Explain why babies with patent ductus arteriosus disorder may have poor growth.
Ductus arteriosus is a blood vessel of developing fetus, which normally closes 2-3 weeks after birth. However, if it remains open (patent ductus arteriosus, PDA), it leads to direct flow of arterial blood from the aorta into the pulmonary artery and finally to the lungs increasing blood pressure in the arteries of lungs. Infants with patent ductus arteriosus often have difficulties with breathing. Feeding difficulties such as disinterest in feeding or tiring while feeding are tightly connected with them. It results in poor appetite and poor growth of infants caused by malnutrition.