Initial Evaluation and Management of Difficulty Breathing

Immediate Assessment and Stabilization

The American College of Cardiology recommends targeting oxygen saturation of 94-98% for most patients using nasal cannulae at 2-6 L/min or simple face mask at 5-10 L/min 1
For patients with suspected COPD, consider a lower target oxygen saturation of 88-92% pending arterial blood gas results, then adjust to 94-98% if PCO2 is normal 1
Arterial blood gas analysis is mandatory to distinguish simple hypoxemia from hypercapnic respiratory failure 1
Recheck blood gases after 30-60 minutes of oxygen therapy 1
A chest radiograph must be obtained urgently to identify pneumonia, pulmonary edema, pleural effusions, pneumothorax, or lung masses 1
CT chest is superior to plain radiography for detecting pulmonary nodules if lung cancer is suspected 1

Assess smoking history and quantification, as tobacco smoke is by far the most important risk factor for COPD worldwide 2, 3
Evaluate symptom pattern, including chronic cough, sputum production, progressive dyspnea, wheezing, and chest tightness 4
Consider age and onset, as COPD typically presents in patients aged 25-75 years with insidious progression over years 2, 3
Assess cardiac risk factors, including age >65 years, orthopnea, history of myocardial infarction, hypertension, or atrial fibrillation 1
Evaluate acute features, such as new focal chest signs, fever >4 days, pulse >100, which may suggest pneumonia 1
Consider recent immobilization or DVT history, which may suggest pulmonary embolism 1

Measure respiratory rate, weight, height, and BMI in all patients 2, 3
Look for displaced apex beat, which may suggest cardiac dysfunction 1
Assess for signs of respiratory distress, use of accessory muscles, and pursed-lip breathing 2, 3
A normal physical examination does not exclude significant respiratory disease, particularly early COPD 2, 3, 4

Spirometry is required to make the diagnosis of COPD, with a post-bronchodilator FEV1/FVC <0.70 confirming persistent airflow limitation 4
BNP or NT pro-BNP levels <40 pg/mL (BNP) or <150 pg/mL (NT pro-BNP) make left ventricular failure unlikely 1
Consider echocardiography if cardiac dysfunction is suspected 1
CRP level >100 mg/L makes pneumonia likely, while <20 mg/L with symptoms >24 hours makes it highly unlikely 1

For COPD exacerbation, initiate or increase bronchodilators, such as β2-agonists and/or anticholinergics 6
For suspected heart failure, use diuretics, vasodilators, and oxygen therapy targeting 94-98% saturation 1
For suspected pneumonia, select antibiotics based on local resistance patterns, with broader coverage than simple amoxicillin for community-acquired pneumonia in elderly patients 1

Treating tobacco use should be regarded as a primary and specific intervention, with systematic assessment of tobacco use at every visit 2, 3
Advise strongly all tobacco users to quit in a clear, strong, personalized manner, and assist with quit plan, including practical counseling and approved pharmacotherapy 2, 3
Smoking cessation is the only intervention proven to reduce mortality and slow disease progression in COPD 2, 3