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Flashcards in The Preterm Infant Deck (66)
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1
Q

What are the medical problems encountered by preterm infants?

A
  1. Respiratory:
    - RDS
    - Apnoea
    - Pneumothorax
  2. CVS:
    - Hypotension
    - PDA
  3. Metabolic:
    - Electrolyte imbalance
  4. Neurological:
    - IVH
  5. GI:
    - Necrotising Enterocolitis
    - Hernias
    - Reflux
  6. Infection
  7. Jaundice
  8. Retinopathy of Prematurity
  9. Temperature control
  10. Nutrition
2
Q

What is the cause of RDS in a preterm infant?

A

Deficiency in surfactant leading to increased alveolar surface tension

3
Q

Which infants are more at risk of RDS?

A

Those born at less than 28wks gestation and male infants

4
Q

What term infants are at risk of RDS?

A
  1. Infants of diabetic mothers

2. Infants with genetic mutations in surfactant genes

5
Q

How can we prevent RDS in preterm infants?

A

Antenatal corticosteroids (glucocorticoids) can be given to stimulate surfactant production

6
Q

What are the clinical signs of RDS in a neonate?

A
  1. Tachypnoea >60bpm
  2. Chest wall recession and nasal flaring
  3. Expiratory grunting
  4. Cyanosis
7
Q

What is the management of RDS in a preterm infant?

A

Surfactant therapy, via tracheal tube or catheter, and respiratory support

8
Q

What types of respiratory support can be offered to a neonate?

A
  1. Non-invasive:
    - CPAP
    - High flow nasal cannula
  2. Invasive:
    - Mechanical ventilation
9
Q

How is the mechanical ventilation adjusted?

A

It is adjusted according to oxygenation, chest wall movements and bloods gas analysis

10
Q

What is pulmonary interstitial emphysema?

A

When air from overdistended alveoli escapes into the interstitium

11
Q

What is a pneumothorax?

A

A pneumothorax is when air leaks into the pleural cavity

12
Q

What are the clinical signs of a pneumothorax in a neonate?

A
  1. Increased oxygen requirement
  2. Decreased breath sounds on affected side
  3. Decreased chest movements on affected side
13
Q

How do we diagnose a pneumothorax in a neonate?

A

It can be diagnosed with transillumination or CXR

14
Q

Define a tension pneumothorax

A

A tension pneumothorax is the progressive build up of air within the pleural space, usually due to a large lung laceration, which allows air to enter the pleural space but not to leave it (one way valve)

15
Q

What is the management of a tension pneumothorax?

A

URGENT decompression with a chest drain

16
Q

How can we prevent a pneumothorax in a neonate?

A

Ventilate with the lowest pressures possible

17
Q

What infants are at risk of apnoea?

A

Very low birthweight infants until they reach about 32wks of gestation

18
Q

What is the mechanism behind the apnoea?

A

Bradycardia occurs and either:

a) Infant stops breathing for over 20-30secs or
b) Breathing continues against a closed glottis

19
Q

What underlying causes of apnoea should be excluded?

A
  1. Hypoxia
  2. Infection
  3. Anaemia
  4. Electrolyte disturbance
  5. Hypoglycaemia
  6. Seizures
  7. Heart failure
  8. Aspiration due to reflux
20
Q

What is the usual cause of apnoea in preterm infants?

A

Immaturity of respiratory control

21
Q

What is the treatment of apnoea in preterm infants?

A
  1. Gentle physical stimulation
  2. Caffeine (central respiratory stimulant)
  3. CPAP or mechanical ventilation if frequent episodes
22
Q

Why are preterm infants at greater risk of hypothermia?

A
  1. Large surface area relative to mass so greater heat loss than heat generation
  2. Higher transepidermal water loss than term infants
  3. Little subcutaneous fat
  4. Cannot conserve heat
23
Q

What are the consequences of hypothermia in a neonate?

A
  1. Increased energy consumption
  2. Hypoxia and hypoglycaemia
  3. Failure to gain weight
24
Q

How can we maintain temperature in a neonate?

A

Incubators - increase ambient humidity so decrease transepidermal water loss
Overhead radiant heaters used initially

25
Q

What are the consequences of a PDA?

A
  1. Shunting of blood from left to right
  2. Apnoea and bradycardia
  3. Increased oxygen requirement
  4. Difficulty weaning from artificial ventilation
26
Q

What are the clinical signs of PDA?

A
  1. Bounding pulses
  2. Prominent precordial impulse
  3. Systolic murmur
27
Q

What investigations are performed for PDA?

A

Echocardiogram

28
Q

What is the pharmacological management of PDA?

A
  1. Prostaglandin synthetase inhibitor
  2. Indomethacin
  3. Ibuprofen
29
Q

What are the surgical options for treatment of PDA?

A

Surgical ligation - only done if pharmacological methods fail and patient is symptomatic

30
Q

What are the fluid requirements of a preterm infant?

A

Requirements vary with chronological and gestational age
1st day of life - 60-90ml/kg
Increase by 20-30ml/kg per day to 150-180ml/kg on day 5

31
Q

How are fluid requirements adjusted?

A

Adjusted according to:

  1. Clinical condition
  2. Plasma electrolytes
  3. Urine output
  4. Weight change
32
Q

Why are the nutritional requirements of a preterm infant higher?

