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
2
Q
What is the problem in RDS?
A
Deficiency of surfactant
3
Q
What is the role of surfactant?
A
Lowers surface tension
4
Q
What is surfactant made up of?
A
A mixture of phospholipids and proteins
5
Q
What excretes surfactant?
A
Type 2 pneumocytes of the alveolar epithelium
6
Q
What does surfactant deficiency lead to?
A
Widespread alveolar collapse and inadequate gas exchange
7
Q
What happens to the incidence of RDS with increasing prematurity?
A
Increases
8
Q
Who is RDS common in?
A
Infants born before 28 weeks
9
Q
In what gender does RDS tend to be more severe in?
A
Boys
10
Q
Can you get surfactant deficiency at term?
A
Rare, but can occur in diabetic mothers
11
Q
How can RDS be avoided?
A
Glucocorticoids given to mother antenatally if preterm delviery is anticipated
12
Q
How does maternal administration of glucocorticoids help in RDS?
A
Stimulates foetus to produce surfactant
13
Q
What has been a major advancement in the treatment of RDS?
A
Development of surfactant therapy
14
Q
What is surfactant therapy made from?
A
Extracts of calf or pig lung
15
Q
How is surfactant therapy administered?
A
Instilled directly into lung via tracheal tube
16
Q
How effective is surfactant therapy in RDS?
A
Shown to reduce mortality from RDS by 40% without increasing morbidity rate
17
Q
When do symptoms of RDS begin?
A
At birth or within 4 hours of birth
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
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
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
21
Q
How is RDS treated?
A
Raised ambient oxygen, may need to be supplemented with CPAP or artificial ventilation via tracheal tube
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
23
Q
What can be used to wean infants from added oxygen therapy in RDS?
A
High-flow humidified oxygen therapy via nasal cannulae
24
Q
What is necrotising enterocolitis?
A
A serious illness associated with bacterial invasion of ischaemic bowel wall
25
Who does necrotising enterocolitis affect?
Mainly preterm infants in first few weeks of life
26
How does the feed of an infant affect their risk of necrotising enterocolitis?
Preterm infants fed on cow's milk formula are more likely to develop this condition than if they are fed only on breast milk
27
How does necrotising enterocolitis present?
- Stops tolerating feeds
- Milk aspirated from stomach
- May be bile-stained vomiting
- Abdomen becomes distended
- Stool sometimes contains fresh blood
28
How might the presentation of necrotising enterocolitis progress?
Infant may rapidly become shocked and require artificial ventilation due to abdominal distention and pain
29
What are the characteristic x-ray features of necrotising enterocolitis?
- Distended loops of bowel
| - Thickening of bowel wall with intramural gas
30
What might complicate necrotising enterocolitis?
Bowel perforation
31
How can bowel perforation in necrotising enterocolitis be detected?
- X-ray
| - Transillumination of abdomen
32
What is the treatment for necrotising enterocolitis?
- Stop oral feeding
- Broad spectrum antibiotics
- Parenteral nutrition
- Artificial ventilation and circulatory support if required
33
What do the antibiotics given in necrotising enterocolitis need to cover?
Aerobic and anaerobic organisms
34
What treatment is required for bowel perforation caused by necrotising enterocolitis?
Surgery
35
What is the mortality of necrotising enterocolitis?
20%
36
What are the long-term complications of necrotising enterocolitis?
- Development of strictures
| - Malabsorption if extensive bowel resection was necessary
37
Why do preterm infants have an increased risk of infection?
- 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
38
When do most infections in pre-term infants occur?
After several days
39
What are infections in pre-term infants often associated with?
- Indwelling catheters
| - Artificial ventilation
40
How long after birth is hypoglycaemia particularly likely?
24 hours of life
41
What can cause hypoglycaemia in the first 24 hours of life?
- Preterm
- IUGR
- Mothers with diabetes
- Large for gestational age
- Hypothermic
- Polycythaemic
- Ill for any reason
42
Why can premature and IUGR babies get hypoglycaemia?
