Paediatrics: Neonatology Flashcards
What cells produce surfactant?
Type II pneumocytes (alveolar cells)
What is the action of lung surfactant?
- Reduces the surface tension of the fluid in the lungs => keep alveoli inflated + maximise alveolar SA
- Promotes equal expansion of all alveoli (because this out as alveolus expands)
what is the impact of surfactant on lung compliance? explain this
Increases lung compliance (reduces force needed to expand alveoli)
At how many weeks gestation does surfactant start to be produced?
starts being produced between 24-34 weeks gestation
After birth: what helps expand previously collapsed alveoli? (first breath)
stress of labour => Ad + cortisol release => stimulate resp effort
explain how the first breath leads to foramen ovale. what does this eventually become?
Alveoli expand => reduced pulmonary resistance => LA>RA pressure => squash atrial septum => foramen ovale (functional closure) => fossa ovalis (structural closure)
Describe how early neonatal cardio-respiratory changes lead to ligamentum arteriosus formation
increased blood oxygenation => decreased relative prostaglandins => ductus arteriosus closure => ligamentum arteriosus
When does the ductus arteriosus stop functioning
within 1-3 days of birth
(due to relative decrease in prostaglandins)
Describe how early neonatal cardio-respiratory changes lead to ligamentum venosum formation
umbilical cord clamping => no umbilical vein blood flow => ductus venosus closure => ligamentum venosum
Explain what can cause common hypoxia in neonates
during labour, contractions mean placenta is unable to carry out normal gaseous exchange => hypoxia
What do you do immediately after the baby has been born? (7)
- Skin to skin
- Delayed cord clamping
- Dry the baby
- warm the baby with hat and blankets
- Vitamin K
- Label baby
- Measure weight and length
What can extended hypoxia in neonates lead to? plus the in between bits
extended hypoxia => anaerobic respiration + bradycardia => decreased consciousness + decreased resp effort => hypoxic-ischaemic encephalopathy
What score is an indicator of progress over the fist few minutes of life
APGAR
what does APGAR stand for? is high or low bad?
Appearance
Pulse
Grimace
Activity
Respiration
(lower => bad)
Why is delayed cord clamping good?
allows for placental transfusion
- Fetal blood from placenta => fetal circulation
What examination can estimate gestational age when it is unknown/unclear?
Dubowitz/ballard examination
Describe the categories for:
- Extreme preterm
- Very preterm
- Moderate to late preterm
- Term
<28 weeks (extreme preterm)
28-32 weeks (very preterm)
32-37 weeks (moderate to late preterm)
37-42 (term)
If fetus is going to preterm, how can you try to delay birth? (not in labour yet)
- prophylactic vaginal progesterone (progesterone helps to reduce contractions)
- prophylactic cervical cerclage
When labour is suspected in a preterm fetus, what can you do?
- Tocolysis (nifedipine - CCB, progesterone (maintenance)
- Maternal corticosteroids
- IV Mg Sulphate
- delayed cord clamping
what can be given antenatally to aid lung development in a preterm fetus?
corticosteroids - dexamethasone
Why might IV Mg Sulphate be given antenatally?
in a suspected preterm fetus
- Protect fetal brain (neuroprotective)
What can be used in neonatal prematurity for treatment of apnoea ? in how many weeks of life is this used
caffeine
(<34 weeks CGA)
What Resp complications might a preterm neonate have? (3)
- RDS
- Surfactant deficient lung disease (insufficient surfactant => increased alveolar surface tension => lung collapse => poor gas exchange => hypoxia)
- CLD
What cardiovascular complications might a preterm neonate have? (2)
- Hypotension
- PDA