen therapy in these patients suppresses that drive, worsens hypercapnia, and can precipitate CO₂ narcosis and respiratory arrest.

Use a Venturi mask for precise oxygen delivery — 24% or 28% initially depending on baseline. Titrate to target. Always get an ABG early to assess pH and CO₂.

FRCEM loves presenting a COPD patient given high-flow oxygen via non-rebreathe mask whose GCS is dropping. The question asks what went wrong and what to do now. Answer: oxygen-induced hypercapnia — reduce to controlled oxygen, get ABG, consider NIV if pH is falling.

[Image Needed] -- Side-by-side comparison: asthma oxygen target (94–98%) vs COPD oxygen target (88–92%) with Venturi mask diagram

ED Management: Step by Step

1. Controlled oxygen — Venturi mask, target SpO₂ 88–92%. ABG on arrival or as soon as possible.

2. Short-acting bronchodilators — salbutamol 2.5–5 mg nebulised (can be air-driven in COPD), with ipratropium 0.5 mg added. Repeat as needed.

3. Prednisolone 30–40 mg orally for 5 days — improves lung function and shortens recovery. Oral and IV are equivalent efficacy; use IV if vomiting or unable to swallow.

4. Antibiotics — indicated when bacterial exacerbation is suspected (purulent sputum, clinical features of infection). Typical agents: amoxicillin, doxycycline, or clarithromycin per local protocol. Course: 5 days per GOLD.

5. Repeat ABG — within 1 hour of starting treatment if pH abnormal, or sooner if deteriorating.

Non-Invasive Ventilation (NIV) — Know This in Detail

NIV is the most important escalation decision in COPD management and one of the most tested topics in FRCEM respiratory questions.

Indications for NIV (GOLD/SIGN):

• pH <7.35 with PaCO₂ >6 kPa (type 2 respiratory failure) despite optimal medical therapy

• Persistent hypoxaemia not correcting with controlled oxygen

• Respiratory rate >30 with increased work of breathing

NIV should be started early — waiting for the patient to deteriorate further before initiating it is a common, dangerous mistake that FRCEM tests.

Contraindications to NIV:

• Respiratory arrest or haemodynamic instability

• Agitated/uncooperative patient who cannot protect airway

• Facial trauma or burns precluding mask fit

• Excessive secretions not manageable without intubation

If NIV fails — involves the patient deteriorating on NIV with worsening acidosis, rising CO₂, declining consciousness — escalate to ICU for consideration of invasive ventilation, taking into account reversibility and patient's wishes.

[Image Needed] -- Decision flowchart: COPD exacerbation management from initial assessment through bronchodilators → steroids → antibiotics → controlled O₂ → ABG → NIV criteria

Antibiotics: When to Give Them

This comes up in SBA scenarios where you're given the clinical presentation and asked to select the appropriate management bundle. Know these criteria cold:

Give antibiotics if:

• All 3 cardinal symptoms present (increased dyspnoea + volume + purulence)

• 2 cardinal symptoms present AND purulence is one of them

• Patient on invasive or non-invasive mechanical ventilation

Do not give antibiotics routinely for every COPD exacerbation — non-purulent exacerbations are predominantly viral and antibiotics offer no benefit.

CRP and procalcitonin may support antibiotic decisions but are not yet standard criteria in most UK guidelines — awareness is sufficient for FRCEM.

Asthma vs COPD: The Key Differences FRCEM Exploits

FRCEM frequently presents a mixed scenario and tests whether you apply the right rules to the right condition. Here's what distinguishes them:

Common FRCEM Mistakes — and How to Avoid Them

Mistake 1: High-flow oxygen in COPD Giving non-rebreathe mask oxygen to a COPD patient is dangerous. Target 88–92% via Venturi. If a question describes GCS dropping in a COPD patient on high-flow oxygen — that's the cause.

Mistake 2: Reassured by normal CO₂ in asthma In acute severe asthma, a "normal" CO₂ (≥4.6 kPa) is a life-threatening feature. The patient has worked hard to maintain it — they are tiring. Escalate immediately.

Mistake 3: Forgetting ipratropium Many candidates jump straight to magnesium. Ipratropium should be added to the nebuliser in all acute severe and life-threatening asthma, before escalating to IV therapies.

Mistake 4: Using aminophylline routinely IV aminophylline is not a routine step. It's reserved for senior/ICU decision-making and carries significant arrhythmia risk. Don't select it as the "next step" in a standard escalation question.

Mistake 5: Delaying NIV in COPD NIV should be initiated early when pH is falling below 7.35 with rising CO₂. Waiting too long to start it is one of the most common errors in COPD management — and FRCEM tests whether you know to act before the patient is in extremis.

Mistake 6: Antibiotics for all COPD exacerbations Antibiotics are only indicated when there are bacterial features — specifically purulent sputum plus other cardinal symptoms. Viral exacerbations are common; antibiotics are not required.

High-Yield FRCEM SBA Practice Cases

Theory is only half the battle. Can you spot the examiner traps?

FRCEM examiners routinely hide life-threatening red flags (like a "normal CO₂") inside a list of otherwise reassuring observations. Knowing the guidelines isn't enough—you have to apply them under pressure.

See exactly how Asthma and COPD look in the real exam:

• Real Exam Format: Navigate tricky, plausible distractors under time pressure.

• High-Yield SBAs: Practice exactly what the SLO curriculum tests.

• Instant Feedback: Learn from detailed, guideline-backed explanations.

Stop reading. Start testing.

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Study Strategy

Asthma and COPD combined account for roughly 8–10 questions across the FRCEM SBA paper. The marks are available because the question patterns are predictable.

For asthma, prioritise:

• Severity thresholds (exact PEF percentages and clinical features)

• Escalation sequence (salbutamol → ipratropium → magnesium → senior/ICU)

• The "normal CO₂ = danger" principle

• Discharge criteria and 24-hour GP notification

For COPD, prioritise:

• Oxygen target 88–92% via Venturi mask

• NIV criteria (pH <7.35, rising CO₂)

• Antibiotic indications (purulent/bacterial features only)

• Steroid: 30–40 mg for 5 days

Work through 40–60 respiratory SBA questions in your final preparation window — the ECG and cardiovascular questions share exam-day time pressure with these, so review both areas together. The FRCEM cardiology ECG guide is useful to pair with this for your SLO 1 revision session.

Asthma and COPD exacerbations are highly predictable once you know the patterns. You now have the severity thresholds, oxygen targets, and NIV criteria locked in. These questions should no longer feel like stressful clinical judgement calls—they are easy, scorable marks.

But memorising the theory is only step one. To pass the FRCEM, you need to prove you can apply these rules under time pressure against expert-level distractors.

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• Real Exam Simulation: High-yield, SLO-mapped respiratory cases.

• Exam Trap Navigation: Practice scenarios designed to catch you out on normal CO₂ levels and oxygen targets.

• Up-to-Date Explanations: Every answer is strictly backed by the latest BTS and GOLD guidelines.

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Guidelines referenced:

• BTS/SIGN British Guideline on the Management of Asthma (SIGN 158, updated) — sign.ac.uk

• BTS/NICE/SIGN Asthma Pathway (latest) — nice.org.uk/guidance/ng244

• GOLD Global Strategy for COPD (latest report) — goldcopd.org