Neuroprotection from acute brain injury in prems Flashcards
Definition of acute brain injury?
Infarction caused by ischemia and/or hemorrhage caused by reperfusion within the cerebral ventricles or parenchyma
Why are premature infants at risk of acute brain injury?
They have a fragile cerebral vasculature and immature autoregulatory system - rapid changes in perfusion will cause ischemia or IVH
In Canada, approximately how many infants born =32+6 weeks GA show an abnormal cranial US?
21%
Which form of periventricular leukomalacia is becoming increasingly recognized due to MRI? Which form is in decline?
- noncystic PVL increasingly recognized
- Cycstic PVL declining
Abnormal brain images in the neonatal period are strongly associated with _______.
Neurodevelopmental impairment in the long term
What is the ‘critical window’?
The first 72h post birth - the highest risk period for acute brain injury
___% of IVH or parenchymal lesions are detected by ____.
95%, Day 5
There is a _____ incidence of chorioamnionitis and PPROM with decreasing gestational age.
Higher
Recommendation re: antibiotics for mother presenting with PPROM?
Administer penicillin and a macrolide (just macrolide if allergic to pen) if expected to deliver at =32+6
Neonate born at =32+6 with suspected or confirmed chorioamnionitis, PPROM, preterm labour, or unexplained onset of nonreassuring fetal status - what to do?
- Careful evaluation
- Blood culture
- Start empiric antibiotics, continue until blood cultures negative at 36-48h
Duration of ROM > ___ hours also an independent RF for IVH or intraparenchymal hemorrhage.
72h
How might corticosteroids protect against brain injury? What have antenatal corticosteroids been shown to do?
- They cause vasoconstriction in the fetal brain
- Reduce neonatal morbidity and mortality, including IVH
Corticosteroids reduce risk of brain injury when interval since last dose is greater than ___ hours compared to less than ___ hours before birth.
48
24
Recommendation re: administering corticosteroids? Optimal interval?
- 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
Benefit of magnesium sulphate?
Decreases risk of CP
Recommendation for mag sulph?
Consider mag sulph for all women experiencing imminent preterm delivery a =33+6
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?
Breech position/malpresentation
Delayed cord clamping reduces the risk of ______.
Acute brain injury
Infants who do not need immediate resuscitation should receive delayed cord clamping of ____s. When can cord milking be considered?
- 30-120 seconds
- when delayed cord clamping cannot occur due to immediate resuc needs
What does cold stress cause physiologically? Hypothermia is associated with risk of ___ in prems?
- Cold stress can accelerate oxygen consumption and impair resuscitation
- Hypothermia has been associated with increased risk for acute brain injury and death
Recommendations for avoiding hypothermia for infants = 31+6?
- 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
Two common definitions of hypotension?
-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
What has the use of inotropes clearly been associated with?
- Mortality and brain injury
- Potential lasting effects on motor development
Recommendations re: hypotension/inotropes?
- 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
Recommendation re: prophylactic use of indomethacin or ibuprofen for PDA? Why?
- 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
In ELBW infants, what is hypercapnia a risk factor for? Mechanism?
- acute brain injury
- may impair cerebral autoregulation and cause vasodilatin
- dose-dependent predictor for IVH risk
PCO2 levels higher than ___mmHg or lower than ___mmHg were bother independently associated with acute brain injury
72, 32
Recommendations re: CO2?
- 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
Early use of rescue HFO may increase the risk of ____.
IVH
What does maintaining a neutral head position in the first 72h of care achieve?
May avoid jugular venous obstruction, reduce ipsilateral venous congestion and potentially lower risk for IVH due to altered cerebral blood flow
Recommendation re: head positioning in first 72h of care? Why?
- 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
Transporting a preterm infant =32+6 between facilities is believed to be an independent risk factor for______. Possible causes? Do studies support this?
- 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
What might the increased rate of acute brain injury in preterm infants born outside tertiary centres relate to?
-Decreased likelihood of receiving antenatal corticosteroids and resuc by teams who may lack specific training and expertise for preterm infant care
Recommendation re: transport?
- 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
Recommendations re: environment?
- 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)
Recommendation re: nutrition?
Early parenteral nutrition to optimize growth, as substandard growth is also associated with brain injury and neurodevelopmental delay
