Perinatal Adaptation

Question 1

Look at X-ray 1 on slide

Answer 1

Meconium aspiration

Question 2

List the functions of the placenta

Answer 2

Foetal homeostasis
Gas exchange
Nutrient transport to foetus
Waste product transport from foetus
Acid base balance
Hormone production
Transport of IgG

Question 3

What are the 3 major shunts in foetal circulation?

Answer 3

1. Ductus Venosus
2. Foramen Ovale
3. Ductus arteriosus

Question 4

How does the baby prepare for third trimester?

Answer 4

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

Question 5

What is the function of surfactant?

Answer 5

Breathing and gas exchange

Reduces surface tension

Question 6

What is the relationship between prematurity and surfactant?

Answer 6

Baby might not have produced enough surfactant leading to respiratory distress

Need to give premature baby surfactant

Question 7

Why do babies swallow amniotic fluid?

Answer 7

By inhaling and swallowing amniotic fluid it inflates the lungs and helps them grow

Question 8

Describe the preparation for labour and delivery

Answer 8

Onset of labour – increased catecholamines / cortisol
Synthesis of lung fluid stops
Vaginal delivery – squeezes lungs

Question 9

What changes occur in the baby during the first seconds post delivery?

Answer 9

Blue
Starts to breathe
Cries – oxygenation mechanism
Gradually goes pink
Cord cut - delayed, allows transfer of blood volume and Igs from mother

Question 10

Look at Xray on slide 12

Answer 10

A:
- lungs full of fluid

B:
- has had a few quick breaths

Question 11

How does circulation change from foetal to regular type (refer slide 13)?

Answer 11

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.

Question 12

What is the fate of the foetal shunts?

Answer 12

Foramen Ovale:
- closes or persists as PFO

Ductus Arteriosus:

• Becomes ligamentum arteriosus
• Persistent ductus arteriosus

Ductus Venosus
- Becomes ligamentum teres

Question 13

What causes Persistent Pulmonary Hypertension in the newborn?

Answer 13

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

Question 14

How to detect PPH of neonate?

Answer 14

Pre and post ductal saturation

Question 15

How to detect PPH of neonate?

Answer 15

Pre and post ductal saturation (there will be a big difference)

Question 16

Management of PPHN

Answer 16

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

Question 17

Look at Xray slide 20

Answer 17

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

Question 18

What adaption occurs in the neonate during first few hours after delivery?

Answer 18

Thermoreg
Glucose homeostasis
Nutrition

Question 19

How does neonatal thermoreg occur?

Answer 19

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

Question 20

Why do babies need to be supported during thermoregulation?

Answer 20

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

Question 21

Hypothermia in neonates

Answer 21

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

Question 22

How to manage/prevent hypothermia in neonates?

Answer 22

Dry
Hat
Skin to skin
Blanket / clothes
Heated Mattress
Incubator

Question 23

Glucose homeostasis in neonates

Answer 23

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

Question 24

Reasons for hypoglycaemia in neonates

Answer 24

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

Question 25

How to avoid/treat hypoglycaemia in neonates

Answer 25

Identify those at risk
Feed effectively
Keep warm
Monitor

Question 26

Is it okay for babies to lose weight initially?

Answer 26

Yes, upto 10% of body weight is okay as babies contain a lot of water

Question 27

Describe the haematological adaptations of neonates

Answer 27

Fetal haemoglobin

• Becomes disadvantageous
• Increase in 2,3 BPG shifts curve to right

Haematopoiesis moves to bone marrow from liver
- this is assessed by retic count

Adult Hb synthesised more slowly than Fetal Hb broken down

• Physiological anaemia
• Nadir at 8-10 weeks

Question 28

List the causes of neonatal jaundice

Answer 28

Liver enzyme pathways present but immature

Physiological Jaundice

• Breakdown of fetal haemoglobin
• Conjugating pathways immature
• Rise in circulating unconjugated bilirubin(most dangerous)
• Generally not harmful unless very high levels

Early or prolonged jaundice may be pathological

Question 29

List types of treatment in case of unconjugated bilirubin (jaundice)

Answer 29

Phototherapy - blue light converts bilirubin into excretable form
Exchange transfusion

Question 30

Risk factors for neonatal adaptation problems

Answer 30

Hypoxia / asphyxia during delivery
Particularly small or large babies
Premature babies – a whole other lecture
Some maternal illnesses and medications
Ill babies – sepsis, congenital anomalies