Truncus Arteriosus is the term used to describe the fusion of the blood vessels that leave the heart.
Usually, Deoxygenated (used/oxygen-deprived) blood flows from the upper part of the heart (Right Atrium) to the lower part (R. ventricle) and out into the Lungs for oxygenation (via the pulmonary artery)……No 1 vessel that leaves the heart.
Following this, the blood returns from the lungs through the pulmonary veins into the left atrium, from which it is further transported down into the Left ventricle (the power site). The left ventricle pumps this blood rich in oxygen into the Aorta (the 2nd vessel that leaves the heart) to distribute to all body parts.
In Truncus Arteriosus however, the 2 vessels leaving the heart for different purpose merge as just 1. you can begin to factor what happens.

There is a VSD (hole between the ventricles of the heart)
The child has low oxygen because of the blood mixture
There is high pressure within the artery going to the lungs (severe pulmonary hypertension)
The patient may have recurrent chest infections, Fast breathing, Low oxygen saturation, Blue coloured lips and fingers are typical signs and symptom these children come with Truncus Arteriosus
Management
Early surgery (Open-heart Surgery) is advised within the first month of life for a better chance of survival.
Our level of awareness is far behind, early detection isn’t so common and that is why we are embarking on project pulse oximetry for all


