title: CO(2)-Dependent vasomotor reactivity of cerebral arteries in patients with severe traumatic brain injury: time course and effect of augmentation of cardiac output with dobutamine.
abstract: Failing cerebral blood flow (CBF) autoregulation may contribute to cerebral damage after traumatic brain injury (TBI). The purpose of this study was to describe the time course of CO(2)-dependent vasoreactivity, measured as CBF velocity in response to hyperventilation (vasomotor reactivity [VMR] index). We included 13 patients who had had severe TBI, 8 of whom received norepinephrine (NE) based on clinical indication. In these patients, measurements were also performed after dobutamine administration, with a goal of increasing cardiac output by 30%. Blood flow velocity was measured with transcranial Doppler ultrasound in both hemispheres. All patients except one had an abnormal VMR index in at least one hemisphere within the first 24 h after TBI. In those patients who did not receive catecholamines, mean VMR index recovered within the first 48 to 72 h. In contrast, in patients who received NE within the first 48 h period, VMR index did not recover on the second day. Cardiac output and mean CBF velocity increased significantly during dobutamine administration, but VMR index did not change significantly. In conclusion, CO(2) vasomotor reactivity was abnormal in the first 24 h after TBI in most of the patients, but recovered within 48 h in those patients who did not receive NE, in contrast to those eventually receiving the drug. Addition of dobutamine to NE had variable but overall insignificant effects on CO(2) vasomotor reactivity.
authors.affiliation: Department of Intensive Care Medicine, Bern University Hospital and University of Bern, Bern, Switzerland. matthias.haenggi@insel.ch
authors.forename: Matthias
authors.initials: M
authors.lastname: Haenggi
authors.forename: Anna
authors.initials: A
authors.lastname: Andermatt
authors.forename: Claudia
authors.initials: C
authors.lastname: Anthamatten
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Galimanis
authors.forename: Marie-Luise
authors.initials: ML
authors.lastname: Mono
authors.forename: Alexander
authors.initials: A
authors.lastname: Alfieri
authors.forename: Christian
authors.initials: C
authors.lastname: Fung
authors.forename: Jukka
authors.initials: J
authors.lastname: Takala
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Jakob
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000188:drug therapy / Q000503:physiopathology*; D002245:Carbon Dioxide / Q000502:physiology*; D002302:Cardiac Output / Q000187:drug effects*; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D002536:Cerebral Arteries / Q000502:physiology*; D004280:Dobutamine / Q000627:therapeutic use*; D005260:Female; D015600:Glasgow Coma Scale; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D010865:Pilot Projects; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D055815:Young Adult
chemical_list: D002316:Cardiotonic Agents; D014662:Vasoconstrictor Agents; D002245:Carbon Dioxide; D004280:Dobutamine; D009638:Norepinephrine