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Zhang Z, Chen WM, Yang XG, Zhang X, Wang X, Huang J, Zhang C, Geng X, Ma X. Dynamic Microcirculation Characteristics of Plantar Skin Under Metatarsal Head of Human Foot in Response to Life-Like Pressure Stimulus. Microcirculation 2024; 31:e12860. [PMID: 38837938 DOI: 10.1111/micc.12860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 04/16/2024] [Accepted: 04/25/2024] [Indexed: 06/07/2024]
Abstract
OBJECTIVE Diabetic foot ulcer (DFU) is a severe complication with high mortality. High plantar pressure and poor microcirculation are considered main causes of DFU. The specific aims were to provide a novel technique for real-time measurement of plantar skin blood flow (SBF) under walking-like pressure stimulus and delineate the first plantar metatarsal head dynamic microcirculation characteristics because of life-like loading conditions in healthy individuals. METHODS Twenty young healthy participants (14 male and 6 female) were recruited. The baseline (i.e., unloaded) SBF of soft tissue under the first metatarsal head were measured using laser Doppler flowmetry (LDF). A custom-made machine was utilized to replicate daily walking pressure exertion for 5 min. The exerted plantar force was adjusted from 10 N (127.3 kPa) to 40 N (509.3 kPa) at an increase of 5 N (63.7 kPa). Real-time SBF was acquired using the LDF. After each pressure exertion, postload SBF was measured for comparative purposes. Statistical analysis was performed using the R software. RESULTS All levels of immediate-load and postload SBF increased significantly compared with baseline values. As the exerted load increased, the postload and immediate-load SBF tended to increase until the exerted load reached 35 N (445.6 kPa). However, in immediate-load data, the increasing trend tended to level off as the exerted pressure increased from 15 N (191.0 kPa) to 25 N (318.3 kPa). For postload and immediate-load SBF, they both peaked at 35 N (445.6 kPa). However, when the exerted force exceeds 35 N (445.6 kPa), both the immediate-load and postload SBF values started to decrease. CONCLUSIONS Our study offered a novel real-time plantar soft tissue microcirculation measurement technique under dynamic conditions. For the first metatarsal head of healthy people, 20 N (254.6 kPa)-plantar pressure has a fair microcirculation stimulus compared with higher pressure. There might be a pressure threshold at 35 N (445.6 kPa) for the first metatarsal head, and soft tissue microcirculation may decrease when local pressure exceeds it.
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Affiliation(s)
- Zhenming Zhang
- Department of Orthopaedics, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Wen-Ming Chen
- Institute of Biomedical Engineering and Technology, Academy for Engineering and Technology, Fudan University, Shanghai, China
| | - Xiong-Gang Yang
- Department of Orthopaedics, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Xingyu Zhang
- Institute of Biomedical Engineering and Technology, Academy for Engineering and Technology, Fudan University, Shanghai, China
| | - Xu Wang
- Department of Orthopaedics, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Jiazhang Huang
- Department of Orthopaedics, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Chao Zhang
- Department of Orthopaedics, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Xiang Geng
- Department of Orthopaedics, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Xin Ma
- Department of Orthopaedics, Huashan Hospital Affiliated to Fudan University, Shanghai, China
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Pauly S, Mo P, Elliott J, Bleakney A, Pappu S, Jan Y. Effects of alternating pressure patterns on sacral skin blood flow responses in people with spinal cord injury. Int Wound J 2024; 21:e14792. [PMID: 38356253 PMCID: PMC10867481 DOI: 10.1111/iwj.14792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/02/2024] [Indexed: 02/16/2024] Open
Abstract
Alternating pressure support surface (APSS) is a common support surface for treating pressure injury in individuals with spinal cord injury (SCI). However, conflicting results on the effectiveness of APSS have been reported and may be associated with inappropriate configurations of APSS. The objectives of this study were to compare the different pressure amplitudes (75/5 mmHg [alternating between 75 and 5 mmHg] vs. 65/15 mmHg) and cycle periods (5 min [4 cycles] vs. 2.5 min [8 cycles]) of alternating pressure on sacral skin blood flow responses in 10 individuals with SCI. Sacral skin blood flow during and after loading of four alternating pressure protocols was assessed using laser Doppler flowmetry and was normalised to the value before loading (10-min baseline, 20-min loading and 10-min recovery). The results demonstrated that during the high-pressure phase, there was a significant difference between the 75/5 and 65/15 mmHg protocols (0.3658 ± 0.0688 for 75/5 mmHg and 0.1702 ± 0.0389 for 65/15 mmHg, p < 0.05); and during the low-pressure phase, there was a significant difference between the 75/5 and 65/15 mmHg protocols (1.7184 ± 0.262 for 75/5 mmHg and 0.5916 ± 0.1378 for 65/15 mmHg, p < 0.05). There were no differences between cycle periods in skin blood flow responses. No adverse events were reported. Our finding indicates that the pressure amplitude of alternating pressure is a significant factor affecting sacral skin blood flow responses. An appropriate configuration of alternating pressure is needed to effectively increase skin blood flow and tissue viability in individuals with SCI.
