title: Elevated cerebral perfusion pressure and low colloid osmotic pressure as a risk factor for subdural space-occupying hygromas?
abstract: BACKGROUND
  Space-occupying subdural hygromas are a late complication of severe traumatic brain injury (TBI) and may delay the patient's recovery. To evaluate the risk factors involved, we performed a semiretrospective, -prospective analysis of three groups of patients, which differed with regard to the techniques used in the management of their cerebral perfusion pressure (CPP) and colloid osmotic pressure (COP) to determine the occurrence of space-occupying subdural hygromas.
  
  
  METHODS
  Between 1989 and 1997 we examined 696 patients after a severe TBI: Group 1. 1989-1994 mean CPP: 67 (elevated for therapeutic reasons by catecholamines, if necessary), mean COP: 19. Group 2. January 1995-October 1996, mean CPP: 77, mean COP: 20. Group 3. November 1996-December 1997, mean CPP: 79, mean COP: 23 (elevated for therapeutic reasons by infusions of colloids). The groups were comparable for other criteria.
  
  
  RESULTS
  Compared to Group 1, Group 2, with a high CPP but lower COP, showed a significantly higher (p < 0.01; chi2-test with correction of Yates) percentage of posttraumatic subdural hygromas with space-occupying aspects, clinical signs of bradycardia, hypertension and impaired consciousness requiring surgery (Group 1: 1.75%; Group 2: 10.46%; Group 3: 0%). In Group 3 we saw no patient with a space-occupying hygroma.
  
  
  CONCLUSIONS
  We conclude that iatrogenic elevated CPP, which has been reported to be helpful in preventing secondary ischemic damage after a severe TBI, may be harmful to a patient if the COP is not maintained within physiological ranges.
authors.affiliation: Department of Neurosurgery, Georg-August-University of Göttingen, Germany.
authors.forename: J K
authors.initials: JK
authors.lastname: Lang
authors.forename: H C
authors.initials: HC
authors.lastname: Ludwig
authors.forename: K
authors.initials: K
authors.lastname: Mursch
authors.forename: B
authors.initials: B
authors.lastname: Zimmerer
authors.forename: E
authors.initials: E
authors.lastname: Markakis
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D001921:Brain / Q000098:blood supply*; D001930:Brain Injuries / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology; D008297:Male; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D013353:Subdural Effusion / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014882:Water-Electrolyte Balance / Q000502:physiology*