144 VOLUME 34 | NUMBER 3 May/June 2009

Annie J. Rohan, MSN, RNC, NNP/PNP, andSergio G. Golombek, MD, MPH, FAAP

HYPOXIAIN

THE Term Newborn:PART TWO—PRIMARY PULMONARY DISEASE, OBSTRUCTION,AND EXTRINSIC COMPRESSION

AbstractPediatric care providers are repeatedly called upon to evaluatea cyanotic newborn in the labor and delivery suite, or in thewell-baby nursery. A myriad of disorders spanning all-organsystems exist as possibilities for each of these problems, al-though several causes for newborn cyanosis are particularlycommon. In this second of a three-part series, primary pul-monary disease, airway obstruction, and extrinsic compressionof the lungs as causes for newborn hypoxia are explored. It is inthis group of disorders that we find the answers for the greatestnumber of these cyanotic dilemmas. Knowledge of the breadthof diagnoses, and respect for the variety of clinical possibilities,is the first step in providing a patient with accurate diagnosis,treatment, and referral.Key Words: Evaluation; Hypoxia; Newborn; Pulmonary;Respiratory.

decreased lung compliance, ventilation-perfusion inequality,intrapulmonary right-to-left shunts, and a resultant varyingdegree of hypoxia in the newborn. Logically, as such, theentire spectrum of neonatal respiratory disorders may pres-ent with cyanosis. In general, hypoxia associated with pul-monary disease presents as tachypnea, grunting, flaring,chest retractions, arterial blood gas usually showing carbondioxide retention, rise in PaO2 when supplemental oxygenis used, and evidence of lung disease on chest radiograph.There are numerous diagnoses included in the category of“primary pulmonary disease,” including:• Transient Tachypnea of the Newborn• Tracheoesophageal Fistula and Esophageal Atresia• Aspiration Syndromes• Respiratory Distress Syndrome• Pneumonia• Pulmonary Hemorrhage• Pulmonary Hypoplasia• Pulmonary Lymphangiectasia• Congenital Pulmonary Cysts• Pulmonary Lobar Emphysema

Transient Tachypnea of the Newborn (TTN). TTN is per-haps the most common respiratory disorder of the termnewborn (Levine, Ghai, Barton, 2001). Like most primaryrespiratory diseases, TTN is a spectrum disorder—it rangesfrom a mild intermittent tachypnea, perhaps more

May/June 2009 MCN 145

What do newborn care providers need to know tomeet the challenge of evaluating hypoxia in theterm newborn infant? The first article in thisthree-part series (see Rohan & Golombek, 2009), discussedcardiopulmonary adaptation of the term newborn, defini-tions and features of neonatal hypoxia, cardiac causes ofhypoxia in the newborn, and neonatal pulmonary hyper-tension. In this Part Two article, we describe causes of new-born hypoxia that have close origins to the respiratorysystem. These causes can be broken down into three dis-tinct categories: (1) primary pulmonary disease (wherepathology originates in the lung parenchyma), (2) airwayobstruction (where pathology originates in the upper air-ways), and (3) extrinsic compression of the lung and airway(where pathology originates outside of the lung but im-pinges upon respiratory structures). In each of these sepa-rate categories is found an array of disorders that can causerespiratory dysfunction and resultant hypoxia (Table 1).

Primary pulmonary disease is the most common etiologyfor cyanosis and hypoxia in this population (AmericanAcademy of Pediatrics, 2002). The prudent clinician, how-ever, will routinely consider alternatives, so as not to causedelayed diagnosis and its associated negative consequencesfor the infant with a less common disorder.