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Affiliation(s)
- Serah Pauly
- Department of Kinesiology and Community HealthUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
| | - Pu‐Chun Mo
- Department of Kinesiology and Community HealthUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
| | - Jeannette Elliott
- Disability Resources and Educational ServicesUniversity of Illinois at Urbana‐ChampaignChampaignIllinoisUSA
| | - Adam Bleakney
- Disability Resources and Educational ServicesUniversity of Illinois at Urbana‐ChampaignChampaignIllinoisUSA
| | - Suguna Pappu
- Department of NeurosurgeryCarle Foundation HospitalUrbanaIllinoisUSA
| | - Yih‐Kuen Jan
- Department of Kinesiology and Community HealthUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
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Effect of Vibration on Alleviating Foot Pressure-Induced Ischemia under Occlusive Compression. JOURNAL OF HEALTHCARE ENGINEERING 2021; 2021:6208499. [PMID: 34733455 PMCID: PMC8560250 DOI: 10.1155/2021/6208499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 10/08/2021] [Indexed: 12/03/2022]
Abstract
Objectives Foot ulcers often occur in people with diabetes because of pressure-induced tissue ischemia. Vibration has been reported to be helpful in alleviating mechanical damage and promoting wound healing. The objective of this study is to explore whether vibration can relieve reactive hyperemia in foot tissue under occlusive compression. Methods Thirteen healthy adults participated in the study. Each foot was placed under occlusive compression without or with vibration intervention, which was randomly assigned every other day. The dorsal foot skin blood flow (SBF) was measured pre- and postintervention for each subject in each test. Temporal variations and spectral features of SBF were recorded for comparison. Results The results showed that subjects displayed an obvious reactive hyperemia in the foot tissue after pressure occlusion, whereas they displayed a more regular SBF when vibration was applied along with occlusive compression. Moreover, the amplitude of metabolic, neurogenic, and myogenic pathways for SBF was significantly reduced during the hyperemia process when vibration was applied. Conclusions This study demonstrated that vibration can effectively reduce the level of hyperemia in foot tissue under occlusive compression and also induce less protective physiological regulatory activities. This is helpful for protecting foot tissue from pressure-induced ischemic injury and foot ulcers.
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Wu FL, Zheng Z, Ma Y, Weng K, Liao F, Jan YK. Effects of cycle periods and pressure amplitudes of alternating pressure on sacral skin blood flow responses. J Tissue Viability 2020; 29:264-268. [PMID: 32978042 DOI: 10.1016/j.jtv.2020.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/02/2020] [Accepted: 09/16/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND There are no guidelines on selecting alternating pressure (AP) configurations on increasing sacral skin blood flow (SBF). AIM The specific aims were to compare different cycle periods and pressure amplitudes of AP on sacral SBF responses in healthy people to establish the efficacy and safety of the protocols. METHODS Two studies were tested, including the cycle period study (8 2.5-min vs 4 5-min protocols) and the pressure amplitude study (75/5 vs 65/15 mmHg protocols). Sacral SBF was measured using laser Doppler flowmetry (LDF) in 20 participants. AP loads were randomly applied using an indenter through the rigid LDF probe. Each protocol included a 10-min baseline, 20-min AP and 10-min recovery periods. A 30-min washout period was provided. The SBF response was normalized to the baseline SBF of each condition of each participant. RESULTS For the cycle period study, the 4 5-min cycle protocol partially restored more SBF than the 8 2.5-min cycle protocol at the low-pressure phase (0.87 ± 0.04 vs 0.71 ± 0.03, p < 0.05) and at the high-pressure phase (0.25 ± 0.03 vs 0.19 ± 0.03, p < 0.05). For the pressure amplitude study, the 75/5 mmHg protocol partially restored more sacral SBF than the 65/15 mmHg protocol at the low-pressure phase (0.87 ± 0.1 vs 0.25 ± 0.03, p < 0.05) but not at the high-pressure phase (0.23 ± 0.02 vs 0.21 ± 0.02, non-significant). CONCLUSION This study demonstrated that 1) a cycle period of 5 min was better than 2.5 min and 2) a pressure amplitude of 75/5 mmHg was better than 65/15 mmHg. The finding provides insights for selecting the AP configurations for increasing SBF.
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Affiliation(s)
- Fu-Lien Wu
- Rehabilitation Engineering Lab, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Zhi Zheng
- Rehabilitation Engineering Lab, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Yinyin Ma
- Rehabilitation Engineering Lab, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Kaixiang Weng
- Rehabilitation Engineering Lab, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Fuyuan Liao
- Department of Biomedical Engineering, Xi'an Technological University, Xi'an, China
| | - Yih-Kuen Jan
- Rehabilitation Engineering Lab, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
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Wu FL, Wang WT, Liao F, Liu Y, Li J, Jan YK. Microvascular Control Mechanism of the Plantar Foot in Response to Different Walking Speeds and Durations: Implication for the Prevention of Foot Ulcers. INT J LOW EXTR WOUND 2020; 20:327-336. [PMID: 32326799 DOI: 10.1177/1534734620915360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Physical activity has been recommended by the American Diabetes Association (ADA) as a preventive intervention of diabetes complications. However, there is no study investigating how microvascular control mechanism respond to different walking intensities in people with and without diabetes. The purpose of this study was to assess microvascular control mechanism of the plantar foot in response to various walking speeds and durations in 12 healthy people using spectral analysis of skin blood flow (SBF) oscillations. A 3×2 factorial design, including 3 speeds (3, 6, and 9 km/h) and 2 durations (10 and 20 minutes), was used in this study. Plantar SBF was measured using laser Doppler flowmetry over the first metatarsal head. Borg Rating of Perceived Exertion (RPE) scale and heart rate maximum were used to assess the walking intensity. Wavelet analysis was used to quantify regulations of metabolic (0.0095-0.02 Hz), neurogenic (0.02-0.05 Hz), myogenic (0.05-0.15 Hz), respiratory (0.15-0.4 Hz), and cardiac (0.4-2 Hz) controls. For 10-minute walking, walking at 9 km/h significantly increased the ratio of wavelet amplitudes of metabolic, neurogenic, myogenic, respiratory, and cardiac mechanisms compared with 3 km/h (P < .05). For 20-minute walking, walking at 6 km/h significantly increased the ratio of wavelet amplitudes of metabolic, myogenic, respiratory, and cardiac compared with 3 km/h (P < .05). RPE showed a significant interaction between the speed and duration factors (P < .01). This is the first study demonstrating that different walking speeds and durations caused different plantar microvascular regulations.
