title: Effects of Brain Temperature on Cerebrovascular Autoregulation During the Acute Stage of Severe Traumatic Brain Injury.
abstract: The pressure reactivity index (PRx) is calculated as a moving correlation coefficient between intracranial pressure (ICP) and mean arterial blood pressure (MABP), and this analytical value is viewed as reflecting a vasomotor response to MABP variability. At present, the factors influencing the PRx value during the acute stage of traumatic brain injury (TBI) are not known. We observed significant cases where changes in the calculated value of PRx seemed to be influenced by changes in brain temperature during the course of acute stage TBI. In one case, a patient was treated for 72 h with therapeutic brain hypothermia after a decompressive hemicraniectomy. During the hypothermic condition, the mean value of PRx was -0.019; however, after gradual rewarming, the value of PRx increased drastically, and the mean value during the rewarming period, when the brain temperature exceeded 35 °C, was 0.331. Similarly, in another case where the patient underwent therapeutic brain hypothermia, the PRx showed a mean value of -0.038 during the hypothermic condition, and a mean value of 0.052 during the rewarming period. In both cases, a trend toward a negative correlation between ICP and MABP during brain hypothermia shifted to a positive correlation upon rewarming.
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, Yamaguchi, Japan. hiroyasu@yamaguchi-u.ac.jp.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Koizumi
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, Yamaguchi, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Suehiro
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, Yamaguchi, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Fujiyama
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, Yamaguchi, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoneda
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, Yamaguchi, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ishihara
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, Yamaguchi, Japan.
authors.forename: Sadahiro
authors.initials: S
authors.lastname: Nomura
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, Yamaguchi, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Fujii
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, Yamaguchi, Japan.
authors.forename: Michiyasu
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D062186:Arterial Pressure / Q000502:physiology*; D000070624:Brain Contusion / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D000070642:Brain Injuries, Traumatic / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D023261:Glasgow Outcome Scale; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D013696:Temperature; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Intracranial pressure; Pressure reactivity index; Therapeutic brain hypothermia; Traumatic brain injury