Rapid ultrasound in shock

The Rapid ultrasound in shock (RUSH) protocol is a structured point-of-care ultrasound examination performed at the time of presentation of a shocked patient. It is a more detailed and longer exam than the FAST scan, with the aim to differentiate between hypovolaemichypovolemic, cardiogenic, obstructive and distributive shock.

It is invariably performed by a clinician, who should be formally trained, and can be considered as an 'extension' of the shock clinical assessment process, to aid rapid decision making.

The protocol ¹ includes assessment of the 'pump, tank and pipes':

• the pump: the heart
  • pericardial effusion
  • signs of tamponade
  • left ventricular (LV) contractility
  • signs of right ventricular (RV) strain
• the tank: the lungs
  • inferior vena cava (IVC) volume and collpasecollapse with inspiration
  • internal jugular vein (IJV) volume
  • free fluid in pleural or peritoneal spaces
  • pulmonary oedema
  • tension pneumothorax
• the pipe: the vessels
  • abdominal aortic aneurysm (AAA) or dissection
  • thoracic aortic aneurysm or dissection
  • lower limb deep vein thrombosis (DVT) (as a source of pulmonary embolus (PE))

Features seen in hypovolemic shock include:

• hypercontractile heart
• small heart size
• flat IVC and IJV
• pleural or peritoneal blood
• ruptured AAA
• aortic dissection

Features seen in cardiogenic shock include:

• hypocontractile heart
• dilated heart size
• distended IVC and IJV
• lung rockets (B-line): echogenic fan pattern of artifactartefact in the lung due to pulmonary oedema
• pleural or peritoneal fluid (effusions, ascites)

Features seen in obstructive shock include:

• pericardial effusion
• RV strain
• hypercontractile heart
• distended IVC and IJV
• pneumothorax
• DVT

Features seen in distributive shock include:

• hypocontractile heart (in late sepsis)
• hypercontractile heart (in early sepsis)
• normal or falt IVC and IJV
• pleural empyema
• peritoneal fluid (peritonitis)

Reference and inspiration courtesy of Dr Frances EM Williamson, a sonographically trained emergency physician.