When should shortness of breath be investigated?

When to Investigate Shortness of Breath

Shortness of breath should be promptly investigated when it occurs at rest, with minimal exertion, is accompanied by concerning symptoms, or occurs in patients with risk factors for serious cardiopulmonary conditions. 1

Initial Assessment

• All acutely ill patients with shortness of breath should be assessed by measuring vital signs including respiratory rate, pulse rate, blood pressure, temperature, and oxygen saturation (the "fifth vital sign") 1
• Oxygen saturation should be measured by pulse oximetry in all breathless and acutely ill patients, with the inspired oxygen device and flow rate recorded alongside the oximetry result 1
• A recognized physiological "track and trigger" system such as the National Early Warning Score (NEWS) should be used for initial assessment and monitoring 1

Red Flag Symptoms Requiring Immediate Investigation

• Shortness of breath at rest or with minimal exertion 1
• Shortness of breath accompanied by chest pain, especially in patients with risk factors for coronary artery disease 1
• Ripping chest pain ("worst chest pain of my life"), especially when sudden in onset and occurring in a hypertensive patient, which suggests acute aortic syndrome 1
• Shortness of breath with syncope or presyncope, which may indicate pulmonary embolism or serious cardiac pathology 1, 2
• Shortness of breath in patients >75 years of age when accompanied by syncope, acute delirium, or following an unexplained fall 1
• Shortness of breath with diaphoresis, tachypnea, tachycardia, hypotension, or crackles, which may indicate acute heart failure 1

Specific Patient Populations Requiring Investigation

Patients with Known or Suspected COPD

• Investigate when patients with COPD report worsening breathlessness, especially when accompanied by increased sputum production or change in sputum color 1
• Patients >50 years of age who are long-term smokers with chronic breathlessness on minor exertion should be treated as having suspected COPD and require spirometric assessment 1
• Patients with COPD who have an mMRC dyspnea score ≥2 (walks slower than people of same age due to breathlessness or stops for breath when walking at own pace) require investigation 1

Women with Shortness of Breath

• Women presenting with shortness of breath are at risk for underdiagnosis of cardiac causes and should always have cardiac causes considered 1
• In women, accompanying symptoms that may indicate acute coronary syndrome include upper abdominal pain, heartburn unrelated to meals, nausea, vomiting, and symptoms on either side of the chest 1, 3

Patients at Risk for Hypercapnic Respiratory Failure

• Patients with COPD, morbid obesity, cystic fibrosis, chest wall deformities, neuromuscular disorders, or bronchiectasis who develop worsening shortness of breath require urgent investigation including blood gas analysis 1
• Patients with previous episodes of hypercapnic respiratory failure require immediate assessment when presenting with shortness of breath 1

Diagnostic Approach Based on Duration

Acute Shortness of Breath (Less Than 4 Weeks)

• Requires immediate assessment with vital signs, oxygen saturation, and focused cardiovascular examination 1, 4
• Chest radiography should be performed promptly, though it has high specificity (96%) but low sensitivity (59%) for cardiac causes 1
• If cardiac cause is suspected, echocardiography is recommended as an important tool to evaluate cardiac structure and function 1

Chronic Shortness of Breath (More Than 4 Weeks)

• Spirometry should be performed to assess for airflow obstruction, particularly in patients with risk factors for COPD 1
• The Modified Medical Research Council (mMRC) dyspnea scale should be used to assess the severity of functional dyspnea 1
• Patients with chronic shortness of breath during exercise should be evaluated for exercise-induced bronchoconstriction, particularly if symptoms occur during or after exercise 1

Imaging Recommendations

• Chest X-ray is the initial imaging study for all patients with unexplained shortness of breath 1
• Transthoracic echocardiography should be performed in all patients with dyspnea of suspected cardiac origin 1
• CT of the chest is appropriate for patients with unexplained shortness of breath when pulmonary causes are suspected 1
• CT angiography of the chest should be considered when pulmonary embolism is suspected 1

Common Pitfalls to Avoid

• Failing to recognize that shortness of breath in elderly patients may present atypically with confusion, delirium, or falls rather than the classic complaint of breathlessness 1
• Overlooking cardiac causes of shortness of breath in women, who may present with atypical symptoms 1, 3
• Administering high-concentration oxygen to patients with COPD or others at risk of hypercapnic respiratory failure, which can worsen respiratory acidosis 1
• Assuming that relief with nitroglycerin is diagnostic of myocardial ischemia; this should not be used as a diagnostic criterion 1
• Neglecting to consider multiple simultaneous causes of shortness of breath, particularly in elderly patients with multiple comorbidities 4