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• Perinatal Asphyxia


  A combination of hypoxia (decreased arterial concentration of oxygen) and ischaemia (insufficient blood flow to maintain normal cell function)
• Causes of fetal hypoxia

  • Inadequate provision of oxygenated blood by the placenta
  • Inadequate oxygenation of maternal blood
  • Low maternal blood pressure
  • Uterine tetany (excess oxytocin)
  • Premature separation of the placenta
  • Obstruction of blood flow in the umbilical cord
  • Placental insufficiency e.g. Pre-eclampsia
• Physiology of fetal hypoxia

  1. Onset of hypoxia: deeper and rapid breathing movements. Falling pO2 leads to unconsciousness. Followed by primary apnoea.

  2. Continued hypoxia: primitive spinal centres produce whole body gasps (12/min)

  3. Continued hypoxia: gasps fade and baby enters terminal apnoea
• Newborn resuscitation


  1. Prepare (Warm room, staff, equipment)

  2. Start the clock. Dry and cover the baby.

  3. Assess the situation (COLOUR, TONE, HEART RATE, BREATHING)

  4. Airway, breathing, chest compressions, (drugs)
• Neonatal Resuscitation


  1. Airway: If baby not breathing, airway opening manoeuvres

  2. Breathing: If still not breathing, five inflation breaths (30cmH2O x 2 seconds), continue ventilatory support if necessary

  3. Circulation: If good chest movement and HR<60bpm, start chest compressions. Rate of 90 per minute, 3 chest compressions to each ventilation breath
• Hypoxia in the newborn period


  Can give rise to a similar clinical picture as pre-/perinatal asphyxia. Causes: Failure of oxygenation, Severe anaemia, Severe shock
• Perinatal asphyxia


  Significant risk of death (15-20%) and neurodevelopmental impairment in survivors (25-30%)
• How damage is caused

  1. Failure of compensatory mechanisms

  2. Primary energy failure (immediate)

  3. Transient recovery leading to free radical and nitric oxide release, gives rise to Secondary cell injury (6-72 hours later)
• Clinical Features of perinatal asphyxia

  • Respiratory distress
  • Apnoea
  • Abnormal neurology (encephalopathy)
  • Unable to suck
  • Irritable, staring
  • Lethargy
  • Abnormal tone
  • Seizures
  • Multi-organ dysfunction (renal, liver, cardiac)
• Multiorgan effects of perinatal asphyxia

  • Central Nervous System: Hypoxic-ischaemic encephalopathy, infarction, intracranial haemorrhage, cerebral oedema
  • Cardiovascular: Myocardial ischaemia, poor contractility, hypotension
  • Pulmonary: Pulmonary hypertension, pulmonary haemorrhage, respiratory distress syndrome
  • Renal: Acute tubular or cortical necrosis
  • Adrenal: Adrenal haemorrhage
  • Gastrointestinal: Perforation, ulceration, necrosis
  • Metabolic: SIADH, hypoglycaemia, hypocalcaemia, myoglobinuria
  • Dermatological: Subcutaneous fat necrosis
• Classification of neurological findings (Sarnat)

  • Grade I: Hyperalert, Normal muscle tone, Mild distal flexion, Overactive stretch reflexes, Strong Moro reflex, Normal suck reflex

  Grade II: Lethargic or obtunded, Mild hypotonia, Strong distal flexion, Overactive stretch reflexes, Incomplete Moro reflex, Weak or absent suck reflex

  Grade III: Stuporous or comatose, Flaccid, Intermittent decerebration, Decreased or absent stretch reflexes, Absent Moro reflex, Absent suck reflex
• Management principles


  Supportive care

  Respiratory: oxygen, (mechanical ventilation)

  Fluids: restrict to 40ml/kg/day initially

  Prevent hypoglycaemia

  Treat seizures

  Continuous EEG monitoring

  Therapeutic hypothermia

  MRI Brain at 5 days
• Management of seizures


  Intravenous access

  Check blood glucose. If low (<3mmol/L or 54mg/dl), give 5ml/kg 10% dextrose

  Give phenobarbitone 20mg/kg IV/IM

  Can repeat phenobarbitone 10mg/kg after 30 minutes if seizure not stopped

  Consider phenytoin if seizure not controlled

  Consider intravenous calcium
• Neurological prognosis


  • Signs of moderate or severe encephalopathy at 48 hours correlate with long-term outcome at 2 and 8 years

  A baby who is alert and sucking by a week of age is likely to do well
• Long term problems


  • Head growth during first year of life correlates with neurodevelopment

  Preterm infants: periventricular leukomalacia, basal ganglia injury, interventricular haemorrhage. Microcephaly, spastic diplegia

  Term infants: cortical necrosis and parasagittal ischaemic injury. Microcephaly, focal seizures, hemiplegia
• Good antenatal and perinatal care, together with effective neonatal resuscitation will help to reduce prevalence of perinatal asphyxia
• Perinatal asphyxia is a multiorgan disease
• Sarnet grading is used to classify severity of encephalopathy
• Management is supportive, with particular attention to preventing hypoglycaemia and controlling seizures