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Affiliation(s)
- Fu-Lien Wu
- University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | | | - Fuyuan Liao
- Xi'an Technological University, Xi'an, Shaanxi, China
| | - Yang Liu
- University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Jiacong Li
- University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Yih-Kuen Jan
- University of Illinois at Urbana-Champaign, Champaign, IL, USA.,Beihang University, Beijing, China
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Zhu T, Wang Y, Yang J, Liao F, Wang S, Jan YK. Wavelet-based analysis of plantar skin blood flow response to different frequencies of local vibration. Physiol Meas 2020; 41:025004. [DOI: 10.1088/1361-6579/ab6e56] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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The effects of local cooling rates on perfusion of sacral skin under externally applied pressure in people with spinal cord injury: an exploratory study. Spinal Cord 2019; 58:476-483. [DOI: 10.1038/s41393-019-0378-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/21/2019] [Accepted: 10/23/2019] [Indexed: 11/09/2022]
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Eickhoff R, Guschlbauer M, Maul AC, Klink CD, Neumann UP, Engel M, Hellmich M, Sterner-Kock A, Krieglstein CF. A new device to prevent fascial retraction in the open abdomen - proof of concept in vivo. BMC Surg 2019; 19:82. [PMID: 31286901 PMCID: PMC6615246 DOI: 10.1186/s12893-019-0543-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 06/24/2019] [Indexed: 12/11/2022] Open
Abstract
Background An open abdomen is often necessary for survival of patients after peritonitis, compartment syndrome, or in damage control surgery. However, abdominal wall retraction relieves delays and complicates abdominal wall closure. The principle of the newly fascia preserving device (FPD) is the application of anteriorly directed traction on both fascial edges over an external support through a longitudinal beam to relieve increased abdominal pressure and prevent fascial retraction. Methods Twelve pigs were randomly divided into two groups. Both groups underwent midline laparotomy under general anesthesia. Group one was treated with the new device, group two served as controls. The tension for closing the abdominal fascia was measured immediately after laparotomy as well as at 24 and 48 h. Vital parameters and ventilation pressure were recorded. Post mortem, all fascial tissues were histologically examined. Results All pigs demonstrated increases in abdominal circumference. In both groups, forces for closing the abdomen increased over the observation period. Concerning the central closing force after 24 h we saw a significant lower force in the FPD group (14.4 ± 3 N) vs. control group (21.6 ± 5.7 N, p < 0.001). By testing the main effects using an ANOVA analysis we found a significant group related effect concerning closing force and abdominal circumference of the FDP-group vs. control group (p < 0.001; p < 0.001). The placement of the device on chest and pelvis did not influence vital parameters and ventilation pressure. Histologic exam detected no tissue damage. Conclusions This trial shows the feasibility to prevent fascial retraction during the open abdomen by using the new device. Thus, it is expected that an earlier closure of the abdominal wall will be possible, and a higher rate of primary closure will be attained.