Primary Pulmonary DiseasePrimary lung disease causes alveolar hypoventilation,

appropriately defined as “delayed transition to extrauterinelife,” up to and including a disease with tachypnea, oxygenrequirement and physical signs closer to respiratory distresssyndrome. Typically, these infants have benign intrapartumcourses and are not at risk for other illnesses. Many ofthem are delivered by cesarean section; some without labor.The most significant discriminatory findings are the onsetof the illness and the degree of distress exhibited by theinfant. Cyanosis and carbon dioxide retention are not hall-marks of the disease, however, are observed on occasion.Typically, the infant becomes tachypneic immediately afterbirth and has very mild respiratory distress. Infants are neu-rologically normal. The chest radiographs generally revealhyperinflation with clear lung parenchyma except for peri-hilar linear densities and fluid in the fissures. There shouldbe no areas of consolidation.

The pathophysiological mechanism is the delayed resorp-tion of fetal lung fluid which eventually clears over the nextseveral hours to days (Kopelman & Mathew, 1995). If fol-lowed closely, infants remain stable for several hours and/or

begin to improve. A worsening clinical picture shouldsuggest another diagnosis.

Tracheoesophageal Fistula and Esophageal Atresia.Esophageal atresia and tracheoesophageal fistula occurswhen the esophagus fails to differentiate and separate fromthe trachea. The most common anatomic type of this disor-der is when the upper esophagus ends in a blind pouch,and there is a fistula connecting the lower esophagus to thetrachea (Martin & Alexander, 1985). The infant typicallypresents with cyanosis and “choking” as a result of in-creased oral secretions. During physical examination, anorogastric catheter is typically unable to be advanced to thestomach, and if left indwelling during chest radiograph, thecatheter is usually seen coiled in the area of the mid thorax.Pediatric surgical consultation is uniformly indicated.

Aspiration Syndromes. The pathophysiologic mechanismfor illness in aspiration syndromes is the obstruction oflarge and small airways with the aspirated material (meconi-

146 VOLUME 34 | NUMBER 3 May/June 2009

PRIMARY PULMONARY DISEASE AIRWAY OBSTRUCTIONEXTRINSIC COMPRESSION OF THE

LUNGS AND AIRWAY

Transient tachypnea of the newborn Choanal atresia, choanal stenosis Pneumothorax

Tracheoesphageal fistula, esophagealatresia

Pierre-Robin sequence Pneumomediastinum

Aspiration syndromes Macroglossia Pleural Effusion

Respiratory distress syndrome Right aortic arch Chylothorax

Pneumonia Thyroid goiter Congenital diaphragmatic hernia

Pulmonary hemorrhage Cystic hygroma Mediastinal masses

Pulmonary hypoplasia Laryngomalacia, tracheomalacia,tracheal stenosis, subglottic stenosis

Thoracic dystophies, thoracicdysplasias

Pulmonary lymphangiectasia Subglottic hemangioma/hematoma Extralobar sequestration

Congenital pulmonary cysts Bronchomalacia, bronchial stenosis Right/double aortic arch

Pulmonary lobar emphysema Laryngeal web Tracheal vascular ring

Vocal cord paralysis Pulmonary artery sling

Foreign body aspiration Cricoid cartilage malformation

Mucous plugging

Table 1. Classification of Disorders: Primary Pulmonary Disease, Airway Obstruction, and ExtrinsicCompression of the Lungs and Airway

um, blood, amniotic fluid, formula or breast milk). As thedisease process progresses, the symptoms and severity ofhypoxemia increase over the subsequent hours. Pulmonaryhypertension may develop when aspiration occurs in con-junction with varying degrees of in utero asphyxia.

Meconium in the amniotic fluid occurs in approximately20% of pregnancies; as a consequence, meconium aspira-tion syndrome (MAS) is considered to be a relatively com-mon event (Wiswell, 2001). Infants with this disorder, andother forms of aspiration, typically have symptoms similarto infants with TTN, but an exaggerated presentation sug-gesting a more severe condition. In addition, while manyinfants have the onset of symptoms at birth, some infantshave an asymptomatic period of several hours before respi-ratory distress becomes apparent. Infants with aspirationsyndromes may require more oxygen, and have greaterdegrees of tachypnea, retractions, and lethargy. The arterialblood gases may reveal more acidosis, hypercapnia, andhypoxemia than in infants with TTN. The chest radi-ographs differ from that of TTN with significant heteroge-neous lung disease, hyperinflated and hypoinflated areas,patchy and linear infiltrates and atelectasis.

