Pathophysiology

Question 1

Massive Pulmonary Embolism

Answer 1

Defn: Hypotension or SBP drop of 40 mmHg or requiring inotropic support in the context of PE.

PA x-sectional area decreases less than 30-50% of PA bed which then stimulates release of pulmonary vasoconstrictor (serotonin and thromboxane.)

• Thromboxane causes pulmonary hypertension.
• Increased RV afterload, RV failure
• Increased RV pressure/dilation pushes septum into LV causing LV diastolic dysfunction
• Lack of perfusion causes V/Q mismatch

Question 2

Acute Kidney Injury Cause on ECMO

Answer 2

Organ hypoperfusion and exacerbation of previous chronic kidney disease are most common.
Inflammatory effluent from lungs and other organs
Hemoglobinuria
Microemboli and mechanical shear stress of blood
Dysregulation of RAAS/ANP system