Poor glycogen stores
43
What are the symptoms of neonatal hypoglycaemia?
- Irritability
- Apnoea
- Lethargy
- Drowsiness
- Seizures
44
Why can many babies tolerate low glucose?
Due to use of lactate and ketones
45
What glucose level is desirable in neonates?
>2.6mmol/L
46
Why is glucose level >2.6mmol/L desirable?
For good neurodevelopment
47
How can neonatal hypoglycaemia be prevented?
Early and frequent feeding with breast milk
| Regular monitoring if at risk
48
When should an infant be given IV glucose infusion?
2 levels <2.6 or one <1.6
49
How should high IV concentrations of glucose be administered?
Centrally
50
Why should high IV concentrations of glucose be administered centrally?
To avoid peripheral skin necrosis
51
Other than glucose, what else may be given in neonatal hypoglycaemia?
- Glucagon
| - Hydrocortisone
52
Why is hypothermia a problem?
Causes increased energy consumption
53
What might the increased energy consumption in hypothermia lead to?
- Hypoxia
- Hypoglycaemia
- Failure to gain weight
- Increased mortality
54
Why are preterm infants vulnerable to hypothermia?
- 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
Why does a large surface area to weight ratio cause hypothermia?
Greater heat loss than heat generation
56
How is hypothermia avoided in preterm infants?
Temperature maintained in incubators or with overhead radiant heaters
57
How do incubators work?
They allow ambient humidity to be provided, which reduces transepidermal heat loss
58
What episodes are common in very low birthweight infants?
- Apnoea
- Bradycardia
- Desaturation
59
When are episodes of apnoea, bradycardia, and desaturation common until in preterm infants?
32 weeks gestation
60
When might apnoea of prematurity cause bradycardia?
When infant stops breathing for >20-30 seconds, or when breathing continues, but against closed glottis
61
What is the most common cause of apnoea in premature infants?
Immaturity of central respiratory control
62
What are the other possible causes of apnoea in premature infants?
- Hypoxia
- Infection
- Anaemia
- Electrolyte disturbance
- Hypoglycaemia
- Seizure
- Heart failure
- Aspiration due to GORD
63
What happens to breathing with gentle physical stimulation in apnoea of prematurity?
Will usually start again after gentle physical stimulation
64
What treatment may be used in apnoea of prematurity?
- Caffeine
| - CPAP
65
How does caffeine work in apnoea of prematurity?
It is a resp stimulant
66
When might CPAP be required in apnoea of prematurity?
If episodes are frequency
67
What does retinopathy of prematurity affect?
Developing blood vessels at the junction of vascularised and non-vascularised retina
68
What happens to the developing blood vessels in retinopathy of prematurity?
There is vascular proliferation
69
What might retinopathy of prematurity progress too?
- Retinal detachment
- Fibrosis
- Blindness
70
What increases the risk of retinopathy of prematurity?
Uncontrolled use of high concentrations of oxygen
71
What % of very low birthweight infants is retinopathy of prematurity seen in?
35%
72
What reduces visual impairment in retinopathy of prematurity?
Laser therapy
73
How is retinopathy of prematurity detected?
The eyes of susceptible preterm infants (<1500g or <32 weeks) are screened every week by ophthalmologist
74
In what % of very low birth weight infants does severe bilateral visual impairment occur?
1%
75
Who is intraventricular haemorrhage very common in?
Very low birth weight infants (60-70% of 500-750g)
76
When does intraventricular haemorrhage present?
First few days of life
77
How does intraventricular haemorrhage present?
- Apnoea
- Lethargy
- Poor muscle tone
- Sleepiness
- May progress to coma and bulging fontanelle
78
How is intraventricular haemorrhage managed?
- Correction of acidosis, anaemia, and hypotension
- Fluid treatment
- Reduction of ICP
79
What is the definitive treatment for intraventricular haemorrhage?
qVentriculoperitoneal shunt
80
Why do preterm infants have high nutritional requirements?
