Bronchopulmonary Dysplasia

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					Bronchopulmonary Dysplasia


      NICU Night Curriculum
      Learning Objectives
• To understand the clinical course and presentation
  of bronchopulmonary dysplasia in the premature
  infant

• To understand the epidemiology and physiology of
  bronchopulmonary dysplasia

• To review the management of bronchopulmonary
  dysplasia
                    Case #1
• It’s July, and you’ve just started your first month as
  a pediatrics intern… and you’re scheduled to start
  in the NICU. Someone signed out to you last night,
  but they were hurrying to make it in time for their
  “I’ll never be an intern again party” and you didn’t
  ask a lot of questions because you didn’t want to
  look dumb (already!). So you really don’t have
  any clue what is going on, and here is your first
  patient…
               Case: One-liner
• Baby Smith is an ex-23 wk infant, now 60 days old,
  who has a history of RDS, grade II IVH, and feeding
  intolerance, who is currently still intubated.

• SO… what can you gather so far?
   o What is the baby’s corrected gestational age?
   o How bad do you think his lungs are?
   o What other things might you want to know from his history that would
     support your assessment of his lung disease?
              Case: One-Liner
• Baby Smith is an ex-23 wk infant, now 60 days old, who
  has a history of RDS, grade II IVH, and feeding
  intolerance, who is currently still intubated

• SO… what can you gather so far?
   o What is the baby’s corrected gestational age?
      • 32 weeks
   o How bad do you think his lungs are?
      • Pretty bad
   o What other things might you want to know from his history that would support
     your assessment of his lung disease?
      • Maternal history, delivery, hospital course
Case: Pertinent History
•   Maternal history:
     o   Mom is a 25yo G2P2 who came into L&D at 23 wks with preterm labor and
         rupture of membranes.
     o   Mom did not receive antenatal steroids
     o   Serologies: A+, RPR NR, Hep B neg, RI, HIV neg, GBS unknown

•   Birth history/Delivery room course:
     o   The peds team was called to a code blue for 23 wk prematurity and
         precipitous delivery (she delivered 1 hour after arriving to L&D).
     o   At delivery, the infant had a HR>100, but no respiratory effort, and was limp
         and blue
     o   He required intubation and PPV and color/tone improved.
     o   Apgars were 2 and 7. BW was 600grams.


•   WHAT ASPECTS OF THIS HISTORY MAKE YOU WORRY
    ABOUT HIS LUNGS?

     o His risk factors for chronic lung disease are:
       Prematurity, NO antenatal steroids, low birth
       weight
        Case: NICU course
• NICU course:
  o Respiratory: Infant was brought back to unit intubated, but was found to
    have a pneumothorax on admission CXR. Chest tube was placed and no
    other doses of surfactant were given.
  o Since then, infant has been intubated. Around DOL 30, extubation was
    attempted, but the baby had significant desaturations and increased
    work of breathing and was reintubated. Same story around DOL 50, but he
    lasted maybe a week before reintubation.
      Case: At the bedside
• At the bedside:
   o Physical exam:
       • Gen: You see a small baby, who is
          intubated.
       • CV:When you listen to his chest, you hear
          regular heart sounds and III/VI systolic
          murmur.
       • Pulm: You notice coarse breath sounds
          bilaterally, with occasional rales, fair chest
          rise with each ventilator breath and
          occasionally, he spontaneously takes his
          own breaths.
       • Abdom: His abdomen is soft and non-
          distended
       • Neuro: He moves his arms and legs around
          while you are examining him.
   o You look over at his ventilator and he’s on the
     following settings:
       • FiO2 55%, Pressure control 20, Pressure
          support 14, rate 45, I-time 0.35, PEEP 6
  Case: Imaging
• His chest xray today:
   o What do you see on this xray (Give 4 findings)?
               Case: Imaging
o What do you see on
  his xray?
   • ETT
   • Nasal Gastric Tube
   • Normal cardiac
      sillhouette
   • Bones look normal
   • GROUND GLASS
      APPEARANCE OF
      LUNGS
             Blood Gas
• Labs: BMP, CBC are normal. Capillary
  blood gas today: 7.25/65/28/+1
   o What does this gas show?
    • RESPIRATORY ACIDOSIS
            Case: Diagnosis?
• Based on this baby’s history, exam, labs and xray
  findings, what do you think is the diagnosis?

• This baby is likely developing bronchopulmonary
  dysplasia (or chronic lung disease)
   o but we will try and make some management changes during your month
     in the NICU to help him out.

   o We can then evaluate the baby at 36 weeks corrected GA (the end of
     your month) to see if he fits the criteria for BPD.
       Bronchopulmonary
           Dysplasia
• Most common severe complication of prematurity

• First defined by Northway in 1967: lung disease resulting from
  prolonged mechanical ventilation in premature infants with
  surfactant deficiency

• NICHD criteria: need for oxygen based on GA and severity
  of disease
         Bronchopulmonary
             Dysplasia
• “Old BPD” (before surfactant
  and steroids)
   o Cystic changes, heterogeneous
     aeration

