Perinatal Adaptation Flashcards
Look at X-ray 1 on slide
Meconium aspiration
List the functions of the placenta
Foetal homeostasis Gas exchange Nutrient transport to foetus Waste product transport from foetus Acid base balance Hormone production Transport of IgG
What are the 3 major shunts in foetal circulation?
- Ductus Venosus
- Foramen Ovale
- Ductus arteriosus
How does the baby prepare for third trimester?
Surfactant production
Accumulation of glycogen – liver, muscle, heart
Accumulation of brown fat – between scapulae and around internal organs
Accumulation of subcutaneous fat
Swallowing and inhalation of amniotic fluid
What is the function of surfactant?
Breathing and gas exchange
Reduces surface tension
What is the relationship between prematurity and surfactant?
Baby might not have produced enough surfactant leading to respiratory distress
Need to give premature baby surfactant
Why do babies swallow amniotic fluid?
By inhaling and swallowing amniotic fluid it inflates the lungs and helps them grow
Describe the preparation for labour and delivery
Onset of labour – increased catecholamines / cortisol
Synthesis of lung fluid stops
Vaginal delivery – squeezes lungs
What changes occur in the baby during the first seconds post delivery?
Blue Starts to breathe Cries – oxygenation mechanism Gradually goes pink Cord cut - delayed, allows transfer of blood volume and Igs from mother
Look at Xray on slide 12
A:
- lungs full of fluid
B:
- has had a few quick breaths
How does circulation change from foetal to regular type (refer slide 13)?
High resistance in lung due to fluid while lwo resistance in placenta during IUL
WHen cord is clamped, low resistance in placenta is cut off, high resistance now comes up arteries. Lungs are more expanded and aerated, fluid is gone and pulmonary resistance drops
Back pressure in the aorta slows down flow across FO and DA, however passage of blood to lungs is much eaiser
As O2 tension rises (2-3Kpa to 9-14kPa), change in flow along with hormones drops circulating prostaglangins helping to shut the ducts.
What is the fate of the foetal shunts?
Foramen Ovale:
- closes or persists as PFO
Ductus Arteriosus:
- Becomes ligamentum arteriosus
- Persistent ductus arteriosus
Ductus Venosus
- Becomes ligamentum teres
What causes Persistent Pulmonary Hypertension in the newborn?
Serious condition - life threatening
Lack of transition
- surfactant deplete
- lungs full of fluid
Oxygenation that should happen in lungs doesn’t occur
Patent foetal shunts - blood flows through PFO and through DA - even though some oxygenation occurs it mixes with deoxygenated blood
How to detect PPH of neonate?
Pre and post ductal saturation
How to detect PPH of neonate?
Pre and post ductal saturation (there will be a big difference)
Management of PPHN
Good and effective ventilation
Oxygen
NO - given via ventilator directly to lungs to dilate pulmonary artery (to try and reduce resistance in the lungs)
Sedation - to avoid baby breathing against ventilator
Inotropes - as cardiac contractility is sometimes affected as a result
ECLS - very invasive
Look at Xray slide 20
Transient tachypnoea
Diagnosis of exclusion
Big healthy babies born by section
If born by section no squeezing of the lungs by contraction
Baby takes longer to absorb the fluid in the lungs
Babies are tachypnoeic
What adaption occurs in the neonate during first few hours after delivery?
Thermoreg
Glucose homeostasis
Nutrition
How does neonatal thermoreg occur?
Large surface area
Wet when born
Heat loss occurs by 4 methods
Cover head and body to stop radiation
High rates of evaporation in premature babies as their epithelial cells are thinner
Why do babies need to be supported during thermoregulation?
No shivering
- Main source of heat production is non shivering thermogenesis
- Heat produced by breakdown of stored brown adipose tissue in response to catecholamines
- Not efficient in the first 12 hours of life
Peripheral vasoconstriction
- feet and hands are a little blue - acrocyanosis
- difficult to cannulate babies
Newborn babies need help with maintaining temperature
Hypothermia in neonates
All babies need help to maintain temp
Small for dates / Preterm
- Low stores of brown fat
- Little subcutaneous fat
- Larger surface area:vol
Hypothermia predisposes to other problems
How to manage/prevent hypothermia in neonates?
Dry Hat Skin to skin Blanket / clothes Heated Mattress Incubator
Glucose homeostasis in neonates
Interruption of glucose supply from placenta
Very little oral intake of milk - mums don’t always produce milk immediately (baby enters starvation state)
Drop in insulin, increase in glycogen
Mobilisation of hepatic glycogen stores for gluconeogenesis
Ability to use ketones as brain fuel
Reasons for hypoglycaemia in neonates
Increased energy demands (high metabolic state)
- Unwell
- Hypothermia
Low glycogen stores
- Small, premature
Inappropriate insulin / glucagon ratio
- Maternal diabetes - improper glucose deposition in babies
- Hyperinsulinism
Some drugs
