Breathlessness in the ED — Approach & Revision

Settle them, and check the basics

all at once, calmly

Red flags — what each should make you think

Silent chest, cyanosis or exhaustionlife-threatening asthma Stridor, lip or tongue swellinganaphylaxis Unilateral absent sounds + hypotensiontension pneumothorax Sudden breathless + hypoxia + VTE riskpulmonary embolism Orthopnoea, frothy sputum, raised JVPpulmonary oedema Drowsy with rising CO₂ventilatory failure — needs support

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Pearl

Exhaustion in a breathless patient is a pre-arrest sign, not a sign they're settling. A quiet chest and a tiring patient means call for help now — the numbers can look almost normal just before they crash.

Your first moves — all at once, calmly

A–EAssess A–E, sit them uprighttreat what kills first as you find it
◔Full obs + continuous monitoringRR · SpO₂ · HR · BP · temp · consciousness
O₂Oxygen if hypoxic — titrate to target94–98%, or 88–92% if COPD / hypercapnia risk
✚IV access + bloods, and a gasVBG/ABG for CO₂, pH and lactate
♥ECGischaemia, AF, or right-heart strain
▤CXR, and peak flow if asthma/COPDpneumothorax, consolidation, oedema

Read the gas — which kind of respiratory failure?

Type 1

low O₂, normal/low CO₂ — the lungs can't oxygenate (PE, pneumonia, oedema, early asthma).

Type 2

low O₂ and high CO₂ — ventilation is failing (COPD, exhaustion, sedation). A low pH with high CO₂ is the trigger to consider NIV.

Lactate

a marker of how sick they are and of poor perfusion.

Understand the breathing & the person

the pattern points the way

Take a focused history — the pattern routes you

Wheeze — asthma, COPD, or anaphylaxis
Pleuritic / sudden — PE or pneumothorax
Orthopnoea, PND, frothy sputum — pulmonary oedema
Fever, productive cough — pneumonia
Sudden after a trigger, with a rash — anaphylaxis

Background that shifts the odds: known asthma/COPD, cardiac history, VTE risk (immobility, cancer, surgery, oestrogen), allergies and exposures, smoking.

Work A–E — assess and act as you go

Examine top to bottom; at each step you're both sorting the causes and treating what you find.

AAirway. Stridor, swelling of lips/tongue, or a sudden trigger → anaphylaxis.IM adrenaline, high-flow O₂, get senior/anaesthetics

BBreathing. Wheeze → asthma/COPD/anaphylaxis. Unilateral absent sounds → pneumothorax. Crackles → oedema or pneumonia.oxygen to target, nebulisers; decompress if tension pneumothorax

CCirculation. Raised JVP + hypotension → tension pneumothorax, massive PE, or cardiogenic cause.IV access, ECG, cautious fluids unless oedema

DDisability. Drowsy or exhausted → rising CO₂ or tiring → this is peri-arrest.escalate, consider NIV/ITU, check glucose

EExposure. Peripheral oedema (heart failure), unilateral calf swelling (PE), urticaria (anaphylaxis), fever (infection).examine legs, temperature, skin

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Pearl

Give oxygen and treat the cause in parallel — don't wait for the diagnosis to start oxygen. But in a COPD patient, aim for 88–92% while you sort it out.

Rule out the killers

tap to open each

Each card gives you what points toward it, what would rule it in, what lets you stand it down, and how to manage it.

points toward it

Known asthma, worsening wheeze, unable to complete sentences, using accessory muscles.

rule in

Any of: PEF < 33% best/predicted, SpO₂ < 92%, silent chest, cyanosis, exhaustion, or altered consciousness.

stand down

Moderate attack responding to bronchodilators with PEF recovering and SpO₂ normal — treat and observe.

manage it

High-flow O₂ to 94–98%, back-to-back salbutamol + ipratropium nebs, steroids, senior + ITU review, consider IV magnesium.

Source: BTS/NICE/SIGN asthma (NG245) — acute care via the BTS/SIGN pathway

points toward it

Sudden onset after a trigger (food, drug, sting), with skin changes plus airway, breathing or circulation compromise.

rule in

Life-threatening A, B or C problem and usually skin/mucosal changes. A clinical diagnosis — treat immediately.

manage it

IM adrenaline 500 micrograms (0.5 mL of 1:1000) into the anterolateral thigh, repeat after 5 minutes if needed. High-flow O₂, lie flat with legs raised, IV fluids, remove the trigger.

