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Neonatal Respiratory DistressNeonatal Respiratory Distress
Priscilla Joe, MDChildren’s Hospital and Research
Center at Oakland
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Neonatal Respiratory DiseaseNeonatal Respiratory Disease
Upper airway diseaseTrue parenchymal diseaseAirleak syndromesDisorders of developmentPrimary pulmonary vascular disease
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Upper Airway DiseaseUpper Airway Disease
Choanal atresiaPierre Robin sequenceVascular rings
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Choanal Atresia
Pierre Robin Syndrome
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Choanal Atresia/Upper Airway Choanal Atresia/Upper Airway ObstructionObstruction
Cyanotic when quiet or at rest, pink with crying
Inability to pass suction catheter through nares
Stridor
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Upper airway obstructionUpper airway obstruction
Insert an oral airwayProvide oxygenSuction secretionsMay require intubation
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Fetal Lung CharacteristicsFetal Lung Characteristics Decreased blood flow
– caused by compression of the pulmonary capillaries by fetal lung fluid
Pulmonary arteries– thick muscular layer present, very reactive to hypoxemia
Lung fluid secretion– fetal lungs secrete fluid, adequate lung volume is necessary for fetal
development
Fetal breathing– contributes to fetal lung development, moves fluid in and out of fetal lung
Surfactant– necessary amount to support breathing after birth, present after ~ 34
weeks gestation
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TransitionTransition
Clearance of fetal lung fluidIncreased complianceIncreased pulmonary blood flow
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Respiratory Distress Respiratory Distress SyndromeSyndrome
Disease of surfactant defiencySurfactant decreases surface tension
and improves lung complianceSurface tension: intrinsic tendency for
alveoli to collapse
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Compliance
Pressure
Volume
Opening pressures
Maximal volume
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RDS: Risk FactorsRDS: Risk Factors
Prematurity: Males Second born twins C-section Caucasian race
Secondary surfactant deficiency:
Maternal diabetes Asphyxia Pneumonia Pulmonary hemorrhage Meconium aspiration Oxygen toxicity
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RDS: Clinical FindingsRDS: Clinical Findings
Non-specific findings of respiratory distress– Grunting– Flaring– Retracting
O2 requirement
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RDS: RadiographyRDS: Radiography
Alveolar disease:• Diffuse reticular granular or “ground
glass”pattern• Air bronchograms• Underaeration
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RDS: TreatmentRDS: Treatment
Maintain FRC (CPAP vs. intubation)Surfactant replacementExogenous surfactants
– Survanta 4cc/kg– Infasurf 3cc/kg
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Surfactant Therapy for RDSSurfactant Therapy for RDS
Decreases mortality
Greatest benefit when used with antenatal steroids
Improvement in compliance, functional residual capacity, and oxygenation
Reduces incidence of air leaks
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Congenital PneumoniaCongenital Pneumonia
Common organisms:Group B streptococcusE.Coli, KlebsiellaChlamydia, Ureaplasma, mycoplasmaListeriaTORCHH. Influenza (nontypeable)
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Pneumonia: Risk FactorsPneumonia: Risk Factors
Maternal chorioamnionitisProlonged rupture of membanesPrematurityPostnatal exposures: Poor hand
washing, open skin lesions, contaminated blood products, infected breast milk
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PneumoniaPneumonia
Inflammation and edemaBronchial pluggingSurfactant inactivation
– Alveolar collapse– Ventilation/perfusion mismatch– Desaturation
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Pneumonia: Clinical FindingsPneumonia: Clinical Findings
Presents with non-specific findings of respiratory distress– Grunting – Flaring– Retracting
O2 requirement
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Pneumonia: RadiographyPneumonia: Radiography
There are no classic x-ray findings, in fact, the X-ray in pneumonia can look like anything– Fairly normal– Classic RDS– Classic for MAS