Because of their rapid growth
81
Describe the growth of an infant born at 28 weeks?
Double weight in 6 weeks and treble it in 12 weeks (compared to term infants who dont treble until a year)
82
At what gestational age can infants suck and swallow milk?
35-36 weeks
83
How will infants under 35-36 weeks gestation need to be fed?
Oro- or nasogastric tube
84
When should enteral feeds be introduced in preterm babies?
As early as possible
85
What feed is given in preterm infants?
Breastmilk is preferable, but needs to be supplemented with phosphate and may need supplementation with proteins, calories, and calcium
86
What might extremely preterm infants be fed on if maternal breast milk is not available in some centres?
Donor breast milk
87
What is available for preterm babies if formula feeding is required?
Special infant formulas designed to meet the increased nutritional requirements of preterm infants
88
What is the limitation of formula feeding preterm babies?
Do not provide protection against infection or other benefits of breast milk
89
What is often required for nutrition in the very immature or sick infant?
Parenteral nutrition
90
How is parenteral nutrition usually given in the very immature or sick infant?
Through a central venous catheter inserted peripherally (PICC line)
91
How is infection prevented when using a PICC line for nutrition?
Should pay strict attention to aseptic technique both during insertion and when fluids are changed
92
What is the risk of PICC lines?
- Significant risk of septicaemia
| - Thrombosis of major vein
93
What is the limitation of giving parenteral nutrition via a peripheral vein?
Extravasation into skin may cause scarring
94
What is osteopenia of prematurity?
Poor bone mineralisation
95
Why is osteopenia of prematurity no longer common?
It is prevented with provision of adequate phosphate, calcium, and vitamin D
96
Why are preterm babies at risk of iron deficiency?
- Iron is mostly transferred to the foetus during the last trimester
- Loss of blood from sampling
- Inadequate erythropoietin response
97
Describe the use of iron supplements in preterm babies?
They are started at several weeks of age, and continued after discharge home
98
What are the advantages of breastmilk in the premature infant?
- 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
When is an infant described as having bronchopulmonary dysplasia?
If they still have an oxygen requirement at a post-gestational age of 36 weeks
100
What causes the lung damage in bronchopulmonary dysplasia?
Pressure and volume trauma from artifical ventilation, oxygen toxicity, and infection
101
What does the CXR show in bronchopulmonary dysplasia?
Widespread areas of opacification, sometimes with cystic changes
102
How are babies weaned off artificial ventilation?
CPAP to additional ambient oxygen, sometimes over several months
103
What may facilitate earlier weaning from the ventilator in premature babies?
Corticosteroid therapy
104
What is the addition benefit of corticosteroids in premature babies?
May reduce oxygen requirements in short term
105
What is the limitation of corticosteroids in premature babies?
Concern about increased risk of abnormal neurodevelopment, including CP, limits use to those at highest risk and only short courses are given
106
What can cause death in RDS?
- Intercurrent infection
- Pulmonary hypertension
- Pneumothorax
107
What infections are common in RDS?
- Pertussis
| - RSV
108
What % of infants ventilated for RDS develop pneumothorax?
10%
109
How does ventilation for RDS cause pneumothorax?
Air from overdistended alveoli may track into interstitum, resulting in pulmonary interstital emphysema, or leak into pleural cavity, causing pneumothorax
110
How is pneumothorax avoided in RDS?
Infants are ventilated at lowest pressure to achieve good oxygenation
111
How is pneumothorax in premature babies treated?
Chest drain
112
What % of very low birthweight infants develop CP?
5-10%
113
What are the most common long term neurodevelopment impairments in premature infants?
Learning difficulties
114
When does long term neurodeveleopmental issues in premature infants become increasingly evident?
When individual child is compared to peers at nursery or school
115
What long-term neurodevelopmental issues may arise in premature babies?
Problems with;
- Fine motor skills
- Concentration
- Behaviour problems
- Abstract reasoning
- Processing several tasks simultaneously
