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Neonatal Respiratory Distress. Priscilla Joe, MD Children’s Hospital and Research Center at Oakland. Neonatal Respiratory Disease. Upper airway disease True parenchymal disease Airleak syndromes Disorders of development Primary pulmonary vascular disease. Upper Airway Disease.
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Neonatal Respiratory Distress Priscilla Joe, MDChildren’s Hospital and Research Center at Oakland
Neonatal Respiratory Disease • Upper airway disease • True parenchymal disease • Airleak syndromes • Disorders of development • Primary pulmonary vascular disease
Upper Airway Disease • Choanal atresia • Pierre Robin sequence • Vascular rings
Choanal Atresia Pierre Robin Syndrome
ChoanalAtresia/Upper Airway Obstruction • Cyanotic when quiet or at rest, pink with crying • Inability to pass suction catheter through nares • Stridor
Upper airway obstruction • Insert an oral airway • Provide oxygen • Suction secretions • May require intubation
Fetal 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
Transition • Clearance of fetal lung fluid • Increased compliance • Increased pulmonary blood flow
Respiratory Distress Syndrome • Disease of surfactant defiency • Surfactant decreases surface tension and improves lung compliance • Surface tension: intrinsic tendency for alveoli to collapse
Prematurity: Males Second born twins C-section Caucasian race Secondary surfactant deficiency: Maternal diabetes Asphyxia Pneumonia Pulmonary hemorrhage Meconium aspiration Oxygen toxicity RDS: Risk Factors
RDS: Clinical Findings • Non-specific findings of respiratory distress • Grunting • Flaring • Retracting • O2 requirement
RDS: Radiography Alveolar disease: • Diffuse reticular granular or “ground glass”pattern • Air bronchograms • Underaeration
RDS: Treatment • Maintain FRC (CPAP vs. intubation) • Surfactant replacement • Exogenous surfactants • Survanta 4cc/kg • Infasurf 3cc/kg
Surfactant 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
Congenital Pneumonia Common organisms: • Group B streptococcus • E.Coli, Klebsiella • Chlamydia, Ureaplasma, mycoplasma • Listeria • TORCH • H. Influenza (nontypeable)
Pneumonia: Risk Factors • Maternal chorioamnionitis • Prolonged rupture of membanes • Prematurity • Postnatal exposures: Poor hand washing, open skin lesions, contaminated blood products, infected breast milk
Pneumonia • Inflammation and edema • Bronchial plugging • Surfactant inactivation • Alveolar collapse • Ventilation/perfusion mismatch • Desaturation
Pneumonia: Clinical Findings • Presents with non-specific findings of respiratory distress • Grunting • Flaring • Retracting • O2 requirement
Pneumonia: 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
Pneumonia: 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
Meconium Aspiration Syndrome • Meconium contains epithelial cells and bile salts • Released with intrauterine stress or asphyxia • Present in 15% of all newborns. • Only 5-10% develop MAS
Meconium 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
Meconium aspiration: Xray • Areas of hyperexpansion mixed with patchy densities and atelectasis
Pneumothorax • 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
Pneumothorax: Clinical Findings • Presents with non-specific signs of respiratory distress • Grunting • Flaring • Retracting • O2 requirement • Unequal, decreased breath sounds
Pneumothorax: 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 able • Evacuate as needed by thoracentesis or chest tube
Developmental disturbances • Pulmonary hypoplasia • Congenital diaphragmatic hernia • Skeletal deformities
Pulmonary 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
Diaphragmatic Hernia • Scaphoid abdomen • Bowel sounds in the chest • Other associated anomalies • Decreased breath sounds • Severe hypoxemia
Diaphragmatic Hernia • Wide range in clinical presentation • Herniation of bowel leads to altered development of the lungs bilaterally
Persistent Pulmonary Hypertension 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
PPHN • 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
PPHN Increased PVR PDA RV outflow PA Aorta
PPHN: Clinical Findings • Respiratory distress with hypotension • Hypoxemia out of proportion to degree of distress • Difference in pre and post ductal sats • Right hand • Lower extremities • Hyperoxia test
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 PPHN
PPHN: Treatment • Improve pulmonary blood flow: • Keep well saturated • Normocarbia • Avoid: • Hypoxia • Hypercarbia • Acidosis • Supportive care: temperature regulation, fluids and lytes, antibiotics
PPHN: Treatment • Conventional ventilation or HFOV • Nitric oxide • Surfactant replacement • ECMO