Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord Injury
Pressure ulcers are one of the most common complications of a spinal cord injury (SCI). Prolonged unrelieved pressure is thought to be the primary causative factor resulting in tissue ischemia and eventually pressure ulcers. Previous studies suggested that local cooling reduces skin ischemia of the...
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MDPI AG
2019-01-01
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| Series: | Entropy |
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| Online Access: | http://www.mdpi.com/1099-4300/21/1/90 |
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| author | Fuyuan Liao Tim D. Yang Fu-Lien Wu Chunmei Cao Ayman Mohamed Yih-Kuen Jan |
| author_facet | Fuyuan Liao Tim D. Yang Fu-Lien Wu Chunmei Cao Ayman Mohamed Yih-Kuen Jan |
| author_sort | Fuyuan Liao |
| collection | DOAJ |
| description | Pressure ulcers are one of the most common complications of a spinal cord injury (SCI). Prolonged unrelieved pressure is thought to be the primary causative factor resulting in tissue ischemia and eventually pressure ulcers. Previous studies suggested that local cooling reduces skin ischemia of the compressed soft tissues based on smaller hyperemic responses. However, the effect of local cooling on nonlinear properties of skin blood flow (SBF) during hyperemia is unknown. In this study, 10 wheelchair users with SCI and 10 able-bodied (AB) controls underwent three experimental protocols, each of which included a 10-min period as baseline, a 20-min intervention period, and a 20-min period for recovering SBF. SBF was measured using a laser Doppler flowmetry. During the intervention period, a pressure of 60 mmHg was applied to the sacral skin, while three skin temperature settings were tested, including no temperature change, a decrease by 10 °C, and an increase by 10 °C, respectively. A multiscale entropy (MSE) method was employed to quantify the degree of regularity of blood flow oscillations (BFO) associated with the SBF control mechanisms during baseline and reactive hyperemia. The results showed that under pressure with cooling, skin BFO both in people with SCI and AB controls were more regular at multiple time scales during hyperemia compared to baseline, whereas under pressure with no temperature change and particularly pressure with heating, BFO were more irregular during hyperemia compared to baseline. Moreover, the results of surrogate tests indicated that changes in the degree of regularity of BFO from baseline to hyperemia were only partially attributed to changes in relative amplitudes of endothelial, neurogenic, and myogenic components of BFO. These findings support the use of MSE to assess the efficacy of local cooling on reactive hyperemia and assess the degree of skin ischemia in people with SCI. |
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| spelling | doaj.art-ebe3bb6d99324aa09c3afd2143bdaaec2022-12-22T02:54:04ZengMDPI AGEntropy1099-43002019-01-012119010.3390/e21010090e21010090Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord InjuryFuyuan Liao0Tim D. Yang1Fu-Lien Wu2Chunmei Cao3Ayman Mohamed4Yih-Kuen Jan5Department of Biomedical Engineering, Xi’an Technological University, Xi’an 710021, ChinaDepartment of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USADepartment of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USADepartment of Sports Science and Physical Education, Tsinghua University, Beijing 100084, ChinaDepartment of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USADepartment of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USAPressure ulcers are one of the most common complications of a spinal cord injury (SCI). Prolonged unrelieved pressure is thought to be the primary causative factor resulting in tissue ischemia and eventually pressure ulcers. Previous studies suggested that local cooling reduces skin ischemia of the compressed soft tissues based on smaller hyperemic responses. However, the effect of local cooling on nonlinear properties of skin blood flow (SBF) during hyperemia is unknown. In this study, 10 wheelchair users with SCI and 10 able-bodied (AB) controls underwent three experimental protocols, each of which included a 10-min period as baseline, a 20-min intervention period, and a 20-min period for recovering SBF. SBF was measured using a laser Doppler flowmetry. During the intervention period, a pressure of 60 mmHg was applied to the sacral skin, while three skin temperature settings were tested, including no temperature change, a decrease by 10 °C, and an increase by 10 °C, respectively. A multiscale entropy (MSE) method was employed to quantify the degree of regularity of blood flow oscillations (BFO) associated with the SBF control mechanisms during baseline and reactive hyperemia. The results showed that under pressure with cooling, skin BFO both in people with SCI and AB controls were more regular at multiple time scales during hyperemia compared to baseline, whereas under pressure with no temperature change and particularly pressure with heating, BFO were more irregular during hyperemia compared to baseline. Moreover, the results of surrogate tests indicated that changes in the degree of regularity of BFO from baseline to hyperemia were only partially attributed to changes in relative amplitudes of endothelial, neurogenic, and myogenic components of BFO. These findings support the use of MSE to assess the efficacy of local cooling on reactive hyperemia and assess the degree of skin ischemia in people with SCI.http://www.mdpi.com/1099-4300/21/1/90local coolingmultiscale entropypressure ulcersregularityspinal cord injury |
| spellingShingle | Fuyuan Liao Tim D. Yang Fu-Lien Wu Chunmei Cao Ayman Mohamed Yih-Kuen Jan Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord Injury Entropy local cooling multiscale entropy pressure ulcers regularity spinal cord injury |
| title | Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord Injury |
| title_full | Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord Injury |
| title_fullStr | Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord Injury |
| title_full_unstemmed | Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord Injury |
| title_short | Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord Injury |
| title_sort | using multiscale entropy to assess the efficacy of local cooling on reactive hyperemia in people with a spinal cord injury |
| topic | local cooling multiscale entropy pressure ulcers regularity spinal cord injury |
| url | http://www.mdpi.com/1099-4300/21/1/90 |
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