Preterm infants.txt

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Preterm infants.txt
2011-06-08 18:26:15

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  1. What are the 3 main respiratory problems of preterm babies?
    • RDS
    • Pneumothorax
    • Apnoea and bradycardia
  2. What is respiratory distress syndrome due to?
    Surfactant deficiency
  3. What does surfactant contain?
    Phospholipids and proteins
  4. What secretes surfactant?
    Type II pneumonocyte of the alveolar epithelium
  5. What is the function of surfactant?
    To lower surface tension in alveoli and prevent collapse during expiration
  6. What happens to the alveolar in RDS and complication?
    Collapsed alveolar and reduced GE
  7. RDS is rare in term babies but which term babies is it more common in?
    Infants of diabetic mothers
  8. What can prevent RDS?
    • Glucocorticoids given antenatally to the mother stimulates fetal surfactant production
    • Give if preterm delivery is anticipated
  9. Is RDS worse in b or g?
  10. What is the major advance in treating RDS?
    Surfactant therapy
  11. How is surfactant therapy given?
    Instilled directly into the lung via tracheal tube
  12. What are the signs of RDS on a baby?
    • Tachypnoea > 60
    • Laboured breathing with chest wall recession – sternal and subcostal indrawing, nasal flaring
    • Expiratory grunting in order to create positive airway pressure during expiration and maintain FRC
    • Cyanosis
  13. What may you see on CXR of RDS
    • Ground glass appearance
    • Air bronchogram outlining large airways
    • Heart border obliterated (severe)
  14. What tubes/lines may you see on CXR of RDS?
    • ET tube
    • Umbilical artery catheter
  15. What is the Rx of RDS?
    • Oxygen – higher conc
    • Ventilation: CPAP (nasal airway) or IPPV via ET tube
    • Surfactant therapy
  16. What 3 things need to be monitored to adjust ventilatory requirements?
    • Continuous O2 sats monitoring,
    • chest wall movement,
    • blood gas analysis
  17. what 2 outcomes does surfactant therapy reduce?
    • Pneumothorax
    • Mortality
  18. What type of ventilation is reserved for severe RDS?
    HFOV – high frequency oscillatory ventilation
  19. When does surfactant deficiency itself resolve spontaneously?
    In 3-7 days as endogenous surfactant is produced
  20. What are the pulmonary complications of RDS?
    • Pneumothorax
    • Interstitial emphysema
    • Secondary infection
    • Chronic lung disease – overventilation can contribute to this
    • Mechanical ventilation can cause acute lung injury
  21. What are the non pulmonary complications of RDS?
    • Intraventricular haemorrhage
    • Patent DA
  22. What defines apnoeic?
    Cessation of respiration for at least 20 seconds
  23. What is apnoea associated with?
    Bradycardia and desaturations
  24. What are the 4 main RF for apnoea?
    • RDS
    • Hypoxia
    • Infection
    • Cranial pathology, especially haemorrhage
  25. What are the 2 main causes of bradycardia in preterms?
    • If stop breathing for long
    • Or when continues to breathe against a closed glottis
  26. What needs to be excluded if preterm has bradycardia?
    • Hypoxia
    • Infection
    • Anaemia
    • Electrolyte disturbance
    • Hypoglycaemia
    • Seizures
    • Heart failure
    • GORD – aspiration
  27. Which respiratory stimulant can be used to treat apnoea? And name 2 other Rx
    • Oral Caffeine
    • Breathing will usualy start after gentle physical stimulation
    • CPAP as well
  28. In a baby with RDS, how can you tell if it develops a pneumothorax?
    • Infants O2 requirement increases
    • Tidal volume decreases
    • Breath sounds and chest movement on affected side reduced
  29. What simple bedside test can you do to identify a pneumothorax?
    Transillumination with bright fibreoptic light source applied to the chest wall
  30. How do you treat a tension PT?
    Inserting a chest drain
  31. What can be done to try and prevent pneumothoraces?
    • Ventilate with the lowest pressures that provide adequate chest movement and satisfactory blood gases
    • Ventilation is adjusted to avoid the infant breathing against the ventilator
  32. what is a common cause of PDA in preterms?