Source: Resuscitation Council UK — anaphylaxis

points toward it

Sudden pleuritic pain + severe breathlessness; unilateral absent breath sounds, hyper-resonance, distended neck veins; tall slim young person, COPD, asthma or trauma.

rule in

Clinical: respiratory distress + hypotension + absent breath sounds. Don't wait for a CXR.

manage it

Immediate decompression (large-bore cannula or finger thoracostomy) then chest drain.

Source: clinical diagnosis · BTS pleural disease

points toward it

Pleuritic pain, sudden breathlessness, tachycardia, hypoxia, unilateral leg swelling, VTE risk factors.

rule in

CTPA positive.

stand down

Two-level Wells: "PE unlikely" (≤4) + negative age-adjusted D-dimer excludes it. Low-risk + PERC negative → no testing. "PE likely" (>4) → CTPA.

manage it

Anticoagulate (a DOAC first-line unless contraindicated). Massive PE with instability → discuss thrombolysis urgently.

Source: NICE NG158 (VTE) · Wells · PERC

points toward it

Orthopnoea, paroxysmal nocturnal dyspnoea, pink frothy sputum, raised JVP, bibasal crackles, cardiac history.

rule in

CXR shows congestion/oedema; raised BNP; reduced function on echo.

manage it

Sit upright, high-flow O₂, IV loop diuretic (furosemide), GTN if not hypotensive, consider CPAP if severe. Find and treat the trigger.

Source: NICE CG187 — acute heart failure

points toward it

Fever, productive cough, focal crackles or bronchial breathing (pneumonia); known COPD with more breathlessness, sputum volume or purulence.

rule in

Consolidation on CXR, raised inflammatory markers. Score pneumonia severity with CURB-65.

manage it

Pneumonia: antibiotics guided by CURB-65 and local policy, oxygen, fluids. COPD: controlled O₂ 88–92%, nebs, steroids, antibiotics if infective; consider NIV if type 2 failure with respiratory acidosis.

Source: NICE CG191 — pneumonia · NICE NG115 — COPD

Don't forget the non-lung causes

Breathlessness isn't always the chest: think metabolic acidosis (DKA — deep sighing breaths), severe anaemia, and anxiety once the dangerous causes are excluded.

Investigate — what to order, when, and what it tells you

test with a question in mind

Blood gas (ABG/VBG)

When

Anyone significantly breathless, hypoxic or unwell.

Tells you

Type 1 vs type 2 failure, pH and CO₂ (low pH + high CO₂ points to NIV), and lactate.

Trap

A "normalising" CO₂ in a tiring asthmatic is ominous, not reassuring.

Chest X-ray

When

Early in most acute breathlessness.

Tells you

Pneumothorax, consolidation, effusion, or pulmonary oedema.

Trap

Often normal in PE and early asthma.

Peak flow & ECG

Peak flow

Grades asthma/COPD severity and tracks response.

ECG

Ischaemia, AF, or right-heart strain (a PE clue).

Bloods & definitive imaging

Bloods

FBC, U&E, CRP; BNP if heart failure suspected; D-dimer only after a Wells score.

CTPA

If PE "likely" or D-dimer positive.

Echo

Heart failure, RV strain, or an unstable patient.

How the plan comes together

disposition · handover

You've supported the breathing, treated the cause, and reassessed. Now: how sick are they, and where do they go?

discharge

Mild, reversible cause responding well, normal oxygen off support, and a safe home.

Safety-net: return advice, GP/asthma review, inhaler technique.

admit / escalate

Ongoing oxygen need, severe or type 2 failure, or an unresolved cause. Life-threatening features → resus / ITU.

Hand over: working diagnosis, oxygen and gas trend, what would change the plan.

A note on scores

For suspected pneumonia, CURB-65 (Confusion, Urea >7, RR ≥30, low BP, age ≥65) supports the admit-vs-home decision. It guides — it never replaces clinical judgement or local policy.

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Pearl

Your handover is part of the plan. "Breathless, working diagnosis X, on this much oxygen, gas showing Y, escalate if Z" is the line that keeps them safe overnight. Nicely done getting here.