title: Temporal artery flow response during the last minute of a head up tilt test, in relation with orthostatic intolerance after a 60 day head-down bedrest.
abstract: OBJECTIVE
  Check if the Temporal flow response to Tilt could provide early hemodynamic pattern in the minutes preceding a syncope during the Tilt test performed after a 60-d head down bedrest (HDBR).
  
  
  METHODS
  Twenty-one men divided into 3 groups [Control (Con), Resistive Vibration (RVE) and Chinese Herb (Herb)] underwent a 60 day HDBR. Pre and Post HDBR a 20 min Tilt identified Finishers (F) and Non Finishers (NF). Cerebral (MCA), Temporal (TEMP), Femoral (FEM) flow velocity, were measured by Doppler during the Tilt. Blood pressure (BP) was measured by arm cuff and cardiopress.
  
  
  CONCLUSIONS
  Four of the 21 subjects were NF at the post HDBR Tilt test (Con gr:2, RVE gr: 1, Herb gr: 1). At 1 min and 10 s before end of Tilt in NF gr, FEM flow decreased less and MCA decreased more at post HDBR Tilt compared to pre (p<0.05), while in the F gr they changed similarly as pre. In NF gr: TEMP flow decreased more at post HDBR Tilt compared to pre, but only at 10 s before the end of Tilt (P<0.05). During the last 10 s a negative TEMP diastolic component appeared which induced a drop in mean velocity until Tilt arrest.
  
  
  CONCLUSIONS
  The sudden drop in TEMP flow with onset of a negative diastolic flow preceding the decrease in MCA flow confirm that the TEMP vascular resistance respond more directly than the cerebral one to the cardiac output redistribution and that this response occur several seconds before syncope.
authors.affiliation: UMPS-CERCOM Médecine Physiologie Spatial, Université-Hôpital Trousseau, Tours, France. arbeille@med.univ-tours.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Arbeille
authors.forename: Ming
authors.initials: M
authors.lastname: Yuan
authors.forename: Yanqiang
authors.initials: Y
authors.lastname: Bai
authors.forename: Shizhong
authors.initials: S
authors.lastname: Jiang
authors.forename: Gullemette
authors.initials: G
authors.lastname: Gauquelin
authors.forename: Patrick
authors.initials: P
authors.lastname: Aubry
authors.forename: Yuming
authors.initials: Y
authors.lastname: Wan
authors.forename: Marc Antoine
authors.initials: MA
authors.lastname: Custaud
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Li
mesh_terms: D000328:Adult; D001510:Bed Rest / Q000009:adverse effects*; D001783:Blood Flow Velocity; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D018475:Head-Down Tilt / Q000009:adverse effects; D006801:Humans; D008297:Male; D054971:Orthostatic Intolerance / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000502:physiology*; D013699:Temporal Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D018667:Tilt-Table Test; D018615:Ultrasonography, Doppler, Color; D014655:Vascular Resistance
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