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Affiliation(s)
- Roman Eickhoff
- Department of General, Visceral and Transplantation Surgery, RWTH Aachen University Hospital, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Maria Guschlbauer
- Center for Experimental Medicine, University of Cologne, Robert-Koch-Str. 10 Building No. 51A, 50931, Cologne, Germany.,Decentral Animal Facility, University Hospital of Cologne, Gleueler Str. 24, 50931, Cologne, Germany
| | - Alexandra C Maul
- Center for Experimental Medicine, University of Cologne, Robert-Koch-Str. 10 Building No. 51A, 50931, Cologne, Germany
| | - Christian D Klink
- Department of General, Visceral and Transplantation Surgery, RWTH Aachen University Hospital, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Ulf P Neumann
- Department of General, Visceral and Transplantation Surgery, RWTH Aachen University Hospital, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Michael Engel
- Department of Surgery, Marienhospital Brühl GmbH, Mühlenstraße, 21-25 50321, Brühl, Germany
| | - Martin Hellmich
- IMSB, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Anja Sterner-Kock
- Center for Experimental Medicine, University of Cologne, Robert-Koch-Str. 10 Building No. 51A, 50931, Cologne, Germany
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Martini R, Bagno A. The wavelet analysis for the assessment of microvascular function with the laser Doppler fluxmetry over the last 20 years. Looking for hidden informations. Clin Hemorheol Microcirc 2018; 70:213-229. [DOI: 10.3233/ch-189903] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Romeo Martini
- Department of Cardio-Thorax and Vascular Sciences, Unit of Angiology, Azienda Ospedaliera Universitaria di Padova, Italy
| | - Andrea Bagno
- Department of Industrial Engineering, Università di Padova, Italy
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Increased skin blood flow during low intensity vibration in human participants: Analysis of control mechanisms using short-time Fourier transform. PLoS One 2018; 13:e0200247. [PMID: 30001409 PMCID: PMC6042750 DOI: 10.1371/journal.pone.0200247] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 06/19/2018] [Indexed: 11/23/2022] Open
Abstract
Aim Investigate the immediate effect of low intensity vibration on skin blood flow and its underlying control mechanisms in healthy human participants. Materials and methods One-group pre-post design in a university laboratory setting. Nine adults underwent two bouts of 10-minute vibration (30Hz, peak acceleration 0.4g). Outcome measures include skin blood flow, and skin temperature on the right foot. To examine the control mechanisms underlying the vibration-induced blood flow response, SHORT-TIME Fourier analyses were computed to obtain the spectral densities for three frequency bands: metabolic (0.0095–0.02Hz), neurogenic (0.02–0.06Hz), and myogenic (0.06–0.15Hz). Non-parametric Friedman’s tests were computed to compare changes of the outcome measures and control mechanisms over the course of vibration. Results Vibration increased skin blood flow during both bouts of vibration, however the effect did not last after vibration was terminated. Myogenic spectral density increased during both bouts of vibration, whereas the metabolic and neurogenic spectral densities increased only during the 2nd bout of vibration. Interestingly, only the metabolic spectral density remained elevated after vibration ended. Conclusion Low intensity vibration produced acute increases in skin blood flow mediated in part by vascular control mechanisms of myogenic origin. Further investigation is warranted to determine whether low intensity vibration induces similar increases in skin blood flow in populations prone to developing chronic non-healing wounds, such as spinal cord injury and diabetes.
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Hoogendoorn I, Reenalda J, Koopman BFJM, Rietman JS. The effect of pressure and shear on tissue viability of human skin in relation to the development of pressure ulcers: a systematic review. J Tissue Viability 2017; 26:157-171. [PMID: 28457615 DOI: 10.1016/j.jtv.2017.04.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 04/12/2017] [Accepted: 04/13/2017] [Indexed: 10/19/2022]
Abstract
Pressure ulcers are a significant problem in health care, due to high costs and large impact on patients' life. In general, pressure ulcers develop as tissue viability decreases due to prolonged mechanical loading. The relation between load and tissue viability is highly influenced by individual characteristics. It is proposed that measurements of skin blood flow regulation could provide good assessment of the risk for pressure ulcer development, as skin blood flow is essential for tissue viability. . Therefore, the aim of this systematic review is to gain insight in the relation between mechanical load and the response of the skin and underlying tissue to this loading measured in-vivo with non-invasive techniques. A systematic literature search was performed to identify articles analysing the relation between mechanical load (pressure and/or shear) and tissue viability measured in-vivo. Two independent reviewers scored the methodological quality of the 22 included studies. Methodological information as well as tissue viability parameters during load application and after load removal were extracted from the included articles and used in a meta-analysis. Pressure results in a decrease in skin blood flow parameters, compared to baseline; showing a larger decrease with higher magnitudes of load. The steepness of the decrease is mostly dependent on the anatomical location. After load removal the magnitude of the post-reactive hyperaemic peak is related to the magnitude of pressure. Lastly, shear in addition to pressure, shows an additional negative effect, but the effect is less apparent than pressure on skin viability.
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Affiliation(s)
- Iris Hoogendoorn
- Faculty of Engineering Technology/ MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands; Roessingh Research and Development, Enschede, The Netherlands.
