title: Blood pressure in head-injured patients.
abstract: OBJECTIVE
  To determine the statistical characteristics of blood pressure (BP) readings from a large number of head-injured patients.
  
  
  METHODS
  The BrainIT group has collected high time-resolution physiological and clinical data from head-injured patients who require intracranial pressure (ICP) monitoring. The statistical features of this dataset of BP measurements with time resolution of 1 min from 200 patients is examined. The distributions of BP measurements and their relationship with simultaneous ICP measurements are described.
  
  
  RESULTS
  The distributions of mean, systolic and diastolic readings are close to normal with modest skewing towards higher values. There is a trend towards an increase in blood pressure with advancing age, but this is not significant. Simultaneous blood pressure and ICP values suggest a triphasic relationship with a BP rising at 0.28 mm Hg/mm Hg of ICP, for ICP up to 32 mm Hg, and 0.9 mm Hg/mm Hg of ICP for ICP from 33 to 55 mm Hg, and falling sharply with rising ICP for ICP >55 mm Hg.
  
  
  CONCLUSIONS
  Patients with head injury appear to have a near normal distribution of blood pressure readings that are skewed towards higher values. The relationship between BP and ICP may be triphasic.
authors.affiliation: Department of Neurosurgery, Newcastle General Hospital, Newcastle upon Tyne, UK.
authors.forename: Patrick
authors.initials: P
authors.lastname: Mitchell
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Gregson
authors.forename: Ian
authors.initials: I
authors.lastname: Piper
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Citerio
authors.forename: A David
authors.initials: AD
authors.lastname: Mendelow
authors.forename: Iain R
authors.initials: IR
authors.lastname: Chambers
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D006259:Craniocerebral Trauma / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010507:Periodicity; D012016:Reference Values