What is the most common sign associated with pulmonary embolism?

Tachypnea is the most common sign associated with pulmonary embolism due to the body's response to decreased oxygenation and impaired blood flow within the pulmonary circulation. When a pulmonary embolism occurs, it obstructs blood flow to a portion of the lungs, leading to ventilation-perfusion mismatch and potential hypoxia. In reaction to this situation, the respiratory rate increases as the body attempts to compensate for the reduced oxygen levels, resulting in tachypnea.

This rapid breathing is a compensatory mechanism that reflects the pulmonary distress associated with the embolism. While other signs and symptoms such as chest pain, hemoptysis, or syncope may also be present, tachypnea stands out as the most prevalent clinical finding in patients with pulmonary embolism.