eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiology

Pulmonary Hypertension, Persistent-Newborn: Differential Diagnoses & Workup

Author: Robin H Steinhorn, MD, Raymond and Hazel Speck Berry Professor of Pediatrics, Division Head of Neonatology, Associate Chair of Pediatrics, Northwestern University School of Medicine
Contributor Information and Disclosures

Updated: Sep 22, 2009

Differential Diagnoses

Congenital Diaphragmatic Hernia
Pulmonary Sequestration
Meconium Aspiration Syndrome
Respiratory Distress Syndrome
Partial Anomalous Pulmonary Venous Connection
Sepsis
Pneumonia
Total Anomalous Pulmonary Venous Connection
Pneumothorax
Transposition of the Great Arteries
Pulmonary Atresia With Intact Ventricular Septum
Tricuspid Atresia
Pulmonary Hypoplasia

Other Problems to Be Considered

Alveolar capillary dysplasia
Surfactant protein B deficiency

Workup

Laboratory Studies

The following studies are indicated in persistent pulmonary hypertension of the newborn (PPHN):

  • ABG
    • Check ABGs initially and frequently, ideally through an indwelling line. Assess the pH, partial pressure of carbon dioxide in arterial gas (PaCO2), and the (PaO2). Using the FiO2, alveolar-arterial (A-a) difference in the partial pressure of oxygen (PaO2) can be calculated.
    • Be aware that the choice of sampling site can affect the ABG results. Newborns with persistent pulmonary hypertension of the newborn frequently have extrapulmonary right-to-left shunting across the patent ductus arteriosus. Therefore, their PaO2 values may be elevated when a preductal sampling site is used.
    • Oxygenation is often assessed by using the oxygenation index (OI), which accounts for the postductal PaO2 and the ventilator settings. The OI is calculated as the mean airway pressure multiplied by the fraction of inspired oxygen (FiO2) and the 100, and the product is divided by the postductal PaO2. An OI of 40 typically prompts consideration of ECMO support.
  • CBC count
    • Evaluate the CBC count for a high hematocrit level because polycythemia and hyperviscosity syndrome may produce or aggravate persistent pulmonary hypertension of the newborn.
    • The WBC count and differential may help in determining whether an underlying sepsis syndrome or pneumonia is present.
    • The platelet count is frequently depressed, particularly in newborns with meconium aspiration syndrome or asphyxia.
  • Serum electrolytes
    • Monitor serum electrolyte and glucose levels initially and frequently.
    • In particular, maintaining glucose and ionized calcium levels within the reference ranges is important because hypoglycemia and hypocalcemia tend to worsen persistent pulmonary hypertension of the newborn. Calcium is a critical cofactor for nitric oxide synthase activity.

Imaging Studies

  • Chest radiography
    • Chest radiography is useful in determining whether underlying parenchymal lung disease (eg, meconium aspiration syndrome, pneumonia, surfactant deficiency) is present. Chest radiography also assists in excluding underlying disorders, such as congenital diaphragmatic hernia.
    • In newborns with idiopathic persistent pulmonary hypertension of the newborn, the lung fields appear clear, with decreased vascular markings.
    • Heart size is typically normal or slightly enlarged.
  • Cardiac ultrasonography (echocardiography)
    • Ultrasonography of the heart (echocardiography) is necessary to exclude cyanotic congenital heart disease. Defining the anatomy of the pulmonary veins can be extremely difficult if extrapulmonary right-to-left shunting of blood is present. Cardiac catheterization is seldom required for diagnosis of persistent pulmonary hypertension of the newborn.
    • Cardiac ultrasonography can also be used to determine if right-to-left shunting of blood across the ductus arteriosus, foramen ovale, or both is present. A skilled ultrasonographer can use the peak velocity of the regurgitant flow across the tricuspid valve to calculate right ventricular systolic pressures and, thus, estimate right-sided vascular pressures.
    • Cardiac ultrasonography is needed before therapy with inhaled nitric oxide (iNO) is begun. The image allows the clinician to rule out left-sided obstructive lesions, such as an interrupted aortic arch, a hypoplastic left ventricle, and critical aortic stenosis. These lesions require right-to-left shunting through the ductus to maintain systemic perfusion and, therefore, are contraindications to iNO treatment.
    • Although right-to-left shunting at the patent ductus arteriosus and patent foramen ovale is typical for persistent pulmonary hypertension of the newborn, predominant right-to-left shunting at the patent ductus arteriosus but left-to-right shunt at the patent foramen ovale may help to identify the important role of left ventricular dysfunction to the underlying pathophysiology. This must be corrected before considering the use of pulmonary vasodilators.
  • Cranial ultrasonography
    • Perform cranial ultrasonography if extracorporeal membrane oxygenation (ECMO) is considered in a newborn to evaluate for intraventricular bleeding and for peripheral areas of hemorrhage or infarct.
    • Doppler flow studies can be a helpful adjunct for determining whether a nonhemorrhagic infarct is present.

Other Tests

  • Pulse oximetry
    • Continuous pulse oximetry is extremely valuable in the ongoing treatment of the newborn with persistent pulmonary hypertension of the newborn, allowing the caregiver to assess the patient's oxygen saturation over time and to determine whether oxygen delivery at the tissue level is adequate.
    • Oximeter probes can be placed on preductal (right hand) and postductal (right or left foot) sites to assess for right-to-left shunt at the level of the ductus arteriosus. Remember that sites on the left hand should be avoided because it may be preductal or postductal.
    • Although it is a useful indicator of persistent pulmonary hypertension of the newborn when present, a ductus-level shunt is frequently absent.
  • Cardiac catheterization: In rare cases, cardiac ultrasonographic findings are not definitive, and cardiac catheterization may be necessary to exclude congenital heart disease, particularly anomalous pulmonary venous return.

