What is the appropriate emergency department management for a stable adult presenting with acute unexplained shortness of breath?

Emergency Department Management of Stable Adult with Acute Unexplained Shortness of Breath

Immediate Assessment (First 60 Seconds)

Begin with rapid assessment of airway, breathing, and circulation while simultaneously measuring oxygen saturation and vital signs to identify life-threatening conditions before proceeding with diagnostic workup. 1, 2

Primary Survey

• Check responsiveness by tapping shoulders and asking "Are you all right?" to confirm the patient is conscious and stable 1, 2
• Assess breathing pattern by looking for chest rise, listening for breath sounds, and feeling for air movement—note that occasional gasps do not count as normal breathing 1, 2
• Measure oxygen saturation immediately using pulse oximetry along with respiratory rate, heart rate, and blood pressure 2
• Auscultate breath sounds bilaterally to detect unilateral absence (suggesting pneumothorax, effusion, or consolidation) 3

Oxygen Therapy

Initiate supplemental oxygen based on saturation targets, using 94-98% for most patients but 88-92% for those at risk of hypercapnic respiratory failure (COPD, obesity hypoventilation). 2

• For patients without COPD risk: Start nasal cannula at 1-4 L/min or simple face mask at 5-10 L/min targeting 94-98% saturation 2
• For patients with COPD or hypercapnic risk: Use controlled oxygen via Venturi mask at 24-28% targeting 88-92% saturation 2
• Document oxygen saturation, delivery system, and flow rate on monitoring charts and reassess frequently 2

Positioning and Non-Pharmacological Interventions

Position the patient upright at 45-90 degrees and have them lean forward with arms bracing to optimize ventilatory mechanics. 2

• Sit patient upright to increase peak ventilation and reduce airway obstruction 2
• Have patient lean forward with arms bracing a chair or knees with upper body supported to improve ventilatory capacity 2
• Teach pursed-lip breathing: Inhale through nose for several seconds, then exhale slowly through pursed lips for 4-6 seconds 2
• Instruct patient to relax shoulders to reduce the hunched posture associated with anxiety 2

Diagnostic Testing for Cardiac vs Non-Cardiac Causes

Obtain BNP or NT-proBNP measurement to differentiate heart failure from non-cardiac causes, using a cutoff of 100 pg/mL for BNP (sensitivity 96%, specificity 61%) or age-adjusted cutoffs for NT-proBNP. 4

BNP Interpretation

• BNP < 100 pg/mL: Heart failure highly unlikely (negative predictive value 96%) 4
• BNP 100-500 pg/mL: Intermediate probability, consider alternative diagnoses 4
• BNP > 500 pg/mL: Heart failure likely, proceed with heart failure management 4

NT-proBNP Interpretation (Age-Adjusted)

• Age < 75 years: Use cutoff of 125 pg/mL (sensitivity 94%, specificity 46%) 4
• Age ≥ 75 years: Use cutoff of 450 pg/mL (sensitivity 94%, specificity 46%) 4
• Optimal cutoff 1,500 pg/mL for elderly patients with severe dyspnea (sensitivity 75%, specificity 76%) 4

Additional Diagnostic Tests

• Chest X-ray to identify pneumonia, pneumothorax, pleural effusion, or pulmonary edema 5, 6
• ECG to detect acute coronary syndrome, arrhythmias, or signs of right heart strain 5
• Complete blood count to assess for anemia or infection 6
• Arterial blood gas if hypercapnia or severe hypoxemia suspected 5

Differential Diagnosis Considerations

Systematically consider cardiac (heart failure, ACS), pulmonary (pneumonia, COPD, asthma, PE), and other causes (anemia, metabolic acidosis, anxiety) based on clinical presentation and initial testing. 5, 6

Cardiac Causes

• Acute heart failure: Elevated BNP/NT-proBNP, pulmonary edema on chest X-ray, elevated jugular venous pressure 4
• Acute coronary syndrome: Chest pain, ECG changes, elevated troponin 5

Pulmonary Causes

• Pneumonia: Fever, productive cough, consolidation on chest X-ray 5, 6
• COPD exacerbation: History of smoking, wheezing, prolonged expiratory phase 7
• Asthma: Wheezing, response to bronchodilators, history of asthma 7
• Pulmonary embolism: Sudden onset, pleuritic chest pain, risk factors for thrombosis 6
• Pneumothorax: Unilateral absent breath sounds, hyperresonance to percussion 3

Other Causes

• Anemia: Pallor, fatigue, low hemoglobin 6
• Metabolic acidosis: Kussmaul breathing, diabetic ketoacidosis, renal failure 5

Monitoring and Reassessment

Continuously monitor oxygen saturation, respiratory rate, heart rate, and blood pressure, and reassess every 15-30 minutes or sooner if clinical deterioration occurs. 2

• Record vital signs and oxygen requirements on monitoring charts 2
• Seek immediate medical consultation if: Patient requires increasing oxygen therapy, National Early Warning Score (NEWS) is rising, or signs of respiratory deterioration are present 2
• Prepare for escalation to non-invasive ventilation or intubation if respiratory distress worsens despite initial interventions 7

Common Pitfalls to Avoid

• Do not assume relief with oxygen rules out serious causes—continue systematic evaluation even if initial oxygen improves symptoms 3
• Do not delay BNP measurement—it significantly reduces time to discharge, need for ICU admission, and overall cost of treatment in patients with acute dyspnea 4
• Do not use bilateral carotid pulse checks—this wastes time and is not supported by resuscitation guidelines 1
• Do not overlook tension pneumothorax—if unilateral absent breath sounds with hemodynamic instability, prepare for needle decompression even in "stable" patients who may decompensate rapidly 3