Neuroprotection from acute brain injury in prems Flashcards

1
Q

Definition of acute brain injury?

A

Infarction caused by ischemia and/or hemorrhage caused by reperfusion within the cerebral ventricles or parenchyma

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2
Q

Why are premature infants at risk of acute brain injury?

A

They have a fragile cerebral vasculature and immature autoregulatory system - rapid changes in perfusion will cause ischemia or IVH

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3
Q

In Canada, approximately how many infants born =32+6 weeks GA show an abnormal cranial US?

A

21%

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4
Q

Which form of periventricular leukomalacia is becoming increasingly recognized due to MRI? Which form is in decline?

A
  • noncystic PVL increasingly recognized

- Cycstic PVL declining

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5
Q

Abnormal brain images in the neonatal period are strongly associated with _______.

A

Neurodevelopmental impairment in the long term

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6
Q

What is the ‘critical window’?

A

The first 72h post birth - the highest risk period for acute brain injury

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7
Q

___% of IVH or parenchymal lesions are detected by ____.

A

95%, Day 5

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8
Q

There is a _____ incidence of chorioamnionitis and PPROM with decreasing gestational age.

A

Higher

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9
Q

Recommendation re: antibiotics for mother presenting with PPROM?

A

Administer penicillin and a macrolide (just macrolide if allergic to pen) if expected to deliver at =32+6

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10
Q

Neonate born at =32+6 with suspected or confirmed chorioamnionitis, PPROM, preterm labour, or unexplained onset of nonreassuring fetal status - what to do?

A
  • Careful evaluation
  • Blood culture
  • Start empiric antibiotics, continue until blood cultures negative at 36-48h
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11
Q

Duration of ROM > ___ hours also an independent RF for IVH or intraparenchymal hemorrhage.

A

72h

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12
Q

How might corticosteroids protect against brain injury? What have antenatal corticosteroids been shown to do?

A
  • They cause vasoconstriction in the fetal brain

- Reduce neonatal morbidity and mortality, including IVH

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13
Q

Corticosteroids reduce risk of brain injury when interval since last dose is greater than ___ hours compared to less than ___ hours before birth.

A

48

24

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14
Q

Recommendation re: administering corticosteroids? Optimal interval?

A
  • Routinely within 7 days to all mothers expected to deliver a premature infant =34+6 weeks - and between 35+0 and 36+6 weeks in select clinical situations
  • Optimal interval >48h between last dose administered and birth
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15
Q

Benefit of magnesium sulphate?

A

Decreases risk of CP

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16
Q

Recommendation for mag sulph?

A

Consider mag sulph for all women experiencing imminent preterm delivery a =33+6

17
Q

What’s the only scenario where routine C/S confers protective benefit over vaginal delivery for preterm infants at risk for mortality, IVH, or intraparenchymal lesions?

A

Breech position/malpresentation

18
Q

Delayed cord clamping reduces the risk of ______.

A

Acute brain injury

19
Q

Infants who do not need immediate resuscitation should receive delayed cord clamping of ____s. When can cord milking be considered?

A
  • 30-120 seconds

- when delayed cord clamping cannot occur due to immediate resuc needs

20
Q

What does cold stress cause physiologically? Hypothermia is associated with risk of ___ in prems?

A
  • Cold stress can accelerate oxygen consumption and impair resuscitation
  • Hypothermia has been associated with increased risk for acute brain injury and death
21
Q

Recommendations for avoiding hypothermia for infants = 31+6?

A
  • Place in bag or wrap
  • Keep delivery rom a 25-26 degreees
  • Pre-heated radiant warmer with temp sensor/Servo control
  • Thermal mattress
  • Hat
  • Preheated transport incubator
22
Q

Two common definitions of hypotension?

A

-Mean arterial BP < infants GA
or <30mmHg for two consecutive measurements
-No consistent definition of hypotension or standardized approach to managing it in preterm infants presently exists

23
Q

What has the use of inotropes clearly been associated with?

A
  • Mortality and brain injury

- Potential lasting effects on motor development

24
Q

Recommendations re: hypotension/inotropes?

A
  • Avoid inotropes to treat hypotension unless a combination of ohter clinical signs are present , e.g. elevated lactate, prolonged capillary refill time, decreased urine output or low cardiac output
  • Avoid iatrogenic causes of hypotension such as lung hyperinflation or dehydration –> Consider CXR and slowly infused fluid bolus before initiating inotropes
25
Q

Recommendation re: prophylactic use of indomethacin or ibuprofen for PDA? Why?

A
  • Prophylactic use of indomethacin or ibuprofen should be targeted based on combined risk factors including GA, exposure to antenatal steroids, and birth site - target to high-risk, extreme prems
  • Because many PDAs close spontaneously and potential for side effects (particularly on renal system) of cyclo-oxygenase inhibitors is significant
26
Q

In ELBW infants, what is hypercapnia a risk factor for? Mechanism?

A
  • acute brain injury
  • may impair cerebral autoregulation and cause vasodilatin
  • dose-dependent predictor for IVH risk
27
Q

PCO2 levels higher than ___mmHg or lower than ___mmHg were bother independently associated with acute brain injury

A

72, 32

28
Q

Recommendations re: CO2?

A
  • Monitoring PCO2 via blood gases or transcutaneous or end-tidal CO2 is recommended for infants born at =32+6, with a goal of achieving PCO2 levels 45-55mmHg in the first 72h post delivery
  • Whenever possible, volume-targeted ventilation should be used in premature infants in the first 72h post delivery
29
Q

Early use of rescue HFO may increase the risk of ____.

A

IVH

30
Q

What does maintaining a neutral head position in the first 72h of care achieve?

A

May avoid jugular venous obstruction, reduce ipsilateral venous congestion and potentially lower risk for IVH due to altered cerebral blood flow

31
Q

Recommendation re: head positioning in first 72h of care? Why?

A
  • Consideration should be given to keeping the infant’s head midline or neutral with the torso and the head of the bed elevated at 30 degrees
  • Based on infant physiology and the relative ease of implementing this practice, and because fluctuations in ICP may increase risk for acute brain injury
32
Q

Transporting a preterm infant =32+6 between facilities is believed to be an independent risk factor for______. Possible causes? Do studies support this?

A
  • Acute brain injury
  • Noise, vibration, and acceleration during travel
  • Several studies found no worse outcomes for infants transferred between neonatal centres, and at least one suggested act of transport not an independent RF for acute brain injury
33
Q

What might the increased rate of acute brain injury in preterm infants born outside tertiary centres relate to?

A

-Decreased likelihood of receiving antenatal corticosteroids and resuc by teams who may lack specific training and expertise for preterm infant care

34
Q

Recommendation re: transport?

A
  • Transport to a tertiary care centre should occur when appropriate
  • When deemed unsafe to move a mother before delivery, antenatal corticosteroids should be administered and neuroprotective measures taken throughout stabilization and transport, in consultation with a tertiary team
35
Q

Recommendations re: environment?

A
  • Fostering a care environment that encourages:
  • skin-to-skin contact
  • maternal voice exposure and interaction
  • light cycling
  • low general noise level
  • Crucial for optimal brain growth

-Developmental care strategies can mitigate painful procedures and decrease opioid use (both associated with adverse neurodevelopmental outcomes)

36
Q

Recommendation re: nutrition?

A

Early parenteral nutrition to optimize growth, as substandard growth is also associated with brain injury and neurodevelopmental delay