  33. what are symptoms of PDA?
    • no symptoms
    • apnoea & bradycardia
    • inc O2 requirement
    • difficulty weaning from artificial ventilation
  34. what is the pulse and HS like in PDA?
    • pulse: bounding from an increased pulse pressure
    • systolic murmur
  35. why may signs of heart failure develop in PDA?
    due to increased circulatory overlaid
  36. when do you decide to close the PDA and how?
    • if symptomatic then close
    • a) drugs: PG synthetase inhibitor - indomethacin, ibuprofen
    • b) surgical ligation
  37. what are the 4 main consequences of hypothermia?
    • energy consumption - leading to hypoxia & hypoglycaemia
    • failure to gain weight
    • inc mortality
  38. why are preterm infants vulnerable to hypothermia?
    • larger SA to mass ratio - so greater heat loss (surface area) than heat generation (mass)
    • thin skin
    • heat permeable skin - so transepidermal water loss is important in first week of life
    • little subcut fat for insulation
    • cannot curl up
    • cannot shiver
  39. what are the 4 main ways of preventing heat loss in preterms?
    • 1. convection: increase air temp in incubator, clothe - cover head, avoid draughts
    • 2. radiation: cover baby, double walls for incubators
    • 3. evaporation: dry and wrap at birth, humidify incubator
    • 4. conduction: nurse on mattress
  40. what is average fluid requirement on first days of life?
    • 60-90ml/kg
    • adjusted according to: clinical condition, U&E, UO, wt change
  41. why do preterms have a higher nutritional requirement than terms?
    rapid growth rate
  42. when are infants mature enough to SUCK AND SWALLOW?
    35-36 weeks
  43. before infants are able to suck and swallow how are they fed?
    oro or naso gastric tube
  44. in very immature or sick infants how are they fed?
    parenteral - PICC line - central venous catheter
  45. what are the 2 main risks of PICC lines?
    • septicaemia
    • thrombosis
  46. what is the disadv of cows milk based formula milk to mothers own breast milk?
    higher rate of NEC
  47. why is osteopenia of prematurity now less common?
    due to addition of phosphate, calcium and vitamin D
  48. why do premature babies have low iron stores and at risk of iron deficiency?
    • as most iron transferred to fetes during LAST TRIMESTER
    • so need iron supplements
  49. why are preterm infants at higher risk of infection?
    • 1. because IgG is transferred in LAST TRIMESTER
    • and they don't get any IgA or IgM
    • 2. infection itself is a reason for preterm labour!
  50. when do most infections of preterm infants happen and what is cause?
    • after few days - nosocomial
    • indwelling catheters
    • artificial ventilation
  51. what are the 3 main consequences of infection in preterms?
    • bronchopulmonary dysplasia - chronic lung disease
    • white matter injury in brain
    • later disability
  52. what are the 2 main preterm brain injuries (big categories)
    • 1. bleeds
    • 2. periventricular white matter injury
  53. what are the 3 main types of bleeds in the brain in preterms?
    • 1. intraparenchymal
    • 2. germinal matrix - typically. this is above caudate nucleus
    • 3. intraventricular
    • what are risk factors for bleed in brain?
    • perinatal asphyxia
    • hypoxia - assoc with RDS
    • pneumothorax
    • hypovolaemia
  54. which bleeds have a higher risk of cerebral palsy?
  55. which is the most severe type of bleed and what is its consequence?
    • unilateraL haemorrhagic infarction involving parenchyma
    • leads to HEMIPLEGIA
  56. what is main consequence of intraventricular bleed, how do you recognise this?
    • CSF resorption impaired so get dilatation of ventricles and maybe hydrocephalus
    • signs: increase in head circumference, tense anterior fontanelles - suture lines separate
  57. what is Rx of hydrocephalus in preterm?
    • initial LP to remove CSF
    • then VP shunt
  58. what happens to half of patients with post bleed ventricular dilatation?
    • cerebral palsy
    • even higher risk if also parenchymal infarction
  59. what causes periventricular white injury?
