What is defined as a decrease in systolic pressure by 10 mm Hg or more during inspiration?

Pulsus paradoxus is characterized by a decrease in systolic blood pressure of 10 mm Hg or more during inspiration. This phenomenon occurs due to changes in intrathoracic pressure during the respiratory cycle, leading to decreased venous return to the heart and reduced stroke volume. In conditions such as cardiac tamponade, severe asthma, or chronic obstructive pulmonary disease (COPD), this decrease may become more pronounced, indicating a significant physiological process at play.

Understanding pulsus paradoxus is important in critical care settings because it can be a clinical sign of underlying pathologies that may require immediate attention. Recognizing this phenomenon can aid in the diagnosis and management of patients experiencing respiratory or cardiac distress.