| | - Jasper Reenalda
- Faculty of Engineering Technology/ MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands; Roessingh Research and Development, Enschede, The Netherlands
| | - Bart F J M Koopman
- Faculty of Engineering Technology/ MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Johan S Rietman
- Faculty of Engineering Technology/ MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands; Roessingh Research and Development, Enschede, The Netherlands
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Bergstrand S, Källman U, Ek AC, Engström M, Lindgren M. Microcirculatory responses of sacral tissue in healthy individuals and inpatients on different pressure-redistribution mattresses. J Wound Care 2015; 24:346-58. [DOI: 10.12968/jowc.2015.24.8.346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- S. Bergstrand
- Department of Hand Surgery, Plastic Surgery and Burns and the Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - U. Källman
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Department of Dermatology, Södra Älvsborgs Sjukhus, Borås, Sweden
| | - A-C. Ek
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - M. Engström
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - M. Lindgren
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
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Bergstrand S, Källman U, Ek AC, Lindberg LG, Engström M, Sjöberg F, Lindgren M. Pressure-induced Vasodilation and Reactive Hyperemia at Different Depths in Sacral Tissue Under Clinically Relevant Conditions. Microcirculation 2014; 21:761-71. [DOI: 10.1111/micc.12160] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 07/31/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Sara Bergstrand
- Department of Hand Surgery, Plastic Surgery and Burns and Department of Medical and Health Sciences; Linköping University; Linköping Sweden
| | - Ulrika Källman
- Department of Medical and Health Sciences; Linköping University; Linköping Sweden
- Department of Dermatology; Södra Älvsborgs Sjukhus; Borås Sweden
| | - Anna-Christina Ek
- Department of Medical and Health Sciences; Linköping University; Linköping Sweden
| | - Lars-Göran Lindberg
- Department of Biomedical Engineering; Linköping University; Linköping Sweden
| | - Maria Engström
- Department of Medical and Health Sciences; Linköping University; Linköping Sweden
| | - Folke Sjöberg
- Department of Clinical and Experimental Medicine; Linköping University; Linköping Sweden
| | - Margareta Lindgren
- Department of Medical and Health Sciences; Linköping University; Linköping Sweden
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Lee B, Benyajati S, Woods JA, Jan YK. Effect of local cooling on pro-inflammatory cytokines and blood flow of the skin under surface pressure in rats: feasibility study. J Tissue Viability 2014; 23:69-77. [PMID: 24513091 DOI: 10.1016/j.jtv.2014.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 12/18/2013] [Accepted: 01/16/2014] [Indexed: 01/11/2023]
Abstract
The primary purpose of this feasibility study was to establish a correlation between pro-inflammatory cytokine accumulation and severity of tissue damage during local pressure with various temperatures. The secondary purpose was to compare skin blood flow patterns for assessing the efficacy of local cooling on reducing skin ischemia under surface pressure. Eight Sprague-Dawley rats were assigned to two protocols, including pressure with local cooling (Δt = -10 °C) and pressure with local heating (Δt = 10 °C). Pressure of 700 mmHg was applied to the right trochanter area of rats for 3 h. Skin perfusion quantified by laser Doppler flowmetry and TNF-∗ and IL-1β levels were measured. Our results showed that TNF-α concentrations were increased more significantly with local heating than with local cooling under pressure whereas IL-1β did not change. Our results support the notion that weight bearing soft tissue damage may be reduced through temperature modulation and that non-invasive perfusion measurements using laser Doppler flowmetry may be capable of assessing viability. Furthermore, these results show that perfusion response to loading pressure may be correlated with changes in local pro-inflammatory cytokines. These relationships may be relevant for the development of cooling technologies for reducing risk of pressure ulcers.
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Affiliation(s)
- Bernard Lee
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Siribhinya Benyajati
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jeffrey A Woods
- Rehabilitation Engineering Laboratory, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Yih-Kuen Jan
- Rehabilitation Engineering Laboratory, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
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Using Reactive Hyperemia to Assess the Efficacy of Local Cooling on Reducing Sacral Skin Ischemia Under Surface Pressure in People With Spinal Cord Injury: A Preliminary Report. Arch Phys Med Rehabil 2013; 94:1982-9. [DOI: 10.1016/j.apmr.2013.03.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 02/18/2013] [Accepted: 03/25/2013] [Indexed: 11/21/2022]
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Jan YK, Shen S, Foreman RD, Ennis WJ. Skin blood flow response to locally applied mechanical and thermal stresses in the diabetic foot. Microvasc Res 2013; 89:40-6. [PMID: 23727385 DOI: 10.1016/j.mvr.2013.05.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/29/2013] [Accepted: 05/20/2013] [Indexed: 12/19/2022]
Abstract
Diabetic foot ulcers are one of the most common complications in diabetics, causing significant disabilities and decreasing the quality of life. Impaired microvascular reactivity contributes to the development of diabetic foot ulcers. However, underlying physiological mechanisms responsible for the impaired microvascular reactivity in response to extrinsic causative factors of foot ulcers such as mechanical and thermal stresses have not been well investigated. A total of 26 participants were recruited into this study, including 18 type 2 diabetics with peripheral neuropathy and 8 healthy controls. Laser Doppler flowmetry was used to measure skin blood flow at the first metatarsal head in response to a mechanical stress at 300mmHg and a fast thermal stress at 42°C. Wavelet analysis of skin blood flow oscillations was used to assess metabolic, neurogenic and myogenic controls. Our results indicated that diabetics have significantly decreased metabolic, neurogenic and myogenic responses to thermal stress, especially in the neurogenic and myogenic controls during the first vasodilatory response and in the metabolic control during the second vasodilatory response. Diabetics have a significantly decreased myogenic response to mechanical stress during reactive hyperemia. Our findings demonstrate that locally applied mechanical and thermal stresses can be used to assess microvascular reactivity and risk of diabetic foot ulcers.
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Affiliation(s)
- Yih-Kuen Jan
- Rehabilitation Research Laboratory, Department of Kinesiology and Community Health, University of Illinois at Urbana - Champaign, Champaign, IL, USA.
