title: Regional redistribution of blood flow in the external and internal carotid arteries during acute hypotension.
abstract: The present study examined to what extent an acute bout of hypotension influences blood flow in the external carotid artery (ECA) and the corresponding implications for blood flow regulation in the internal carotid artery (ICA). Nine healthy male participants were subjected to an abrupt decrease in arterial pressure via the thigh-cuff inflation-deflation technique. Duplex ultrasound was employed to measure beat-to-beat ECA and ICA blood flow. Compared with the baseline normotensive control, acute hypotension resulted in a heterogeneous blood flow response. ICA blood flow initially decreased following cuff release and then returned quickly to baseline levels. In contrast, the reduction in ECA blood flow persisted for 30 s following cuff release. Thus, the contribution of common carotid artery blood flow to the ECA circulation decreased during acute hypotension (-10 ± 4%, P < 0.001). This finding suggests that a preserved reduction in ECA blood flow, as well as dynamic cerebral autoregulation likely prevent a further decrease in intracranial blood flow during acute hypotension. The peripheral vasculature of the ECA may, thus, be considered an important vascular bed for intracranial cerebral blood flow regulation.
authors.affiliation: Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan; ogoh@toyo.jp.
authors.forename: Shigehiko
authors.initials: S
authors.lastname: Ogoh
authors.affiliation: Université de Caen Basse-Normandie and Institut National de la Santé et de la Recherche Médicale, U-1075, F-14032, Caen, France; and.
authors.forename: Romain
authors.initials: R
authors.lastname: Lericollais
authors.affiliation: Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan;
authors.forename: Ai
authors.initials: A
authors.lastname: Hirasawa
authors.affiliation: Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan;
authors.forename: Sadayoshi
authors.initials: S
authors.lastname: Sakai
authors.affiliation: Université de Caen Basse-Normandie and Institut National de la Santé et de la Recherche Médicale, U-1075, F-14032, Caen, France; and.
authors.forename: Hervé
authors.initials: H
authors.lastname: Normand
authors.affiliation: Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, United Kingdom.
authors.forename: Damian M
authors.initials: DM
authors.lastname: Bailey
mesh_terms: D000208:Acute Disease; D002342:Carotid Artery, External / Q000000981:diagnostic imaging / Q000502:physiology*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007022:Hypotension / Q000503:physiopathology*; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology*; D013848:Thigh / Q000098:blood supply; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult
keywords: arterial baroreflex; arterial blood pressure; common carotid artery; humans; skin blood flow