    • ischaemia
    • inflammation
    • may occur in absence of bleed
  60. how do you detect white matter injury? and what is the outcome/course?
    • USS - echodense flare
    • may resolve in a week - low risk CP
    • may develop cysts - shows definite loss of white matter - high risk CP
  61. what is PVL? what do you see on US?
    • periventricular leukomalacia
    • bilateral multiple cysts
  62. if PVL is posteriorly sited what is there a risk of?
    spastic diplegia (symmetrical parts of body affected)
  63. what is the pathology of NEC?
    bacterial invasion of ischaemic bowel
  64. what may accelerate NEC?
    feeding with formula milk than only breast milk
  65. what are the symptoms of NEC?
    • infants stops tolerating feeds
    • milk is aspirated from stomach
    • vomiting - bile stained
  66. what may you see OE NEC?
    • abdomen distended
    • stool - fresh blood
    • infant becomes rapidly shocked
  67. why may you need to ventilate baby with NEC?
    due to abdominal distension and pain
  68. what are XR features of NEC?
    • distended loops of bowel
    • thickening of bowel wall - intramural gas
    • gas in portal tract
  69. what is complication of NEC and how detect - 2 ways
    • perforation
    • detect by XR or transillumination of abdomen
  70. what is Rx of NEC?
    • stop oral feed
    • broad spec abx - cover both aerobic and anaerobic
    • parenteral nutrition
    • artificial ventilation
    • circulatory support
  71. what are the long term consequences of NEC?
    • strictures
    • malabsorption
    • if extensive bowel resection has been necessary
  72. which parts of bowel does NEC usually involve?
    • distal ileum
    • proximal colon
  73. which preterms are at risk of getting the long term consequences?
    very low birth weight ones
  74. what are the 3 main long term consequences of prematurity?
    • Retinopathy of prematurity
    • chronic lung disease of prematurity
    • neurodevelopment problems
  75. where does retinopathy of prematurity affect?
    developing blood vessels at the JUNCTION of the vascular and nonvascularised retina
  76. what happens in ROP - process? (4 things)
    abnormal vascular proliferation --> progress to fibrosis, retinal detachment and blinding
  77. what is the cause of ROP?
    • response to injurious factors
    • may be hyperoxia PaO2 > 12kPa
  78. what is the 'screening' of ROP?
    • all infants with very LBW >1500g or less than 32 weeks GA
    • have eyes screened 6-8 weeks after birth
  79. what is Rx of ROP
    • laser therapy for severe disease
    • most canses resolve spontaneously
  80. what is the definition of bronchopulmonary dysplasia?
    requiring supplemental oxygen beyond 36 weeks corrected GA
  81. what is the cause of BPD? 3 main things
    • lung damage from pressure (barotrauma) and volume (volutrauma) trauma from artificial ventilation
    • oxygen toxicity
    • infection
  82. what does CXR of BPD show?
    • widespread opacities
    • patchy translucent areas
    • sometimes cystic changes
  83. what is the cause of death of some babies with severe BPD?
    • intercurrent infection
    • pulmonary hypertension
  84. what is the treatment of BPD?
    • initially - may still need assisted ventilation or CPAP and supplemented O2
    • dexamethasone for weaning from ventilatory support but increases risk of neurodevpt impairment so only use in severe cases
    • strict attention to nutrition
  85. what is the main worry in using steroids in BPD?
    neurodevelopment problems
  86. what are the common reasons for readmission to hospital for BPD patient?
    • recurrent wheezing
    • bronchiolitis
    • chest infecitons
  87. what can be use to reduce admission of preterm infants?
    palivizumab - monoclonal Ab to RSV
  88. what is the nutritional advice for preterms?
    iron supplements until 6 months corrected age when iron is available from solid foods
  89. which preterm babies are at higher risk of getting neuro problems?
    • very LBW
    • born very early <26 weeks
  90. what are the range of neurodevelopment problems?
    • cerebral palsy
    • cognitive delay
    • visual impairment
    • hearing loss
    • seizures
    • behavioural and educational problems

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