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Skin blood flow dynamics and its role in pressure ulcers. J Tissue Viability 2013; 22:25-36. [PMID: 23602509 DOI: 10.1016/j.jtv.2013.03.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 03/05/2013] [Accepted: 03/06/2013] [Indexed: 11/20/2022]
Abstract
Pressure ulcers are a significant healthcare problem affecting the quality of life in wheelchair bounded or bed-ridden people and are a major cost to the healthcare system. Various assessment tools such as the Braden scale have been developed to quantify the risk level of pressure ulcers. These tools have provided an initial guideline on preventing pressure ulcers while additional assessments are needed to improve the outcomes of pressure ulcer prevention. Skin blood flow function that determines the ability of the skin in response to ischemic stress has been proposed to be a good indicator for identifying people at risk of pressure ulcers. Wavelet spectral and nonlinear complexity analyses have been performed to investigate the influences of the metabolic, neurogenic and myogenic activities on microvascular regulation in people with various pathological conditions. These findings have contributed to the understanding of the role of ischemia and viability on the development of pressure ulcers. The purpose of the present review is to provide an introduction of the basic concepts and approaches for the analysis of skin blood flow oscillations, and present an overview of the research results obtained so far. We hope this information may contribute to the development of better clinical guidelines for the prevention of pressure ulcers.
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Jan YK, Lee B, Liao F, Foreman RD. Local cooling reduces skin ischemia under surface pressure in rats: an assessment by wavelet analysis of laser Doppler blood flow oscillations. Physiol Meas 2012; 33:1733-45. [PMID: 23010955 DOI: 10.1088/0967-3334/33/10/1733] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The objectives of this study were to investigate the effects of local cooling on skin blood flow response to prolonged surface pressure and to identify associated physiological controls mediating these responses using the wavelet analysis of blood flow oscillations in rats. Twelve Sprague-Dawley rats were randomly assigned to three protocols, including pressure with local cooling (Δt = -10 °C), pressure with local heating (Δt = 10 °C) and pressure without temperature changes. Pressure of 700 mmHg was applied to the right trochanter area of rats for 3 h. Skin blood flow was measured using laser Doppler flowmetry. The 3 h loading period was divided into non-overlapping 30 min epochs for the analysis of the changes of skin blood flow oscillations using wavelet spectral analysis. The wavelet amplitudes and powers of three frequencies (metabolic, neurogenic and myogenic) of skin blood flow oscillations were calculated. The results showed that after an initial loading period of 30 min, skin blood flow continually decreased under the conditions of pressure with heating and of pressure without temperature changes, but maintained stable under the condition of pressure with cooling. Wavelet analysis revealed that stable skin blood flow under pressure with cooling was attributed to changes in the metabolic and myogenic frequencies. This study demonstrates that local cooling may be useful for reducing ischemia of weight-bearing soft tissues that prevents pressure ulcers.
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Affiliation(s)
- Yih-Kuen Jan
- Rehabilitation Research Laboratory, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
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Dai XQ, Lu YH, Lin H, Bai L. Mechanisms of control of human skin blood flow under external pressure. BIOL RHYTHM RES 2012. [DOI: 10.1080/09291016.2011.571027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Skin blood flow response to 2-hour repositioning in long-term care residents: a pilot study. J Wound Ostomy Continence Nurs 2012; 38:529-37. [PMID: 21860333 DOI: 10.1097/won.0b013e31822aceda] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this noninvasive pilot study was to examine the changes in transcutaneous oxygen (tcO2), skin temperature, and hyperemic response in the heels, sacrum, and trochanters in a 2-hour loading-unloading condition in nursing home residents who are positioned in supine and lateral positions. DESIGN A 1-group, prospective, repeated-measures design was used. SUBJECTS AND SETTING Nine subjects (5 males, 4 females) with a mean age of 85.3 ± 10.86 years (mean ± SD) who required help in turning and positioning at a skilled nursing facility participated in the study. METHODS Oxygen and temperature sensors were placed on the heels, trochanters, and sacrum. The subject was (1) positioned lateral for 30 minutes (preload); (2) turned to the supine position with head of the bed at 30° for 2 hours (both sacrum and heels were on the bed surface) (loading); and (3) positioned lateral for 2 hours (unloading). Subjects were turned to either the right or the left side. RESULTS Friedman test showed no statistical differences in tcO₂ or skin temperature on the sacrum, heels, or trochanters during preload, supine, and lateral positioning (P > .5). Individual data revealed that hyperemic response was seen in 6 of the 9 subjects when the position was changed from supine to lateral. Only one-third of the subjects attained a sacral tcO₂ of 40 mm Hg or more at the end of the 2-hour lateral positioning. tcO₂ on both heels decreased within the first 30 minutes of loading. CONCLUSION Two hours of staying in the supine position lowered sacral oxygenation to less than 40 mm Hg, in some subjects, regardless of whether there was adequate tcO₂ at preload. Repositioning to a lateral position after 2 hours of placement in a supine position did not cause the tcO₂ to return to preload level. The efficacy of a 2-hour repositioning schedule requires further investigation. Since heel tcO₂ was reduced after 30 minutes of loading, further work is needed to determine whether the heels should be offloaded with more frequent repositioning.
