Ontogeny of cerebrovascular critical closing pressure

Pediatr Res. 2015 Jul;78(1):71-5. doi: 10.1038/pr.2015.67. Epub 2015 Mar 31.


Background: Premature infants are at risk of vascular neurologic insults. Hypotension and hypertension are considered injurious, but neither condition is defined with consensus. Cerebrovascular critical closing pressure (CrCP) is the arterial blood pressure (ABP) at which cerebral blood flow (CBF) ceases. CrCP may serve to define subject-specific low or high ABP. Our objective was to determine the ontogeny of CrCP.

Methods: Premature infants (n = 179) with gestational age (GA) from 23-31 wk had recordings of ABP and middle cerebral artery flow velocity twice daily for 3 d and then daily for the duration of the first week of life. All infants received mechanical ventilation. CrCP was calculated using an impedance-model derivation with Doppler-based estimations of cerebrovascular resistance and compliance. The association between GA and CrCP was determined in a multivariate analysis.

Results: The median (interquartile range) CrCP for the cohort was 22 mm Hg (19-25 mm Hg). CrCP increased significantly with GA (r = 0.6; slope = 1.4 mm Hg/wk gestation), an association that persisted with multivariate analysis (P < 0.0001).

Conclusion: CrCP increased significantly from 23 to 31 wk gestation. The low CrCP observed in very premature infants may explain their ability to tolerate low ABP without global cerebral infarct or hemorrhage.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arterial Pressure
  • Blood Flow Velocity / physiology*
  • Blood Pressure / physiology
  • Cerebrovascular Circulation / physiology*
  • Female
  • Gestational Age
  • Humans
  • Infant, Newborn
  • Infant, Premature
  • Male
  • Middle Cerebral Artery
  • Monitoring, Physiologic
  • Multivariate Analysis
  • Prospective Studies
  • Respiration, Artificial
  • Ultrasonography, Doppler, Transcranial
  • Vascular Resistance / physiology