Document Detail


Cardiovascular responses to short-term head-down positioning in healthy young and older adults.
MedLine Citation:
PMID:  15991485     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND PURPOSE: Isolated head-down postural drainage is assumed to acutely load the cardiovascular system. Consequently, it is considered a relative contraindication in the presence of severe cardiovascular disease. Evidence demonstrating that the head-down manoeuvre as used by physiotherapists does significantly load the cardiovascular system is lacking. The present study documents the cardiovascular responses t short-term 30 degrees head-down positioning in healthy subjects. The results are a point of reference for respiratory patients with and without cardiovascular disease. METHOD: A quasi-experimental research design was used, with multiple measurements obtained at rest (long sitting and in the head-down position. Twenty-one young subjects (mean age 25 years (standard deviation, (SD) 3 years)) and 19 older subjects (mean age 66 years (SD 6 years)) were studied. Applanation tonometry and sphygmocardiography were used to measure temporal and pressure variables, and indices that estimate myocardial work and coronary blood flow. RESULTS: Absolute differences existed between the two age groups for all variables at rest (p < 0.001). No age-time interaction was observed for any variable in the head-down position (p > 0.05). Serial measures in the head-down position did not vary across time (p > 0.05). Small (<9%) but significant (p < or = 0.02) decreases in heart rate, relative diastolic duration, mean arterial blood pressure and diastolic time indices, and small (<12%) but significant (p < or = 0.002) increases in cardiac cycle time, ejection duration (relative and absolute) and absolute diastolic duration were observed in the head-down position compared with rest. A small (9%) but significant (p < 0.001) fall in the sub-endocardial viability ratio occurred in the head down position. CONCLUSION: The findings have little consequence in health, but they suggest that head-down postural drainage may be of concern for chest physiotherapy recipients with reduced cardiac reserve or impaired barorefilex function.
Authors:
Justine M Naylor; Chin-Moi Chow; Anthony S McLean; Robert C Heard; Albert Avolio
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Physiotherapy research international : the journal for researchers and clinicians in physical therapy     Volume:  10     ISSN:  1358-2267     ISO Abbreviation:  Physiother Res Int     Publication Date:  2005  
Date Detail:
Created Date:  2005-07-04     Completed Date:  2005-09-29     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9612022     Medline TA:  Physiother Res Int     Country:  England    
Other Details:
Languages:  eng     Pagination:  32-47     Citation Subset:  IM    
Affiliation:
School of Exercise and Sport Sciences, University of Sydney, NSW, Australia. Justine.Naylor@swsahs.nsw.gov.au
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MeSH Terms
Descriptor/Qualifier:
Adult
Age Factors
Aged
Baroreflex / physiology*
Blood Pressure
Head-Down Tilt / physiology*
Heart Rate
Hemodynamics*
Humans
Male
Middle Aged
Myocardium / metabolism*
Oxygen / metabolism*
Oxygen Consumption
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

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


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