The deleterious effects of gastroesophageal reflux (GER) ininfants have been recognized with increasing frequency, andput the neonate at risk for aspiration of stomach contents.The spectrum of symptoms caused by GER in the infant isdistinctly different than in the adult, but is frequently recog-nized in the neonatal period with intermittent episodes of hy-poxia, during, after or between feedings, with or withoutvomiting. When presenting with cyanosis, diagnosis is gener-ally made in the term infant by pH probe or esophagramstudy, only after other causes of hypoxia have been ruled out.

Respiratory Distress Syndrome. Respiratory distress syn-drome (RDS), once known as hyaline membrane disease, isone of the most predominant lung problems experienced byneonates. It mainly strikes infants under 35 weeks gestation,however, it has been well documented in the term and latepreterm infant (Golombek & Truog, 2000), classically in the in-fant of a diabetic mother, or in cases of perinatal hemorrhage.

The etiology of RDS is understood to be a deficiency inpulmonary surfactant either by lack of production, or, morecommonly in the late preterm infant, by inactivation of thissurfactant. Surfactant is thought to be produced near the22nd week of gestation; however, production can easily bedisrupted by hypoxemia, hypothermia, or acidosis.

Infants with RDS have progressively more severe respira-tory distress after birth. The classic findings of cyanosis, nasalflaring, intercostal and subcostal retractions, and tachypneaare present. Grunting classically occurs as the infant attemptsto maintain the gas volume within the lung by causing expi-ratory braking using the vocal cords and glottis. Apnea mayoccur as work of breathing increases. There is decreased lung

compliance, decreased lung volumes, atelectasis, decreasedalveolar ventilation, hypoperfusion, and subsequent hypoxia.The symptoms of RDS usually worsen gradually for the first48 to 72 hours, followed by stabilization, and a slow recov-ery period. Stabilization of the disease is often associatedwith diuresis. Like aspiration syndromes and pneumonia,pulmonary hypertension may develop when RDS occurs inthe context of an opportune setting.

Chest radiograph in RDS has features suggesting general-ized atelectasis. In the preterm infant, this presents with ageneralized reticulogranular “ground glass” appearance ofthe lung fields with air bronchograms. In the term infant,however, there is not as typical a picture, and features ofatelectasis vary from generalized to patchy. One must use his-tory and clinical evaluation to differentiate between RDS andother generalized pulmonary diseases, although distinctionfrom pneumonia, in particular, is very difficult at the onset.

Pneumonia. Enteric organisms such as Escherichia coli andGroup B Streptococcus are the frequent causative bacterialagents of congenital pneumonia, and viruses are increasinglyrecognized as culprits for this infection. Rarely, a postnatallyacquired pneumonia is observed in the early newborn. A tableof organisms that can cause pneumonia in the neonate is inTable 2.

The diagnosis of neonatal pneumonia is typically animprecise science. It is generally based on the history, physi-cal examination, chest X-ray results, and lab data. Whilepneumonia in newborns is relatively rare, premature infantshave at least a 10-fold increased incidence of infectionswhen compared to term infants. Mothers with intrapartumfever and prolonged rupture of membranes have a greaterrisk of transmitting infections to their infants. Symptoms ofpneumonia in a neonate, which often present within 48hours of delivery, include vital signs instability and respira-tory distress. Laboratory data often suggests infection.Chest radiograph typically depicts unilateral or bilateralstreaky densities of the perihilar region in bilateral lungfields. Like RDS, symptoms are highly variable and dictatethe degree of supportive care.

Pulmonary Hemorrhage. Rarely occurring in isolation,pulmonary hemorrhage is typically found in an infant sickwith RDS, pneumonia, heart disease, or asphyxia. It hasbeen noted with higher incidence in infants receiving pul-monary surfactant. Significant bleeding may also occur as acomplication of trauma to the respiratory epithelium duringairway suctioning.

