Abstract

Background and significance. Traumatic brain injury (TBI) affects 1.7 million Americans annually leading to significant morbidity and health care costs. An important cause of morbidity in TBI is secondary brain injury due to abnormal cerebrovascular autoregulation (CA). Standard measures of CA are not amenable to use outside of the intensive care unit (ICU) and patients continue to be at risk for secondary brain injury post- ICU. Baroreflex sensitivity (BRS) is a non-invasive assessment of autonomic tone that may be useful in evaluating CA. Evaluation of BRS and its relation to CA has not been examined in patients with TBI and predictors of CA are unknown. Purpose. The specific aims for this study were to (1) examine the association between BRS and CA in patients with TBI, (2) compare BRS and CA in TBI patients and age and gender matched healthy volunteers (HV) and (3) identify predictors of BRS and CA in TBI. Methods. This study used a two group comparative design with 52 subjects (26 with moderate to severe TBI; 26 HV). Measurement of variables. BRS was calculated as heart rate/mean arterial pressure; CA was calculated as cerebral blood flow velocity using transcranial Doppler; and cognition was assessed using the Galveston Orientation and Amnesia Test (GOAT). Results. There was no significant correlation between BRS and CA, however, BRS had high specificity (77%) for normal CA. BRS was not significantly different between TBI and HV subjects, those with normal or abnormal CA nor was BRS an independent predictor of CA. Forty six percent of TBI subjects had abnormal CA after their TBI (mean = 59.58 ± 36.54 days) and 34.6% of HV had abnormal CA. Predictors of abnormal CA were male gender, ACE-Inhibitors and GOAT. Implications . BRS can be used to identify normal CA. The GOAT has potential for routine assessment of CA status in non-ICU areas. Large proportions of TBI subjects long after a TBI event and HV had abnormal CA. Thus assessment of CA status is important in TBI subjects after ICU discharge and further research is needed on the impact of pre-existing CA abnormalities in HV.

Description

This dissertation has also been disseminated through the ProQuest Dissertations and Theses database. Dissertation/thesis number: 3511290; ProQuest document ID: 1022495550. The author still retains copyright.

Norma D. McNair

Author Details

Dr. Norma D. McNair, PhD, RN

Sigma Membership

Delta Mu, Gamma Mu

Type

Dissertation

Format Type

Text-based Document

Study Design/Type

Quasi-Experimental Study, Other

Research Approach

Quantitative Research

Keywords:

Neurology Patients, Intensive Care Patients, Inpatients

Advisors

Woo, Mary A.

Degree

PhD

Degree Grantor

University of California, Los Angeles

Degree Year

2012

Rights Holder

All rights reserved by the author(s) and/or publisher(s) listed in this item record unless relinquished in whole or part by a rights notation or a Creative Commons License present in this item record.

All permission requests should be directed accordingly and not to the Sigma Repository.

All submitting authors or publishers have affirmed that when using material in their work where they do not own copyright, they have obtained permission of the copyright holder prior to submission and the rights holder has been acknowledged as necessary.

Review Type

None: Degree-based Submission

Acquisition

Proxy-submission

Date of Issue

2020-07-10

Full Text of Presentation

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