4. CHD w/ Increased Pulmonary Blood Flow

what does increased pulmonary blood flow mean?

more blood than normal is being sent to the lungs

what is a left-to-right shunt? *

blood crosses an abnormal opening from the left side of the heart to the right side (because of higher pressure)

why does a left-to-right shunt increase blood flow to the lungs? *

blood that already received oxygen returns to the right side and gets pumped through the lungs again

why can a large left-to-right shunt cause heart failure?

the extra blood volume makes the heart work harder until it cannot keep up + causes Right ventricular hypertrophy

how does body compensate for increased pulmonary blood flow? *

tachypnea, tachycardia

which defects commonly cause increased pulmonary blood flow? *

• atrial septal defect (ASD)

• ventricular septal defect (VSD)

• patent ductus arteriosus (PDA)

what is an atrial septal defect (ASD)? *

a hole in the wall separating the atria

(blood is pumped L to R because theres more pressure in L)

how does an atrial septal defect (ASD) increase pulmonary blood flow?

extra blood enters the right atrium, moves into the right ventricle, and is pumped to the lungs

what is a ventricular septal defect (VSD)? *

a hole in the wall separating the ventricles

how does a ventricular septal defect (VSD) increase pulmonary blood flow?

extra blood enters the right ventricle and gets pumped to the lungs

what is a patent ductus arteriosus (PDA)? *

the fetal vessel connecting the pulmonary artery and aorta stays open after birth

• blood flows from the aorta into the pulmonary artery

why does blood flow from the aorta into the pulmonary artery through an isolated patent ductus arteriosus (PDA)?

aortic pressure is higher than pulmonary artery pressure after birth

how does a patent ductus arteriosus (PDA) increase pulmonary blood flow?

blood in the aorta is redirected toward the lungs instead of continuing to the body

what assessment findings can occur with defects that increase pulmonary blood flow?

• poor feeding and poor weight gain

• delayed growth and development

• heart murmur

• heart failure signs: shortness of breath; edema; tachycardia, tachypnea

what tests help evaluate defects that increase pulmonary blood flow?

• echocardiogram

• EKG

• MRI

• chest x-ray

• cardiac catheterization

how are defects that increase pulmonary blood flow treated?

surgical closure, catheter-based repair, or medication, depending on the defect

what complications can develop from defects that increase pulmonary blood flow?

• pulmonary hypertension

• heart failure

• atrial arrhythmias stroke

what effect do prostaglandins have on the ductus arteriosus?

relax the vessel’s muscle, helping the ductus arteriosus stay open

why is prostaglandin medication given for certain congenital heart defects? *

to keep the ductus arteriosus open and preserve needed blood flow until treatment

what is indomethacin?

NSAID that closes a PDA by inhibiting prostaglandins

because its an NSAID, indomethacin can mask signs of _____

infection

when should the nurse question an indomethacin order for an infant with a heart defect? *

when the infant depends on an open ductus arteriosus for adequate blood flow

• ex: tricuspid atresia, TGV, HLHS