Undifferentiated Hypotension

Circulatory shock is hypoperfusion of end-organs due to an underlying illness and is frequently characterized by hypotension. Left untreated, circulatory shock results in rapid multi-organ failure, precipitous drop in blood pressure, and ultimately cardiac arrest. Shock is often categorized by its pathophysiologic etiology into distributive, obstructive, cardiogenic, and hypovolemic etiologies. While the history and physical exam can often point the clinician to the etiology of shock and guide empiric treatment successfully, it is unfortunately often insufficient in the rapid evaluation of shock, especially when the patient is quickly deteriorating. This chapter reviews the sonographic features of the various pathophysiologies of shock, codified in a scanning protocol known as the RUSH exam (Rapid Ultrasound in SHock). An intervention-based approach is then described, which integrates the pathophysiologic findings of the RUSH exam with the guidance of specific interventions which can be performed in a limited resource environment.