Patent Ductus Arteriosus Flashcards
What is the ductus arteriosus?
It is defined as the connection between the pulmonary trunk and descending aorta
When does the ductus arteriosus normally close?
It usually stops functioning within 1-3 days of birth, and closes completely within the first 2 – 3 weeks of life
What is patent ductus arteriosus (PDA)?
It is defined as a congenital heart disease, in which the ductus arteriosus fails to close following birth
What is the pathophysiological consequence of patent ductus arteriosus?
The pressure in the aorta is greater than is the pulmonary vessels, which means that blood flows from the aorta to the pulmonary artery across the ductus arteriosus
This creates a left-to-right shunt, in which blood from the left side of the heart crosses to the right sided circulation and lungs
This increases the pressure in the pulmonary vessels causing pulmonary hypertension and leading to right heart strain as the right ventricle struggles to contract against the increased resistance
Ultimately, this results in right ventricular hypertrophy
The increased blood flowing through the pulmonary vessels and returning to the left side of the heart leads to left ventricular hypertrophy
What three risk factors are associated with patent ductus arteriosus?
Family History
Prematurity
Maternal Rubella Infection
When does patent ductus arteriosus tend to present?
3 - 5 days of birth
What are the eight clinical features of patent ductus arteriosus?
Failure To Thrive
Feeding Difficulties
Dyspnoea
Continuous Machinery Murmur
Large Volume Collapsing Pulse
Wide Pulse Pressure
Left Subclavicular Thrill
Heaving Apex Beat
Describe the murmur assoicated with patent ductus arteriosus
There is a normal first heart sound with a continuous crescendo-decrescendo machinery murmur - which may continue during the second heart sound
It is typically heart at the upper left sternal border, below the left clavicle
What is the gold standard investigation used to diagnose patent ductus arteriosus?
ECHO scans
What are the three features of patent ductus arteriosus on ECHO scans?
Left-To-Right Shunt Flow
Right Ventricular Hypertrophy
Left Ventricular Hypertrophy
What are the two pharmacological management options of patent ductus arteriosus?
NSAIDs
Prostaglandin E1
When are NSAIDs used to manage patent ductus arteriosus?
They are the first line management
option in preterm neonates
What is the mechansim of action of NSAIDs?
It inhibits prostaglandin synthesis, which is a hormone involved in maintenance of the patent ductus arteriosus
Name two NSAIDs used to manage patent ductus arteriosus
Indomethacin
Ibuprofen
When is prostaglandin E1 used to manage patent ductus arteriosus?
It is used to manage patent ductus arteriosus in individuals who present with another congenital heart defect – which is amendable to surgery
