What is the appropriate initial assessment, diagnostic work‑up, and treatment plan for an adult patient presenting with acute shortness of breath?

Initial Management of Acute Shortness of Breath in Adults

For an adult presenting with acute dyspnea, immediately assess oxygen saturation and target SpO2 88-92% with supplemental oxygen, obtain vital signs including respiratory rate and heart rate, perform focused physical examination for accessory muscle use and auscultation, and obtain chest X-ray, ECG, and arterial blood gas if SpO2 <92%. 1

Immediate Clinical Assessment (First 15 Minutes)

Vital Signs and Oxygen Management

• Check pulse oximetry immediately - if SpO2 <92% on room air, initiate supplemental oxygen to achieve target saturation of 88-92% 1
• Avoid high-flow oxygen (>6 L/min) when possible to reduce aerosol generation risk; use standard low-flow systems with air-entrainer and Ventimask to provide 30-40% oxygen 1
• Obtain arterial blood gas if oxygen saturation <92% to assess acid-base status and PaCO2 1

Focused Physical Examination

• Assess work of breathing: look for accessory muscle use, chest retractions, respiratory rate, and ability to speak in full sentences 1
• Auscultate lungs for wheezing, crackles, or decreased breath sounds 1
• Check for signs of respiratory failure: drowsiness is a critical predictor of impending respiratory failure and warrants immediate consideration for ventilatory support 1
• Evaluate for other organ dysfunction and relevant comorbidities (cardiac disease, diabetes, neuromuscular disease) 1

Diagnostic Work-Up

Essential Initial Tests

• Chest X-ray to identify pneumonia, pulmonary edema, pneumothorax, or pleural effusion 1
• ECG to evaluate for cardiac ischemia or arrhythmia 1
• Laboratory tests: complete blood count, electrolytes, renal function, liver function tests, lactate dehydrogenase, creatinine kinase, and C-reactive protein 1
• Point-of-care ultrasonography (POCUS) when added to standard diagnostic pathway significantly improves diagnostic accuracy for heart failure, pneumonia, pulmonary embolism, pleural effusion, and pneumothorax 1

Spirometry for Suspected Obstructive Disease

• For suspected asthma exacerbation: measure FEV1 or peak expiratory flow (PEF) immediately 1
• Classify severity: FEV1/PEF ≥40% = mild-to-moderate; <40% = severe exacerbation 1
• Repeat lung function measures at 1 hour after initial treatment - this is the strongest single predictor of hospitalization need 1

Initial Treatment Based on Clinical Presentation

For Suspected Asthma/COPD Exacerbation

• Inhaled short-acting beta-agonist (SABA) by nebulizer or MDI with valved holding chamber every 20 minutes for first hour 1
• Add ipratropium bromide to SABA for moderate-to-severe exacerbations 1
• Oral or IV corticosteroids immediately if no response to initial bronchodilator or if patient recently used systemic steroids 1
• Consider adjunctive IV magnesium sulfate if FEV1/PEF remains <40% after initial treatment 1

For Suspected Acute Hypercapnic Respiratory Failure

• Non-invasive ventilation (NIV) is the primary intervention when pH <7.35 and PaCO2 elevated 1
• Ensure NIV-experienced clinician involvement and ICU consultation for high-risk patients 1
• Document clear care plan including escalation criteria for intubation and mechanical ventilation 1

For Suspected Pneumonia/Infection

• Administer antibiotics promptly: IV co-amoxiclav 1.2g TDS or cefuroxime 1.5g TDS plus erythromycin 500mg QDS or clarithromycin 500mg BD 1
• Provide IV fluids as needed for adequate hydration 1

Reassessment and Disposition (1-4 Hours)

Criteria for Hospital Admission

• Persistent severe exacerbation: FEV1/PEF <40% after 1-3 hours of treatment 1
• Inadequate response to initial therapy with ongoing respiratory distress 1
• High-risk features: drowsiness, inability to complete sentences, persistent tachypnea, or accessory muscle use 1
• Hypoxemia requiring ongoing supplemental oxygen 1

Discharge Planning for Improved Patients

• Continue inhaled SABA and complete course of oral corticosteroids 1
• Consider initiating inhaled corticosteroids if not already prescribed 1
• Schedule follow-up within 1-4 weeks with primary care provider or specialist 1
• Review inhaler technique and provide written action plan 1

Critical Pitfalls to Avoid

• Do not delay NIV in hypercapnic respiratory failure - early initiation improves outcomes and reduces mortality 1
• Do not use abdominal thrusts or back blows unless foreign body airway obstruction is suspected - these maneuvers can cause harm and delay appropriate treatment 1
• Do not withhold oxygen from hypoxemic patients due to concerns about CO2 retention - target SpO2 88-92% is safe 1
• Do not discharge patients with persistent abnormal vital signs or inadequate response to treatment without senior consultation 1
• Ensure ICU consultation for patients at risk of requiring intubation rather than waiting for NIV failure 1