Respiratory problems in neonate

1. RespiRatoRy pRoblems
in neonate
DR/Mohamed abdelaziz ali
ali
31-12-2013

2. Embryology and post-natal development of the
respiratory system
•Embryonic phase (3-5 weeks' gestation) - the lung bud begins as an
endodermal outgrowth of foregut. This branches into the surrounding mesoderm to
form the main bronchi
•Pseudoglandular phase (6-1 6 weeks) - airways branch further to terminal
bronchioles (preacinar airways). Cartilage, lymphatics and cilia form. Main
pulmonary artery forms from sixth left branchial arch
• Canalicular phase (1 7-24 weeks) - airways lengthen, epithelium becomes
cuboidal, pulmonary circulation develops The acinar structures (gas-exchanging
units) begin to develop and surfactant production begins by 24 weeks' gestation a
type 1 and 2 pneumocytes become distinguishable. Lungs fill with amniotic fluid,
which facilitates further lung growth
• Terminal sac phase (24-40 weeks) - further development of the acinar
structures (respiratory bronchioles, alveolar ducts and terminal sacs (alveoli)) occurs
and increasing amounts of surfactant are produced. Type 1 pneumocytes eventually
cover approximately95% of the alveolar surface and facilitate gas exchange. The
surfactant-producing type 2

3. cells cover only about 5%. 'Development of the pulmonary circulation continues and
results in a thicker intra-arteriolar smooth muscle layer by term, which may respond to
intrauterine hypoxia by vasoconstriction. This regresses rapidly after birth
• Post-natal lung development - the number and size of alveoli increases
rapidly during the first 2 years (approximately 150 million at term to 400 million by 4
years). The conducting airways also increase in size
• Diaphragm development - arises as a sheet of mesodermal tissue, the
septum transversum. It begins close to the third, fourth and fifth cervical segments and
therefore its nerve supply, the phrenic nerve, is derived from this area. The primitive
septum transversum migrates caudally to form the pleural space and the two
posterolateral canals in which the lung buds develop fuse. Failure to do this results in a
Bochdalek hernia. Failure of the retrosternal part of the septum transversum to form
causes a Morgagni-type diaphragmatic hernia. The diaphragm is completed as primitive
musclecells migrate from the body wall. If this fails eventration of the diaphragm results

4. 1-Surfactant deficiency
•Endogenous surfactant is produced by type 2 pneumocytes, which line 5- 10% of
the alveolar surface. Surfactant-containing osmiophilic granular inclusion bodies
cause these to appear different from the thinner and more numerous type 1
pneumocytes, which are responsible for gas exchange.
•Composition of endogenous surfactant
1-Phospholipids - 85%
2-Neutral lipids - 1O%
3-Apolipoproteins - 5 %
•Estimated incidence of surfactant deficiency by gestational age
(without maternalsteroids)
Gestation (completed weeks) Incidence of surfactant deficiency (%)
26 90%
28 80%
30 70%
32 55%
34 25%
36 12%
38 3%
40 >1-2%

5. Surfactant deficiency is decreased in:
• Female sex
• PROM
• Maternal opiate use
• IUGR
• Antenatal glucocorticoids
• Prophylactic surfactant
Surfactant deficiency is increase in:
• prematurity
• male sex
• sepsis
• maternal diabetes
• second twin
• elective caesaren section
• strong family history
Amniotic fluid (or gastric aspirate) lecithin : sphingomyelin (L : S)
ratios .
<1.5 = immature - 70% risk of surfactant deficiency
1.5-1.9 = borderline - 40% risk of surfactant deficiency
2.0-2.5 = mature - very small risk unless mother is diabetic
>2.5 = safe

6. Management of surfactant deficiency:
1-maternal antenatal corticosterids (betamethasone or dexamethasone before
preterm birth reduse the effects of surfactant and have been shown to:
• reduce neonatal mortality by about 31%
• decrease inttraventricular hge by about 46%
• reduce risk of necrotisig enterocolitis (NEC)
• decrease need of respiratory support for respiratory distress syndrome(RDS)
• reduce risk in infection in the frist 24 hs
the current royal college of obestetrician and gynnecologist (RCOG) suggest
given corticosteroids to women with likely preterm birth betweeb week 24 and 34 of
gestation, and also consider in those from 23 week as well as before before any
elective caesarean section up to 38 week.
1-no evidence that routine high-frequency oscillation is of any long-term
benefit in pre-term infants with surfactant deficiency, although this mode of ventilation
maybe used as a 'rescue' in severe cases.

