One of the most interesting aspects of pediatric pathophysiology are the congenital heart defects. In this post we’ll talk about the key components of atrial septal defect nursing assessments and interventions, starting with a review of the pathophysiology.

What is the pathophysiology of an atrial septal defect? 

An atrial septal defect (ASD) is an opening in the septum between the atria. The first thing to understand when you’re looking at any cardiac anomoly is the pathway of blood flow through the heart. Knowing this ONE THING really well will help you think through a large number of cardiac defects so that you don’t have to memorize one darn thing…just think it through!

So, thinking about the heart and how it works…which side is working with higher pressures? The right side of the heart, which pushes blood into the lungs, or the left side of the heart which pushes blood into the ENTIRE body? If you answered the LEFT SIDE, then you get a gold star! 

With the heart’s high pressures being on the LEFT, we have a situation where oxygenated blood from the left atrium is forced through that ASD opening into the right side of the heart. This oxygenated blood mixes with the oxygen-poor blood in the right atrium and is sent back to the lungs. The result is that the lungs get increased pulmonary blood flow as well as increased pulmonary pressure.

Over time, with increased pulmonary pressures, the patient ends up with pulmonary edema and congestive heart failure. The increased pulmonary blood flow also puts the patient at risk for the development of emboli, but note that these complications typically occur much later and only if the ASD is left untreated for many years. 

What are the signs a baby has an atrial septal defect? 

Most ASDs produce few, if any, symptoms. However, large ones can cause:

  • An infant that tires with feeding
  • Frequent respiratory infections
  • Heart murmur
  • Tachypnea

So, when looking at atrial septal defect nursing assessments, you’ll focus them on things like heart sounds, respiratory rate and lung sounds. It’s also key to ask mom if baby tires with feeding and to look back at the record to see if baby has had frequent respiratory infections. All of these could be related to an undiagnosed ASD.

How is an atrial septal defect diagnosed? 

  • Chest X-Ray could show an enlarged heart or pulmonary changes
  • Echocardiogram shows the blood flow through the heart. We do what is called a “bubble study” or “agitated saline study” to see if an opening is present in the heart where it shouldn’t be. As the echo technician is taking pictures of the heart using ultrasound, the nurse agitates a syringe of saline and then injects it through the IV. The agitated saline is comprised of thousands of tiny bubbles that are highly visible on ultrasound, enabling the technician to see abnormal flow in the heart. The reason we call it a “bubble study” is because of all the bubbles! This video shows how we agitate the saline and work in coordination with the echo technician. The nurse in this video makes it look easy, but it actually takes a fair amount of hand strength to maneuver the syringes like this!
  • Cardiac catheterization that uses contrast dye to show detailed anatomy and physiological abnormalities.

How is an atrial septal defect treated?

  • Surgery can correct the defect by placing a patch over the opening; this can be done via a cardiac catheterization procedure which means we don’t have to open the chest. However, when a chest-wall approach is needed, we use as minimally an invasive approach as possible.
  • Medications to treat symptoms, namely diuretics to help with fluid overload in the lungs.

The short version: Infants with atrial septal defects can have higher-than-average pulmonary pressures which can lead to pulmonary edema and congestive heart failure. It is treated through surgery and medications like diuretics.

Get this on audio in Episode 70!


References

American Heart Association. (2019). Atrial Septal Defect (ASD) | American Heart Association. Retrieved from https://www.heart.org/en/health-topics/congenital-heart-defects/about-congenital-heart-defects/atrial-septal-defect-asd

CDC. (2019, January 22). Congenital Heart Defects—Facts about Atrial Septal Defects | CDC. Retrieved August 28, 2019, from Centers for Disease Control and Prevention website: https://www.cdc.gov/ncbddd/heartdefects/atrialseptaldefect.html

Cininnati Children’s. (n.d.). Atrial Septic Defects (ASD) in Children; Symptoms, Diagnosis & Treatment. Retrieved from https://www.cincinnatichildrens.org/patients/child/encyclopedia/defects/asd