Transcript Bronchopulmonary Dysplasia

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
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Birth history/Delivery room course:
o
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Mom is a 25yo G2P2 who came into L&D at 23 wks with preterm labor and
rupture of membranes.
Mom did not receive antenatal steroids
Serologies: A+, RPR NR, Hep B neg, RI, HIV neg, GBS unknown
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).
At delivery, the infant had a HR>100, but no respiratory effort, and was limp
and blue
He required intubation and PPV and color/tone improved.
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 nondistended
• 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.