Context

Shock is a state of circulatory dysfunction causing reduced tissue perfusion and metabolic upset. It is commonly encountered in the emergency department and mortality in non-traumatic shock can be as high as 25% (2)

Shock can be classified as (1):

• Hypovolaemic or haemorrhagic
• Distributive (sepsis, anaphylaxis, neurogenic)
• Cardiogenic
• Obstructive (pneumothorax, massive pulmonary embolism, cardiac tamponade)

Diagnosing the aetiology of shock in a patient can be challenging, as many causes share a similar clinical picture. 

A recent study has shown adding point-of-care ultrasound (POCUS) to the clinical assessment increases diagnostic accuracy for the aetiology of shock from 45% to 89%. (2)

Another study showed early use of POCUS in patients with hypotension accurately guided diagnosis, significantly reduced diagnostic uncertainty, and substantially changed management and resource utilization in the emergency department. (3)

The Rapid Ultrasound for Shock and Hypotension (RUSH) protocol is commonly used to assist the emergency physician in diagnosing the aetiology of shock in a rapid but systematic manner.