This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'Preterm baby with PDA, which is the least idly findings? \nSelect and explain. \nA. CO2 washout, B. Bounding pulses, C. Pulmonary hemorrhage, D. Necrotising enterocolitis', 'role': 'user'}, {'content': "Answer: A \nExplanation: PDA in preterm neonate\n\nIn previous explanations I have explained that chances of spontaneous closure of PDA are higher in premature infants as there is no structural abnormality. However, you should keep in mind that this fact is true when we are comparing the spontaneous closure of PDA between term and pre-term neonate. Overall, the percentage of spontaneous closure of PDA in preterm neonate is very low. To avoid confusion, I am explaining following facts in brief :-\n\n\n\nNormal neonate :- Ductus arteriosus closes functionally within about 15 hours of birth.\nFDA in term (mature) neonate :- The persistence of ductus arteriosus beyond 24 hours after birth is considered as PDA in term neonate. Spontaneous closure of PDA does not usually occur because PDA results from structural abnormality.\nFDA in pre-term (pre-mature) neonate :- The ductus arteriosus in pre-term neonate is not as responsive to increased oxygen content as it is in term neonate. However, there is no structural abnormality.\n\n\nChances of spontaneous closure are very less (compared to normal term neonate).\nChances of spontaneous closure are more than the term-neonate with PDA. However, in premature neonate, where hypoxic pulmonary disease is common place, the ductus being sensitive to hypoxia, remains open.\n\n\nSo, it is very unlikely that spontaneous closure of PDA will occur in pre-term neonate. But chances are more when compared to term neonate with PDA (not nonnal term neonate in which ductus arteriosus closes within 15 hours of birth).\n\nManifestations of PDA in pre-term neonate\n\nApnea for unexplained reasons in an infant recovering from RDS;\nA hyperdynamic precordium, bounding peripheral pulses, wide pulse pressure, and a continuous or systolic murmur with or without extension into diastole or an apical diastolic murmur, multiple clicks resembling the shaking of dice;\nCarbon 'oxide retention;\nIncreasing oxygen dependence;\nX-ray evidence of cardiomegaly and increased pulmonary vascular markings; and\nHepatomegaly\n\n\nIncreased pulmonary blood flow and compromised ventricular function accompanying dropping pulmonary resistance in the setting of a P A is a significant risk factor for pulmonary hemorrhage.\nThe greatest risk factor for NEC is prematurity. Any etiology which leads on to hemodynamic or hypoxic insult predisposes to NEC. PDA is common in preteen infants and it definitely causes hemodynamic stress and is a risk factor for development of NEC.", 'role': 'assistant'}]