Complications of Prematurity

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• Complications of Prematurity

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Neonatal mortality
Causes of neonatal death in Cambridge Maternity
Hospital 1982 - 89
1990 - 94 Respiratory distress
syndrome 137 38 Infection
24 13 Birth asphyxia
15 14 Extreme prematurity 14 44 Pulmonary
hypoplasia 10 19 Other causes 10 0 Total
non-malformed neonatal deaths 210 128 Malformatio
ns 84 46 Total neonatal deaths 294 174
The majority of these babies had a
periventricular haemorrhage
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Gestational age and RDS
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Predisposing factors

• Gender
• Caesarean section
• Asphyxia
• Maternal diabetes
• Multiple birth
• Hypothermia
• IUGR (IntraUterine Growth Restriction)

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Role of antenatal steroids

• Structural maturation
• Increase in lung volume
• Epithelial barrier function

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RDS pathophysiology

• Alveolar damage
• Formation of exsudate from leaky capillaries
• Inflammation
• Repair

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Surfactant deficiency - vicious cycle
Depleted surfactant
Decreased FRC Increased dead space Alveolar
collapse
Respiratory acidosis
Reducedcompliance
Severe hypoxia
Further inhibitionof surfactant by serum proteins
Increased work of breathing
Epithelial damage occurs through suction effect
of gasping
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Reduction in compliance
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Histology
Normal
RDS
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Atelectasis
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Patent Ductus Arteriosus (PDA)

• Premature infants at risk
• Duct does not respond to close signals
• Leads to symptoms of congestive heart failure
• Oxygen requirements are high
• Exacerbates RDS

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Pulmonary haemorrhage

• Rare
• Bleeding into the lungs
• Increases the need for ventilatory support
• Occurs mainly 2-4 days after birth
• Predisposing factors include mechanical
  ventilation, immaturity and PDA

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Pneumothorax
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Bronchopulmonary dysplasia
Simple definition
Oxygen requirement at 36 weeks post
conceptional age
5-20 of ventilated neonates with RDS
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Lung damage

• Barotrauma
• Volutrauma
• Oxygen toxicity
• Inflammation (Biotrauma)

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Oxygen free radicals
O2
cell
O2,H2O2
Superoxide Dismutase (SOD)
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Pressures

• High pressures damage walls
• High volumes over inflation
• Large swings cyclic collapse