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Pneumonia: TreatmentPneumonia: Treatment
Respiratory support as indicated with either O2 or positive pressure
Treatment with appropriate antimicrobials– Initial ampicillin/gentamicin or
ampicillin/cefotaxime– Broader spectrum antibiotics for
nosocomial bacteria
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Meconium Aspiration Meconium Aspiration SyndromeSyndrome
Meconium contains epithelial cells and bile salts
Released with intrauterine stress or asphyxia
Present in 15% of all newborns. Only 5-10% develop MAS
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Meconium AspirationMeconium Aspiration
Airway plugging, with air trapping Inflammation, leading to inactivation of
surfactant Surfactant inactivation leads to decreased
compliance, and alveolar collapse Alveolar collapse = loss of FRC Loss of FRC = V/Q mismatch V/Q mismatch = desaturation
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Meconium aspiration: XrayMeconium aspiration: XrayAreas of hyperexpansion mixed with
patchy densities and atelectasis
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PneumothoraxPneumothorax
May occur spontaneously during delivery
Most common when receiving positive pressure
Space occupying lesion within the chest displacing lung, and if under tension, compromising venous return
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Pneumothorax: Clinical Pneumothorax: Clinical FindingsFindings
Presents with non-specific signs of respiratory distress– Grunting– Flaring– Retracting
O2 requirementUnequal, decreased breath sounds
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Pneumothorax: TreatmentPneumothorax: Treatment
O2 as needed– Nitrogen washout (pneumo contains 21%
O2, >75% nitrogen, if lung has 100% O2, nitrogen will diffuse out of pneumothorax)
Try to avoid positive pressure if ableEvacuate as needed by thoracentesis
or chest tube
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Developmental disturbancesDevelopmental disturbances
Pulmonary hypoplasiaCongenital diaphragmatic herniaSkeletal deformities
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Pulmonary hypoplasiaPulmonary hypoplasia
Cannot be assessed radiographically, pulmonary hypoplasia is a pathologic diagnosis
Suspect pulmonary hypoplasia if:– Rupture of membranes with anhydramnios– Renal anomalies– Restriction of the chest wall– Congenital diaphragmatic hernia
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Diaphragmatic HerniaDiaphragmatic Hernia
Scaphoid abdomenBowel sounds in the chestOther associated anomaliesDecreased breath soundsSevere hypoxemia
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Diaphragmatic HerniaDiaphragmatic Hernia
Wide range in clinical presentationHerniation of bowel leads to altered
development of the lungs bilaterally
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Persistent Pulmonary Persistent Pulmonary Hypertension of the NewbornHypertension of the Newborn
Primary pulmonary hypertension is a pure vascular disease
More often present in a mixed picture as in the setting of meconium aspiration syndrome or asphyxia
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PPHNPPHN
In response to an asphyxia event in utero, the fetus diverts all blood flow possible to vital organs (brain/heart/adrenals)
This leads to vasoconstriction of non-vital vascular beds, including the pulmonary bed
Remodeling of smooth muscle can occur
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PPHNPPHN
IncreasedPVR
RV outflow
AortaPA
PDA
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PPHN: Clinical FindingsPPHN: Clinical Findings
Respiratory distress with hypotensionHypoxemia out of proportion to degree
of distressDifference in pre and post ductal sats
– Right hand– Lower extremities– Hyperoxia test
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PPHNPPHN
Decreases R L shunt:
Decrease PVR
Increase pulmonary blood flow– Hyperoxia– Hypocarbia– Lack of acidosis
Increases R L shunt:
Increase PVR
Decrease pulmonary blood flow– Hypoxia– Hypercarbia– Acidosis
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PPHN: TreatmentPPHN: TreatmentImprove pulmonary blood flow:
– Keep well saturated– Normocarbia
Avoid:– Hypoxia– Hypercarbia– Acidosis
Supportive care: temperature regulation, fluids and lytes, antibiotics
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PPHN: TreatmentPPHN: Treatment
Conventional ventilation or HFOVNitric oxideSurfactant replacementECMO