Which of the following is not a sign of PDA in a preterm baby?
Ans. d. Narrow pulse pressure (Ref: Ghai 7/e p405-406; http://www.merckmanuals.com/professional/pediatrics/congenital_cardiovascular_anomalies/patent_ductus_arteriosus_pda.htmI)"Premature newborns cannot tolerate PDA, so it results in heart failure, respiratory distress or necrotizing enterocolitis. So they require prompt management"- Ghai 7/e p406Patent Ductus ArteriosusPDA is a communication between pulmonary artery and aorta.The aortic attachment to the ductus arteriosus is just distal toQ the left subclavian artery.Hemodynamics:PDA results in a left to right shuntQ from the aorta to the pulmonary artery.Flow occurs during systole and diastole as the pressure gradient is present throughout the cardiac cycle between the two great arteries, if the pulmonary artery pressure is normal, the flow of blood results in murmur, hence it is a continuous murmurQ.Clinical Features:Clinical presentation depends on PDA sizeQ and gestational age at deliveryQ.Infants and children with a small PDA are generally asymptomatic: infants with a large PDA present with signs of heart failureQ (e.g. failure to thrive, poor feeding, tachypnea, dyspnea with feeding, tachycardia).Premature newborns can't tolerate PDA, so it results in heart failure, respiratory distress or necrotizing enterocolitisQ.Premature infants may present with respiratory distress, apnea, worsening mechanical ventilation requirement or other serious complications (e.g. necrotizing enterocolitisQ).Signs of heart failure occur earlier in premature infants than in full-term infants and may be more severe.A large ductal shunt in a premature infant often is a major contributor to the severity of the lung disease of prematurity.Patients of PDA may become symptomatic in early life and develop CCF around 6-10 weeks of ageQ.Older children give history of effort intolerance, palpitations and frequent chest infectionsQ.The flow from the aorta to the pulmonary artery is a leak from the systemic flow.This results in a wide pulse pressure and many of the signs of wide pulse pressure seen in patient with aortic regurgitation.Differential Cyanosis (characteristic of PDA)Since the right to left shunt through the PDA, blood flows down the descending aorta, cyanosis is present in toes, but not in fingers. This is called differential cyanosisQ and is characteristic of PDA with pulmonary arterial hypertension and right to left shunt.SoundsS1: Accentuated, loud M1S2: Normal splitting and movement, single or paradoxical P2 + to P2 ++S3: With large shuntsX: ConstantMurmursShunt murmurs: Continuous (machinery)Flow murmurs:Mitral delayed diastolic2. Aortic ejection systolic Treatment:Indomethacin or ibuprofen (0.1 mg/kg 12 hourly for 3 doses)PDA in full-term babies may close spontaneouslyIndications of surgery in PDASmall infant with large ductQPre-term infantsQDucts that are very largeQ
Apnea
Tachycardia
Necrotizing enterocolitis
Narrow pulse pressure
C.H.D.