Neuroprotection from acute brain injury in preterm infants Flashcards
Infants born under what gestational age are at increased risk of intracranial ischemic or hemorrhagic injury?
<32+6 weeks
When are these injuries most likely to occur?
Within the first 72 hours after birth
What is the pathophysiology of acute brain injury in young preterm infants?
- Fragile cerebral vasculature
- Immature autoregulatory system with rapid changes in perfusion causing ischemia or intraventricular hemorrhage into the brain
What percentage of preterm infants with have abnormalities on brain imaging?
Approximately 21% of preterm infants born at ≤32+6 weeks gestational age (GA) show an abnormal brain image (IVH or parenchymal lesions) on cranial ultrasound
Strongly associated with neurodevelopemental impairment in the long term
What type of brain injury is being picked up on MRI?
Non-cystic PVL increasingly recognized
*Cystic PVL on the decline
PVL= periventricular leukomalacia
What percentage of brain injuries are picked up by Day 5 of life?
95%
What is the relationship between rupture of membranes and brain injury?
Duration of rupture of membranes for longer than 72 hours is also an independent risk factor for IVH or intraparenchymal hemorrhage (odds ratio (OR) 2.33, 95% confidence interval (CI) 1.420 to 3.827)
What is a primary risk factor for preterm delivery?
Chorioamnionitis
Why are corticosteriods thought to be protective against brain injury?
Vasoconstriction is apparent in the fetal brain when antenatal corticosteroids are used, which may protect against injury.
What are the SOGC guidelines for antibiotic administration for PPROM?
Penicillin and a macrolide (or a macrolide alone if a patient is allergic to penicillin) to any mother presenting with PPROM and expected to deliver at ≤32+6 weeks GA
What is the optimal the timing of corticosteriod to prevent brain injury?
> 48 hours prior to delivery
What are the SOGC recommendation for the administration of corticosteriods?
Routinely administering antenatal corticosteroids within 7 days to all mothers expected to deliver a premature infant ≤34+6 weeks GA (and between 35+0 and 36+6 weeks GA in select clinical situations) is recommended, with the optimal interval being greater than 48 hours between the last dose administered and birth
How is magnesium sulphate thought to help with neuroprotection for preterm infants?
Magnesium has several intracellular actions, including anti-inflammatory effects and inhibiting the influx of calcium into cells
- Effectively decreases the risk for CP
What are the SOGC recommendations for the administration of magnesium sulphate?
The current recommendation is to consider magnesium sulphate for all women experiencing imminent preterm delivery (≤ 33+6 weeks GA)
Is there a preferred method of delivery to help protect against brain injury in preterm infants?
No!
There is no evidence that routine caesarean section confers protective benefit over vaginal delivery for preterm infants at risk for mortality or IVH, including intraparenchymal lesions except when they are in breech position
What is the relationship between cord clamping and brain injury in preterm infants?
Delayed cord clamping or cord milking, when compared with immediate cord clamping, reduces overall risk for acute brain injury
What are the recommendations for cord clamping vs cord milking for preterm infants?
All infants who do not need immediate resuscitation should receive delayed cord clamping of 30 to 120 seconds (level of evidence: 1a)
Delayed cord clamping is preferred over umbilical cord milking because the studies assessing impacts of cord milking are few, techniques vary, and there have been no follow-up studies
Cord milking may be considered when delayed cord clamping cannot occur
What is the association between hypothermia and the risk of brain injury?
Associated with increased risk of brain injury
Cold stress can accelerate oxygen consumption and impair resuscitation efforts
What is the definition of hypotension in preterm infants?
No standardized definition or standardized approach to managing hypotension
- Generally accepted definition:
- MAP < GA or <30 mmHg for two consecutive measurements
What is the association between ionotrope use and brain injury?
Considered to be a significant risk factor for the development of brain injury
Studies have demonstrated no clinically significant improvement in cerebral perfusion with the use of ionotropes among extremely low birth weight infants
What are indications to start inotropic support in a preterm infant?
Low blood pressure, a combination of prolonged capillary refill, decreased urine output, elevated lactate or echocardiography findings
*demonstration of poor end organ perfusion
What other causes of hypotension should be considered prior to the administration of ionotropes?
- Iatrogenic causes:
- Hyperinflation- chest xray to rule this out
- Dehydration- NS bolus
What is the association between PDA and brain injury in premature infants?
Preterm infants with hemodynamically significant PDAs are at greater risk of brain injury** however studies have shown that use of indomethacin OR ibuprofen did not actually change long term neurodevelopmental outcomes at 18 months
What are considerations when determining if prophylaxis for PDA closure should be given?
Because many PDAs often close spontaneously and the potential for side effects from cyclo- oxygenase inhibitors are significant, the prophylactic use of indomethacin or ibuprofen should be targeted based on combined risk factors including GA, exposure to antenatal steroids, and birth site [58] (level of evidence: 1a).
