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CBF reactivity in hypotensive and normotensive preterm infants
Dulip Jayasinghe1, A Bryan Gill, Malcolm I Levene
1Division of Paediatrics and Child Health, Clarendon Wing, The General Infirmary at Leeds, Leeds LS2 9NS, United Kingdom.
Pediatric Research
|August 9, 2003
Summary
Hypotension in preterm infants may impair cerebrovascular autoregulation, increasing the risk of brain injury. This study found hypotensive infants had significantly reduced cerebral blood flow responses compared to normotensive infants.
Area of Science:
- Neonatal neurology
- Cerebrovascular physiology
- Perinatal medicine
Background:
- Perinatal distress and hypotension in preterm neonates are linked to neonatal cerebral lesions.
- Loss of cerebrovascular autoregulation is a key factor in lesion development.
Purpose of the Study:
- To assess and compare the cerebrovascular autoregulatory capacity of hypotensive and normotensive preterm infants.
- To investigate the relationship between hypotension and cerebral blood flow (CBF) regulation.
Main Methods:
- Utilized the 133Xe technique to measure global cerebral blood flow (CBF).
- Measured mean arterial blood pressure (MABP) via intra-arterial catheter in ventilated infants.
- Assessed MABP-CBF and CO2-CBF reactivity in both normotensive and hypotensive groups.
Main Results:
- Global CBF was similar between normotensive (13.3 mL/100 g/min) and hypotensive (13.6 mL/100 g/min) infants.
- MABP-CBF reactivity was identical (1.9%/mm Hg) in both groups.
- CO2-CBF reactivity was significantly diminished in hypotensive infants (4.1%/KPa deltaPaCO2) compared to normotensive infants (11.1%/KPa deltaPaCO2).
Conclusions:
- Normotensive infants may have intact autoregulation with a reduced response to CO2 fluctuations.
- Hypotensive preterm infants exhibit attenuated or absent autoregulation, with minimal CBF response to CO2 changes.
- These findings suggest impaired autoregulation in hypotensive neonates may contribute to neonatal brain injury.