In this edition of our pediatric nursing lecture, we’ll be focusing on the different congenital heart defects that are experienced by pediatric infant clients.
It is advisable that you have a strong background regarding the different cardiac conditions for adults in your medical-surgical nursing. If not, you’ll find this subject a bit complicated because not only is this going to focus on the anatomy and physiology of proper cardiac blood flow but also the different structural issues that arise with pediatric clients.
We’ll make this overview quick and straightforward. Let’s begin.
Anatomy and Physiology
First off, we’ll get a brief rundown of the normal physiology of the lungs and heart. So, what are the important pointers that you have to take note of?
- The right side of the heart (right atrium and right ventricle) – pumps deoxygenated blood into the pulmonary arteries to become re-oxygenated. The hemoglobin in red blood cells are the carriers of oxygen.
- The left side of the heart (left atrium and left ventricle) – receives oxygenated blood from the lungs. The left atrium pumps oxygenated blood through the left ventricle (preload) then, the left ventricle forcefully contracts to squeeze oxygenated blood into the aorta to be distributed to the rest of the body.
So, this how the heart and lungs work together to provide a sufficient amount of oxygen to the different parts of the body.
Arteries vs. Veins
One of the major confusions that students usually encounter when it comes to the heart and lungs is differentiating between arteries and veins.
To easily remember which does what, here’s a trick:
- Arteries – away from the heart
- Veins – vacuums back blood to the heart
So, you would notice that “arteries” and “away” both start with “a,” while “veins” and “vacuums back” both start with “v.”
Remember, arteries carry oxygenated blood away from the heart to be distributed to the whole body, while the veins vacuum blood back to the heart to receive oxygen.
This concept is also applied to pulmonary arteries and veins. Pulmonary arteries push blood away, and it really doesn’t matter if the blood is oxygenated or de-oxygenated. And the pulmonary veins will pull blood back into the heart.
Right and Left-Sided Pathophysiology
Normally, the right side of the heart pushes blood into the lungs. However, in cases of fibrosis or stiff lungs, there will be a backing-up of blood that can lead to right-sided heart failure. One prominent manifestation would be edema.
On the other hand, if the body is already experiencing fluid overload or edema, blood will go back up into the left side of the lung which will cause left-sided heart failure.
Congenital Cardiac Defects for Pediatric Clients
Here, we’ll go through the major types of congenital cardiac defects that pediatric clients experience especially during infancy. The main cardiac defects are:
- Increased pulmonary blood flow
- Decreased pulmonary blood flow
- Outflow problems
- A mixture of saturated and de-saturated oxygen in the blood – Transportation of Great Vessels
We’ll go through each one briefly as a basic overview. Then, we’ll be discussing each elaborately in separate lectures to provide a more in-depth focus on what really happens with every condition.
Increased Pulmonary Blood Flow
Increased pulmonary blood flow or what is also known as increased lung blood flow has a couple of conditions under its umbrella. The conditions are the following:
- Atrial septal defect – a hole between the atriums causes blood to flow from the left aorta to the right aorta, resulting to increased pressure on the right side of the heart, which can lead to right-sided heart failure.
- Ventricular septal defect – a hole in the ventricles causes blood to go to the right side of the heart, thus; increasing pressure and size.
- Patent ductus arteriosus – here, the atriums are normal, but the pulmonary aorta is problematic because a connection between the pulmonary artery and the aorta has been created. The consequence of this abnormal connection is that deoxygenated blood gets mixed with oxygenated blood and this mixture goes to the rest of the body.
- Atrial-ventricular canal – with the presence of an extra-large canal or hole, the AV canal can be categorized into atrial septal defect and ventricular septal defect. This condition is commonly seen in clients with Down Syndrome.
Decreased Pulmonary Blood Flow
With decreased pulmonary blood flow, there is decreased blood flow into the lungs. Therefore, the primary manifestation would be cyanosis or bluish discoloration of the skin. Cyanosis is not apparent with increased pulmonary blood flow conditions since there is increased blood going inside the lungs.
Signs and symptoms seen in infants with decreased pulmonary blood flow are:
- Bluish lips and skin
- Clubbing/rounding of the fingers
Tetralogy of Fallot
Tetralogy of Fallot (TOF) is the main condition for decreased pulmonary blood flow.
When pediatric clients have “Tet spells,” this means that the baby has been crying too much, resulting in decreased oxygen levels in the body. A common sign that pediatric clients are experiencing Tet spells is when they curl their knees to their chest or when they crouch down to add pressure and increase blood flow to the lungs and help them breathe better.
With Tetralogy of Fallot, the client has a right to left shunting of blood with the defect of the obstruction going to the pulmonary outflow; meaning, there is not enough blood flowing into the lungs, but there is increased blood flowing into the aorta.
Normally, oxygenated blood from the left ventricle is pumped out to the rest of the body through the aorta. However, with Tetralogy of Fallot, deoxygenated blood is going through the aorta and is distributed all over the body. Without oxygen, the client will become cyanosis.
In this congenital heart defect, there is an obstruction of the cardiac chambers. The types of outflow problems are:
- Coarctation of the aorta – a narrowed aorta caused by twisting
- Pulmonic stenosis – narrowing of the pathway going to the lungs
- Aortic stenosis – narrowing and hardening of the aorta
Medical management for outflow problems is surgery.
Transposition of Great Arteries
Also called as “trans of great vessels,” the transposition of great arteries happens when saturated and de-saturated oxygen gets mixed up.
How does this happen?
The pathways or canals where blood flows are not situated correctly – the aorta is connected to the right ventricle while the left ventricle is connected to the lungs; which is not the normal structure.
Remember, that the right side is supposed to pump de-oxygenated blood to the lungs, and the left side is supposed to pump oxygenated blood to the aorta then gets distributed to the different parts of the body.
With the transposition of great arteries, the right side of the heart pumps de-oxygenated blood back to the body, and the left side pumps oxygenated blood right back to the lungs. Because of this mixed-up structure, there will be severe cyanosis because the body does not receive blood with oxygen.
Transposition of great arteries, like the Tetralogy of Fallot, also requires surgical intervention.
So, that’s a quick overview of the different pediatric congenital heart defects. We’ll have a more elaborate discussion of each condition with the nursing and medical interventions in our next videos.