Massive Pulmonary Embolism and Response to Fluids and Mechanical Ventilation

Massive pulmonary embolism leads to acute pulmonary hypertension and right ventricular overload. This leads to release of troponin and a "bowing" of the interventricular septum on echocardiography. Deviation of the septum then leads to a decrease in left-sided cardiac output. 

A few interesting clinical pearls:

• Administration of IV fluids to patients with massive PE often leads to a decrease in BP. This happens as a result of increasing preload causing further bowing of the septum and a subsequent further drop in left ventricular cardiac output, leading to hypotension. 
• Patients with massive PE who require intubation often demonstrate an increase in BP due to positive pressure ventilation causing a drop in preload and a reduction of septal bowing into the left ventricle.