Thermoregulatory And Inflammatory Mechanisms Of Shivering After Cardiopulmonary Bypass In Cardiac Surgery Patients

2.50
Hdl Handle:
http://hdl.handle.net/10755/165951
Category:
Abstract
Type:
Presentation
Title:
Thermoregulatory And Inflammatory Mechanisms Of Shivering After Cardiopulmonary Bypass In Cardiac Surgery Patients
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:
Heat debt occurs in patients after mild hypothermic (30-32(C) cardiopulmonary bypass (CPB) during cardiac surgery. Warming mechanisms, including vasoconstriction in the cutaneous bed and shivering, are thought to activate in early hours after surgery to effect thermal recovery. However, these mechanisms may be activated after synthesis, release and intravascular accumulation of pyrogenic inflammatory cell mediators released following the blood-biosynthetic interface between patient and CPB pump tubing. Endogenous pyrogens are thought to elevate thermostatic setpoint and cause blood temperature to be sensed as "cold", activating vasoconstriction and shivering to correct thermal gradients between setpoint and actual blood temperature. It is not clear if postoperative shivering is driven by heat debt or inflammatory mediator release. Therefore, purposes of this study are to examine effects of accumulation of inflammatory mediators (Interleukin-1 b; Tumor Necrosis Factor-a) in cardiac surgery patients on 1) thermal balance, 2) cutaneous blood flow, and 3) onset, severity and duration of shivering activity during the initial 12 hours following separation from CPB. In addition, relationships between 1) skin-to-core thermal gradients, 2) cutaneous blood flow, and 3) propensity to shiver during these 12 hours are also of interest. Study design includes a description of possible mechanisms of shivering onset, comparison of shivering and non-shivering subjects, and correlation of Interleukin-1 b and Tumor Necrosis Factor-a levels with thermal, shivering, and hemodynamic data. Subjects and setting include 30 males (determined by power analysis for ANOVA and Correlational procedures, alpha=0.05, 80% power and large effect size) aged 50-80, scheduled for surgical procedures requiring CPB at a large South Texas heath care facility. Subjects may not 1) be female, 2) be a child, 3) experience neuromuscular disorders, 4) require hemodialysis, 5) be diagnosed with inflammatory disorders, 6) be within 6 months of a myocardial infarction, or 7) require valve replacement for infectious processes. Variables and Instruments: 1) Shivering is assessed by the Shivering Severity Scale and electromyography. 2) Thermal data from the pulmonary artery catheter, urinary bladder catheter thermistor, and six skin sites. 3) Hemodynamic parameters from pulmonary artery catheter and arterial line. 4) Cardiac output by thermodilution. 5) Oxygenation by mixed venous oxygen saturation pulmonary artery catheter, fingertip pulse oximetry, and arterial blood gases. 6) Inflammatory response by Interleukin-1 B and Tumor Necroisis Factor-A plasma levels using commercially produced enzyme linked immunoassay. 7) Complete Blood Count with differential by whole blood sample. 8) Cutaneous blood flow for vasoconstriction by laser Doppler flowmetry. Data Analysis: Graphic display with scatter plots and double axis plots will identify appropriate variables for statistical analysis. Descriptive statistics to describe the sample; ANOVA for differences between shivering and non-shivering subjects, repeated measures ANOVA for within subject differences, and correlations between inflammatory mediators, thermal and shivering data.
Repository Posting Date:
27-Oct-2011
Date of Publication:
27-Oct-2011
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.titleThermoregulatory And Inflammatory Mechanisms Of Shivering After Cardiopulmonary Bypass In Cardiac Surgery Patientsen_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/10755/165951-
dc.description.abstractHeat debt occurs in patients after mild hypothermic (30-32(C) cardiopulmonary bypass (CPB) during cardiac surgery. Warming mechanisms, including vasoconstriction in the cutaneous bed and shivering, are thought to activate in early hours after surgery to effect thermal recovery. However, these mechanisms may be activated after synthesis, release and intravascular accumulation of pyrogenic inflammatory cell mediators released following the blood-biosynthetic interface between patient and CPB pump tubing. Endogenous pyrogens are thought to elevate thermostatic setpoint and cause blood temperature to be sensed as "cold", activating vasoconstriction and shivering to correct thermal gradients between setpoint and actual blood temperature. It is not clear if postoperative shivering is driven by heat debt or inflammatory mediator release. Therefore, purposes of this study are to examine effects of accumulation of inflammatory mediators (Interleukin-1 b; Tumor Necrosis Factor-a) in cardiac surgery patients on 1) thermal balance, 2) cutaneous blood flow, and 3) onset, severity and duration of shivering activity during the initial 12 hours following separation from CPB. In addition, relationships between 1) skin-to-core thermal gradients, 2) cutaneous blood flow, and 3) propensity to shiver during these 12 hours are also of interest. Study design includes a description of possible mechanisms of shivering onset, comparison of shivering and non-shivering subjects, and correlation of Interleukin-1 b and Tumor Necrosis Factor-a levels with thermal, shivering, and hemodynamic data. Subjects and setting include 30 males (determined by power analysis for ANOVA and Correlational procedures, alpha=0.05, 80% power and large effect size) aged 50-80, scheduled for surgical procedures requiring CPB at a large South Texas heath care facility. Subjects may not 1) be female, 2) be a child, 3) experience neuromuscular disorders, 4) require hemodialysis, 5) be diagnosed with inflammatory disorders, 6) be within 6 months of a myocardial infarction, or 7) require valve replacement for infectious processes. Variables and Instruments: 1) Shivering is assessed by the Shivering Severity Scale and electromyography. 2) Thermal data from the pulmonary artery catheter, urinary bladder catheter thermistor, and six skin sites. 3) Hemodynamic parameters from pulmonary artery catheter and arterial line. 4) Cardiac output by thermodilution. 5) Oxygenation by mixed venous oxygen saturation pulmonary artery catheter, fingertip pulse oximetry, and arterial blood gases. 6) Inflammatory response by Interleukin-1 B and Tumor Necroisis Factor-A plasma levels using commercially produced enzyme linked immunoassay. 7) Complete Blood Count with differential by whole blood sample. 8) Cutaneous blood flow for vasoconstriction by laser Doppler flowmetry. Data Analysis: Graphic display with scatter plots and double axis plots will identify appropriate variables for statistical analysis. Descriptive statistics to describe the sample; ANOVA for differences between shivering and non-shivering subjects, repeated measures ANOVA for within subject differences, and correlations between inflammatory mediators, thermal and shivering data.en_GB
dc.date.available2011-10-27T14:37:09Z-
dc.date.issued2011-10-27en_GB
dc.date.accessioned2011-10-27T14:37:09Z-
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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