A

Their requirements are higher due to rapid growth

33
Q

What mode do we use to feed preterm infants?

A

Mode of nutrition depends on gestational age
35-36wks = mature enough to suck and swallow milk
Less mature = orogastric or nasogastric tube

34
Q

How can we meet the nutritional requirements of a very preterm infant?

A

Introduce enteral feeds ASAP
Supplement breast milk with phosphate
Can also supplement with protein, calories and calcium

35
Q

What are the advantages and disadvantages of special infant formulas?

A

They can meet the increased nutritional requirements of preterm infants but they provide no protection against infection, unlike breast milk

36
Q

How do we meet the nutritional requirements of the extremely preterm or sick neonate?

A

Parenteral nutrition via a PIC line or an umbilical venous catheter

37
Q

Why are preterm infants more predisposed to iron deficiency and how do we prevent it?

A

As most of the iron transfer from the mother is in the third trimester.
Combat this by starting supplements at several weeks of age.

38
Q

Why are preterm infants at greater risk of infection?

A
  1. IgG mainly transferred in 3rd trimester
  2. No IgA or IgM transfer
  3. Infection of mother’s cervix can be a cause of preterm labour
39
Q

When do most infections occur?

A

Most occur at several days of age

40
Q

What increases risk of infection for these infants?

A
  1. Indwelling catheters

2. Mechanical ventilation

41
Q

Define Necrotising Enterocolitis (NEC)

A

NEC is damage to vulnerable bowel via ischaemic injury or bacterial invasion which occurs in the first few weeks of life

42
Q

What are the clinical signs of NEC?

A
  1. Feed intolerance
  2. Bile stained vomit
  3. Distended abdomen
  4. Fresh blood in stool
43
Q

What are the features of NEC on x-ray?

A
  1. Distended loops of bowel
  2. Thickening of the bowel wall
  3. Intramural gas
  4. May have gas in portal venous tract
44
Q

What is the management of NEC?

A
  1. Stop oral feed
  2. Broad spectrum antibiotics (cover aerobes and anaerobes)
  3. TPN
  4. Mechanical ventilation
  5. Circulatory support
  6. Surgery if perforation
45
Q

What are the complications of NEC?

A
  1. Bowel perforation
  2. Strictures
  3. Malabsorption
  4. Increased risk of poor neurodevelopmental outcome
46
Q

What are the risk factors for IVH?

A
  1. Very low birth weight infant
  2. Perinatal asphyxia
  3. Severe RDS
  4. Pneumothorax
47
Q

What are the complications of a large IVH?

A

Impaired drainage leading to hydrocephalus - treated with a ventriculo-peritoneal shunt

48
Q

What are the complications of sever IVH?

A

Hemiplegia

49
Q

Define Retinopathy of Prematurity

A

Retinopathy of Prematurity is abnormal replacement of sensory retina by fibrous tissue and blood vessels

50
Q

What are the complications of retinopathy of prematurity?

A
  1. Retinal detachment
  2. Fibrosis
  3. Blindness
51
Q

What are the risk factors for developing retinopathy of prematurity?

A
  1. Very low birth weight infants

2. Uncontrolled use of high concentrations of oxygen

52
Q

How is retinopathy of prematurity managed?

A
  1. Laser therapy can decrease visual impairment

2. Intravitreal anti-VEGF is being investigated but is not routine

53
Q

Define Hyponatraemia

A

Na+ <130mmol/L

54
Q

What are the causes of hyponatraemia in a neonate?

A
  1. Water overload
  2. Maternal fluid overload
  3. Iatrogenic
  4. Sick infant
  5. Excess renal loss
  6. GI loss
  7. Drainage of ascites/CSF
  8. Hypoadrenalism
55
Q

What are the symptoms of hyponatraemia in a neonate?

A
  1. Irritability
  2. Apnoeas
  3. Seizures
56
Q

How is hyponatraemia managed?

A

Management depends on the underlying cause

Too rapid correction can cause neurological damage

57
Q

Define Hypernatraemia

A

Na+ >150mmol/L

58
Q

What are the causes of hypernatraemia in a neonate?

A
  1. Water depletion

2. Excess Na+ administration

59
Q

What infants are at increased risk of hypernatraemia?

A
  1. Extremely preterm infants in first days of life

2. Breastfed infants with poor intake

60
Q

How do we manage hypernatraemia in a neonate?

A

Increase fluid intake

Be cautious with rapid correction

61
Q

Define Hypokalemia

A

K+ <2.5mmol/L

62
Q

What are the causes of hypokalemia in a neonate?

A
  1. Excess losses

2. Inadequate intake

63
Q

How do we manage hypokalemia in a neonate?

A

Correct with supplementation (either IV or enteral)

Be aware with IV infusion as risk of arrhythmias

64
Q

Define Hyperkalemia

A

K+ >7.5mmol/L OR >6.5mmol/L + ECG changes

65
Q

What are the causes of hyperkalemia in a neonate?

A

Failure of K+ excretion (renal failure)

66
Q

How do we manage hyperkalemia in a neonate?

A
  1. Administer calcium gluconate for myocardial stabilisation
  2. Eliminate the excess K+ with calcium resonium and dialysis
  3. Redistribute the K+ using Salbutamol and Insulin (SE of these is hypokalemia)