Procedures

  • Mechanical ventilation
    • Endotracheal intubation and mechanical ventilation are almost always necessary for the newborn with persistent pulmonary hypertension of the newborn. The goal of mechanical ventilation should be to maintain normal functional residual capacity (FRC) by recruiting areas of atelectasis but also to avoid overexpansion.
    • Adjust ventilator settings to maintain normal expansion (ie, of approximately 9 ribs) on chest radiography. Monitoring of tidal volume and pulmonary mechanics monitoring is frequently helpful in preventing overexpansion, which can elevate PVR and aggravate right-to-left shunting.
    • In newborns with severe airspace disease who require high peak inspiratory pressures (ie, >30 cm H2 O) or mean airway pressures (>15 cm H2 O), consider high-frequency ventilation (HFV) to reduce barotraumas and associated air leak syndrome. When HFV is used, the goal should still be to optimize lung expansion and FRC and to avoid overdistension.
  • Central venous catheter placement
    • Place a central venous catheter into the umbilical or other vein to allow for the administration of inotropic agents or hypertonic solutions (eg, calcium gluconate solution).
    • Avoid catheter placement into the jugular vessels; save these vessels for extracorporeal support, if needed.
  • Arterial catheter placement: Place an indwelling catheter into the umbilical artery or a peripheral artery (eg, radial or posterior tibial artery) to allow for frequent monitoring of ABGs.
  • Surfactant administration
    • Parenchymal lung disease of the term or near-term newborn is often associated with surfactant deficiency, inactivation, or both.
    • Data from small studies suggest that a benefit occurs after surfactant is administered to the newborn with meconium aspiration syndrome.
    • In a large multicenter study, the administration of surfactant reduced the need for extracorporeal support and appeared to be most effective early in the course of disease. The reduced need for ECMO was most apparent in newborns with primary diagnoses of meconium aspiration syndrome or sepsis.
  • HFV
    • HFV is another important modality if a newborn has underlying parenchymal lung disease with low lung volumes. This modality is best used in a center with physicians experienced in achieving and maintaining optimal lung distension.
    • The response to HFV can be rapid, and care must be taken to prevent hypocarbia and lung overdistension.
  • ECMO
    • ECMO is used when optimal support fails to maintain acceptable oxygenation and perfusion. This therapy, which is an adaptation of cardiopulmonary bypass, is provided at less than 100 centers in the United States.
    • Recent developments allow ECMO support to be provided by using a double-lumen catheter in the internal jugular vein; thus, ligation of the right common carotid artery can be avoided.

More on Pulmonary Hypertension, Persistent-Newborn

Overview: Pulmonary Hypertension, Persistent-Newborn
Differential Diagnoses & Workup: Pulmonary Hypertension, Persistent-Newborn
Treatment & Medication: Pulmonary Hypertension, Persistent-Newborn
Follow-up: Pulmonary Hypertension, Persistent-Newborn
Multimedia: Pulmonary Hypertension, Persistent-Newborn
References
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References

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Further Reading

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Keywords

persistent fetal circulation, PFC, persistent pulmonary hypertension in the newborn, persistent pulmonary hypertension of the newborn, PPHN, pulmonary vascular resistance, PVR, pulmonary perfusion, black lung PPHN, clear lung PPHN, pulmonary vasodilation, persistent newborn pulmonary hypertension, patent foramen ovale, patent ductus arteriosus, meconium aspiration syndrome, respiratory distress syndrome, pneumonia, congenital diaphragmatic hernia, bronchopulmonary dysplasia, hypothermia, hypoglycemia, cystic adenomatoid malformations, treatment, diagnosis

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Contributor Information and Disclosures

Author

Robin H Steinhorn, MD, Raymond and Hazel Speck Berry Professor of Pediatrics, Division Head of Neonatology, Associate Chair of Pediatrics, Northwestern University School of Medicine
Robin H Steinhorn, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Heart Association, American Pediatric Society, American Thoracic Society, and Society for Pediatric Research
Disclosure: Ikaria (INO Therapeutics) Consulting fee Consulting

Medical Editor

Steven M Donn, MD, Professor of Pediatrics, University of Michigan Medical School; Director, Division of Neonatal-Perinatal Medicine, Department of Pediatrics, CS Mott Children's Hospital, University of Michigan Health System
Steven M Donn, MD is a member of the following medical societies: American Pediatric Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Arun K Pramanik, MD, MBBS, Professor of Pediatrics, Director of Neonatal Fellowship, Louisiana State University Health Sciences Center
Arun K Pramanik, MD, MBBS is a member of the following medical societies: American Academy of Pediatrics, American Thoracic Society, National Perinatal Association, and Southern Society for Pediatric Research
Disclosure: Nothing to disclose.

CME Editor

Gilbert Z Herzberg, MD, Assistant Professor, Department of Pediatrics, Section of Pediatric Cardiology, New York Medical College; Consulting Staff, Department of Pediatrics, Sound Shore Medical Center
Gilbert Z Herzberg, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Chief Editor

Stuart Berger, MD, Professor of Pediatrics, Division of Cardiology, Medical College of Wisconsin; Chief of Pediatric Cardiology, Medical Director of Pediatric Heart Transplant Program, Medical Director of The Heart Center, Children's Hospital of Wisconsin
Stuart Berger, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American College of Chest Physicians, American Heart Association, and Society for Cardiac Angiography and Interventions
Disclosure: Nothing to disclose.

 
 
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