Shivering Effects on Left Ventricular Performance and Mixed VenousOxygen Saturation (DISS)

2.50
Hdl Handle:
http://hdl.handle.net/10755/166334
Category:
Abstract
Type:
Presentation
Title:
Shivering Effects on Left Ventricular Performance and Mixed VenousOxygen Saturation (DISS)
Author(s):
Phillips, Rebecca
Author Details:
Rebecca Phillips, MSN, Doctoral Student, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA, email: phillipsr@uthscsa.edu
Abstract:
Shivering following open heart surgery increases tissue oxygen demand 5 times above non-shivering requirements, the same demand required for running. Response to this demand is to increase cardiac output, something the impaired ventricle may not be able to accomplish. The relationship between the impaired left ventricle and shivering is not clear. This comparative study tests the effects of oxygen demand and shivering in patients with normal or impaired ventricular performance. Cardiac surgery patients (n=60) with ventricular ejection fractions 31% or higher (normal ventricular performance group; n=30) and 30% or lower (impaired ventricular performance group; n=30) comprise the sample. Mixed venous oxygen saturation level (SvO2) reflects tissue oxygen demand and is monitored by the Opticath Oximetric Thermodilution Balloon Flotation Pulmonary Artery Catheter (Abbott Critical Care, Mountain View, Ca.). Assessment of cardiac performance is done using the same catheter and the thermodilution cardiac output technique. Onset of shivering causes masseter muscle tension, measured by electromyography (EMG). The specific aims of this study are to determine: 1) effect of heat loss on hemodynamic variables and mixed venous oxygen saturation during cardiac surgery; 2) differences in mixed venous oxygen saturation level during post-operative shivering in cardiac surgery patients with normal or impaired ventricular performance; and 3) associations between ventricular performance and mixed venous oxygen saturation during each stage of shivering in cardiac surgery patients with normal or impaired ventricular performance. To achieve these aims this study tests the following hypotheses: 1) Left ventricular stroke work index levels are higher immediately before initiation of hypothermic cardiopulmonary bypass than at the point of discontinuation of bypass support; 2) Patients exhibit lower mixed venous oxygen saturation levels during stage 4 shivering than during stage 3, stage 2, or stage 1 post-operative shivering; and 3) There is a direct association between left ventricular ejection fraction and mixed venous oxygen saturation in all cardiac surgery patients at each stage of shivering. Data are analyzed in the following manner: 1) hypothesis #1 is tested using the paired t-test since data is collected from the same patient before and after the use of hypothermia during the surgical procedure; 2) hypothesis #2 is tested using Repeated Measures Analysis of Variance to check for differences between various stages of shivering; 3) hypothesis #3 is tested using a non-parametric Spearman Rho Correlation since shivering data is ordinal; and 4) descriptive statistics will describe sample characteristics.
Repository Posting Date:
27-Oct-2011
Date of Publication:
27-Oct-2011
Conference Date:
Feb 29 - Mar 2, 1996
Conference Host:
Southern Nursing Research Society
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.titleShivering Effects on Left Ventricular Performance and Mixed VenousOxygen Saturation (DISS)en_GB
dc.contributor.authorPhillips, Rebeccaen_US
dc.author.detailsRebecca Phillips, MSN, Doctoral Student, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA, email: phillipsr@uthscsa.eduen_US
dc.identifier.urihttp://hdl.handle.net/10755/166334-
dc.description.abstractShivering following open heart surgery increases tissue oxygen demand 5 times above non-shivering requirements, the same demand required for running. Response to this demand is to increase cardiac output, something the impaired ventricle may not be able to accomplish. The relationship between the impaired left ventricle and shivering is not clear. This comparative study tests the effects of oxygen demand and shivering in patients with normal or impaired ventricular performance. Cardiac surgery patients (n=60) with ventricular ejection fractions 31% or higher (normal ventricular performance group; n=30) and 30% or lower (impaired ventricular performance group; n=30) comprise the sample. Mixed venous oxygen saturation level (SvO2) reflects tissue oxygen demand and is monitored by the Opticath Oximetric Thermodilution Balloon Flotation Pulmonary Artery Catheter (Abbott Critical Care, Mountain View, Ca.). Assessment of cardiac performance is done using the same catheter and the thermodilution cardiac output technique. Onset of shivering causes masseter muscle tension, measured by electromyography (EMG). The specific aims of this study are to determine: 1) effect of heat loss on hemodynamic variables and mixed venous oxygen saturation during cardiac surgery; 2) differences in mixed venous oxygen saturation level during post-operative shivering in cardiac surgery patients with normal or impaired ventricular performance; and 3) associations between ventricular performance and mixed venous oxygen saturation during each stage of shivering in cardiac surgery patients with normal or impaired ventricular performance. To achieve these aims this study tests the following hypotheses: 1) Left ventricular stroke work index levels are higher immediately before initiation of hypothermic cardiopulmonary bypass than at the point of discontinuation of bypass support; 2) Patients exhibit lower mixed venous oxygen saturation levels during stage 4 shivering than during stage 3, stage 2, or stage 1 post-operative shivering; and 3) There is a direct association between left ventricular ejection fraction and mixed venous oxygen saturation in all cardiac surgery patients at each stage of shivering. Data are analyzed in the following manner: 1) hypothesis #1 is tested using the paired t-test since data is collected from the same patient before and after the use of hypothermia during the surgical procedure; 2) hypothesis #2 is tested using Repeated Measures Analysis of Variance to check for differences between various stages of shivering; 3) hypothesis #3 is tested using a non-parametric Spearman Rho Correlation since shivering data is ordinal; and 4) descriptive statistics will describe sample characteristics.en_GB
dc.date.available2011-10-27T14:45:04Z-
dc.date.issued2011-10-27en_GB
dc.date.accessioned2011-10-27T14:45:04Z-
dc.conference.dateFeb 29 - Mar 2, 1996en_US
dc.conference.hostSouthern Nursing Research Societyen_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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