2-Routine paralysis is not used in most neonatal units,although this sedation with
opiates and various modes of trigger ventilation may help to reduce the incidence of
pneumothoraces.
3-Exogenous surfactant considerably reducesortality and incidence of
pneumothoraces and chronic lung disease. Early treatment withsurfactant and use of
animal rather than synthetic surfactants enhance these outcomes.

7. The production of pulmonary surfactant

8. Sufactant deficiency use

9. 2-Chronic lung disease
(bronchopulmonary dysplasia)
Definition:
•respiratory support with supplementary oxygen +I- mechanical ventilation for>28
days with typical chest X-ray changes.
•In very-low-birth-weight (VLBW)infants an alternative definition has been suggested
- requiring oxygen +I- mechanical ventilation >36 weeks' corrected gestational age
and typical chest X-ray changes.
Risk factors for chronic lung disease:
•Prematurity
•Prolonged mechanical ventilation with high pressures and high functional inspired
oxygen (Fi02)
•Baro- (volume) trauma
•Pulmonary air leak (pneumothoraces or pulmonary interstitial emphysema)
•Gastro-oesophageal reflux
•Patent ductus arteriosus (PDA)
•Pulmonary infection (particularly Ureaplasma urealyticum)

10. Radiological stages:
Stage 1 1 st few days indistinguishable from surfactant deficiency
Stage 2 2nd week generalized opacity of lung fields
Stage 3 2-4 weeks streaky infiltrates
Stage 4 >4 weeks hyperinflation, cysts, areas of collapse or
consolidation,cardiomegally
Management of chronic lung disease:
• Ventilatory support as required
•Supplementary oxygen to maintain oxygen saturations 94-96% or p(02) >7 kPa (to
reduce risk of pulmonary hypertension and cor pulmonale)
•Good nutrition is of paramount importance; increased alveolar growth accompanies
general growth - particularly in the first 1-2 years
•Treatment of underlying exacerbating factors - infection, gastro-oesophageal
reflux, fits, cardiac problems, etc.
•Dexamethasone - the only proven benefit is to facilitate weaning off mechanical
ventilation but concern has been raised over short- and long-term side-effects,
particularly adverse neurodevelopmental outcome

11. •Inhaled steroids - only proven benefit is to reduce the need for systemic steroids
Bronchodilators
•Diuretics – only likely to be of benefit in the presence of PDA, cor pulmonale or
excessive weight gain
•Respiratory syncytial virus (RSV) prophylaxis with monoclonal antibodies
(Palivizumab) has been shown to reduce hospitalization in high risk cases, but use is
controversial because of the high cost of the drug and the need for monthly
intramuscular injectionsthroughout the RSV season

12. bronchopulmonary dysplasia

13. 3-Meconium aspiration syndrome
(MAS)
Risk factors
•Term or post-term (incidence much higher in births after 42 weeks)
•Small for gestational age
•Perinatal asphyxia
•Rare in pre-term but said to occur with congenital listeriosis (more likely to be pus
than meconium). The passage of meconium in fetal distress may. -be the result of
increased secretion of motilin. Meconium may be inhaled antenatally or- post-natally.
Antenatal inhalation is more likely in fetal distress because of abnormal fetal
breathing (equivalent to gasping) that occurs with hypoxia and acidosis.
Major effects of MAS on lung function
•Airway blockage
lncreased airways resistance with ball-valve mechanism and gas trapping
High risk of pneumothorax
•Chemical pneumonitis
•lncreased risk of infection
Even though meconium is sterile
Escherichia coli is the most common infective agent
•Surfactant deficiency
Lipid content of meconium displaces surfactant from alveolar surface
Persistent pulmonary hypertension of the newborn
MAS changes on chest X-rays include initial patchy infiltration and hyperinflation.
Pneumothoraces are common at this stage. A more homogeneous opacification of the
lung

14. management
•Uncontrolled trials of vigorous airway suction immediately after delivery suggest that
it is possible to reduce the incidence of MAS.
• Intubation for lower airway suction is only neededif meconium can be seen below
the vocal cords.
•Thoracic compression and routine bronchial lavage have no proven benefit.
•Thoracic compression and routine bronchial lavage have no proven benefit.
Intermittent positive-pressure ventilation with a relatively long expiratory time to
prevent further gas trapping may be required in moderate to severe MAS.
•Surfactant replacement therapy in infants with MAS has proven benefit, but large
doses may be required.
•Extracorporeal membrane oxygenation (ECMO) may be used in the most severe
cases.

