2.50
Hdl Handle:
http://hdl.handle.net/10755/163662
Category:
Abstract
Type:
Presentation
Title:
Effects of transmural pressure on forearm flow dynamics in humans
Author(s):
Lott, Mary
Author Details:
Mary Lott, Pennsylvania State University, Milton S. Hershey Medical Center, Harrisburg, Pennsylvania, USA, email: mlott@psu.edu
Abstract:
Purpose: The purpose of this study was to examine the characteristics of both acute and sustained changes in forearm blood flow velocity (e.g. myogenic response) at rest and after a brief static handgrip in human subjects. Specific Aims: It was hypothesized that changes in flow would occur rapidly with vasoconstriction and vasodilation when tank pressure was changed to negative and positive pressure, respectively. In addition, it was hypothesized that the handgrip would enhance or counterbalance changes in transmural pressure with negative and positive pressure changes, respectively. Methods: Transmural pressure was altered using a specially designed pressure tank that raised or lowered forearm pressure by 50 mmHg within .2 s. Flow velocity was measured with Doppler in the arm directly above the site of forearm pressure change. Pressure changes were evoked during resting conditions and following a 5 s handgrip contraction at 25% maximal voluntary contraction. Results and Conclusions: Changes in transmural pressure evoked almost immediate directionally similar changes in blood flow velocity. This was followed by impressive and rapid adjustments (-2.14 +/- .24 cm/s [vasoconstriction] during negative pressure and +2.14 +/- .45cm/s [vasodilatation] during positive pressure). These adjustments served to return blood flow velocity to resting levels. This regulatory influence remained operative after brief handgrip contractions. Of note, changes in transmural pressure were also capable of altering the timing (heartbeat [HB]) of the peak flow response (5 +/- 0, 2 +/- 0, 6 +/- 1 HB) as well as the speed of flow adjustment (-2.03 +/- .18; -2.48 +/- .15; -.84 +/- .19 cm/s/s) following handgrip contractions under ambient, negative, and positive pressure, respectively. These findings represent the most detailed characterization of the effects of transmural pressure on flow regulation in humans. We believe these experiments provide the most convincing evidence to date that the myogenic response plays a pivotal role in flow regulation in human subjects. Implications: This study provides further insight to potential differences in blood flow to pressure changes during posture changes and exercise.
Repository Posting Date:
27-Oct-2011
Date of Publication:
27-Oct-2011
Conference Date:
2002
Conference Name:
14th Annual Scientific Sessions
Conference Host:
Eastern Nursing Research Society
Conference Location:
University Park, Pennsylvania, USA
Note:
This is an abstract-only submission. If the author has submitted a full-text item based on this abstract, you may find it by browsing the Virginia Henderson Global Nursing e-Repository by author. If author contact information is available in this abstract, please feel free to contact him or her with your queries regarding this submission. Alternatively, please contact the conference host, journal, or publisher (according to the circumstance) for further details regarding this item. If a citation is listed in this record, the item has been published and is available via open-access avenues or a journal/database subscription. Contact your library for assistance in obtaining the as-published article.

Full metadata record

DC FieldValue Language
dc.type.categoryAbstracten_US
dc.typePresentationen_GB
dc.titleEffects of transmural pressure on forearm flow dynamics in humansen_GB
dc.contributor.authorLott, Maryen_US
dc.author.detailsMary Lott, Pennsylvania State University, Milton S. Hershey Medical Center, Harrisburg, Pennsylvania, USA, email: mlott@psu.eduen_US
dc.identifier.urihttp://hdl.handle.net/10755/163662-
dc.description.abstractPurpose: The purpose of this study was to examine the characteristics of both acute and sustained changes in forearm blood flow velocity (e.g. myogenic response) at rest and after a brief static handgrip in human subjects. Specific Aims: It was hypothesized that changes in flow would occur rapidly with vasoconstriction and vasodilation when tank pressure was changed to negative and positive pressure, respectively. In addition, it was hypothesized that the handgrip would enhance or counterbalance changes in transmural pressure with negative and positive pressure changes, respectively. Methods: Transmural pressure was altered using a specially designed pressure tank that raised or lowered forearm pressure by 50 mmHg within .2 s. Flow velocity was measured with Doppler in the arm directly above the site of forearm pressure change. Pressure changes were evoked during resting conditions and following a 5 s handgrip contraction at 25% maximal voluntary contraction. Results and Conclusions: Changes in transmural pressure evoked almost immediate directionally similar changes in blood flow velocity. This was followed by impressive and rapid adjustments (-2.14 +/- .24 cm/s [vasoconstriction] during negative pressure and +2.14 +/- .45cm/s [vasodilatation] during positive pressure). These adjustments served to return blood flow velocity to resting levels. This regulatory influence remained operative after brief handgrip contractions. Of note, changes in transmural pressure were also capable of altering the timing (heartbeat [HB]) of the peak flow response (5 +/- 0, 2 +/- 0, 6 +/- 1 HB) as well as the speed of flow adjustment (-2.03 +/- .18; -2.48 +/- .15; -.84 +/- .19 cm/s/s) following handgrip contractions under ambient, negative, and positive pressure, respectively. These findings represent the most detailed characterization of the effects of transmural pressure on flow regulation in humans. We believe these experiments provide the most convincing evidence to date that the myogenic response plays a pivotal role in flow regulation in human subjects. Implications: This study provides further insight to potential differences in blood flow to pressure changes during posture changes and exercise.en_GB
dc.date.available2011-10-27T11:11:34Z-
dc.date.issued2011-10-27en_GB
dc.date.accessioned2011-10-27T11:11:34Z-
dc.conference.date2002en_US
dc.conference.name14th Annual Scientific Sessionsen_US
dc.conference.hostEastern Nursing Research Societyen_US
dc.conference.locationUniversity Park, Pennsylvania, USAen_US
dc.description.noteThis is an abstract-only submission. If the author has submitted a full-text item based on this abstract, you may find it by browsing the Virginia Henderson Global Nursing e-Repository by author. If author contact information is available in this abstract, please feel free to contact him or her with your queries regarding this submission. Alternatively, please contact the conference host, journal, or publisher (according to the circumstance) for further details regarding this item. If a citation is listed in this record, the item has been published and is available via open-access avenues or a journal/database subscription. Contact your library for assistance in obtaining the as-published article.-
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