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Bogie K, Powell HL, Ho CH. New concepts in the prevention of pressure sores. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:235-246. [PMID: 23098716 DOI: 10.1016/b978-0-444-52137-8.00014-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Pressure sores are a serious, and costly, complication for many patients with reduced mobility and sensation. Some populations, such as those with spinal cord injury (SCI), remain at high risk throughout their lifetime. Prevention is highly preferable and while the concept is readily definable, it is much more challenging to develop valid preventative measures. Subjective and objective approaches to risk factor assessment before pressure sores develop are reviewed, including risk status scales and emerging techniques to assess deep tissue injury. Devices to prevent pressure sores have traditionally focused on pressure-relieving cushions and mattresses. Technological advances being applied in the development of new pressure sore prevention devices are presented. Clinical evidence-based practice is integral to pressure sore prevention. Comprehensive assessment must include evaluation of systemic diseases, anatomical and physiological factors, together with environmental and psychosocial factors, which can all contribute to pressure sore development. Extrinsic factors need to be considered in conjunction with intrinsic tissue health factors and are reviewed together with an evaluation of currently available clinical practice guidelines. This chapter presents the broad diversity of factors associated with pressure sore development and highlights the need for an interdisciplinary team approach in order to maximize successful prevention of pressure sores.
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Affiliation(s)
- Kath Bogie
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA.
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Liao F, Jan YK. Using recurrence network approach to quantify nonlinear dynamics of skin blood flow in response to loading pressure. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2012:4196-4199. [PMID: 23366853 PMCID: PMC3586281 DOI: 10.1109/embc.2012.6346892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This paper presents a recurrence network approach to quantify dynamic complexity of skin blood flow oscillations (BFO) in response to loading pressure. This approach consists of three processes, including 1) phase space reconstruction by means of time delay embedding, 2) construction of a recurrence matrix that represents neighboring states in phase space, and 3) consideration of the recurrence matrix as an adjacency matrix representing links in a network and the use of clustering coefficients to characterize phase space properties. By using the Lorenz system and real data, we demonstrate that the global clustering coefficient is robust to the embedding parameters. We applied this approach to study skin BFO at baseline and during loading pressure, a causative factor of skin breakdown. The results showed that global clustering coefficients of BFO significantly decreased in response to loading ( <0.05). Moreover, surrogate tests indicated that such a decrease was associated with a loss of nonlinearity of BFO. Our results suggest that the recurrence network approach can practically quantify the nonlinear dynamics of BFO.
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Affiliation(s)
- Fuyuan Liao
- Department of Rehabilitation Science, University of Oklahoma Health Sciences Center
| | - Yih-Kuen Jan
- Department of Rehabilitation Science, University of Oklahoma Health Sciences Center. phone: 405-271-2131
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Wong VK, Stotts NA, Hopf HW, Dowling GA, Froelicher ES. Changes in Heel Skin Temperature under Pressure in Hip Surgery Patients. Adv Skin Wound Care 2011; 24:562-70. [DOI: 10.1097/01.asw.0000408466.88880.f8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Comparison of skin perfusion response with alternating and constant pressures in people with spinal cord injury. Spinal Cord 2010; 49:136-41. [DOI: 10.1038/sc.2010.58] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gryglewska B, Nęcki M, Cwynar M, Baron T, Grodzicki T. Local heat stress and skin blood flowmotion in subjects with familial predisposition or newly diagnosed hypertension. Blood Press 2010; 19:366-72. [DOI: 10.3109/08037051.2010.488053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Reenalda J, Jannink M, Nederhand M, IJzerman M. Clinical Use of Interface Pressure to Predict Pressure Ulcer Development: A Systematic Review. Assist Technol 2009; 21:76-85. [DOI: 10.1080/10400430903050437] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Post pressure response of skin blood flowmotions in anesthetized rats with spinal cord injury. Microvasc Res 2009; 78:20-4. [DOI: 10.1016/j.mvr.2008.09.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Accepted: 09/22/2008] [Indexed: 11/19/2022]
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Bergstrand S, Lindberg LG, Ek AC, Lindén M, Lindgren M. Blood flow measurements at different depths using photoplethysmography and laser Doppler techniques. Skin Res Technol 2009; 15:139-47. [DOI: 10.1111/j.1600-0846.2008.00337.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Jan YK, Brienza DM, Geyer MJ, Karg P. Wavelet-based spectrum analysis of sacral skin blood flow response to alternating pressure. Arch Phys Med Rehabil 2008; 89:137-45. [PMID: 18164343 DOI: 10.1016/j.apmr.2007.07.046] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 07/27/2007] [Accepted: 07/27/2007] [Indexed: 11/19/2022]
Abstract
OBJECTIVES To provide insight into the physiologic mechanisms associated with alternating pressure, using wavelet analysis of skin blood flow (SBF) oscillations, and to determine whether the application of alternating pressure induces myogenic responses, thereby enhancing SBF as compared with constant loading. DESIGN Repeated-measures design. SETTING University research laboratory. PARTICIPANTS Healthy, young adults (N=10; 5 men, 5 women; mean age +/- standard deviation, 30.0+/-3.1 y). INTERVENTION Alternating pressure for 20 minutes (four 5-min cycles with either 60 mmHg or 3 mmHg) and constant loading for 20 minutes at 30 mmHg on the skin over the sacrum. MAIN OUTCOME MEASURES A laser Doppler flowmeter was used to measure sacral SBF response to both alternating pressure and constant loading. Wavelet-based spectrum analysis of SBF oscillations was used to assess underlying physiologic mechanisms including endothelium-related metabolic (.008-.02 Hz), neurogenic (.02-.05 Hz), and myogenic (.05-.15 Hz) controls. RESULTS Alternating pressure stimulated an increase in sacral SBF of compressed soft tissues as compared with constant loading (P<.01). SBF during the high-pressure phase of 4 alternating pressure cycles showed an increasing trend. An increase in power in metabolic frequency range and a decrease in power in the myogenic frequency range during alternating pressure were observed compared with SBF prior to loading. Power increased in the myogenic frequency range during the low-pressure phase of alternating pressure and decreased during the high-pressure phase. CONCLUSIONS SBF control mechanisms, as assessed by the characteristic frequencies embedded in SBF oscillations, show different responses to 2 loading pressures with the same average pressure but different patterns. Our study suggests that optimization of operating parameters and configurations of alternating pressure support surfaces to compensate for impaired SBF control mechanisms in pathologic populations may be possible using wavelet analysis of blood flow oscillations.
