Shortness of breath: workup and approach
Acute dyspnea in an adult. Assess airway, work of breathing and oxygenation first, then separate cardiac, pulmonary and systemic causes with ECG, CXR, gas and focused ultrasound.
Presenting complaint
Adult · US guidelines
Draft · awaiting physician review
01Orient
What's new in the evidence
- 2026 AHA/ACC PE guideline introduces PE clinical categories A–E
- GOLD 2026 grades COPD exacerbation severity by findings at presentation
- GINA 2026 discourages SABA-only treatment at discharge after an asthma attack
- SCCM 2024 strongly recommends corticosteroids for severe community-acquired pneumonia
Differential diagnoses
- Acute decompensated heart failure
- Pulmonary embolism
- Pneumonia
- COPD or asthma exacerbation
- Acute coronary syndrome
- Pneumothorax
- Pleural effusion
- Arrhythmia (AF with RVR)
- Metabolic acidosis (DKA, sepsis, toxins)
- Anemia
- Anxiety (diagnosis of exclusion)
02Assess
Risk scores and decision tools
- Wells and PERC for PE
- BLUE protocol (lung ultrasound) to separate edema, pneumonia, PTX and PE
- CURB-65 or PSI for pneumonia
- NT-proBNP cut-offs for heart failure
Key history questions
- Onset: sudden (PE, pneumothorax) vs gradual (HF, effusion)
- Orthopnea, PND, leg swelling, weight gain
- Fever, productive cough, pleuritic pain
- Wheeze, known COPD or asthma, inhaler use
- VTE risk factors, hemoptysis
- Chest pain, palpitations
Examination findings
- RR, SpO2, accessory muscle use, ability to speak in sentences
- JVP, S3, peripheral edema, bibasal crackles
- Focal crackles, bronchial breathing
- Wheeze or silent chest
- Unilateral reduced breath sounds
- Unilateral calf swelling
03Investigate
Initial investigations
- ECG
- Chest X-ray
- Arterial or venous blood gas with lactate
- CBC, BMP, troponin, BNP or NT-proBNP
- Point-of-care lung and cardiac ultrasound (B-lines, effusion, RV dilation)
Advanced investigations
- D-dimer if PE pre-test probability low-moderate; CTPA if high or D-dimer positive
- Echocardiogram
- Sputum and blood cultures if infection suspected
- Spirometry once stable
04Treat
Immediate management
- Sit upright; oxygen to SpO2 94-98% (88-92% if CO2 retention risk)
- NIV (CPAP/BiPAP) for pulmonary edema or hypercapnic COPD with acidosis
- Escalate early for rising RR, falling consciousness or worsening gas
- Needle decompression for tension pneumothorax
First-line treatment
- Treat the cause: diuretics for HF, bronchodilators and steroids for COPD/asthma, antibiotics for pneumonia, anticoagulation for PE
Second-line treatment
- Intubation if NIV fails or contraindicated
- Thoracentesis for large symptomatic effusion
Specialist referrals
- ICU for respiratory failure or NIV requirement
- Cardiology or pulmonology depending on cause
05Disposition
Admission criteria
- New oxygen requirement or SpO2 below 92% on air
- Increased work of breathing or RR above 24
- Cause requiring IV therapy
- Hypercapnia or acidosis
Safe discharge criteria
- Normal oxygenation at rest and on ambulation
- Clear treatable cause with reliable outpatient plan
- No high-risk features
Follow-up timing
- Primary care review within 1 week
Patient instructions
- Return if breathlessness worsens, at rest, or with chest pain or confusion
Monitoring
- Continuous SpO2 and RR while unwell
- Repeat gas after starting NIV (about 1 h)
Clinical pearls and pitfalls
- Ambulatory SpO2 testing unmasks hypoxia missed at rest
- More than one cause often coexists, e.g. pneumonia triggering HF
RefGuidelines and landmark evidence
For education only. Typical adult starting points; confirm doses against renal function, allergies, interactions and your institution's protocols. Not a substitute for clinical judgment or senior review.