Rapid ultrasound in shock

The rapid ultrasound in shock (RUSH) protocol is a structured point-of-care ultrasound (POCUS) 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 hypovolemic, 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.

Protocol

The protocol 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 collapse with inspiration
  • internal jugular vein (IJV) volume
  • free fluid in pleural or peritoneal spaces
  • pulmonary edema
  • 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))

Findings

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 artifact in the lung due to pulmonary edema
• 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 fat IVC and IJV
• pleural empyema
• peritoneal fluid (peritonitis)