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Updated: Sep 14, 2026
Non-invasive Optical Measurement of Cerebral Metabolism and Hemodynamics in Infants
Published on: March 14, 2013
Upper limits of brain blood flow autoregulation in stable infants of various conceptional age
V T Ramaekers1, P Casaer, H Daniels
1Department of Paediatrics and Neonatal Medicine, Katholieke Universiteit Leuven, University Hospital Gasthuisberg, Belgium.
Insights
Cerebral blood flow autoregulation in infants shows an upper limit that increases with conceptional age. This study determined the range of autoregulation and its upper limit in stable infants.
Area of Science:
- Neonatal physiology
- Cerebrovascular regulation
- Pediatric neurology
Background:
- Cerebral blood flow is autoregulated in healthy adults within a mean arterial blood pressure (MAP) range of 60-150 mmHg.
- Understanding cerebral blood flow autoregulation in infants is crucial for managing neurological health.
Purpose of the Study:
- To determine the range and upper limit of cerebral blood flow autoregulation in stable infants.
- To investigate the relationship between conceptional age and the upper limit of autoregulation.
Main Methods:
- Doppler measurements of mean flow velocity in the anterior cerebral artery were recorded in 27 stable infants (33-50 weeks conceptional age).
- Mean arterial blood pressures (MAP) were recorded simultaneously over a 6-hour period.
- The range and upper limit of autoregulation were determined based on these measurements.
Main Results:
- The upper limit of cerebral blood flow autoregulation was found to increase with advancing conceptional age.
- In infants aged 33-35 weeks, the upper limit ranged from 45-60 mmHg.
- At 47 weeks conceptional age, the upper limit shifted to a MAP of 100 mmHg.
- A significant positive linear relationship was observed between the upper limit of autoregulation and conceptional age.
Conclusions:
- Cerebral blood flow autoregulation in infants is age-dependent, with the upper limit increasing as conceptional age advances.
- These findings provide valuable insights into the developmental trajectory of cerebrovascular autoregulation in neonates.
- The study highlights a significant correlation between conceptional age and the capacity for cerebral blood flow autoregulation.
Abstract:
In healthy adults cerebral blood flow is autoregulated and kept constant over a wide range of mean arterial blood pressures (MAP) between 60 and 150 mmHg. In 27 stable infants with different conceptional ages ranging from 33 to 50 weeks, Doppler measurements of mean flow velocity at the anterior cerebral artery have been recorded simultaneously with mean arterial blood pressures (MAP) during a period of 6 h. The range of autoregulation and its upper limit could thus be determined. The upper limit was found to increase with advancing age. In the infants with conceptional ages between 33 and 35 weeks, the upper limit of autoregulation varied between 45 and 60 mmHg, while the upper limit shifted to a MAP of 100 mmHg at 47 weeks conceptional age. A significant positive linear relationship existed between the upper limit of autoregulation and conceptional age.
