title: Position of probe determines prognostic information of brain tissue PO2 in severe traumatic brain injury.
abstract: BACKGROUND
  Monitoring brain tissue PO2 (PbtO2) is part of multimodality monitoring of patients with traumatic brain injury (TBI). However, PbtO2 measurement is a sampling of only a small area of tissue surrounding the sensor tip.
  
  
  OBJECTIVE
  To examine the effect of catheter location on the relationship between PbtO2 and neurological outcome.
  
  
  METHODS
  A total of 405 patients who had PbtO2 monitoring as part of standard management of severe traumatic brain injury were studied. The relationships between probe location and resulting PbtO2 and outcome were examined.
  
  
  RESULTS
  When the probe was located in normal brain, PbtO2 averaged 30.8 ± 18.2 compared with 25.6 ± 14.8 mm Hg when placed in abnormal brain (P < .001). Factors related to neurological outcome in the best-fit logistic regression model were age, PbtO2 probe position, postresuscitation motor Glasgow Coma Scale score, and PbtO2 trend pattern. Although average PbtO2 was significantly related to outcome in univariate analyses, it was not significant in the final logistic model. However, the interaction between PbtO2 and probe position was statistically significant. When the PbtO2 probe was placed in abnormal brain, the average PbtO2 was higher in those with a favorable outcome, 28.8 ± 12.0 mm Hg, compared with those with an unfavorable outcome, 19.5 ± 13.7 mm Hg (P = .01). PbtO2 and outcome were not related when the probe was placed in normal-appearing brain.
  
  
  CONCLUSIONS
  These results suggest that the location of the PbtO2 probe determines the PbtO2 values and the relationship of PbtO2 to neurological outcome.
authors.affiliation: Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: Lucido L
authors.initials: LL
authors.lastname: Ponce
authors.forename: Shibu
authors.initials: S
authors.lastname: Pillai
authors.forename: Jovany
authors.initials: J
authors.lastname: Cruz
authors.forename: Xiaoqi
authors.initials: X
authors.lastname: Li
authors.forename: H
authors.initials: H
authors.lastname: Julia
authors.forename: Shankar
authors.initials: S
authors.lastname: Gopinath
authors.forename: Claudia S
authors.initials: CS
authors.lastname: Robertson
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism / Q000503:physiopathology; D001930:Brain Injuries / Q000378:metabolism / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D010100:Oxygen / Q000032:analysis*; D010313:Partial Pressure; D012189:Retrospective Studies
chemical_list: D010100:Oxygen