• “New BPD” (after surfactant
  and steroids)
   o More uniform inflation and less
     fibrosis, absence of small and large
     airway epithelial metaplasia and
     smooth muscle hypertophy
   o Some parenychmal opacities, but
     more homogenous aeration and less
     cystic areas
   o PATHOLOGIC HALLMARKS: larger
     simplified alveoli and dysmorphic
     pulmonary vasculature
                    Epidemiology
• Incidence:
   o 42-46% (BW-501-750g)
   o 25-33% (BW=751-1000g)
   o 11-14% (BW=1001=1250g)
   o 5-6% (BW=1251-1500g)


• Risk factors:
   o Prematurity, low BW
   o White boys
   o Genetic heritability
Pathogenesis
               Pathophysiology
•   Old BPD:
    o Airway injury, inflammation and
      parenchymal fibrosis due to
      mechanical ventilation and oxygen
      toxicity




•   New BPD:
     o Decreased septation and alveolar
      hypoplasia leading to fewer and
      larger alveoli, so less surface area
      for gas exchange
    o Dysregulation of vascular
      development leading to
      abnoraml distribution of alveolar
      capillaries and thickened
      muscular layer of pulmonary
      arterioles
      Clinical Presentation
• Need for supplemental oxygen. Hypoxemic and
  hypercapneic.
• Exam: tachypnea, retractions, scattered rales
• CXR: diffusely hazy with alternating areas of atelectasis
  and hyperexpansion; streaky densities or cystic areas,
  edema


• CLINICAL COURSE: Tend to slowly improve and wean off
  respiratory support. May have intermittent episodes of
  acute deterioration if severe disease. May also develop
  pulmonary hypertension when severe
    Treatment: Prevention
• Prevention:
  o Avoidance of preterm birth
  o Antenatal steroids
Treatment: management
      by phases
                  Case: Current
                  Management
•   FEN: TF 150ml/kg/d of continuous NGT feeds of SSC 24 kcal. Has
    been gaining about 70 grams/week for the last two weeks.

•   Resp: currently intubated at the aforementioned settings with
    blood gas from last slide.

•   CV: last echo done 2 weeks ago shows a small PDA and PFO. No
    evidence of RVH.

•   Heme: Hematocrit=24 checked 2 days ago

•   Meds: multivitamin, iron, caffeine

•   So, in practical terms, what things could you do to optimize his
    management over the next few weeks?
                  Case: Current
                  Management
• FEN:
   o Fluid restriction/diuretics
   o Optimize caloric intake and growth

• Resp:
   o Ventilator management
   o Give steroids before another extubation attempt?

• CV:
   o PDA closure?

• Heme:
   o Transfusion to improve oxygen carrying capacity
                          Prognosis
• Morbidity:
   o Higher rates of hospitalization in the first year of life e.g. resp infections
   o Respiratory symptoms may persist into adulthood
        • Abnormal pulmonary function
        • Asthma-like symptoms
   o Airway abnormalites e.g. tracheomalacia
   o Pulmonary artery hypertension


• BPD associated with worse neurodevelopmental
  outcomes
        Review Questions
• 1. What is BPD?

• 2. Who is at risk for developing BPD?

• 3. How is old and new BPD different?

• 4. What is the clinical course of BPD?

• 5. What are some methods of managing BPD?

• 6. What is the long-term outcomes of BPD?
                 Review Answers
•   1. What   is BPD?

    Lung disease of premature infants, characterized by abnormal
    alveolarization and pulmonary vascularization.

• 2. What are the greatest risk factors for developing BPD?

    Prematurity and low birth weight

• 3. How is old and new BPD different?

    Old is before surfactant and antenatal steroids, and has more
    inflammation and fibrosis, whereas new BPD is post-surfactant and
    steroids, and shows fewer and larger alveoli.
            Review Answers
• 4. What is the clinical course of BPD?.

  Infants with BPD tend to improve slowly over time, requiring
  less and less respiratory support. But in severe cases, infants
  can have “BPD exacerbations”, require tracheostomy, or
  develop cor pulmonale.

• 5. What are some methods of managing BPD?

  Fluid restriction, diuretics, optimize nutrition, permissive
  hypercapnea, lower goal oxygen saturations, steroids

• 6. What is the long-term outcomes of BPD?

  Infants with BPD may have abnormal respiratory function,
  asthma-like symptoms, airway problems, and/or require more
  frequent hospitalization later in childhood. In addition, studies
  show that BPD is associated with worse neurodevelopmental
  outcomes.
                      References
•   Adams et al. Pathogenesis and clinical features of
    bronchopulmonary dysplasia. UpToDate. May 2011.

•   Bhandari A and Vineet Bhandari. Pitfalls, Problems, and Progress
    in Brocnhopulmonary Dysplasia. Pediatrics. 2009;123; 1562-1573.

•   Fanaroff AA, et al. Trends in neonatal morbidity and mortality for
    very low birthweight infants. Am J Obstet Gynecol. 2007: 196(2):
    147.e1-147.e8.

•   Harris et al. Pulmonary outcomes in bronchopulmonary dysplasia.
    UpToDate. May 2011.

•   Jobe Alan H. The new bronchopulmonary dysplasia. Current Opin
    Peds. 2011, 23: 167-172.

				
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posted:6/13/2012
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