The manifestation of pulmonary hemorrhage is the presenceof blood or bloody fluid from the airway, and runs the spec-trum from scant bloody aspirate to massive bleeding. It followsthat clinical examination may be minimally altered frombaseline, or range up to sudden deterioration with shock,

May/June 2009 MCN 147

bradycardia and death. Clotting factors can be consumed rap-idly, and supportive care may include management of coagu-lopathy blood product loss/consumption with transfusion.

Pulmonary Hypoplasia. Pulmonary hypoplasia is part ofthe spectrum of malformations characterized by incompletedevelopment of lung tissue. Circulating amniotic fluid,composed primarily of fetal urine, is an important factor inthe development of the fetal lung. When a fetus has absentor minimal urine production because of renal agenesis orother severe renal malformation, the result is oligohydram-nios and concomitant pulmonary hypoplasia or pulmonaryaplasia.

Originally described by Potter (1946), the “oligohydram-nios sequence” (formerly called “Potters syndrome”) pro-duces severe pulmonary hypoplasia with typically flattenedfacial features and limb deformation on the physical examina-tion. There may be renal findings on abdominal exam, andthe obvious oliguria. Lung hypoplasia can be seen on chestradiograph, but is overwhelmingly evident on clinical examwhere the conscious infant has marked respiratory distress.

Pulmonary hypertension leads to cyanosis and hypoxia, andfailure of mechanical ventilation is often associated with pneu-mothorax. The spiral to death is inevitable in severe cases, dueto failure of ventilation and advanced renal dysfunction. This“oligohydramnios sequence” can also occur, although oftenless dramatically, in the presence of a more benign renalabnormality, or when there is prolonged rupture of the mem-branes and chronic loss of amniotic fluid before 26 weeksgestation. In these cases, and depending on severity along thespectrum, less severe pulmonary hypoplasia can be supportedwith mechanical ventilation in the NICU.

Pulmonary Lymphangiectasia. This rare entity is also a re-sult of developmental abnormality where there is congenitaldilation of the pulmonary lymphatic channels. Prenatalsonography can typically detect the lobulation caused bydiffuse dilation of the pleural lymphatics. At birth, in addi-tion to severe respiratory distress, these infants may alsohave coexistent lymphedema. Congenital cardiac malfor-mation is also common. Chest radiograph reveals variablepatterns of marked hyperinflation and atelectasis. When

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BACTERIAL VIRAL OTHER

Group B streptococcus Cytomegalovirus Candida albicans (and other fungi)

Escherichia coli Adenovirus Ureaplasma

Klebsiella Rhinovirus Chlamydia

Staphylococcus aureus Respiratory syncytial virus Syphilis

Listeria monocytogenes Parainfluenza Pneumocystsis jiroveci (carinii)

Enterobacter Enterovirus Tuberculosis

Haemophilus influenza Rubella

Pneumococcus

Pseudomonas

Bacteroides

Citrobacter

Streptococci viridans

Acinetobacter

Stenotrophomonas maltophilia

Table 2. Organisms That May Cause Pneumonia in the Neonate

Note: Adapted from Fisher & Boyce (2005).

unanticipated, diagnosis of this rare disorder is difficult,since the clinical presentation often mimics more commonforms of severe respiratory distress.

Congenital Pulmonary Cysts. Like pulmonary lymphang-iectasia, congenital pulmonary cysts are uncommon, butcan often be detected on prenatal sonography. Cysts cancause disease either as a result of pulmonary hypoplasiawhen there is generalized intrapulmonary cyst formation,or as a result of airway compression in the face of a largeextrapulmonary cyst. The most common congenitalpulmonary cyst is the congenital cystic adenomatoid mal-formation (CCAM) (Al-Bassam et al., 1999). This intrapul-monary disease has a wide range of presentations, fromsingle to multiple cysts, affecting some or all the lung. Cys-tic adenomatoid malformations most commonly presentwith acute respiratory distress in the first few hours of life.Alternatively, it can present at several months of age asrecurrent pneumonias.

