How does pulmonary embolus interferes with respiratory function?

Blood supply loss: A pulmonary embolus is mostly when a blood clot from the lower part of the body, gets loose, passes through the right side of the heart and lodges in one of the pulmonary arteries cutting off circulation to that part of the lung. This causes respiratory distress in relationship to how much of the blood supply is affected. This is an emergency and you should go to an er pronto.

Blocks blood: The pulmonary embolus blocks blood flow through the lungs, so blood cannot pick up oxygen or cannot be pumped through the lung. The bigger the embolus, the bigger the problem. Patients can die from a big enough embolus, such as a saddle embolus which blocks blood flow to both lungs at the same time.