Ductal dependent lesion in neonates

25 Sep

While searching for answers in ductal dependent blood flow (while listening to the EMRAP of this month), I thought it would be nice to share my very short summary with you.

Gr Laura

Neonatal cardiology – Ductal Dependant blood flow

Atlas of Pediatric EM:

Hypoplastic left heart syndrome (HLHS) refers to a spectrum of CHDs that have very small LV and other associated anatomic abnormalities. There is inadequate anterograde flow to support the systemic circulation because of the hypoplasia of the left heart. Because systemic circulation is supported by the right side of the heart through the ductus arteriosus, these lesions are referred to as ductal-dependent lesions. Examples of ductal-dependent systemic blood flow lesions include HLHS, critical coarctation of the aorta and aortic arch interruption. Examples of right-sided ductal-dependent lesions (pulmonary circulation dependent on patency of the ductus arteriosus) include pulmonary atresia with intact ventricular septum, tricuspid atresia and critical pulmonary stenosis.

APLS, SSHK, Turner:

Obstruction pulmonary blood flow: first days of life progressive cyanosis, dyspnea or cardiogenic shock. Often enlarged liver palpable.

Obstruction systemic blood flow:  problems feeding, dyspnea, syncope’s, bad peripheral circulation, abnormal skin color. Cardiogenic shock, difficulty palpating peripheral pulsations.

EMRAP sept 2013: How can you tell if it is ductal dependent pulmonary flow or systemic flow in a true neonate (less than 30 days old)?

  1. 1.     Oxygen saturation. The blue baby is more likely to have ductal dependent pulmonary blood flow.
  2. 2.     Look at the chest x-ray. If their oxygen saturation is 40% and they have a pristine clear x-ray, it is ductal dependent pulmonary blood flow. Start them on prostaglandins.
o If they are pink but shocky with poor perfusion, hypotension, tachycardia, think about a ductal dependent systemic blood flow.
  3. 3.     Check the blood pressure in all four extremities. Look for a gradient of upper and lower extremity blood pressures and oxygen saturation. This is looks for a critical coarctation.

Treatment, Atlas of Pediatric EM:

ABCs

Maintain ductal patency with Prostaglandins, in the Netherlands Alprostadil = Prostin 0.05 mcg/kg/min till 0.2 mcg/kg/min.

Treat metabolic acidosis (leads to increased systemic vascular resistance, and in turn increases pulmonary blood flow)

Avoid any maneuvers that decrease pulmonary vascular resistance and pulmonary pressure as these will steal blood flow from the systemic circulation. Aim for normal ABG.

Risk of Prostaglandins: apnea and hypotension.

Suggested pressors, EMRAP sept 2013:

Phenylephrine is a good choice in the blue kid that is ductal dependent. Milrinone (or dobutamine) is a good option (providing pump support and slight vasodilation) in a patient with coarctation who is already clamped down. Giving epinephrine or levophed to a coarctation could make them worse. You may need to use push dose pressors to get them through intubation.

Total anomalous pulmonary venous return (TAPVR) is a contra-indication for prostaglandins, but if the pt doesn’t come in with this diagnosis you will not know, and the patient wil get clinically worse with the drip.

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