Other rare forms of congenital pulmonary cyst includebronchogenic cyst and pulmonary sequestration. Similar tothe case of pulmonary lymphangiectasia, without a sugges-tive prenatal sonogram, congenital pulmonary cysts as anetiology for newborn hypoxia can be an elusive diagnosis.

Pulmonary Lobar Emphysema. This congenital disorder ischaracterized by overdistention of one or more lobes of aninfant’s lungs. This overdistension can be due to an intrinsicairway obstruction or alveolar overgrowth. Severity of symp-toms depends upon the degree of overinflation, and theresultant compression of surrounding lung tissue. Symptomsoften begin at 1 to 2 months of age, but also can present ear-lier in the neonatal period. Similar to pneumothorax, physi-cal examination may reveal decreased breath sounds over theaffected lobe and apical heartbeat displaced to the contralat-eral side. Chest radiograph will demonstrate the hyperinflat-ed lobe, but may be difficult to differentiate from atypicalpneumothorax, congenital pulmonary cysts, or diaphragmat-ic hernia. Diagnosis is radiographic—generally by CT scanafter conventional radiograph is markedly abnormal. Becausenearly 10% of infants displaying this condition have associat-ed anomalies, especially congenital heart defects, genetic eval-uation is suggested (Lacy, Shaw, Pilling, & Walkinshaw,1999).

Airway ObstructionThe newborn is particularly disadvantaged to deal with air-way obstructions because of very small tracheal andbronchial diameters. The risk of obstruction, even frommucus plugging is much increased in neonates than inadults. In addition, chest musculature is weak and the chestwall is relatively compliant, so coughing and deep breathingis comparatively ineffective.

Airway obstruction causes mechanical interference withventilation and results in alveolar hypoventilation. Theneonate with an airway obstruction is usually in obviousdistress. Fortunately, physical examination or chest radi-ograph can usually reveal the source of the obstruction.Both physical examination and chest radiograph are highlyvariable, depending on the etiology of the obstruction, butin many cases, are diagnostic.

Some of the more common airway obstructions are:

Choanal Atresia and Stenosis. This is a complete or par-tial blockage at the posterior nasal chamber, which can beunilateral (80%-90%) or bilateral (Keller & Kacker, 2000).Infants usually present with respiratory distress immediatelyafter birth, because the infant is an obligate nasal breather.Unusually, they become more pink with crying. Duringphysical examination, a 6-Fr catheter cannot be passed intothe nasopharynx. An artificial airway should be providedas soon as possible, until pediatric otolaryngologic evalua-tion is available.

Pierre-Robin Sequence. In this disorder, there is a hy-poplastic mandible, usually associated with a cleft palate,and readily noted on physical examination. Hypoxia occurssecondary to airway obstruction when the tongue falls tothe back of the oral cavity, obstructing the oropharynx.Pulling the tongue forward, caring for this neonate in theprone position, and possibly providing a nasopharyngeal orendotracheal airway may be necessary until otolarygologicevaluation can be obtained.

Macroglossia. In a similar scenario to the Pierre-Robin se-quence, macroglossia results in airway obstruction and hypox-ia when the oversized tongue obstructs the oropharynx. Onphysical examination, the large—or relatively large—tonguecan be realized, and often is noted as one of several features ofa genetic syndrome, such as Beckwith-Wiedemann syndromeor Trisomy 21.

Thyroid Goiter. Neonatal hyperthyroidism is rare inneonates, but is serious and potentially life threatening. Inutero exposure to PTU or excessive iodine may result ingoiter formation, or can result from the transplacental pas-sage of immunoglobulins in mothers with Graves disease.Occasionally, a goiter is sufficiently large to compromisethe neonatal airway, resulting in respiratory difficulty andhypoxia. These large goiters are typically diagnoses in uteroby ultrasonography, but are readily evident on physical ex-amination at birth.

