Neonatology Flashcards
What are the three shunts of the foetal circulation?
Ductus venosus
Foramen ovale
Ductus arteriosus
How much of the foetal circulation does via the lungs?
7%
How does the foetus prepare during the 3rd trimester?
Surfactant production Accumulation of glycogen in liver, muscle and heart Accumulation of brown fast: - Between scapulae - Around internal organs Accumulation of S/C fat Swallowing amniotic fluid
What happens to catecholamines and cortisol at the onset of labour?
Levels increase
What happens to the synthesis of lung fluid at labour?
Stops
What effect does vaginal delivery have on foetal lungs?
Squeezes them
How does the baby appear during the first few seconds after birth?
Initially blue
Starts to breathe and turns pink
Cries
What happens to vascular resistance after birth?
Pulmonary resistance drops
Systemic resistance increases
What happens to oxygen tension after birth?
Increases
What happens to circulating prostaglandins in the foetus after birth?
Drop
When the ductus constricts, what happens?
Increased pO2
Reduced flow and prostaglandins
What does the ductus arteriosus become normally?
Ligamentum arteriosum
How is a patent ductus arteriosus treated in preterm infant?
Indometacin
OR
Ibuprofen
What does the ductus venosus become?
Ligamentum teres
A baby is born with signs of asphyxia. She is tachypnoeic and has a loud S2 and harsh systolic murmur (tricuspid regurgitation). Her Apgar scores are persistently low. There is some meconium staining. The baby is cyanosed, with a low systemic BP. Signs of shock.
Persistent Pulmonary Hypertension of the Newborn
How is Persistent Pulmonary Hypertension of the Newborn managed?
Ventilation Oxygen NO Sedation Inotropes Extracorporeal Life Support
What physiological changes happen in the first few hours of life?
Thermoregulation
Glucose homeostasis
Nutrition
What is the main method of heat generation following birth?
Non-shivering thermogenesis:
- Breakdown of stored brown adipose tissue to catacholamines
Why do neonates need help with maintaining temperature?
Wet when born Large surface area;body mass ratio No shivering Non-shivering thermogenesis is not efficient in first 12 hours Peripheral vasoconstriction
What infants are at increased risk of hypothermia?
Low stores of brown fat
Little S/C fat
Large SA;Vol. ratio
What is glucose homeostasis following birth?
Drop in insulin; increase in glycogen
Mobilisation of hepatic glycogen stores for gluconeogenesis
Ability to use ketones as brain fuel
How can hypoglycaemia arise due to increased energy demands?
Unwell
Hypothermia
What effect does an increase in 2,3-diphosphoglycerate do to the Hb dissociation curve?
Shifts it right
Where does haematopoeisis shift to after birth?
Bone marrow