The Rapid Ultrasound in Shock (RUSH) exam is used to help determine the etiology of medical shock.
There are four causes of shock: Hypovolemia, Cardiac, Distributive, and Obstructive.
Common causes of obstructive shock are: Tension Pneumothorax, Pericardial Tamponade, and Pulmonary Embolus.
An uncommon cause of obstructive shock is the abdominal compartment syndrome.
Another uncommon cause of obstructive shock is HOCM with SAM discussed briefly by Dr. Turner, Intensive Care Specialist from 28:50 to 30:50 in her YouTube video RUSH: Rapid Ultrasound in Shock, March 18, 2013. 35:31.
The echo shows a small LV and an enlarged septum especially proximally, with acute mitral regurgitation from systolic anterior motion of the anterior leaflet of the mitral valve. The lung scan shows pulmonary edema and the IVC scan shows a small collapsed IVC.
“So, in patients like this, often little old ladies who have long standing hypertension and who have gotten dehydrated; when they go into systole, the anterior leaflet of the mitral valve can become adherent to the septum. . . . at the beginning of systole, if you freeze the picture, the anterior leaflet of the mitral valve is suctioned against the septum which impairs the aortic outflow. And instead creates a situation where you have mitral regurgitation such as here.”
“These patients will often present hypotensive with pulmonary edema due to the mitral regurgitation. And the natural tendency, when you have a patient with pulmonary edema, is to give them Lasix. However, in this situation, this situation was set up because the patient was hypovolemic. And the walls of the chambers became too close during systole.”
“So the therapy for this type of pulmonary edema is to provide boluses of fluid until the walls of the septum and the anterior leaflet of the mitral valve do not approximate each other so closely. And therefore, the mitral regurgitation will go away.”
“This patient also showed diffuse pulmonary edema as seen in the right image and a completely collapsible IVC. And this is often the combination you’ll see [on the RUSH exam]. So any time you see a patient with pulmonary edema but other indications of hypovolemia, consider that they might have a situation of acute mitral regurgitation from this physiology.