Birth asphyxia Flashcards
What has evolution meant that the fetus can deal with in terms of asphyxia?
10-15min of absolute anoxia can be compatible with normal survival
Wha are 2 examlpes of events that can cause absolute anoxia to the fetus?
- Massive placental abruption
- Cord prolapse
What complication might asphyxia lead to?
cerebral palsy - motor disorder affecting posture and movement, variably accompanied by mental impairment, epilepsy or sensory defects
What proportion of cerebral palsy is caused primarily by perinatal asphyxia?
<10%
When do neonatologists make a diagnosis of perinatal asphyxia? Need 3 things for diagnosis
- good antenatal history e.g. abruption AND
- neonatal depression e.g. poor Apgar scores AND
- evidence of subsequent multi-organ failure - e.g. seizures, cerebral oedema, oliguria, haematuria, coagulopathy, jaundice, pulmonary haemorrhage
What are 7 possble signs of multi-organ failure subsequent to perinatal asphyxia?
- Seizures
- Cerebral oedema
- Oliguria
- Haematuria
- Coagulopathy
- Jaundice
- Pulmonary haemorrhage
What is the difficulty with perinatal asphyxia and long term complications?
difficult to predict likelihood of neurological injury following specific birth and hard to say whether subsequent developmental abnormality was caused by specific intrapartum insult
What treatment is available following perinatal asphyxia?
- therapeutic-induced hypothermia: ‘cooling’
- to rectal temperature of 33-34oC for 72h
- evidence this improve survival and neurological outcome at 18 months of age in infants with moderate or severe perinatal asphyxial encephalopathy
At what age can therapeutic-induced hypothermia be considered?
infants of >36 weeks completed gestation and admitted to neonatal unit with one or more of the set criteria
In addition to gestation of >36 weeks, what are the 4 criteria that an infant must have 1 of to be considered for therapeutic-induced hypothermia?
- apgar ≤5 at 10 min of age
- continued need for resuscitation, including endotracheal or mask ventilation, at 10 min after birth
- acidosis within 60 min of birth (defined as any occurrence of umbilical cord, arterial or capillary pH <7.00)
- base deficit ≥16 mmol/L in umbilical cord or any blood sample (arterial, venous or capillary) within 60 min of birth.
If infants fulfil the criteria for therapeutic-induced hypoxia, what must they be closely monitored for? 2 things
- Signs of seizures
- Moderate to severe encephalopathy evidenced by
- altered state of consciousness (reduced or absent response to stimulation) and
- abnormal tone (focal or general hypotonia or flaccid) and
- abnormal primitive reflexes (weak or absent suck or Moro response)
What are 3 signs of moderate to severe encephalopathy in an infant?
- altered state of consciousness (reduced or absent response to stimulation) and
- abnormal tone (focal or general hypotonia, or flaccid) and
- abnormal primitive reflexes (weak or absent suck or Moro response).
Overall how is a decision made whether an infant is considered for cooling?
>36 weeks gestation, have one of the 4 signs when admitted to neonatal unit (apgar, resuscitation, acidosis, base deficit) and show signs of seizures or moderate to severe encephalopathy
When should cooling for perinatal asphyxia be initiated?
as soon as possible after resuscitation - unlikely to be beneficial if >6-8h after birth
What is required for cooling and what are 2 of the techniques?
- require specialist cooling equipment in specialist centre
- techniques:
- selective head cooling
- whole body cooling