15. Meconium aspiration syndrome

16. 4-Pneumonia
Pneumonia can be congenital, intrapartum or nosocomial.
Congenital
Onset is usually within 6 hours of birth.
•Bacterial
Streptococci (group B streptococcus)
Coliforms (E. coli, Klebsiella, Serratia, Shigella, Pseudomonas etc.)
Pneumococci
Listeria
•Viral
CMV
Rubella virus
Herpes simplex virus
Coxsackievirus
•Other
Toxoplasmosis
Chlamydia
Ureaplasma urealyticum
Candida

17. Intraparturn
Onset is usually within 48 hours.
• Bacterial
Group B streptococci
Coliforms (as above)
Haemophilus
StaphylococciPneumococci
Listeria
•Viral
Herpes simplex virus
Varicella zoster virus
Nosocomial
Onset is after 48 hours.
•Bacterial
Staphylococci
Streptococci
Pseudornonas
Klebsiella
•Viral
RSV
Adenovirus
Influenza viruses
Parainfluenza viruses
Common cold viruses

18. 5-Pulmonary air leak
Pneumothorax:
• Occurs in up to 1% of otherwise healthy term
infants (it is usually asymptomatic).
• Overdistension of alveoli is more likely to occur
in immature lungs because of a decreased
number of pores of Kohn, which redistribute
pressure between alveoli. Air ruptures through
overdistended alveolar walls and moves towards
the hilum where it enters the pleural or
mediastinal space.
• More common in surfactant deficiency, MAS,
pneumonia and pulmonary hypoplasia.
• Risk is reduced by lower ventilator pressures to
avoid overdistension, faster rate ventilation with
shorter inspiratory times, paralysis of infants
fighting the ventilator and sutfactant replacement
therapy.

19. Pulmonary interstitial emphysema:
• May occur in up to 25% of VLBW infants, usually confined to those with the worst
surfactant deficiency
• May be more common in chorioamnionitis
• Alveolar rupture results in small cysts in the pulmonary interstitium
• Ventilation is difficult and mortality and incidence of chronic lung disease are
high
Pneumomediastinum
•May complicate surfactant deficiency or other forms of neonatal lung disease, when it
may coexist with pneumothorax or may be iatrogenic following tracheal rupture
secondary to intubation
•No symptoms may occur in isolated pneumomediastinum, but respiratory and
cardiovascular compromise are more likely to occur if pneumothorax is also present

20. 6-Congenital lung problems
Pulmonary hypoplasia
Primary pulmonary hypoplasia is rare but may present with persistent
tachypnoea which resolves with lung growth several months after birth
Secondary pulmonary hypoplasia may be the result of:
•Reduced amniotic fluid volume - Potter syndrome (renal agenesis) or other severe
congenital renal abnormalities resulting in markedly decreased urine volume
(infantile (autosomal recessive) polycystic kidney disease, severe bilateral renal
dysplasia, posterior urethral valves)
•Pre-term rupture of membranes - only occurs if membranes ruptured before 26
weeks; 23% of pregnancies with rupture of membranes before 20 weeks are
unaffected; outcome with rupture of membranes before 24 weeks is usually poor,
•Amniocentesis - mild to moderate respiratory symptoms are more likely to occur in
the neonatal period and incidence of respiratory symptoms in the first year of life is
increased
•Lung compression - pulmonary hypoplasia is common in small-chest syndromes
including asphyxiating thoracic dystrophy and thanatophoric dwarfiim, diaphragmatic
hernia, congenital cystic adenomatoid malformation and pleural effusions Reduced
fetal movements - pulmonary hypoplasia occurs in congenital myotonic dystrophy,
spinal muscular atrophy and other congenital myopathies.
•Outcome with pulmonary hypoplasia depends on the severity and the underlying
cause.

21. Pulmonary hypoplasia

22. Congenital diaphragmatic hernia
• Commonest congenital abnormality of the respiratory system - incidence is 1 in
2,500-3,500 births
• Twice as common in males
• Other congenital malformations are common: 30% have karyotype abnormalities and
17% have other lethal abnormalities; 39% have abnormalities in other systems -
malrotation occurs in 20%; those with other congenital abnormalities have double the
mortality rate
• 90% are Bochdalek or posterolateral hernias
• 85-90% are left-sided
• Bilateral pulmonary hypoplasia occurs - ipsilateral >contralateral
• Usually diagnosed on routine antenatal ultrasound. May present with polyhydramnios.
Those that have a normal routine antenatal ultrasound scan are likely to have a
betteroutcome because the hernia usually occurs later, allowing for reasonable lung
growth. In utero repair and tracheal plugging have been attempted but with variable
outcomes
• Respiratory distress (usually severe), heart sounds on the right side of the chest,
bowel sounds on the left side, a scaphoid abdomen and vomiting may be found at
birth. Less severe cases may not present initially but develop increasing respiratory
distress over the first 24 hours as the gut becomes more air-filled. Differential
diagnosis is congenital cystic adenomatoid malformation (or even pneumothorax)

