What investigations are essential in the primary care setting to confirm the diagnosis of obstructive shock?

Essential investigations in primary care to confirm obstructive shock include:

• Clinical assessment: A detailed history and physical examination to identify signs of shock and potential causes such as pulmonary embolism or cardiac tamponade are critical first steps.
• Chest X-ray: To exclude other causes of shock such as pneumothorax, pneumonia, or pulmonary oedema, and to identify signs suggestive of obstructive causes like a widened mediastinum or pleural effusion.
• Electrocardiogram (ECG): To detect signs of right heart strain or ischaemia that may suggest pulmonary embolism or cardiac causes.
• D-dimer test: If pulmonary embolism is suspected and the clinical probability is low to moderate, a D-dimer test can be used to rule out PE in primary care, ideally using a quantitative or age-adjusted test.
• Point-of-care ultrasound (if available): To assess for pericardial effusion, right ventricular dilation, or pneumothorax, which are causes of obstructive shock.

Definitive imaging such as CT pulmonary angiography or echocardiography is usually required but typically performed in secondary care settings. However, initial investigations in primary care focus on clinical assessment, chest X-ray, ECG, and D-dimer to guide urgent referral and management NICE NG158,NICE CG95.