Search results
Results from the WOW.Com Content Network
Patent ductus arteriosus (PDA) is a medical condition in which the ductus arteriosus fails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs from the aorta, which has a higher blood pressure, to the pulmonary artery, which has a lower blood pressure.
During fetal development, the ductus arteriosus is kept open by high levels of a vasodilator prostaglandin E2 which is made by the placenta and by the ductus arteriosus itself. At birth a bunch of things change, though—oxygen levels in the blood go up dramatically and the lungs become the main source of oxygenated blood.
In both conditions, the presence of a patent ductus arteriosus (and, when hypoplasia affects the right side of the heart, a patent foramen ovale) is vital to the infant's ability to survive until emergency heart surgery can be performed, since without these pathways blood cannot circulate to the body (or lungs, depending on which side of the ...
The ductus arteriosus, also called the ductus Botalli, named after the Italian physiologist Leonardo Botallo, is a blood vessel in the developing fetus connecting the trunk of the pulmonary artery to the proximal descending aorta. It allows most of the blood from the right ventricle to bypass the fetus's fluid-filled non-functioning lungs.
Some acquired shunts are modifications of congenital ones: a balloon septostomy can enlarge a foramen ovale (if performed on a newborn), PFO or ASD; or prostaglandin can be administered to a newborn to prevent the ductus arteriosus from closing. Biological tissues may also be used to construct artificial passages.
The severity of symptoms depends on the type of TGV, and the type and size of other heart defects that may be present (ventricular septal defect, atrial septal defect, or patent ductus arteriosus). Most babies with TGA have blue skin color (cyanosis) in the first hours or days of their lives, since dextro-TGA is the more common type.
Patent ductus arteriosus may present as a continuous murmur radiating to the back. Severe coarctation of the aorta can present with a continuous murmur. One may hear the systolic component at the left infraclavicular region and the back. This is due to the stenosis. One may hear the diastolic component over the chest wall.
For example, nitrate levels are subject to monitoring to comply with drinking water quality standards in the United States and other countries. [ 24 ] [ 25 ] The link between blue baby syndrome and nitrates in drinking water is widely accepted, but as of 2006 some studies indicated that other contaminants or dietary nitrate sources, might also ...