Pulsus Paradoxus

Excerpt

Pulsus paradoxus is an exaggerated drop in a patient’s blood pressure by more than 10 mmHg during inspiration. Pulsus paradoxus arises from changes in the mechanical forces imposed on the chambers of the heart and pulmonary vasculature. These changes are often due to pericardial diseases, particularly cardiac tamponade and, to a lesser degree, constrictive pericarditis. However, it is important to understand that pulsus paradoxus may be observed in non-pericardial cardiac diseases such as right ventricular myocardial infarction and restrictive cardiomyopathy. In addition, noncardiac disease states, including pulmonary diseases such as severe chronic obstructive pulmonary disease, asthma, tension pneumothorax, large bilateral pleural effusions, and pulmonary embolism, and any condition that causes cardiac compression such as iatrogenic injuries during surgery, marked obesity, and pectus excavatum, can occasionally lead to pulsus paradoxus. Finally, pulsus paradoxus may also manifest secondary to severe hypovolemic shock.

Recognizing pulsus paradoxus early in the emergency department can help diagnose cardiac tamponade rapidly. The measurement of pulsus paradoxus is also helpful in assessing the severity of acute asthma and its response to therapy. In addition, noninvasive devices are now available to measure variations in arterial pressure, improving the assessment of pulsus paradoxus at the bedside.