Document Detail


Rate of change in cerebral oxygenation and blood pressure in response to passive changes in posture: a comparison between pure autonomic failure patients and controls.
MedLine Citation:
PMID:  16594152     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The cardiovascular and cerebrovascular responses to head-up postural change are compromised in pure autonomic failure (PAF) patients because of sympathetic denervation. The aim of this study was to characterize the rate of change of systemic mean blood pressure (MBP) and cerebral haemodynamics in response to passive posture changes. Nine PAF patients and 9 age-matched controls took part in this study. MBP and oxy- (O2Hb), deoxy-haemoglobin (HHb), and tissue oxygenation index (TOI) on the forehead were continuously monitored non-invasively using the Portapres and near-infrared spectroscopy (NIRS), respectively. From visual inspection of the haemoglobin difference signal (Hb(diff) = O2Hb-HHb), seven distinct phases were marked (1: supine, 2: start passive tilt, 3: head up to 60 degrees degrees, 4: end of tilt, 5: tilt reversal, 6: return to supine, 7: rest); the same time points were used for all of the other signals. For each phase, the slope was calculated using a linear regression algorithm. Significant differences were found between PAF patients and controls in the Hb(diff) slope magnitudes for phases 3 (P < .05) and 5 (P = .01), and the duration of phase 2 (P < .05). MBP slope magnitudes showed significant differences for phases 2 (P < .01) and 5 (P < .01). These differences in the rate of change suggest differences in blood vessel resistance related to sympathetic activation.
Authors:
Ilias Tachtsidis; Clare E Elwell; Terence S Leung; Katharine Bleasdale-Barr; Katharine Hunt; Nathan Toms; Martin Smith; Christopher J Mathias; David T Delpy
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Advances in experimental medicine and biology     Volume:  566     ISSN:  0065-2598     ISO Abbreviation:  Adv. Exp. Med. Biol.     Publication Date:  2005  
Date Detail:
Created Date:  2006-04-05     Completed Date:  2006-06-05     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0121103     Medline TA:  Adv Exp Med Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  187-93     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Aged
Autonomic Nervous System Diseases / metabolism*,  physiopathology*
Blood Pressure / physiology*
Brain / metabolism*
Case-Control Studies
Hemoglobins / metabolism
Humans
Middle Aged
Oxygen / metabolism*
Oxyhemoglobins / metabolism
Posture / physiology*
Spectroscopy, Near-Infrared
Chemical
Reg. No./Substance:
0/Hemoglobins; 0/Oxyhemoglobins; 7782-44-7/Oxygen; 9008-02-0/deoxyhemoglobin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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