What is the approach to a patient with shortness of breath in the emergency department, considering various underlying causes such as chronic obstructive pulmonary disease (COPD) or asthma, and suspected heart failure?

Emergency Department Approach to Shortness of Breath

All patients presenting with acute shortness of breath to the emergency department should undergo immediate systematic assessment using the ABCDE (Airway, Breathing, Circulation, Disability, Exposure) approach with simultaneous measurement of vital signs including oxygen saturation, followed by targeted oxygen therapy based on risk stratification for hypercapnic respiratory failure. 1, 2

Immediate Assessment and Stabilization

Primary Survey (ABCDE Approach)

The ABCDE approach should be completed within 10 minutes of patient arrival and includes: 2, 3

• Airway: Assess patency; ensure airway is open and maintainable
• Breathing: Measure respiratory rate, assess work of breathing, auscultate for adventitious sounds (wheezes, rales, rhonchi), and obtain pulse oximetry 1, 4
• Circulation: Measure pulse rate, blood pressure, assess perfusion and circulating volume 1
• Disability: Assess level of consciousness and neurological status
• Exposure: Measure temperature, examine for signs of trauma or other pathology 2

Vital Signs and Oxygen Saturation Monitoring

Oxygen saturation must be measured by pulse oximetry in all breathless patients and recorded as the "fifth vital sign" along with the inspired oxygen device and flow rate. 5, 1 A National Early Warning Score (NEWS) or similar track-and-trigger system should be implemented to guide escalation of care. 5, 1

Oxygen Therapy: Risk-Stratified Approach

For Patients WITHOUT Risk of Hypercapnic Respiratory Failure

Target oxygen saturation: 94-98% 5, 1

This applies to most acutely ill patients including those with:

• Suspected acute coronary syndrome
• Pulmonary embolism
• Pneumonia
• Pulmonary edema
• Asthma (without concurrent COPD) 5

For Patients WITH Risk of Hypercapnic Respiratory Failure

Target oxygen saturation: 88-92% pending blood gas results 5, 1

This lower target applies to patients with:

• Known COPD
• Morbid obesity
• Cystic fibrosis
• Chest wall deformities
• Neuromuscular disorders
• Bronchiectasis with fixed airflow obstruction 5, 1

Critical Pitfall: Administering high-concentration oxygen to patients at risk of hypercapnic respiratory failure can worsen respiratory acidosis and outcomes. 5, 1 However, if these patients present with critical illness (shock, sepsis, major trauma), initially use the same 94-98% target until blood gas results are available, then adjust accordingly. 5

Life-Threatening Conditions Requiring Immediate Recognition

Red Flag Presentations

Immediately activate resuscitation protocols for: 5, 1

• Cardiac arrest or peri-arrest: Use highest possible inspired oxygen (reservoir mask at 15 L/min or bag-valve-mask) until spontaneous circulation restored 5
• Shock, sepsis, major trauma, anaphylaxis: Target SpO2 94-98% with high-flow oxygen 5
• Ripping chest pain in hypertensive patient: Suspect acute aortic syndrome 1
• Shortness of breath with syncope/presyncope: Consider pulmonary embolism or cardiac pathology 1
• Carbon monoxide poisoning: Give maximum oxygen via reservoir mask; disregard normal pulse oximetry readings as they cannot differentiate carboxyhemoglobin from oxyhemoglobin 5

Condition-Specific Emergency Management

Asthma/COPD Exacerbation

Administer inhaled bronchodilators (albuterol/salbutamol) immediately for patients with known asthma or COPD presenting with acute dyspnea and wheezing. 5

• Dosing: 2.5 mg albuterol (one 3 mL vial of 0.083% solution) via nebulizer over 5-15 minutes 6
• Can be repeated three to four times as needed 6
• Adverse events are minimal (no significant changes in heart rate, blood pressure, or electrolytes in most patients) 5
• Warning: Paradoxical bronchospasm can occur; if it does, discontinue immediately and use alternative therapy 6

Suspected Heart Failure

Position the patient upright if possible, as oxygenation is reduced in the supine position. 5 Fully conscious hypoxaemic patients should maintain the most upright posture tolerable unless contraindicated by trauma. 5

Anaphylaxis

If respiratory difficulty occurs with cutaneous manifestations (hives, lip/eye swelling) or cardiovascular effects (hypotension, shock), this represents anaphylaxis involving two or more body systems. 5 Assist with or administer epinephrine autoinjector if available. 5

Diagnostic Workup in the Emergency Department

Immediate Testing

• Arterial blood gas: Essential for patients at risk of hypercapnic respiratory failure to guide oxygen therapy 5, 1
• Chest X-ray: Initial imaging study for all patients with unexplained shortness of breath 1
• ECG: For all patients, especially those with chest pain or cardiac risk factors 1
• BNP/NT-proBNP: If heart failure suspected; BNP <100 pg/mL has 96-99% sensitivity for ruling out heart failure 7

Additional Investigations Based on Clinical Suspicion

• Echocardiography: For suspected cardiac causes (valvular disease, heart failure, right ventricular dysfunction) 1
• CT angiography: When pulmonary embolism suspected 1
• Spirometry: For suspected COPD or asthma (may be deferred until acute phase resolves) 1

Critical Pitfalls to Avoid

1. Failing to recognize atypical presentations in elderly patients: Shortness of breath may manifest as confusion, delirium, or falls rather than classic dyspnea complaints 1

2. Overlooking cardiac causes in women: Women frequently present with atypical symptoms; always consider cardiac etiology 1

3. Using nitroglycerin response as diagnostic criterion: Relief with nitroglycerin does not confirm myocardial ischemia and should not guide diagnosis 1

4. Delaying assessment for sudden 3% oxygen saturation drop: Even within target range, this may be the first sign of acute deterioration and requires immediate reassessment 5

5. Assuming normal pulse oximetry rules out serious pathology: In carbon monoxide poisoning, pulse oximetry will be falsely normal 5

When to Escalate Care

Call for intensive care consultation or activate resuscitation team for: 5

• Patients requiring oxygen therapy who cannot maintain target saturations
• Signs of impending respiratory failure (altered mental status, inability to speak in full sentences, accessory muscle use)
• Hemodynamic instability despite initial resuscitation
• Any patient triggering high-risk criteria on NEWS or similar scoring system 5, 1