Chapter 26: Patent Ductus Arteriosus (PDA) (Children)

Question 1

Patent Ductus Arteriosus (PDA)

Answer 1

acyanotic

• left-to-right shunting
• A condition where a temporary vessel (ductus arteriosus) between the two major blood vessels leading from the heart fail to close after birth
• defect occurs alone or in combination with coarctation of the aorta

Question 2

Normal Development of Ductus Arteriosus

Answer 2

the ductus arteriosus is a normal structure during fetal life
-in utero, the pulmonary resistance is high because the lungs are filled with fluid rather than air. The blood is oxygenated through the placenta by the umbilical vein. Instead of the blood flowing from the pulmonary artery to the lungs, the ductus is a “pop-off” valve for the large volume of fluid; as blood flow follows the “path of least resistance,” the blood moves through the ductus, into the aorta, and out of the body tissues; directly after birth and the baby’s first breaths, the pulmonary resistance drops and the blood flows from the pulmonary artery into the lungs; because there is a decreased flow through the PDA, the duct starts to close (changes in prostaglandin level assist in closure)
-in 8-10% of the population, the PDA remains open; it can take as long as 1 year for the PDA to close completely; the pediatric cardiologist monitors the asymptomatic child up to 1 year for spontaneous closure of the PDA
>if a large PDA is not closed, severe long term sequalae may ensue

Question 3

When the Large PDA does not close

Answer 3

at birth the pulmonary resistance is higher than the left sided pressures
-as this gradient reverses, the left-sided pressure forces blood toward the right side through the PDA; eventually the fluid congests the right side of the heart and pulmonary bed; the right ventricle hypertrophies as it attempts to mobilize fluid forward

Question 4

Signs and Symptoms

Answer 4

> the PDA murmur is distinctive in sound and location
-best heard at the left subclavicular margin
-described as machine like, to and fro, or continuous
frequent colds
susceptibility to respiratory syncytial virus
-fatigue
-poor feeding
-poor growth pattern
-blood pressure reveals a wide pulse pressure

Question 5

Diagnosis

Answer 5

• presence of the characteristic machine-like murmur under the left clavicle along with symptoms of heart failure
• chest radiograph shows an enlarged heart and evidence of an excessive blood flow to the lungs
• echocardiogram confirms the diagnosis, demonstrating the size of the ductus arteriosus and enlargement of heart chambers because of the extra blood flow

Question 6

Nursing Care

Answer 6

focuses on post-surgical measures such as wound care, monitoring vital signs, and ensuring adequate hydration and nutrition
>if closed with a transcatheter device, monitor for signs of migration; if dislodges, the child will suddenly have a wide pulse pressure; cardiac interventionalist is notified for further actions

Question 7

Medical Care

Answer 7

PDA may be closed surgically or with a transcatheter device

-may also be closed with medication indomethacin (Indocin)

Question 8

indomethacin (Indocin)

Answer 8

a medication that may be used to close the PDA

Question 9

What will happen if the transcatheter device used to closed the PDA dislodges?

Answer 9

the child will suddenly have a wide pulse pressure (difference between diastolic and systolic pressure)
-cardiac interventionalist is notified for further actions