23. During resuscitation
• Bag and mask positive-pressure ventilation should be avoided
• Wide-bore nasogastric tube should be placed as soon as possible to deflate gut and
to confirm diagnosis, and therefore distinguish between differential diagnoses of
congenital cystic adenomatoid malformation or pneumothorax on subsequent chest X-
ray
• Consider paralysing baby to avoid air swallowing and to reduce the risk of
pneumothorax
Surgical management
• There is some evidence to suggest that stabilizing the baby before surgery improves
outcome
• Malrotation is corrected if present; the diaphragmatic defect is usually closed with a
synthetic patch
Post-operative care’
• High-frequency oscillation, nitric oxide or ECMO may be of benefit, but evidence for
routine use of these is lacking
• Mortality overall is approximately 50-6O%
• Survivors may have problems associated with underlying puimonary hypoplasia

24. Diaphragmatic hernia

25. Congenital cystic adenomatoid malformation (CCAM)
• Rare, abnormal proliferation of bronchial epithelium, containing cystic and
adenomatoid portions
• Lower lobes affected more frequently
• May disappear or become smaller spontaneously before or after birth
• Differential diagnosis is congenital diaphragmatic hernia
• Prognosis worse with associated hydrops, pre-term birth and with type 3 lesions
• Recurrent infection and malignant change have been described
There are three types
Type 1 CCAM
• Single or small number of large cysts
• Commonest type (50% cases)
• May cause symptoms by compression or may be asymptomatic initially
• Good prognosis after surgery
Type 2 CCAM
• Multiple small cysts
• Usually cause symptoms by compression of surrounding normal lung
• Prognosis variable
Type 3 CCAM
• Airless mass of very small cysts giving the appearance of a solid mass
• Worst prognosis

26. Congenital cystic adenomatoid malformation
(CCAM)

27. Congenital lobar emphysema
• Affected lobe is overinflated
• Left upper lobe is most commonly affected (also right middle and upper lobes); rare in
lower lobes
• More common in males
• Associated with congenital heart disease in 1 : 6 cases (usually as a result of
compression of airways by aberrant vessels)
• Unaffected lobes in affected lung are compressed
• Mediastinal shift and compression of the contralateral lung may also occur
• Presents with signs of respiratory distress, wheezing, chest asymmetry and
hyperresonance
• Chest X-ray shows hyperlucent affected lobe +Ic-om pression of other lobes
• Reduced ventilation and perfusion of the affected lobe is seen on a
ventilationlperfusion scan in more severe cases
• Surgical correction of underlying vascular abnormalities or resection of the affected
lobe
• may be required but symptoms and signs may resolve following bronchoscopy

28. Chylothorax
• Effusion of lymph into the pleural space as a result of either:
Underlying congenital abnormality of the pulmonary lymphatics
Iatrogenic following cardiothoracic surgery
• Diagnosis by antenatal ultrasound scan allows antenatal drainage by insertion of
intercostal drains, which may reduce the risk of pulmonary hypoplasia and facilitate
resuscitation after birth
• Ventilatory support may be required post-natally, along with intermittent intercostal
drainage
• Volume of chyle can be reduced by using a medium-chain triglyceride milk formula or
avoiding enteral feeds for up to several weeks as the underlying abnormality resolves
with time; protein and lymphocyte depletion may complicate this
• Surgical treatment is needed for the small number of cases that do not resolve
spontaneously

29. 7-Chest wall abnormalities
Asphyxiating thoracic
dystrophy
•Autosomal recessive
•Variable severity
•Short ribs with bell-shaped chest
•May have polydactyly and other
skeletal abnormalities also
•Long-term prognosis good in infants
who survive >1 year
Ellis van Crefeld syndrome
•Autosomal recessive
•Short ribs, polydactyly, congenital heart
disease, cleft lip and palate
•Pulmonary hypoplasia is usually not
severe and symptoms improve later

30. Short-rib polydactyly syndromes
• Four variants - all autosomal recessive
• Death from severe respiratory insufficiency occurs in the neonatal period
Thanatophoric dysplasia
• Usually sporadic
• Very short limbs - femur X-ray described as 'telephone handle' shape
• Very small, pear-shaped chest
• Death from lung/chest hypoplasia occurs in the neonatal period
Camptomelic dysplasia
• Autosomal recessive
• Very bowed, shortened long bones
• Death from respiratory insufficiency usually occurs in childhood

