Document Detail


Cardiovascular and humoral readjustment after different levels of head-up tilt in humans.
MedLine Citation:
PMID:  11277285     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: To get a more complete picture of cardiovascular regulation after postural changes, this investigation directly monitored volume-related, hemodynamic, and endocrine variables during and after 30 min of passive head-up tilt (HUT) of various degrees. It was hypothesized that the return of variables to pre-tilt control level is of system-specific duration and different from what is found after lower body negative pressure (LBNP). DESIGN: We tested 7 persons on 5 different days using, in random order, no (HUT0) or different intensity (12 degrees , 30 degrees , 53 degrees , and 70 degrees ) of passive orthostasis (HUT12, HUT30, HUT53, HUT70). Data were collected before (supine), during, and after (supine) HUT and compared with synchronous data from HUT0. RESULTS: There was graded alteration with the sine of tilt angle for all hormones and directly volume-related variables. The effects of HUT70 were of the same magnitude as previously documented by others. After HUT, hemodynamic variables and catecholamines returned to control levels most rapidly. Heart rate depression, as observed in a companion LBNP study in the same subjects, did not occur. Vasopressin, PRA, plasma volume and Z0 returned to nominal values more slowly. Plasma aldosterone was still elevated 50 min after reassuming supine posture. CONCLUSION: Besides specific dose-responses within hemodynamic, volume-dependent, and hormonal variables after orthostatic loading of different degree, the return to control levels after HUT occurs with distinctly different time-courses, which are not identical with those seen after LBNP-simulated orthostasis.
Authors:
Z László; A Rössler; H G Hinghofer-Szalkay
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  72     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-03-29     Completed Date:  2001-05-17     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  193-201     Citation Subset:  IM; S    
Affiliation:
Csepeli Weiss Manfréd Kórház Belgyógyászati, Budapest.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aldosterone / blood*
Dizziness / physiopathology
Epinephrine / blood*
Gravitation
Hemodynamics / physiology*
Humans
Hydrocortisone / blood*
Lower Body Negative Pressure
Male
Renin-Angiotensin System / physiology
Syncope / blood,  etiology,  physiopathology
Tilt-Table Test*
Vasopressins / blood
Chemical
Reg. No./Substance:
11000-17-2/Vasopressins; 50-23-7/Hydrocortisone; 51-43-4/Epinephrine; 52-39-1/Aldosterone

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


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