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Vasomotor origin of intracranial pressure waves in hydrocephalic infants
Insights
Intracranial pressure (ICP) waves during REM sleep in infants with hydrocephalus are caused by cerebral blood vessel dilation. This study measured ICP and cerebral blood volume (CBV) non-invasively to confirm this link.
Area of Science:
- Pediatric Neurology
- Neurosurgery
- Radiology
Background:
- Hydrocephalus in infants can lead to dangerous increases in intracranial pressure (ICP).
- Understanding the physiological mechanisms behind ICP fluctuations during sleep is crucial for effective management.
- Rapid Eye Movement (REM) sleep is associated with specific physiological changes that may impact ICP.
Purpose of the Study:
- To investigate the relationship between cerebral blood volume (CBV) and intracranial pressure (ICP) during REM sleep in infants with stabilized hydrocephalus.
- To determine the underlying cause of ICP waves observed during REM sleep in this population.
Main Methods:
- Non-invasive monitoring of nine infants with stabilized hydrocephalus.
- Polysomnography to identify REM sleep phases.
- Fontanel palpation transducer for ICP measurement.
- 99mTc red blood cell labeling and head-level activity recording for CBV variation assessment.
Main Results:
- ICP waves during REM sleep correlated with a simultaneous increase in cerebral blood volume.
- The observed increase in blood volume was localized to the cerebral sector.
- No corresponding increase in blood volume was detected in the external carotid artery region.
Conclusions:
- Intracerebral vasodilation is the primary cause of ICP waves during REM sleep in infants with hydrocephalus.
- This finding highlights the role of dynamic CBV changes in ICP regulation during sleep in pediatric hydrocephalus.
- Non-invasive techniques can effectively elucidate the pathophysiology of ICP variations in infants.
Abstract:
By measuring cerebral blood volume (CBV) and intracranial pressure (ICP) variations at the same running time during sleep, it has been demonstrated that the ICP wave which appears during the REM sleep in hydrocephalic infants is produced by intracerebral vaso-dilatation. Nine infants with stabilized hydrocephalus were investigated by non-invasive means: REM phases were distinguished with the usual polysomnographic electrodes. Intracranial pressure was measured with a fontanel palpation transducer and CBV variations were obtained by recording 99mTc activity at the head level after in vivo labelling of red cells with 99mTc--pertechnetate. The time-activity curves, obtained from regions of interest and selected on the sequential radioisotope images, show that an increased ICP wave, occurring during the REM period, is related to a simultaneous increase in the blood volume, limited to the cerebral sector and not to the area of the external carotid artery.