Neonatology Flashcards
What cells produce surfactant?
Type II alveolar cells
What are the two sides to the surfactant?
The hydrophilic side that faces the water, and the hydrophobic side that faces the air
What is the action of surfactant?
Increases the lung compliance
Why would the alveoli collapse without surfactant?
Due to the surface tension of the water surrounding them
What is compliance?
When the surfactant reduces the force needed to expand the alveoli and therefore the lungs during inspiration
How does surfactant increase lung compliance?
Reduces the surface tension of the fluid in the lungs to keep the alveoli inflated and maximise their surface area
How does surfactant promote equal expansion of all alveoli?
As an alveolus expands, the surfactant becomes more thinly spread and therefore the surface tension increases, making it more difficult to expand further
At what gestation do alveolar cells become mature enough to start producing surfactant?
24-34 weeks gestation
What stimulates the first breath?
Birth, temperature change, sound and physical touch
What is released by the baby in response to the stress of labour that stimulates respiratory effort?
Adrenalin and cortisol
What happens during the first breaths the baby takes?
The alveoli expand for the first time, decreasing pulmonary vascular resistance
What changes to the cardiovascular system do the first breaths trigger?
Decrease in pulmonary vascular resistance causes fall in pressure in right atrium, causing left atrial pressure to be greater and the closure of the foramen ovale.
What changes happen to the cardiovascular system after birth?
Closure of foramen ovale and ductus arteriosus
Ductus venosus stops functioning
Pressure becomes greater in left atrium
What are the key problems that would trigger the need for neonatal resuscitation?
Hypoxia- placenta can’t carry out normal gaseous exchange during contractions
Hypothermia- large surface area: weight ratio and are born wet
May have aspirated meconium
What are the key steps in neonatal resuscitation?
Warm them Calculate APGAR score Stimulate breathing Inflation breaths Chest compressions
How can you warm the baby?
Get them dry as quickly as possible
Warm delivery rooms and heat lamps
Put in plastic bag if <28 weeks
What is the APGAR score?
Used to indicate progress after the first minutes after birth
What does APGAR stand for?
Appearance Pulse Grimmace (response to stimulation) Activity Respiration
How often should the APGAR score be calculated?
At 1, 5 and 10 minutes
How can you stimulate breathing immediately after birth?
Shake vigorously
Place head in neutral position to keep airway open
Check for airway obstruction
When are inflation breaths given?
When the neonate is gasping or not breathing despite adequate initial stimulation
How many inflation breaths are given?
Two cycles of five inflation breaths
If no response- 30 seconds of ventilation breaths
When performing inflation what should be used?
Air for term babies
Air + oxygen for pre-term babies
When should chest compressions be started in neonates?
If HR< 60 despite resuscitation and inflation breaths