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Affiliation(s)
- Yih-Kuen Jan
- Department of Rehabilitation Science and Technology, University of Pittsburgh, Pittsburgh, PA 15203, USA.
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The Effect of Clinically Relevant Pressure Duration on Sacral Skin Blood Flow and Temperature in Patients After Acute Spinal Cord Injury. Arch Phys Med Rehabil 2007; 88:1673-80. [DOI: 10.1016/j.apmr.2007.07.037] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 07/11/2007] [Accepted: 07/21/2007] [Indexed: 11/18/2022]
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Li Z, Leung JY, Tam EW, Mak AF. Wavelet analysis of skin blood oscillations in persons with spinal cord injury and able-bodied subjects. Arch Phys Med Rehabil 2006; 87:1207-12; quiz 1287. [PMID: 16935056 DOI: 10.1016/j.apmr.2006.05.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2005] [Accepted: 05/29/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To assess the blood oscillations in the skin over the ischial tuberosity (high-risk area for pressure ulcer) using spectral analysis of laser Doppler flowmetry signals based on wavelet transform. DESIGN Wavelet analysis of skin blood oscillations in persons with spinal cord injury (SCI) and able-bodied subjects. SETTING Seating and body support interface laboratory. PARTICIPANTS Ten men were recruited for this study, of whom 5 were able-bodied subjects (age, 31.2+/-3.3 y) and 5 were persons with SCI (age, 37.2+/-7.3 y). INTERVENTIONS External pressure of 16.0 kPa (120 mmHg) was applied to the ischial tuberosity via 1 specifically designed pneumatic indentor. The loading duration was 30 minutes. MAIN OUTCOME MEASURES Skin blood flow was monitored for 10 minutes prior to loading and 20 minutes after the prescribed loading period. With spectral analysis based on wavelet transform, 5 frequency intervals were identified (.01-.02, .02-.06, .06-.15, .15-.40, .40-2.0 Hz) corresponding to endothelial related metabolic, neurogenic, myogenic, respiratory, and cardiac activities, respectively. RESULTS The relative amplitude of the metabolic component for persons with SCI was significantly lower (F=5.26, P=.032) during the resting conditions as compared with able-bodied subjects. During the postloading period, the response of oscillatory activities was evidently lower in the skin over the ischial tuberosity for persons with SCI when compared with able-bodied subjects. In addition, the relative amplitude of the neurogenic component (.02-.06 Hz) during postloading was significantly lower for persons with SCI (F=5.44, P=.029). CONCLUSIONS These findings suggest that the contributions of endothelial related metabolic and neurogenic activities to the blood perfusion regulation become relatively less for persons with SCI during the resting and postloading periods, respectively.
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Affiliation(s)
- Zengyong Li
- Department of Health Technology and Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
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Jan YK, Brienza DM, Geyer MJ. Analysis of week-to-week variability in skin blood flow measurements using wavelet transforms. Clin Physiol Funct Imaging 2005; 25:253-62. [PMID: 16117727 DOI: 10.1111/j.1475-097x.2005.00621.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The study of skin blood flow responses is confounded by temporal variability in blood flow measurements. Spectral analysis has been shown useful in isolating the effects of distinct control mechanisms on various stimuli in the microcirculatory system. However, the sensitivity of spectral analysis to temporal blood blow variability has not been reported. This study was designed to assess week-to-week variability in blood flow measurements using wavelet-based spectrum analysis. Ten healthy, young subjects (mean age+/-SD, 30.0+/-3.1 years) were recruited into the study. Incremental heating (35-45 degrees C, 1 degrees step min-1) was applied on the skin over the sacrum once per week for three consecutive weeks. Wavelet analysis was used to decompose the laser Doppler blood flow signal into frequency bands determined to be associated with endothelial nitric oxide (0.008-0.02 Hz), neurogenic (0.02-0.05 Hz), myogenic (0.05-0.15 Hz), respiratory (0.15-0.4 Hz), and cardiac (0.4-2.0 Hz) control mechanisms. The results showed that coefficients of variation for the power in each frequency band at baseline are smaller than the coefficients of variation of blood flow at baseline or at maximal blood flow ratio (P<0.05). Myogenic and respiratory frequency bands showed the highest coefficients of variation among the five frequency bands. An increase in power in the endothelial nitric oxide frequency band and a decrease in power in the myogenic frequency band of the maximal blood flow response were reproduced in three consecutive weeks. Our study suggests that wavelet analysis is an effective method to overcome temporal variability in skin blood flow measurements.
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Affiliation(s)
- Yih-Kuen Jan
- Department of Rehabilitation Science and Technology, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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