Pulmonary embolism is the obstruction of pulmonary arterial bed by dislodged thrombus, heart valve growth, or foreign substance. This is considered as the common pulmonary complication in hospitalized patients, usually fatal with massive embolism.
How does pulmonary embolism happen?
- Blood clot forms in the deep venous system
- Clot dislodges and travels through the systemic venous system, right chambers of the heart, and into the pulmonary circulation
- Clot lodges in a branch of the circulatory system
- Blood flow distal to obstruction is blocked
- Embolus prevents alveoli from producing enough surfactant to maintain alveolar integrity
- Alveoli collapse and atelectasis develops
- Large clot can cause tissue death.