What is the initial approach to examining a patient presenting with Shortness Of Breath (SOB)?

Initial Examination of a Patient Presenting with Shortness of Breath

Begin by immediately assessing vital signs including respiratory rate, pulse rate, blood pressure, temperature, and oxygen saturation by pulse oximetry, with documentation of the inspired oxygen device and flow rate alongside the oximetry result. 1

Immediate Assessment and Risk Stratification

• Use a physiological "track and trigger" system such as the National Early Warning Score (NEWS) for initial assessment and ongoing monitoring to identify patients requiring urgent intervention 1

• Measure oxygen saturation in all breathless patients, ensuring you record both the SpO2 value and the oxygen delivery method (e.g., room air, 2L nasal cannula, 28% Venturi mask) 1

• Assess for red flag symptoms that require immediate investigation:

  • Chest pain, particularly in patients with coronary artery disease risk factors 1
  • Ripping chest pain with sudden onset in hypertensive patients (suggests acute aortic syndrome) 1
  • Syncope or presyncope (may indicate pulmonary embolism or serious cardiac pathology) 1
  • Shortness of breath at rest or with minimal exertion 1

Focused History Taking

Obtain specific details about the dyspnea pattern and associated symptoms:

• Duration: Acute (hours to days) versus chronic (>1 month) presentation, as this fundamentally changes the differential diagnosis 2

• Exertional pattern: Determine if dyspnea occurs at rest, with minimal exertion, or only with significant activity 1

• Associated symptoms to specifically inquire about:

  • Chest pain quality and radiation 1
  • Cough and sputum production (color, volume, change in character) 3, 1
  • Fever or chills 3
  • Wheezing or stridor 3
  • Orthopnea and paroxysmal nocturnal dyspnea 3
  • Leg swelling 3

• Critical risk factors and exposures:

  • Smoking history (pack-years) - patients >50 years with chronic breathlessness on minor exertion who are long-term smokers should be treated as having suspected COPD 1
  • Occupational and chemical exposures 2
  • Medication history, including chemotherapy drugs, "alternative therapies," alcohol, and illicit drugs 3
  • Recent travel and sick contacts 4
  • Vaping history (both nicotine and tetrahydrocannabinol products) 4

Physical Examination Components

Perform a systematic examination focusing on cardiopulmonary findings:

• Volume status assessment: Look for jugular venous distention, peripheral edema, and signs of fluid overload 3, 2

• Orthostatic vital signs: Measure blood pressure and pulse in supine and standing positions 3

• Respiratory examination:

  • Respiratory rate and pattern 1
  • Breath sounds: decreased, wheezing, crackles, or pleural rub 2
  • Listen for inspiratory stridor versus expiratory wheezing to differentiate exercise-induced laryngeal dysfunction from bronchoconstriction 3, 5
  • Accessory muscle use 1

• Cardiovascular examination:

  • Heart sounds for murmurs or gallops 3
  • Peripheral pulses 3

• Additional findings:

  • Digital clubbing (suggests interstitial lung disease or chronic hypoxemia) 2
  • Body mass index calculation 3
  • Signs of skeletal deformities or chest wall abnormalities 5

Functional Assessment

• Use the Modified Medical Research Council (mMRC) dyspnea scale to quantify the severity of functional impairment 1

• Assess the patient's ability to perform routine and desired activities of daily living as part of the initial evaluation 3

• For patients with suspected exercise-induced symptoms, use the Borg scale to rate baseline dyspnea and overall fatigue 3

Initial Laboratory and Diagnostic Testing

Order the following initial tests for all patients with unexplained shortness of breath:

• Complete blood count (to assess for anemia or infection) 3
• Basic metabolic panel including electrolytes, blood urea nitrogen, and serum creatinine 3, 2
• Arterial blood gas analysis in patients with suspected COPD exacerbation, those at risk for hypercapnic respiratory failure, or those with severe respiratory distress 3, 1
• Chest radiograph (PA and lateral) as the initial imaging study for all patients 3, 1
• 12-lead electrocardiogram 3

Additional testing based on clinical suspicion:

• Brain natriuretic peptide (BNP) if heart failure is suspected (helps exclude cardiac causes) 2
• D-dimer if pulmonary embolism is in the differential 2
• Spirometry for patients with risk factors for COPD or suspected airflow obstruction 1, 5
• Transthoracic echocardiography for suspected cardiac causes 1

Special Population Considerations

Women: Always consider cardiac causes, as women are at risk for underdiagnosis of cardiac pathology and may present with atypical symptoms 1

Elderly patients: Recognize that shortness of breath may present atypically with confusion, delirium, or falls rather than the classic complaint of breathlessness 1

Known COPD patients: Investigate when they report worsening breathlessness, especially with increased sputum production or change in sputum color 1

Patients with obesity, cystic fibrosis, chest wall deformities, neuromuscular disorders, or bronchiectasis: Require urgent investigation including blood gas analysis if dyspnea worsens 1

Critical Pitfalls to Avoid

• Do not administer high-concentration oxygen (>28% FiO2 or >2L/min via nasal cannula) to patients with COPD or those at risk of hypercapnic respiratory failure until arterial blood gas results are known 3, 1

• Do not use relief with nitroglycerin as a diagnostic criterion for myocardial ischemia 1

• Do not rely on patient history alone - symptoms may not correlate with the actual cause, as demonstrated by cases where presumed pneumonia or COPD exacerbation were actually foreign body aspiration 6

• Do not diagnose exercise-induced bronchoconstriction based on self-reported symptoms alone - objective testing with bronchoprovocation challenge is required 3, 5