Dependent Circulation Newborn

Types

• PDA dependent• Pulmonary blood flow• Systemic blood flow

• PFO dependent• PDA and PFO both

Ductal-Dependent Pulmonary Blood Flow• Critical pulmonary stenosis• Pulmonary atresia• Severe tricuspid valve stenosis• Tricuspid atresia without a

ventricular septal defect• Severe TOF

• Prostaglandin infusion soon• Ductal stenting etc. afterwards

Ductal-dependent Systemic Flow

• Critical AS• Interrupted aortic arch• HLHS•

• Reversed flow across the foramen ovale (left atrium to right atrium) has been shown to be predictive of the need to maintain ductal patency• Delivery at a centre with a

neonatologist who has access to pediatric cardiology consultation is recommended

Foramen Ovale–Dependent Lesions

• HLHS are dependent • d-TGA

• The ratio of pulmonary vein forward to reversed velocity-time integral was used to determine potential need for intervention- a ratio <3 is predictive of an increased likelihood of needing emergent opening of the atrial septum

• Maternal hyperoxia challenge test in the third trimester in which 100% O2 is delivered via nonrebreather facemask to the expectant mother has been shown to predict fetuses with HLHS at risk for delivery room compromise. Lack of pulmonary vasodilation as measured by the calculated Doppler pulsatility index of the branch pulmonary arteries during the hyperoxia challenge predicted fetuses who needed intervention to open the atrial septum at delivery.

PFO dependent cont………

• The foramen ovale was found to be at risk for closure in 1 study 585 if the angle of septum primum was <30° to the atrial septum, if there was bowing of the septum primum into the left atrium >50%, or if there was a lack of normal swinging motion of the septum primum

• Immediate septostomy is required if baby is hypotensive and hypoxic

PDA and PFO dependent

• Severe right heart obstruction• HLHS

Thank your interest