PBL 3: Birth Asphyxia Flashcards
What is CTG?
Cardiotocography
means of recording foetal heartbeat and uterine contractions during pregnancy.
During labour, the foetal heartbeat should be between ?
110-160 bpm
variability of >5bpm, usually between 10-25bpm.
What is external CTG?
One transducer on the foetal heart, and the other at the fundus
What is internal CTG?
A wire electrode attached to foetal scalp connected to the monitor
What are accelerations?
abrupt increase in the baseline heart rate >15bpm for over 15 seconds.
What in terms of accelerations are normal?
2 accelerations every 15 minutes, and they should run alongside the uterine contractions.
How can you induce accelerations?
- Gently rocking the mother’s abdomen.
- Pressing on the baby’s head through the cervix with a finger.
- Administering a short burst of sound.
What are the 4 types of decelerations?
Type 1/ Early
Type 2/ Late
Variable
Prolonged
When do type 1 decelerations begin and end
Start when uterine contractions begin and recover when they stop
What causes type 1 decelerations?
Increased intracranial pressure causing increased vagal tone
What do type 2 decelerations indicate?
Insufficient blood flow through the uterus and placentia
What does insufficient blood flow through uterus will cause?
Reduced foetal blood flow
Hypoxia
Acidosis
What can cause reduced utero-placental blood flow?
- Maternal hypotension.
- Pre-eclampsia.
- Uterine hyper stimulation.
What are variable decelerations?
- Rapid fall in baseline rate with a variable recovery phase.
- They are variable in duration and may have no relationship to uterine contractions.
When are variable decelerations seen?
patients with reduced amniotic fluid volume
What causes variable decelerations?
umbilical cord compression
What are prolonged decelerations?
• Decelerations lasting more than 2 minutes.
When is a prolonged deceleration abnormal?
> 3 mins
What criteria must be met to give birth?
- Engaged foetal cephalic presentation (head first).
- Ruptured membrane
- Empty bladder.
- No foetal obstruction.
- Adequate analgesia.
- Experienced operator
What is meconium made up of?
desquamated bowel cells and bowel secretions (bile)
What does meconium look like?
greenish/black colour with a thick consistency
What can cause the passing of meconium?
Foetal hypoxia
Also stimulates gasping movements so meconium passes into the airways
Consequences of meconium aspiration syndrome?
- Further hypoxia.
- Pneumonitis.
- Pulmonary hypertension.
- Mechanical blockage and surfactant dysfunction.
- circulatory physiological changes will fail to occur
What’s it called if you inhale meconium?
meconium aspiration syndrome
What is used to aid aspirating of meconium?
Surfactant
What happens with circulatory physiological changes?
- Ductus venosus closes.
- Foramen ovale closes.
- Ductus arteriosus closes.
- Pulmonary vascular resistance massively drops.
Describe process of first breath
- Lung secretions are reabsorbed during birth, also chest compression forces liquid out.
- First gasp is generated by the negative intrathoracic pressure.
- Surfactant is released and aeration occurs.
- Pulmonary artery blood flow increases, and pulmonary vascular resistance drops.
When is apgar score done?
at 1 minute after birth, and again after 5 minutes.
What are 5 apgar categories?
- Appearance (complexion).
- Pulse rate.
- Grimace (response to stimulation).
- Activity (movement).
- Respiratory effort.
What is birth asphyxia?
deprivation of oxygen to a new-born infant that lasts long enough during the birth process to cause brain damage.
Define hypoxia
An inadequate supply of oxygen to a tissue.
Causes of birth asphyxia?
- Uterine rupture.
- Placental abruption.
- Cord compression.
What can perinatal asphyxia cause?
hypoxic-ischemic encephalopathy
What does hypoxic-ischemic encephalopathy manifest into?
- Altered consciousness.
- Altered muscle tone.
- Seizures.
What grades hypoxic-ischemic encephalopathy
Sarnat scale
How many grades on sarnat scale?
3
The baby in scenario falls into grade 3
What neurological deficits will baby in scenario have as in sarnat grade 3?
- Microcephaly (small head).
- Spastic quadriplegia.
- Difficulty in controlling fits.
- Learning difficulties.
- Feeding difficulties.
- Deafness.
- Blindness.
- Cerebral palsy.
What is phenobarbitone?
Treats epilepsy in children
How does phenobarbitone work?
- Increases net flux of Cl- into neurones to cause inhibition
- Works by increasing duration of opening of GABAA channel.
- Also blocks glutamate transmission.
What is therapeutic hypothermia?
• Involves cooling the baby down to a temperature of 33-34C for 72 hours.
Function of therapeutic hypothemia?
- This reduces brain damage, improving the infants chance of survival and reducing disability.
- Cerebral hypoxic ischaemia results in increased cerebral oxidative metabolism.
- This forms more lactic acid and can result in necrotic cell death.
- The mild hypothermia prevents this from occurring by reducing the metabolic needs of the brain.
- The number of cells undergoing apoptosis is now reduced.
