title: Relationship of brain tissue PO2 to outcome after severe head injury.
abstract: OBJECTIVE
  To determine thresholds of brain tissue PO2 (PbtO2) that are critical for survival after severe head injury.
  
  
  METHODS
  Prospective data collection.
  
  
  METHODS
  Neurosurgical intensive care unit of Ben Taub General Hospital, a comprehensive academic neurosurgical facility and Level I trauma center.
  
  
  METHODS
  Forty-three severely head-injured patients who were not obeying commands on presentation or whose condition deteriorated to this level shortly after admission.
  
  
  METHODS
  Intracerebral placement of Licox (n=39) or Paratrend (n=4) PO2 probes during craniotomy or in the intensive care unit.
  
  
  RESULTS
  PbtO2 monitoring continued for an average of 84.6+/-41.8 hrs. The probes were calibrated before insertion according to the manufacturer's specifications. After removal, probes were tested in room air and in blood gas standard calibration solutions. PbtO2 data were analyzed by comparing the average time that PbtO2 was below the values of 20, 15, 10, 8, 6, 4, and 2 torr (2.7, 2.0, 1.3, 1.0, 0.8, 0.5, and 0.3 kPa, respectively) in patients who were living 3 mos after injury vs. those who died. A Tobit regression analysis using maximum likelihood methods was utilized. Both Licox and Paratrend probes functioned well in room air and in the Level I control. However, in the zero-oxygen solution, the Paratrend probes gave an average reading of 7.0+/-1.4 torr (0.9+/-0.2 kPa), compared with 0.3+/-0.3 torr (0.04+/-0.04 kPa) for the Licox probes.
  
  
  CONCLUSIONS
  Analysis of the PbtO2 monitoring data suggested that the likelihood of death increased with increasing duration of time at or below a PbtO2 of 15 torr (2.0 kPa) or with the occurrence of any PbtO2 values of < or =6 torr (< or =0.8 kPa).
authors.affiliation: Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030-2706, USA.
authors.forename: A B
authors.initials: AB
authors.lastname: Valadka
authors.forename: S P
authors.initials: SP
authors.lastname: Gopinath
authors.forename: C F
authors.initials: CF
authors.lastname: Contant
authors.forename: M
authors.initials: M
authors.lastname: Uzura
authors.forename: C S
authors.initials: CS
authors.lastname: Robertson
mesh_terms: D000293:Adolescent; D000328:Adult; D015308:Anaerobic Threshold; D001921:Brain / Q000378:metabolism*; D001930:Brain Injuries / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism*; D003422:Critical Care / Q000379:methods; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D010100:Oxygen