What is the initial management of a patient presenting with shortness of breath (SOB)?

Initial Management of Shortness of Breath

Immediate ABC Assessment and Vital Signs

Begin with airway, breathing, and circulation assessment, followed immediately by pulse oximetry, respiratory rate, heart rate, and blood pressure measurement 1, 2. This initial assessment takes priority over detailed history-taking in acute presentations 1.

• Pulse oximetry must be available and measured in all patients with breathlessness 1, 2
• Record respiratory rate and heart rate as these are more sensitive indicators of physiologic distress than oxygen saturation alone 2
• Obtain a 12-lead ECG urgently, even when oxygen saturation is normal, as breathlessness with tachycardia may indicate acute myocardial infarction, arrhythmia, or pulmonary embolism 2
• Measure blood pressure to assess for hemodynamic instability 1

Oxygen Therapy Algorithm

The decision to administer oxygen depends entirely on measured oxygen saturation:

For SpO2 ≥94%: Do NOT routinely administer oxygen 1, 2. Supplemental oxygen is not indicated when saturation is within normal range and may delay recognition of respiratory failure 1.

For SpO2 88-93%: Target saturation 94-98% in most patients 1:

• Start oxygen at 2-6 L/min via nasal cannulae or 5-10 L/min via simple face mask 2
• Exception: For patients at risk of hypercapnic respiratory failure (COPD, cystic fibrosis, neuromuscular disease, chest wall deformities, morbid obesity), target 88-92% 1, 3

For SpO2 <85%: Initiate high-flow oxygen at 15 L/min via reservoir mask immediately 2.

Critical Caveat for COPD Patients

• If COPD is known or suspected, use controlled oxygen therapy targeting 88-92% saturation 1
• Use 28% or 24% Venturi mask or 1-2 L/min nasal cannulae 1
• Monitor for hypercapnia with arterial blood gases within 30-60 minutes 1
• Never abruptly stop oxygen once started, as this causes life-threatening rebound hypoxemia 1

Non-Pharmacological Interventions (Initiate Immediately)

These should be offered before or alongside pharmacological treatment:

• Position patient upright or in coachman's seat to optimize ventilation 1, 2
• Use a hand-held fan directed at the face as first-line treatment when oxygen saturation is normal 3
• Open windows, use small ventilators for cooling effect 1
• For pregnant women >20 weeks gestation: use full left lateral position to avoid aortocaval compression 1, 3
• Provide reassurance and education to reduce anxiety and panic 1, 2

Immediate Diagnostic Workup

While stabilizing the patient, obtain:

Essential immediate tests:

• 12-lead ECG to exclude acute coronary syndrome, arrhythmia, or findings suggestive of pulmonary embolism 1, 2
• Chest X-ray (if patient stable enough) 1
• Arterial blood gas if clinical concern about hypercapnia or if patient appears more unwell than SpO2 suggests 1, 3

Additional tests based on clinical context:

• Cardiac troponin if chest pain present or ECG abnormal 2
• Complete blood count, electrolytes, creatinine 1
• Brain natriuretic peptide if heart failure suspected 1
• Peak expiratory flow if asthma suspected 1

Disease-Specific Pharmacological Management

For Suspected Asthma/COPD Exacerbation:

• Administer nebulized albuterol 2.5 mg (one 3 mL vial of 0.083% solution) via nebulizer over 5-15 minutes 4
• Can repeat three to four times daily as needed 4
• Add ipratropium bromide for COPD 1
• Consider systemic corticosteroids (typically 7-day course) 1

For Suspected Cardiac Etiology with Chest Pain:

• Administer morphine 4-8 mg IV with additional 2 mg doses at 5-15 minute intervals until pain relieved 1, 2
• Give antiemetic concurrently (metoclopramide 5-10 mg IV) 2
• Nitroglycerin reduces myocardial oxygen demand and should be considered 1

For Palliative Care/Advanced Cancer:

• Low-dose opioids are the only pharmacological agents with sufficient evidence for palliation of dyspnea 1, 3
• Oral or parenteral morphine can be used without causing clinically significant respiratory depression 1
• Manage constipation prophylactically 1

Continuous Monitoring Requirements

• Continuous pulse oximetry until patient is stable 1
• Continuous ECG monitoring during emergency department evaluation to detect arrhythmias 1
• Reassess respiratory rate frequently—rate >30 breaths/min requires immediate escalation even with adequate SpO2 2
• Repeat arterial blood gases in 30-60 minutes if oxygen therapy initiated or clinical deterioration occurs 2, 3

Red Flags Requiring Immediate Escalation

• Respiratory rate >30 breaths/min 2
• SpO2 <85% despite oxygen therapy 2
• Altered mental status 1
• Hemodynamic instability 1
• pH <7.26 on arterial blood gas (indicates severe respiratory acidosis) 1
• Failure to respond to initial bronchodilator therapy within expected timeframe 4

Common Pitfalls to Avoid

• Do not assume hyperventilation is anxiety-related without excluding pulmonary embolism, acute coronary syndrome, and other life-threatening causes 5
• Do not give high-flow oxygen to patients with known or suspected COPD without controlled titration 1
• Do not continue oxygen therapy in non-hypoxemic patients without documented benefit 3
• Do not delay obtaining ECG while waiting for other tests 2
• Consider foreign body aspiration in patients with persistent wheezing not responding to standard therapy 6