Cystic Hygroma. Cystic hygroma arises as a result of ab-normal development of the lymphatic channels, usually inthe lateral neck. A large ill-defined mass presents in this

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area, and can extend to the scapular, axilla or thorax. Cys-tic hygroma of the mediastinum has also been reported, al-though this more likely presents as a supraclavicular mass.When evident, cystic hygroma distorts the subglottic areaand usually compromises the airway, often requiring endo-tracheal intubation to secure oxygenation and ventilation.

Laryngomalacia, Tracheomalacia, Subglottic Stenosis,and Tracheal Stenosis. In some infants, a combination of anarrow tracheal diameter and insufficient cartilaginous sup-

port in the neck results in luminal compromise with eachinspiration. A characteristic stridor is evident on physicalexamination, and is accentuated with crying. Usually this isa self-limiting condition that resolves by 6 to 12 months ofage. In the rare case where excessive work of breathing andhypoxia is a feature, the high degree of airway obstructionmay require tracheostomy (Gatz, 2001).

Other less common causes of airway obstruction in thenewborn include, but are not limited to the following:• Subglottic Hematoma or Hemangioma• Bronchomalacia or Bronchial Stenosis• Laryngeal Web• Vocal Cord Paralysis• Foreign Body Aspiration• Mucous Plugging

Extrinsic Compression of the Lungsand AirwayExtrinsic lung compression occurs when a space-occupyinglesion consumes volume within the thoracic compartment.Similar to the case of primary pulmonary disease, oxygenwill usually improve a patient’s PaO2 if ventilation is ade-quate. In many cases, however, oxygenation and ventilationis still inadequate despite supplemental oxygen, and me-chanical ventilation needs to be provided to treat hypoxiaand hypercarbia.

Pneumothorax and Pneumomediastinum. The dissectionof air from the alveoli into the mediastinum, and further in-

to the pleural cavity, creates a pneumomediastinum and/orpneumothorax. This air leak occurs more frequently in theneonatal period than any other time in life (Fanaroff, Miller,& Martin, 2002). Spontaneous air leak typically presents asa complication of meconium aspiration, pneumonia, RDS,pulmonary hypoplasia, or any other disease associated withpoor lung compliance, but can also occur in infants withoutunderlying pathology. It is also commonly associated withpositive pressure ventilation or vigorous resuscitation. Pneu-mothorax is reported to occur in approximately 1% of all

live births, but this is probably underreport-ed since asymptomatic air leaks often go un-detected (Al-Bassam et al., 1999).

Clinical signs of pneumothorax includerespiratory distress, tachypnea, nasal flaringand grunting, cyanosis, and even movementof the apical pulse away from the side of thepneumothorax. The most accurate diagnosiscan be made from radiographs, althoughtransillumination of the chest by a skilledclinician can be suggestive with large pneu-mothorax. Severe distress and displacementof the mediastinum (“tension pneumotho-rax”) may require evacuation of air with a

needle or small catheter, or insertion of a closed system chesttube with continuous suction.

Pleural Effusion or Chylothorax. Fluid accumulation in thepleural space most typically represents a chylothorax in theneonate; however, a pleural effusion, empyema, or pleuralhemorrhage can produce similar radiographic changes andclinical findings. Chylothorax is the accumulation of lymphat-ic fluid in the pleural space, and when found in the otherwisehealthy term newborn, may represent. Thoracic duct ruptureat delivery. This is the most frequent cause of a large pleuraleffusion in newborn. In chylothorax, pleural fluid is initiallyserous, but usually turns chylous after milk feedings. Chy-lothorax, and other types of pleural accumulations, are typi-cally diagnosed and managed successfully with thoracenteses.

Congenital Diaphragmatic Hernia. Diaphragmatic hernia,which occurs in about 1 in 2,200 births, is an emergency atbirth, and must be treated upon diagnosis (Golombek,2002). Usually detectable on prenatal sonography, thisanomaly presents with herniation of abdominal contentsinto the thorax because of incomplete formation of thediaphragm. Left sided hernias occur five times more oftenthan those on the right (Braby, 2001; Golombek, 2002).

