Generic Investigations
All patients in respiratory distress require:
- Pulse oximetry
- Chest radiography
- ECG
- ABG
- Consideration of ancillary investigations
Indications listed below.
Generic investigations are outlined as follows:
| Test | Comment |
| Pulse oximetry | Essential in all patients presenting with dyspnoea
Determine degree of hypoxia Determine need for, and response to, oxygen supplementation |
| Arterial blood gases | Essential in all patients with respiratory distress
Essential in all patients with suspected metabolic disturbance Accurate determination of acid/base status Accurate determination of O2/CO2 status Determination of metabolic or respiratory/acidosis or alkalosis Determination of Alveolar-arterial (A-a) gradient Determines the need for supplemental oxygen or ventilatory support Determines response to supplemental oxygen or ventilatory support |
| CXR | Essential in all patients with respiratory distress of possible cardiorespiratory aetiology
To support clinical diagnosis (e.g. pneumonia) To quantify severity of pathology (e.g. pulmonary oedema, effusion) To exclude certain pathologies (e.g. pneumothorax) Generically if diagnosis uncertain (e.g. COPD vs LVF) |
| ECG | Essential in all patients with respiratory distress associated with ischaemic pain acute coronary syndrome (ACS) or other possible cardiac pathology
To determine presence of right ventricular strain in patients with possible pulmonary embolism or pulmonary hypertension |
Each test is discussed on the next four pages.