Reasoning GP · Algorithm · 1-page summary
Breathlessness in adults
For: adults, face to face or remote, in hours or OOH/111. Not for: children, major trauma, or ongoing asthma, COPD, HF or PE care (separate pathways). Pregnancy, postpartum, cancer → block 2.
Core rule: measure RR, SpO₂, pulse and BP before the history; judge SpO₂ against the patient's own target (94–98%; 88–92% if hypercapnic risk). New or falling hypoxia, RR ≥25 or breathlessness at rest is an acute-care decision — never "just anxiety" or "just their COPD".
0Stop — call 999 now — before any history
- Cannot speak in sentences, silent chest, exhaustion, cyanosis, drowsiness; severe hypoxia or SpO₂ below target; RR rising with tiring → 999
- Life-threatening asthma (PEF <33%, SpO₂ <92%, bradycardia, confusion); stridor, drooling, tongue swelling; anaphylaxis → 999
- Pulse >120 or <40, systolic BP <90; tracheal deviation; pulmonary oedema; suspected ACS or malignant arrhythmia → 999
- While waiting: sit upright; oxygen to target; IM adrenaline 500 micrograms if anaphylaxis (repeat after 5 min); salbutamol via spacer if wheeze; aspirin 300 mg for suspected ACS unless allergic. Do not delay transfer for CXR, bloods or ECG.
1Measure, then triage — before the full history
RR over a full minute, SpO₂ on air (vs usual), pulse, BP, temperature, GCS, PEF if wheeze, NEWS2. A 3% fall from a previous SpO₂ matters.
| Finding | Action |
|---|---|
| Any block 0 feature | 999 |
| New hypoxia or rest breathlessness | Same-day hospital |
| RR ≥25 | Urgent escalation; destination by trajectory and diagnosis |
| Onset in minutes | Pneumothorax, PE, anaphylaxis, arrhythmia → block 2 |
2Screen — one row is enough
- Acute severe asthma (PEF 33–50%, RR ≥25, pulse ≥110; BTS/SIGN 158) → treat; any feature persisting → Admit; deteriorating → 999. COPD not safe at home → Same-day; drowsy → 999
- PE / pneumothorax: pleuritic or sudden onset, pulse >100, haemoptysis, leg swelling, risk factors → Same-day acute; hypoxic, hypotensive, syncope → 999. Wells >4: imaging, not D-dimer.
- Acute HF / arrhythmia: orthopnoea, new crackles, raised JVP, irregular pulse → Same-day hospital
- Pneumonia: CRB65 ≥2 → consider hospital; sepsis → 999
- Pregnant or ≤6 weeks postpartum, cancer, immunosuppressed, anticoagulated → Same-day maternity / acute / oncology. Pregnancy: no Wells or D-dimer — urgent objective testing; LMWH meanwhile unless contraindicated.
- ≥40, unexplained breathlessness plus cough, fatigue, chest pain, weight or appetite loss (or alone if ever smoked or asbestos) → CXR ≤2 weeks. Unexplained haemoptysis ≥40 → Cancer pathway
3Assess — once blocks 0–2 are answered
☐ Repeat observations after treatment ☐ Trachea, percussion, breath sounds, JVP, oedema, calves, clubbing ☐ ECG if new and unexplained ☐ Targeted CXR ☐ FBC, ferritin, U&E, TFT, HbA1c
Not here: CTPA, echo without NT-proBNP, steroid trials, spirometry in an exacerbation; no throat exam if epiglottitis.
4Classify — only if the screen is negative
- Asthma — variable wheeze; confirm: FeNO ≥50 ppb, FEV₁ up 12% + 200 mL, or PEF variability >20% over 2 weeks. Never on symptoms.
- COPD — over 35, smoking or exposure; post-bronchodilator FEV₁/FVC <0.7. Never without spirometry.
- Heart failure — orthopnoea, oedema, raised JVP → NT-proBNP + ECG: 400–2000 ng/L → echo ≤6 weeks; >2000 → ≤2 weeks. <400: HF unlikely, cause still unexplained.
- Anaemia, thyroid, metabolic, deconditioning — needs positive findings. Iron deficiency in a man or postmenopausal woman → GI cancer route.
- Breathing pattern disorder / panic — normal observations; only after organic causes are tested.
- Uncertain — say so; name who reviews and when. Fine crackles + clubbing (ILD) → urgent CXR and respiratory referral.
5Treat today — doses: SPC, local formulary
- Acute asthma: salbutamol 4–10 puffs via spacer every 10–20 min (or 5 mg nebulised); prednisolone 40–50 mg daily until recovery, ≥5 days. Repeat PEF and SpO₂; no response or SpO₂ <92% → admit. Review promptly (≤2 working days after discharge).
- COPD exacerbation: more bronchodilator; prednisolone 30 mg for 5 days; antibiotic only if sputum more purulent or unwell. Review at 48 h.
- Pneumonia, CRB65 0 (or 1 if safe): amoxicillin 500 mg TDS for 5 days (penicillin allergy: doxycycline or clarithromycin). Review at 48–72 h.
- Not: diuretic without NT-proBNP, ECG and overload; community care of suspected PE or pneumothorax.
6Refer routinely
- Still uncertain after objective tests, bronchiectasis, pulmonary hypertension; asthma uncontrolled on moderate-dose MART or ≥2 steroid courses in 12 months → respiratory.
- COPD MRC ≥3, or after an admission for a flare → pulmonary rehab. Occupational asthma → occupational lung service.
- Breathing pattern disorder → physiotherapy; recurrent panic → NHS Talking Therapies.
7Never reassure by
- A normal chest, CXR (common in PE) or between-attack peak flow.
- No wheeze — absent in life-threatening asthma.
- A low NEWS2 — PE, asthma and ACS can be critical first.
- A familiar label — not improving needs spirometry, not another inhaler.
- "Anxiety" while RR, SpO₂ or pulse is abnormal.
- A remote call that cannot measure.
8Safety-net — say it, then document it
999 “Call 999 if you cannot speak in full sentences, your lips turn blue, you become drowsy, or your breathing suddenly worsens.” Same day: “Contact us today for breathlessness at rest, a reliever lasting under 4 hours, chest pain, coughing blood, a swollen painful leg, or waking breathless.”
Remote or OOH: convert to face-to-face or emergency if they cannot complete sentences; RR, SpO₂, pulse or PEF cannot be measured; they worsen on the call; pregnant, immunosuppressed or previous asthma ITU; or no safe transport.
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Observations at baseline
Cause proven, or uncertainty stated
Review owner and date
Safety-net documented
Summary of the full Reasoning GP breathlessness algorithm, which holds the detail and evidence. Sources: NICE NG245, NG115, NG114, NG250, NG106, NG158, CG95, NG12 (updated April 2026), CG113; BTS oxygen; RCUK anaphylaxis; RCOG 37b. Clinical reference — follow local policies and check doses in the SPC and your local formulary.