[88] Prematurity Flashcards

1
Q

What common problems are associated with prematurity?

A
  • Respiratory distress syndrome
  • Necrotising enterocolitis
  • Infection-
  • Hypoglycaemia
  • Temperature control
  • Retinopathy of prematurity
  • Intraventricular haemorrhage
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2
Q

What is the problem in RDS?

A

Deficiency of surfactant

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3
Q

What is the role of surfactant?

A

Lowers surface tension

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4
Q

What is surfactant made up of?

A

A mixture of phospholipids and proteins

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5
Q

What excretes surfactant?

A

Type 2 pneumocytes of the alveolar epithelium

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6
Q

What does surfactant deficiency lead to?

A

Widespread alveolar collapse and inadequate gas exchange

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7
Q

What happens to the incidence of RDS with increasing prematurity?

A

Increases

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8
Q

Who is RDS common in?

A

Infants born before 28 weeks

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9
Q

In what gender does RDS tend to be more severe in?

A

Boys

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10
Q

Can you get surfactant deficiency at term?

A

Rare, but can occur in diabetic mothers

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11
Q

How can RDS be avoided?

A

Glucocorticoids given to mother antenatally if preterm delviery is anticipated

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12
Q

How does maternal administration of glucocorticoids help in RDS?

A

Stimulates foetus to produce surfactant

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13
Q

What has been a major advancement in the treatment of RDS?

A

Development of surfactant therapy

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14
Q

What is surfactant therapy made from?

A

Extracts of calf or pig lung

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15
Q

How is surfactant therapy administered?

A

Instilled directly into lung via tracheal tube

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16
Q

How effective is surfactant therapy in RDS?

A

Shown to reduce mortality from RDS by 40% without increasing morbidity rate

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17
Q

When do symptoms of RDS begin?

A

At birth or within 4 hours of birth

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18
Q

What are the clinical signs of RDS?

A
  • Tachypnoea >60breaths/min
  • Laboured breathing with chest wall recession and nasal flaring
  • Expiratory grunting
  • Cyanosis if severe
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19
Q

What causes expiratory grunting in RDS?

A

It is to try and create positive airway pressure during expiration and maintain functional residual capacity

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20
Q

What does the CXR shown in RDS?

A

Diffuse granular or ‘ground glass’ appearance of lungs
Air bronchogram
Heart border becomes indistinct or completely obscured with severe disease

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21
Q

How is RDS treated?

A

Raised ambient oxygen, may need to be supplemented with CPAP or artificial ventilation via tracheal tube

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22
Q

What do the ventilation requirements need to be adjusted on the basis of in RDS?

A

According to infants oxygenation, chest wall movements, and blood gas analysis

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23
Q

What can be used to wean infants from added oxygen therapy in RDS?

A

High-flow humidified oxygen therapy via nasal cannulae

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24
Q

What is necrotising enterocolitis?

A

A serious illness associated with bacterial invasion of ischaemic bowel wall

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25
Q

Who does necrotising enterocolitis affect?

A

Mainly preterm infants in first few weeks of life

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26
Q

How does the feed of an infant affect their risk of necrotising enterocolitis?

A

Preterm infants fed on cow’s milk formula are more likely to develop this condition than if they are fed only on breast milk

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27
Q

How does necrotising enterocolitis present?

A
  • Stops tolerating feeds
  • Milk aspirated from stomach
  • May be bile-stained vomiting
  • Abdomen becomes distended
  • Stool sometimes contains fresh blood
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28
Q

How might the presentation of necrotising enterocolitis progress?

A

Infant may rapidly become shocked and require artificial ventilation due to abdominal distention and pain

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29
Q

What are the characteristic x-ray features of necrotising enterocolitis?

A
  • Distended loops of bowel

- Thickening of bowel wall with intramural gas

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30
Q

What might complicate necrotising enterocolitis?

A

Bowel perforation

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31
Q

How can bowel perforation in necrotising enterocolitis be detected?

A
  • X-ray

- Transillumination of abdomen

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32
Q

What is the treatment for necrotising enterocolitis?

A
  • Stop oral feeding
  • Broad spectrum antibiotics
  • Parenteral nutrition
  • Artificial ventilation and circulatory support if required
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33
Q

What do the antibiotics given in necrotising enterocolitis need to cover?

A

Aerobic and anaerobic organisms

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34
Q

What treatment is required for bowel perforation caused by necrotising enterocolitis?

A

Surgery

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35
Q

What is the mortality of necrotising enterocolitis?

A

20%

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36
Q

What are the long-term complications of necrotising enterocolitis?

A
  • Development of strictures

- Malabsorption if extensive bowel resection was necessary

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37
Q

Why do preterm infants have an increased risk of infection?

A
  • IgG is mostly transferred across placenta in last trimester, and no IgA and IgM transferred - Infection in or around cervix is often reason for preterm labour, and may cause infection shortly after birth
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38
Q

When do most infections in pre-term infants occur?