When the herniation occurs on the left side, the stomachand intestines may enter the thorax and compress the lung,pushing the mediastinum to the right. The degree of distressnoted in the neonate depends on the severity of the herniation.As the neonate begins breathing, the presence of the abdomi-

150 VOLUME 34 | NUMBER 3 May/June 2009

Primary pulmonary diseaseis the most common

etiology for cyanosis andhypoxia in the newborn

population.

nal contents compresses the lungs, making it very difficult tocomplete inspiration. As swallowed air further distends the in-testines and stomach, compressing the lungs even more, theneonate’s respiratory distress worsens.

Symptoms of diaphragmatic hernia include cyanosis, res-piratory distress, a scaphoid abdomen, and sometimes bowelsounds in the chest on auscultation. Chest radiograph show-ing the loops of bowel in the thorax confirms the diagnosis.

Immediate insertion of a nasal gastric tube attached tosuction to evacuate abdominal gas is indicated. Ventilation isusually needed and should be done through an endotrachealtube, as bag and mask ventilation introduces air into the gas-trointestinal tract, further compromising space in the chestcavity. Respiratory therapies should address the frequently as-sociated hypoxia of persistent pulmonary hypertension. Ur-gent evaluation by a pediatric surgical team is requisite.

Mediastinal Masses. Mediastinal masses in neonates occurinfrequently. Teratomas and dermoids are the most commonof these lesions. They are neurogenic in origin, and typicallylocated in the anterior mediastinum. On chest radiograph,soft tissue density characteristic, and there may be calcificationor fat density areas within the region of the mass as well. An-terior mediastinal masses can displace the trachea, producinga clinical picture similar to airway obstruction. Middle andposterior mediastinal masses are less likely to produce respira-tory distress and hypoxia, as displacement of the esophagus ismore likely. Ultrasonography, CT, MRI and contrast radi-ographs are all useful in the evaluation of these lesions.

Thoracic Dystrophies or Dysplasias. Now exceedingly un-common, these problems result from shortened ribs, anelongated thoracic cage and a resultant respiratory compro-mise. Many are associated with other congenital defects ordwarfism. Jeune syndrome (or “asphyxiating thoracic dys-trophy”) is one such complex disorder, which often resultsin death during infancy or early childhood.

Extralobar Sequestration. Extralobar sequestration occurswhen lung tissue develops with no identifiable bronchialcommunication, and that receives its blood supply fromone or more anomalous arteries. Infants can be asympto-matic, present with respiratory distress at birth, or presentlater in infancy with a chronic cough. In addition to vascu-lar anomalies, the malformation has been reported in asso-ciation with CHD (Harris, 2004). Diagnosis is generallymade by CT scan after abnormal radiographic or sono-graphic evaluation. Surgical intervention or vascular em-bolization is often indicated.

Other less common causes of extrinsic compression ofthe airway and lungs in the newborn include:• Right/Double Aortic Arch• Tracheal Vascular Ring• Pulmonary Artery Sling• Cricoid Cartilage Malformation

In the final of this three-part series to be found in theJuly/August 2009 issue of MCN (volume 34, no. 4),neurologic, metabolic, and hematologic disorders will bereviewed as a basis for newborn hypoxia. �

Annie J. Rohan is a Senior Nurse Practitioner, Stony BrookHospital-Stony Brook, and Jonas Nursing Scholar, Colum-bia University School of Nursing, PhD Program, New York,NY. She can be reached via e-mail at ajr73@columbia.edu

Sergio G. Golombek is an Associate Professor of Pediatricsand Clinical Public Health, New York Medical College, NewYork, NY, and Attending Neonatologist, Maria Fareri Chil-dren’s Hospital of Westchester Medical Center, Valhalla, NY.

The authors have disclosed that they have no financialrelationships related to this article.

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