09.04 Obstructive Heart (Cardiac) Defects

Hey guys, in this lesson we are going to talk about obstructive heart defects.

Obstruction usually happens because the blood vessel is narrow or stenosed. In the area before the stenosis there will increased pressure and in the area after the stenosis the pressure is decreased. This is important because it will help you think through what signs and symptoms to expect.

The first obstructive heart defect that we’re going to talk about is coarctation of the aorta and this is when there is a narrowing in the descending aorta after the subclavian artery. Because the stenosis happens after the subclavian artery this means that there’s going to be increase blood flow to the upper body and decrease blood flow to the lower body. And this explains the classic symptoms that we see with coarctation of the aorta which are high blood pressure and bound impulses in the upper extremities and low blood pressure and weak or absent pulses in the lower extremities. In older kids this can actually present as dizziness or even nosebleeds from the high blood pressure.

This diagnosis one of the reasons why it’s so important to make sure you always check peripheral pulses and compare them.

The next obstructive defect we going to talk about is Aortic Stenosis and this is when there is a narrowing at the aortic valve that is where the left ventricle meets the aorta. This stenosis is really going to decrease cardiac output and make the left side of the heart work extremely hard to get blood out into systemic circulation. Because blood has a difficult time leaving the left side of the heart it will back up into the pulmonary system causing pulmonary congestion.

The symptoms you are going to see with this are a murmur and then patients are show signs of having poor cardiac output, like weak pulses, low blood pressure and tachycardia because the heart is working extra hard. And as we’ve seen with all of these cardiac defects kids are going to have a difficult time feeding which can lead to failure to thrive.

Pulmonic stenosis is when there is a narrowing of the pulmonary valve. So thinking about the anatomy of the heart, this means pressure is going to be increased on the right side and decrease on the left.

The right side of the heart is going to have to work extra hard and you can end up systemic congestion and signs like peripheral edema.

These patients will have a murmur and they can be cyanotic if the stenosis is severe.

For therapeutic management one of the first things that we can do is administer prostaglandin E1. WE usually give this via IV infusion and what it does is it helps to keep that Ductus Arteriosus open which can help improve oxygenated blood flow while waiting for catheterization or surgery. This is usually done for patients with Coarctation of the Aorta.

Treatment for these obstructions is usually cardiac catheterization and surgery. With catheterization they may try a balloon angioplasty or valvuloplasty. If surgery is required they can perform a valve replacement or resection to remove the stenosed area.

Nursing care for a paediatric patient after cardiac surgery is all about decreasing that cardiac workload the heart can heal. So we really want to encourage rest and make sure the patient is not overworking with their feeds.
We also have to manage their pain and watch out for complications like hemorrhage, stroke and pneumothorax.

Your priority nursing concepts for a pediatric patient with an obstructive congenital heart defect are perfusion, oxygenation, and gas exchange.

Okay so let’s go over your key points for this lesson. We went over the obstructive heart effects. Obstruction means that there is a stenosed area which is blocking blood flow. Most of the time this happens at a valve and what it causes pressure changes in the heart. The pressure before the narrowing is increased and the pressure after is narrowing is decreased.

Coarctation of the Aorta is where there is a narrowing in the aorta after the subclavian artery. This causes increased pressure on the upper extremities and decrease pressure in the lower extremities. Always make sure to check femoral pulses so you can identify this problem.

Aortic Stenosis causes decreased cardiac output and increased work for the left ventricle.

Pulmonic stenosis causes decreased pulmonary blood flow and increased work for the right side of the heart which causes systemic congestion.

These defects are all going to require surgery to open up the stenosed area and restore blood flow!

That's it for our lesson on Obstructive Heart Defects. Make sure you check out all the resources attached to this lesson. Now, go out and be your best self today. Happy Nursing!