A

After several days

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39
Q

What are infections in pre-term infants often associated with?

A
  • Indwelling catheters

- Artificial ventilation

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40
Q

How long after birth is hypoglycaemia particularly likely?

A

24 hours of life

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41
Q

What can cause hypoglycaemia in the first 24 hours of life?

A
  • Preterm
  • IUGR
  • Mothers with diabetes
  • Large for gestational age
  • Hypothermic
  • Polycythaemic
  • Ill for any reason
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42
Q

Why can premature and IUGR babies get hypoglycaemia?

A

Poor glycogen stores

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43
Q

What are the symptoms of neonatal hypoglycaemia?

A
  • Irritability
  • Apnoea
  • Lethargy
  • Drowsiness
  • Seizures
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44
Q

Why can many babies tolerate low glucose?

A

Due to use of lactate and ketones

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45
Q

What glucose level is desirable in neonates?

A

> 2.6mmol/L

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46
Q

Why is glucose level >2.6mmol/L desirable?

A

For good neurodevelopment

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47
Q

How can neonatal hypoglycaemia be prevented?

A

Early and frequent feeding with breast milk

Regular monitoring if at risk

48
Q

When should an infant be given IV glucose infusion?

A

2 levels <2.6 or one <1.6

49
Q

How should high IV concentrations of glucose be administered?

A

Centrally

50
Q

Why should high IV concentrations of glucose be administered centrally?

A

To avoid peripheral skin necrosis

51
Q

Other than glucose, what else may be given in neonatal hypoglycaemia?

A
  • Glucagon

- Hydrocortisone

52
Q

Why is hypothermia a problem?

A

Causes increased energy consumption

53
Q

What might the increased energy consumption in hypothermia lead to?

A
  • Hypoxia
  • Hypoglycaemia
  • Failure to gain weight
  • Increased mortality
54
Q

Why are preterm infants vulnerable to hypothermia?

A
  • Large surface area to weight ratio
  • Skin is thin and heat permeable
  • Little subcutaneous fat for insulation
  • Often nursed naked and cannot conserve heat by curling up or generate heat by shivering
55
Q

Why does a large surface area to weight ratio cause hypothermia?

A

Greater heat loss than heat generation

56
Q

How is hypothermia avoided in preterm infants?

A

Temperature maintained in incubators or with overhead radiant heaters

57
Q

How do incubators work?

A

They allow ambient humidity to be provided, which reduces transepidermal heat loss

58
Q

What episodes are common in very low birthweight infants?

A
  • Apnoea
  • Bradycardia
  • Desaturation
59
Q

When are episodes of apnoea, bradycardia, and desaturation common until in preterm infants?

A

32 weeks gestation

60
Q

When might apnoea of prematurity cause bradycardia?

A

When infant stops breathing for >20-30 seconds, or when breathing continues, but against closed glottis

61
Q

What is the most common cause of apnoea in premature infants?

A

Immaturity of central respiratory control

62
Q

What are the other possible causes of apnoea in premature infants?

A
  • Hypoxia
  • Infection
  • Anaemia
  • Electrolyte disturbance
  • Hypoglycaemia
  • Seizure
  • Heart failure
  • Aspiration due to GORD
63
Q

What happens to breathing with gentle physical stimulation in apnoea of prematurity?

A

Will usually start again after gentle physical stimulation

64
Q

What treatment may be used in apnoea of prematurity?

A
  • Caffeine

- CPAP

65
Q

How does caffeine work in apnoea of prematurity?

A

It is a resp stimulant

66
Q

When might CPAP be required in apnoea of prematurity?

A

If episodes are frequency

67
Q

What does retinopathy of prematurity affect?

A

Developing blood vessels at the junction of vascularised and non-vascularised retina

68
Q

What happens to the developing blood vessels in retinopathy of prematurity?

A

There is vascular proliferation

69
Q

What might retinopathy of prematurity progress too?

A
  • Retinal detachment
  • Fibrosis
  • Blindness
70
Q

What increases the risk of retinopathy of prematurity?

A

Uncontrolled use of high concentrations of oxygen

71
Q

What % of very low birthweight infants is retinopathy of prematurity seen in?

A

35%

72
Q

What reduces visual impairment in retinopathy of prematurity?

A

Laser therapy

73
Q

How is retinopathy of prematurity detected?

A

The eyes of susceptible preterm infants (<1500g or <32 weeks) are screened every week by ophthalmologist

74
Q

In what % of very low birth weight infants does severe bilateral visual impairment occur?

A

1%

75
Q

Who is intraventricular haemorrhage very common in?

A

Very low birth weight infants (60-70% of 500-750g)

76
Q

When does intraventricular haemorrhage present?

A

First few days of life

77
Q

How does intraventricular haemorrhage present?

A
  • Apnoea
  • Lethargy
  • Poor muscle tone
  • Sleepiness
  • May progress to coma and bulging fontanelle
78
Q

How is intraventricular haemorrhage managed?

