Expectant Management of Patent Ductus Arteriosus

Introduction:

Congenital heart diseases affect the structure of a baby's heart. It affects the blood flow and how it flows through the heart and the rest of the body. Congenital heart disease can be classified as severe or mild. Mild is like a small hole in the heart, or severe such as missing or poorly formed parts of the heart. In premature babies and stillborns, this incidence is more. There are three types of congenital heart disease, left-to-right shunt, right-to-left shunt, and obstructive congenital heart disease.

What Are the Basic Structure and Blood Supply of the Heart?

The heart's structure is explained below:

• Four chambers are present in the heart. The left and right atriums are the upper chambers, and the right and left ventricles are the lower chambers.

• The septum divides the left and right atria and the left and right ventricles.

• The aorta is a large vessel that delivers oxygen-rich blood to the body.

• The pulmonary vessels supply blood from the heart to the lungs. They carry oxygen-poor (deoxygenated) blood. The main pulmonary artery (pulmonary trunk) leaves your right ventricle at the pulmonary valve.

• It soon splits into your right and left pulmonary arteries, which carry blood to each lung.

What Is Ductus Arteriosis?

Ductus arteriosis is explained below:

• Shunt means blood from the right or left side of the heart is mixing pathologically. Under certain circumstances, we can see left through right shunt congenital heart disease.

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• Ductus arteriosis is a channel between the pulmonary trunk and the aorta.

• It affects how blood flows through a baby's lungs. The classic example of left to right shunt is patent ductus arteriosis. The major hemodynamic problem is the left-to-right shunt.

• During intrafetal life, the lungs do not work. The highly oxygenated atrial side of the blood is mixed with the less oxygenated venous side of the blood. At the bifurcation of the pulmonary artery, ductus arteriosis is located.

• When the baby is in the uterus, the baby will not breathe. So the lungs do not work because there is no oxygen going to the lungs. Since oxygen is the dilator for the blood vessels, the blood arteries become spastic (closed). The blood flows through the ductus arteriosis to reach the aorta and does not flow through the pulmonary artery. The pulmonary artery supplies the lungs.

• Hypoxia is a contributing factor for pulmonary arterioles. When the baby is in the uterus, the present pulmonary artery is constricted because there is no oxygen. During intrauterine life, there is no oxygen going through the lungs. The blood from the vena cava moves into the right atrium and to the right ventricle, and the blood then moves through the pulmonary artery; there is very high resistance in the pulmonary artery. During intrafetal life, nature does not want the blood to flow through the pulmonary artery because the placenta oxygenates this blood.

• During intrafetal life, the blood is not oxygenated by blood, and the placenta oxygenates it. The pulmonary arteries are constricted, and blood flows through the pulmonary artery and into the aorta, which is proximal to the origin of the subclavian artery.

• There is always a physiological hole between the left and right atrium. After the baby is born, the pulmonary vessels dilate, and the resistance falls into the pulmonary vasculature, so blood will start flowing through pulmonary arteries and eventually to the lungs.

• So, the blood flow through ductus arteriosis will reduce after birth. Secondly, prostaglandins (PGE2) play an important role in prenatal life because they open the ductus arteriosis.

• After PGE2 levels go down, the ductus arteriosis closes.

What Is Patent Ductus Arteriosis?

The pathological form of ductus arteriosis is explained below:

• Normally, in a healthy newborn, ductus arteriosis closes. But in some babies, it remains pathologically open. This pathological opening is called patent ductus arteriosis.

• Patent ductus arteriosis (PDA) is a heart defect that may develop soon after birth.

• If someone has patent ductus arteriosis, there is persistent blood flow through the aorta. The blood pressure in the aorta becomes very high. This is a classic example of well-oxygenated blood mixing with deoxygenated blood. This is another example of a functional left-to-right shunt.

• Patent ductus arteriosis is a vessel that connects the pulmonary artery at its bifurcation to the aorta.

• Whenever the right ventricle pumps blood into the pulmonary circulation, as lungs are not functional in babies, the blood goes to the right heart, through the pulmonary artery, through ductus arteriosis, and the aorta. Ductus arteriosis opens before birth.

• Ideally, after birth, the ductus arteriosis has to close. But if it does not close, it causes significant large cardiovascular problems. After it closes, fibrosis takes place. This fibrotic piece is called the ligamentous arteriosum in adults.

What Is the Treatment for Patent Ductus Arteriosis?

The following are the pharmacological treatment for patent ductus arteriosis:

• Medications help the closure of the patent ductus arteriosus.

• It is used in premature babies but not older children or adults. Ibuprofen inhibits the prostaglandins for closing the patent ductus arteriosis.

• Nonsteroidal anti-inflammatory drugs (NSAIDs) close the patent ductus arteriosis in premature babies and infants. Since the immature ductus is more sensitive to prostaglandin E2, Ibuprofen is used in preterm babies.

• Ibuprofen inhibits cyclooxygenase-1 and cyclooxygenase-2.

• These enzymes convert arachidonic acid to various prostaglandins. It inhibits prostaglandin synthesis.

• Ibuprofen is a protein-bound drug and the liver mainly metabolizes the drug, and 80 % of the dose is excreted in the urine as hydroxyl and carboxyl metabolites.

• Adverse events associated with ibuprofen include bleeding, skin irritation, hypoglycemia (decreased glucose level), hypocalcemia (decreased calcium level), adrenal insufficiency, respiratory failure, IVH (intraventricular hemorrhage), and renal insufficiency.

• The dose for treating PDA with Ibuprofen mainly consists of three doses.

• The recommended initial dose is 10 milligrams per kilogram intravenously.

• This is followed by two doses of five milligrams per kg 24 and 48 hours later.

• If the urine output is less than 0.6 milliliters per kilogram per hour, subsequent doses are held until renal functions are normal.

• A second dose of ibuprofen is given when the ductus arteriosis fail to close re reopens later.

• The concentration of Ibuprofen available is lysine is 17.1 milligram per milliliter (equivalent to 10 milligram per milliliter ibuprofen).

• Each single-use vial contains two milliliters of sterile solution. Vials are stored at room temperature (20 to 25 degrees Celsius) and protected from light.

• Ibuprofen is used within 30 minutes of preparation. The dose is infused over 15 minutes continuously. It is not administered in the same intravenous line with total parenteral nutrition.

Conclusion:

About one percent of live birth are born with CHDs. Babies with CHD require surgery or other procedures in the initial year of life. Congenital heart diseases are diseases in the heart and great vessels. Approximately every one percent of the child in hundred life births has congenital heart disease. With proper medication and surgery, this disease can be cured.