Recommended initial investigations for a patient presenting with acute respiratory distress include:
- Measurement of oxygen saturation using pulse oximetry to assess hypoxia, ideally at rest and breathing room air.
- Chest X-ray to evaluate for lung pathology such as consolidation, pleural effusion, pneumothorax, or heart failure.
- Arterial blood gas analysis if oxygen saturation is low or if there is suspicion of respiratory failure, to assess oxygenation and carbon dioxide levels.
- Electrocardiogram (ECG) to exclude cardiac causes such as arrhythmia or acute coronary syndrome.
- Full blood count to identify infection or anaemia contributing to respiratory distress.
- Clinical examination including assessment of respiratory rate, use of accessory muscles, breath sounds, and signs of respiratory muscle weakness or airway obstruction.
Additional investigations may be guided by clinical suspicion, such as sputum culture if infection is suspected, spirometry if chronic obstructive pulmonary disease (COPD) or asthma is considered, and computed tomography (CT) of the chest if pulmonary embolism or other diagnoses are suspected.
Oxygen therapy should be administered according to oxygen saturation targets, with careful monitoring to avoid hypercapnia in at-risk groups such as COPD patients.
Referral for urgent hospital assessment is indicated if there are signs of severe respiratory distress, hypoxia, or other high-risk features.
These recommendations are based on UK clinical guidelines and expert consensus for the assessment of acute respiratory distress in primary care and hospital settings.
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