2.50
Hdl Handle:
http://hdl.handle.net/10755/166097
Category:
Abstract
Type:
Presentation
Title:
Validity And Reliability Of A Shivering Severity Scale
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:
Background: Shivering generates heat by involuntary muscle contractions in response to sensed heat loss. Friction from muscle fibers generates thermal energy, but at high metabolic cost. Despite high oxygen consumption, shivering is only 11% efficient in providing body heat. It is crucial that early identification of shivering onset be made to intervene quickly in vulnerable populations. Electromyograph has been the "gold standard" for shivering measurement, however this method is beset with problems of poor consistency and specificity. The Shivering Severity Instrument (SSI), developed by Abbey and Holtzclaw, rates shivering on a 5 point scale (0-4) with the cephalad to caudal progression of muscle involvement. Despite the growing use of the SSI by Holtzclaw and others, no formal validation or estimation of reliability of the instrument have been reported. Therefore, this study was designed to test whether the SSI was reliable and valid in assessing the phenomenon of thermoregulatory shivering. Specific aims were to (a) test the SSI for interrater reliability in grading the severity of shivering, and (b) to test the content, construct, and validity of the SSI in correctly identifying shivering onset and progression. Methodology: Subjects were a convenience sample of adult cardiac surgery patients (n = 22) monitored in the Post Anesthesia Care and Surgical Intensive Care Units following hypothermic bypass. Study variables included: (a) palpable mandibular vibration ("hum"), (b) visible face, neck and chest fasciculations, (c) visible abdominal muscle fasciculations, (d) extremity involvement, (e) EMG evidence of mandibular tension, (f) Rate Pressure Product (calculated from RPP = heat rate x systolic blood pressure). Reliability was tested using an interrater approach with raters scoring shivering severity (a) at the same time, (b) in an independent manner, and (c) on the same patient. Due to the extremely transient nature of stage 1 of shivering, and the heavy dependence of this stage on the subsequence occurrence of all other stages, no other method was considered feasible for this test of reliability. Content, construct, concurrent and criterion validity were determined. Clinical experts in critical care or post anesthesia care units helped determine content validity. Convergent validity was tested by determining if RPP is higher during stage 4 shivering than during stage 3, 2, or 1. Electromyography (EMG) was used as concurrent validity that the palpated "hum" indicates referred muscle contraction. Presence or absence of phasic burst EMG signal gave criterion referenced validity to document that activity from the masseter exists during the palpable vibration at the mandibular ridge and is absent when no vibration is palpated. Results: Percent Agreement and Cohen's Kappa analyses support the reliability of detecting shivering onset and severity. Percent Agreement, Cohen's Kappa and Content Validity Index supported capability of instrument to appropriately identify shivering. Convergent validity was hampered by the use of beta blocking drugs, affecting RPP values, and too few stages were seen among subjects to confirm convergent validity.
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.titleValidity And Reliability Of A Shivering Severity Scaleen_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/10755/166097-
dc.description.abstractBackground: Shivering generates heat by involuntary muscle contractions in response to sensed heat loss. Friction from muscle fibers generates thermal energy, but at high metabolic cost. Despite high oxygen consumption, shivering is only 11% efficient in providing body heat. It is crucial that early identification of shivering onset be made to intervene quickly in vulnerable populations. Electromyograph has been the "gold standard" for shivering measurement, however this method is beset with problems of poor consistency and specificity. The Shivering Severity Instrument (SSI), developed by Abbey and Holtzclaw, rates shivering on a 5 point scale (0-4) with the cephalad to caudal progression of muscle involvement. Despite the growing use of the SSI by Holtzclaw and others, no formal validation or estimation of reliability of the instrument have been reported. Therefore, this study was designed to test whether the SSI was reliable and valid in assessing the phenomenon of thermoregulatory shivering. Specific aims were to (a) test the SSI for interrater reliability in grading the severity of shivering, and (b) to test the content, construct, and validity of the SSI in correctly identifying shivering onset and progression. Methodology: Subjects were a convenience sample of adult cardiac surgery patients (n = 22) monitored in the Post Anesthesia Care and Surgical Intensive Care Units following hypothermic bypass. Study variables included: (a) palpable mandibular vibration ("hum"), (b) visible face, neck and chest fasciculations, (c) visible abdominal muscle fasciculations, (d) extremity involvement, (e) EMG evidence of mandibular tension, (f) Rate Pressure Product (calculated from RPP = heat rate x systolic blood pressure). Reliability was tested using an interrater approach with raters scoring shivering severity (a) at the same time, (b) in an independent manner, and (c) on the same patient. Due to the extremely transient nature of stage 1 of shivering, and the heavy dependence of this stage on the subsequence occurrence of all other stages, no other method was considered feasible for this test of reliability. Content, construct, concurrent and criterion validity were determined. Clinical experts in critical care or post anesthesia care units helped determine content validity. Convergent validity was tested by determining if RPP is higher during stage 4 shivering than during stage 3, 2, or 1. Electromyography (EMG) was used as concurrent validity that the palpated "hum" indicates referred muscle contraction. Presence or absence of phasic burst EMG signal gave criterion referenced validity to document that activity from the masseter exists during the palpable vibration at the mandibular ridge and is absent when no vibration is palpated. Results: Percent Agreement and Cohen's Kappa analyses support the reliability of detecting shivering onset and severity. Percent Agreement, Cohen's Kappa and Content Validity Index supported capability of instrument to appropriately identify shivering. Convergent validity was hampered by the use of beta blocking drugs, affecting RPP values, and too few stages were seen among subjects to confirm convergent validity.en_GB
dc.date.available2011-10-27T14:40:08Z-
dc.date.issued2011-10-27en_GB
dc.date.accessioned2011-10-27T14:40:08Z-
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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