title: Cerebral blood flow in traumatic contusions is predominantly reduced after an induced acute elevation of cerebral perfusion pressure.
abstract: OBJECTIVE
  To evaluate the response to an acute elevation of cerebral perfusion pressure (CPP) of the regional cerebral blood flow (rCBF) measured in the edematous area of traumatic contusions.
  
  
  METHODS
  rCBF was measured in the intracontusional low-density area, in the pericontusional healthy-appearing brain tissue surrounding the contusion, in a healthy-appearing area in the contralateral hemisphere, in 16 head-injured patients with 16 traumatic contusions larger than 2 cm at baseline, and after 20 minutes of norepinephrine-induced 20-mmHg elevation of CPP levels.
  
  
  RESULTS
  After an induced acute elevation of CPP from baseline values of 65.8 ml/100 g/min (standard deviation, 8.6) to final values of 88.7 ml/100 g/min (standard deviation, 8.9; P < or = 0.0001), we found that rCBF mean levels decreased in the intracontusional low-density area (P = 0.0278), and change in rCBF was inversely associated to the baseline values. After grouping contusions according to the rCBF response to induced acute CPP elevation, rCBF mean values recorded at baseline were significantly lower in lesions with "rCBF improvement" than in those with "rCBF reduction" in the intracontusional low-density area (P = 0.0435).
  
  
  CONCLUSIONS
  Our findings suggest that CPP elevation induced by norepinephrine is effective in improving contusional rCBF only in selected cases, which are represented by a subset of contusions with critical perfusion, which can be identified by rCBF measurements. Conversely, in contusions with rCBF higher than critical low values, the CPP elevation could probably induce a temporary breakdown of the blood brain barrier, and the norepinephrine leads to a vasoconstriction with a worsening of regional perfusion.
authors.affiliation: Neurosurgical and Trauma Intensive Care Unit, Maurizio Bufalini Hospital, Cesena, Italy. achiere@ausl-cesena.emr.it
authors.forename: Arturo
authors.initials: A
authors.lastname: Chieregato
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tanfani
authors.forename: Christian
authors.initials: C
authors.lastname: Compagnone
authors.forename: Rosario
authors.initials: R
authors.lastname: Pascarella
authors.forename: Luigi
authors.initials: L
authors.lastname: Targa
authors.forename: Enrico
authors.initials: E
authors.lastname: Fainardi
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D006259:Craniocerebral Trauma / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006801:Humans; D019586:Intracranial Hypertension / Q000139:chemically induced; D007427:Intracranial Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000494:pharmacology / Q000627:therapeutic use; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology
chemical_list: D009638:Norepinephrine