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Effectiveness of local cooling on enhancing tissue ischemia tolerance in people with spinal cord injury

Tzen, Yi-Ting (2010) Effectiveness of local cooling on enhancing tissue ischemia tolerance in people with spinal cord injury. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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People with spinal cord injury (SCI) are at risk of pressure ulcer development due to impaired mobility, sensation or changes in tissue properties. Increased skin temperature is one of the least explored risk factors for pressure ulcers. Since people with SCI also encounter thermoregulation deficits, investigation of the effectiveness of local skin cooling in this population is particularly important. Three groups of subjects were recruited: 1) 14 subjects with SCI at T6 and above, 2) 8 subjects with SCI below T6, and 3) 14 healthy controls. Reactive hyperemic response was the main study outcome and was measured after three different combinations of stimuli: 1) pressure only, 2) pressure with fast cooling (-4°C/min) and 3) pressure with slow cooling (-0.33°C/min). Spectral density of the skin blood flow (SBF) was used to investigate the underlying microcirculatory control mechanisms. Five of the subjects did not have reactive hyperemia in all test sessions and were excluded from statistical analysis. In the control group, the normalized peak SBF and perfusion area were close to significantly greater in pressure only as compared to fast cooling (p=0.023 and p=0.023, respectively) and slow cooling (p=0.033 and p=0.016, respectively). Although this phenomenon was not significant when analyzing subjects with SCI alone, significant changes were observed in the signal attributed to the metabolic control mechanism and were observed in this population with pressure only (p=0.019) and pressure with slow cooling (p=0.041). Since the reactive hyperemic response is mediated by different control mechanisms, the less obvious changes in reactive hyperemia in people with SCI may be due to alterations in microcirculation after injury. Results from this study suggest that local skin cooling is beneficial to ischemic tissue by decreasing the metabolic demand, and this is generally consistent with previous animal studies and our pilot study. Findings from this study also suggest that investigating time domain parameters and time-dependent spectral analysis of the SBF signal is helpful in understanding circulatory control in people with different levels of neurological deficits. This study contributes toward justification for the development of support surfaces with microclimate controls to enhance tissue integrity.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Tzen, Yi-Tingyit10@pitt.eduYIT10
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairCarvell, George Egcarvell@pitt.eduGCARVELL
Committee CoChair Brienza, David Mdbrienza@pitt.eduDBRIENZA
Committee Member Geyer, Mary Jomygeyer@pitt.eduMYGEYER
Committee MemberKarg, Patricia Etkarg@pitt.eduTKARG
Committee Member Loughlin, Patrick Jloughlin@pitt.eduLOUGHLIN
Date: 23 December 2010
Date Type: Completion
Defense Date: 28 July 2010
Approval Date: 23 December 2010
Submission Date: 30 September 2010
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: School of Health and Rehabilitation Sciences > Rehabilitation Science
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: laser Doppler flowmetry; skin temperature; spinal cord injury; local cooling; pressure ulcer
Other ID:, etd-09302010-174606
Date Deposited: 10 Nov 2011 20:02
Last Modified: 15 Nov 2016 13:50


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