Emergency Medical Technician (EMT) Practice Test

What happens to pulse and blood pressure levels during inhalation in pulsus paradoxus?

1. Decrease

2. Increase

3. Remain constant

4. Vary unpredictably

The correct answer is: Decrease

During inhalation in the presence of pulsus paradoxus, the pulse and blood pressure levels typically decrease. Pulsus paradoxus is defined as an exaggerated drop in systemic blood pressure during inspiration, which is commonly observed in conditions like cardiac tamponade, severe asthma, or other forms of obstructive lung disease. When a person inhales, the diaphragm moves down, and the chest cavity expands, leading to a decrease in intrathoracic pressure. This negative pressure causes an increase in venous return to the right side of the heart. However, with certain pathologies, this increased return can lead to impaired filling of the left ventricle, resulting in a more significant drop in stroke volume and, consequently, blood pressure. As the blood pressure decreases during inhalation, you may also notice that the pulse pressure becomes narrower, and the heart rate could compensate, but overall, the significant point is that there is a decrease in both pulse and blood pressure during inhalation in cases of pulsus paradoxus. This response highlights the intricate relationship between respiratory mechanics and cardiovascular physiology in pathologic states.