title: Cerebral perfusion pressure below 60 mm Hg is common in the intraoperative setting.
abstract: BACKGROUND
  Maintaining adequate cerebral perfusion pressure (CPP) is of clinical concern in patients with neurological injury. Although there are extensive data on CPP in the ICU setting, there has been little quantitative study of CPP in the intraoperative setting.
  
  
  METHODS
  We retrospectively analyzed the electronic intraoperative records of neurosurgical and trauma patients with concurrent intracranial and arterial pressure monitoring devices in continuous use for ≥45 minutes to calculate CPP (=mean arterial pressure-intracranial pressure). We assessed the total minutes and frequency of 5-minute epochs, during which the median CPP was <60 mm Hg, and the associated risk factors.
  
  
  RESULTS
  A total of 155 trauma and neurosurgical patients were studied. In the neurosurgery cohort (n=88), 74% had at least one 5-minute epoch during which the median CPP was <60 mm Hg and the median total minutes of CPP<60 mm Hg was 39 [interquartile range (67), length of surgery 274 (300) min]. In the trauma cohort (n=67), 82% had at least one 5-minute epoch of <60 mm Hg, and the median total minutes CPP of <60 mm Hg was 35 [(59), length of surgery 159 (160) min]. For the entire cohort (n=155), patients with CPP<60 mm Hg were found to have higher intracranial pressure compared with patients with CPP≥60 mm Hg (P<0.001). Unlike the neurosurgical cohort, trauma patients with CPP<60 mm Hg had a greater frequency of episodes of mean arterial pressure <70 mm Hg (P=0.001).
  
  
  CONCLUSIONS
  CPP<60 mm Hg is common in the intraoperative setting of a tertiary medical center in 2 different surgical populations with intracranial pathology. Prospective studies of intraoperative CPP and neurological outcomes are warranted.
authors.affiliation: Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48109-5048, USA. laurelmo@umich.edu
authors.forename: Laurel E
authors.initials: LE
authors.lastname: Moore
authors.forename: Milad
authors.initials: M
authors.lastname: Sharifpour
authors.forename: Amy
authors.initials: A
authors.lastname: Shanks
authors.forename: Sachin
authors.initials: S
authors.lastname: Kheterpal
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Tremper
authors.forename: George A
authors.initials: GA
authors.lastname: Mashour
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D015992:Body Mass Index; D001930:Brain Injuries / Q000503:physiopathology / Q000601:surgery; D002560:Cerebrovascular Circulation; D015331:Cohort Studies; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D019585:Intracranial Hypotension / Q000453:epidemiology / Q000503:physiopathology*; D007427:Intracranial Pressure / Q000502:physiology*; D007431:Intraoperative Complications / Q000453:epidemiology / Q000503:physiopathology*; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D019635:Neurosurgical Procedures; D012307:Risk Factors; D016896:Treatment Outcome