31. 8-Upper airway obstruction
•Neonates are obligate nasal breathers.
Choanal atresia:
•Incidence is 1 : 8,000
•More common in females
•Occurs as a result of a failure of breakdown of bucconasal membrane
•May be unilateral or bilateral, bony or membranous
•60% associated with other congenital abnormalities including the CHARGE
association: C = colobomata, H = heart defects, A = atresia of choanae, R =
retarded growth and development, G = genital hypoplasia in males, E = ear
deformities.
•Presents at birth with respiratory distress and difficulty passing a nasal catheter.
Oral airway insertion relieves respiratory difficulties. Diagnosis confirmed by
contrast study or CT scan
•Surgical correction by perforating or drilling the atresia requires post-operative
nasal stents .
 Laryngomalacia
•Commonest cause of stridor in the first year of life
•lnspiratory stridor increases with supine position, activity, crying and upper
respiratory tract infections,
•Usually resolves during the second year of life
•Upper airway endoscopy is merited if persistent accessory muscle use occurs,
with recurrent apnoea or faltering growth.

32. Pierre Robin sequence
• Consists of protruding tongue, small mouth and
jaw, and cleft palate
• Incidence 1 : 2,000
• Problems include obstructive apnoea, difficulty
with intubation and aspiration
• To maintain airway patency and prevent
obstructive apnoea, prone position should
beused initially; If this fails an oral airway should
be inserted; intubation may be needed in severe
case which may eventually require
tracheostomy
• Glossopexy and other surgical procedures have
been attempted with some degree of success.
• Gradual resolution of airway problems occurs as
partial mandibular catch-up growth occurs during
the first few years of life.

33. Subglottic stenosis:
May be congenital but usually acquired
risk factors for acquired subglottic stenosis:
• prematurity.
• Recurrent re intubation.
• prolonged intubation.
• traumatic intubation.
• large or small endotracheal tube.
• black babies(keloid scar).
• oral in opposite to nasal tube(theoretical but unproven)
• gastro-osephegeal reflux.
• infections.
Systemic steroids may facilitate extubation in mild to moderately severe subglottic
stenosis. Laser or cryotherapy to granulomatous tissue seen on upper airway
endoscopy may also be of benefit in these cases, Severely affected babies require
surgery - anterior cricoid split or tracheostomy.
Tracheomalacia:
• Causes expiratory stridor
• Usually caused from extrinsic compression - most commonly as a result of vascular
rings
• Also associated with tracheo-oesophageal fistula
• Surgical treatment of underlying pathology usually leads to resolution, but
tracheostomy and positive-pressure ventilation may be required.

34. Principles of mechanical ventilation in
neonates
•Aims are:
To ensure adequate oxygenation
To adequately remove carbon dioxide to prevent respiratory acidosis
To minimize the risk of lung injury
•Pressure-limited, time-cycled ventilation is used most commonly via either
an oral or a nasal endotracheal tube. Patient-trigger modes may improve
synchronicity with the baby's own respiratory efforts thus improving
oxygenation, reducing the risk of air leak and facilitating weaning from the
ventilator
•Volume cycle ventilation is being used more recently because of advances in
ventilator technology, and may reduce the time taken to wean off the ventilator
•High-frequency oscillation may be used initially for any cause of neonatal
respiratory failure, but is usually used as 'rescue' in severe cases where
conventional ventilation has failed
•Nasal continuous positive airway pressure is often used in pre-term babies
once extubated. This maintains functional residual capacity aid reduces the
work of breathing

35. Extracorporeal membrane oxygenation
(ECMO)
•A membrane 'lung' is used to rest the lungs and allow them to recover in
severe respiratory failure. ECMO may be:
•Venoarterial (VA) - blood removed from right atrium (usually via right internal
jugular vein) and returned via a common carotid artery
•Venovenous (VV) - a double-lumen, right atrial cannula is used
•ECMO should be considered in severe neonatal respiratory failure if:
Lung disease is reversible
Infant is > 35 weeks' gestation
Weight > 2 kg
Cranial ultrasound scan shows no intraventricular haemorrhage > grade1
No clotting abnormality
Oxygenation index > 40
• Oxygenation index (0I) is used to quantify the degree of respiratory
failure It is measured as:
•0I= (mean airway pressure X Fi02 X 100) + p(02)
•where mean airway pressure is in cmHzO, Fi02 (fractional inspired oxygen) is
a fraction and PO2 is in mmHg.
•01 > 25 indicates severe respiratory failure
•01 > 40 indicates very severe respiratory failure with a predicted mortality of
>8O0%

36. ECMO

37. Thank you