A
  • Correction of acidosis, anaemia, and hypotension
  • Fluid treatment
  • Reduction of ICP
79
Q

What is the definitive treatment for intraventricular haemorrhage?

A

qVentriculoperitoneal shunt

80
Q

Why do preterm infants have high nutritional requirements?

A

Because of their rapid growth

81
Q

Describe the growth of an infant born at 28 weeks?

A

Double weight in 6 weeks and treble it in 12 weeks (compared to term infants who dont treble until a year)

82
Q

At what gestational age can infants suck and swallow milk?

A

35-36 weeks

83
Q

How will infants under 35-36 weeks gestation need to be fed?

A

Oro- or nasogastric tube

84
Q

When should enteral feeds be introduced in preterm babies?

A

As early as possible

85
Q

What feed is given in preterm infants?

A

Breastmilk is preferable, but needs to be supplemented with phosphate and may need supplementation with proteins, calories, and calcium

86
Q

What might extremely preterm infants be fed on if maternal breast milk is not available in some centres?

A

Donor breast milk

87
Q

What is available for preterm babies if formula feeding is required?

A

Special infant formulas designed to meet the increased nutritional requirements of preterm infants

88
Q

What is the limitation of formula feeding preterm babies?

A

Do not provide protection against infection or other benefits of breast milk

89
Q

What is often required for nutrition in the very immature or sick infant?

A

Parenteral nutrition

90
Q

How is parenteral nutrition usually given in the very immature or sick infant?

A

Through a central venous catheter inserted peripherally (PICC line)

91
Q

How is infection prevented when using a PICC line for nutrition?

A

Should pay strict attention to aseptic technique both during insertion and when fluids are changed

92
Q

What is the risk of PICC lines?

A
  • Significant risk of septicaemia

- Thrombosis of major vein

93
Q

What is the limitation of giving parenteral nutrition via a peripheral vein?

A

Extravasation into skin may cause scarring

94
Q

What is osteopenia of prematurity?

A

Poor bone mineralisation

95
Q

Why is osteopenia of prematurity no longer common?

A

It is prevented with provision of adequate phosphate, calcium, and vitamin D

96
Q

Why are preterm babies at risk of iron deficiency?

A
  • Iron is mostly transferred to the foetus during the last trimester
  • Loss of blood from sampling
  • Inadequate erythropoietin response
97
Q

Describe the use of iron supplements in preterm babies?

A

They are started at several weeks of age, and continued after discharge home

98
Q

What are the advantages of breastmilk in the premature infant?

A
  • Provides ideal nutrition for infants during first 4-6 months of life
  • Life saving in developing countries
  • Reduces risk of GI infection and necrotising enterocolitis
  • Enhances mother child relationship
  • Reduces risk of diabetes, hypertension, and obesity later in life
  • More easily digested than other sources
99
Q

When is an infant described as having bronchopulmonary dysplasia?

A

If they still have an oxygen requirement at a post-gestational age of 36 weeks

100
Q

What causes the lung damage in bronchopulmonary dysplasia?

A

Pressure and volume trauma from artifical ventilation, oxygen toxicity, and infection

101
Q

What does the CXR show in bronchopulmonary dysplasia?

A

Widespread areas of opacification, sometimes with cystic changes

102
Q

How are babies weaned off artificial ventilation?

A

CPAP to additional ambient oxygen, sometimes over several months

103
Q

What may facilitate earlier weaning from the ventilator in premature babies?

A

Corticosteroid therapy

104
Q

What is the addition benefit of corticosteroids in premature babies?

A

May reduce oxygen requirements in short term

105
Q

What is the limitation of corticosteroids in premature babies?

A

Concern about increased risk of abnormal neurodevelopment, including CP, limits use to those at highest risk and only short courses are given

106
Q

What can cause death in RDS?

A
  • Intercurrent infection
  • Pulmonary hypertension
  • Pneumothorax
107
Q

What infections are common in RDS?

A
  • Pertussis

- RSV

108
Q

What % of infants ventilated for RDS develop pneumothorax?

A

10%

109
Q

How does ventilation for RDS cause pneumothorax?

A

Air from overdistended alveoli may track into interstitum, resulting in pulmonary interstital emphysema, or leak into pleural cavity, causing pneumothorax

110
Q

How is pneumothorax avoided in RDS?

A

Infants are ventilated at lowest pressure to achieve good oxygenation

111
Q

How is pneumothorax in premature babies treated?

A

Chest drain

112
Q

What % of very low birthweight infants develop CP?

A

5-10%

113
Q

What are the most common long term neurodevelopment impairments in premature infants?

A

Learning difficulties

114
Q

When does long term neurodeveleopmental issues in premature infants become increasingly evident?

A

When individual child is compared to peers at nursery or school

115
Q

What long-term neurodevelopmental issues may arise in premature babies?

A

Problems with;

  • Fine motor skills
  • Concentration
  • Behaviour problems
  • Abstract reasoning
  • Processing several tasks simultaneously