Blood Pressure Left Leads Systolic Side Heart Filling

 ________ of  ____   ________ and  ________ leads to characteristic  ________ sign

on x-ray. 

Severe croup can result in  ________  ________ 2° to upper airway obstruction.

"is defined as an exaggeration (more than 10 torr) of the normal variation during the inspiratory phase of respiration, in which the blood pressure declines as one inhales and increases as one exhales. It is a sign that is indicative of several conditions including cardiac tamponade, pericarditis, chronic sleep apnea, croup, and obstructive lung disease 

Normally during inspiration, systolic blood pressure decreases ≤10 mmHg, and pulse rate goes up slightly. This is because the intrathoracic pressure becomes more negative relative to atmospheric pressure. This increases systemic venous return, so more blood flows into the right side of the heart. **However, the decrease in intrathoracic pressure also expands the compliant pulmonary vasculature. This increase in pulmonary blood capacity pools the blood in the lungs, and decreases pulmonary venous return, so flow is reduced to the left side of the heart. Also the increased venous return to the right side of the heart expands the right heart and directly compromises filling of the left side of the heart. Reduced left-heart filling leads to a reduced stroke volume which manifests as a decrease in systolic blood pressure. The decrease in systolic blood pressure leads to a faster heart rate due to the baroreceptor reflex, which stimulates sympathetic outflow to the heart.

an increase in right ventricular filling pressures because of increased volume and stretch, leading to a bulging of the intraventricular septum towards the left ventricle, thus decreasing the left ventricular size and filling volume due to this protrusion. Thus, there is a subsequently decreased left sided stroke volume and therefore a lower systolic blood pressure."