What is pulsus paradoxus?

Pulsus paradoxus refers to a significant drop in blood pressure during inhalation, which is often characterized by variation in the pulse pressure and blood pressure with respirations. This phenomenon is clinically observed when the difference in blood pressure during expiration and inspiration exceeds 10 mmHg. It usually indicates certain medical conditions, such as cardiac tamponade, severe asthma, or chronic obstructive pulmonary disease (COPD), where the dynamics of heart and lung interaction are disturbed.

The correct answer accurately describes the essence of this physiological phenomenon, highlighting the relationship between respiration and cardiovascular parameters. Understanding pulsus paradoxus is crucial for respiratory care professionals, as it can provide critical insight into a patient's hemodynamic status and respiratory function.