| 1. |
- Bergstrand, Sara, et al.
(författare)
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Existence of Tissue Blood Flow in Response to External Pressure in the Sacral Region of Elderly Individuals - Using an Optical Probe Prototype
- 2010
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Ingår i: MICROCIRCULATION. - : Taylor and Francis. - 1073-9688 .- 1549-8719. ; 17:4, s. 311-319
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Tidskriftsartikel (refereegranskat)abstract
- Pandgt;Objective: The aim was to investigate the existence of sacral tissue blood flow at different depths in response to external pressure and compression in elderly individuals using a newly developed optical probe prototype. Methods: The tissue blood flow and tissue thickness in the sacral area were measured during load in 17 individuals using laser Doppler flowmetry and photoplethysmography in a combined probe, and digital ultrasound. Results: The mean age was 68.6 +/- 7.0 years. While loading, the mean compression was 60.3 +/- 11.9%. The number of participants with existing blood flow while loading increased with increased measurement depth. None had enclosed blood flow deep in the tissue and at the same time an existing more superficial blood flow. Correlation between tissue thickness and BMI in unloaded and loaded sacral tissue was shown: r = 0.68 (P = 0.003) and r = 0.68 (P = 0.003). Conclusions: Sacral tissue is highly compressed by external load. There seems to be a difference in responses to load in the different tissue layers, as occluded blood flow in deeper tissue layers do not occur unless the blood flow in the superficial tissue layers is occluded.
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| 2. |
- Bergstrand, Sara, et al.
(författare)
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Pressure-induced vasodilation and reactive hyperemia at different depths in sacral tissue under clinically relevant conditions
- 2014
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Ingår i: Microcirculation. - : John Wiley & Sons. - 1073-9688 .- 1549-8719. ; 21:8, s. 761-771
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To characterize pressure-induced vasodilatation and reactive hyperemia at different sacral tissue depths in different populations under clinically relevant pressure exposure.METHODS: Forty-two subjects (< 65 years), 38 subjects (≥ 65 years), and 35 patients (≥ 65 years) participated. Interface pressure, skin temperature, and blood flow at tissue depths of 1 mm, 2 mm, and 10 mm (using laser Doppler flowmetry and photoplethysmography) were measured in the sacral tissue before, during, and after load in a supine position.RESULTS: pressure-induced vasodilatation and reactive hyperemia were observed at three tissue depths. At 10 mm depth, the proportion of subjects with a lack of pressure-induced vasodilatation was higher compared to superficial depths. The patients had higher interface pressure during load than the healthy individuals, but there were no significant differences in blood flow. Twenty-nine subjects in all three study groups were identified with a lack of pressure-induced vasodilatation and reactive hyperemia.CONCLUSIONS: pressure-induced vasodilatation and reactive hyperemia can be measured at different tissue depths. A lack of these responses was found in healthy individuals as well as in patients indicating an innate susceptibility in some individuals, and are potential important factors to evaluate in order to better understand the etiology of pressure ulcers.
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| 3. |
- Bergstrand, Sara, 1978-
(författare)
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Preventing pressure ulcers by assessment of the microcirculation in tissue exposed to pressure
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis was to combine optical methods into a system with the ability to simultaneously measure blood flow changes at different tissue depths. The goal of such a system was to reveal vascular mechanisms relevant to pressure ulcer etiology under clinically relevant conditions and in relation to the evaluation of pressure-redistribution support surfaces.This thesis consists of four quantitative, cross-sectional studies measuring blood flow responses before, during, and after pressure exposure of the sacral tissue. Two optical methods – photoplethysmography and laser Doppler flowmetry – were combined in a newly developed system that has the ability to discriminate blood flows at different tissue depths. Studies I and II explored blood flow responses at different depths in 17 individuals. In Study I the blood flow was related to tissue thickness and tissue compression during pressure exposure of ≥ 220 mmHg. In Study II, the sacral tissue was loaded with 37.5 mmHg and 50.0 mmHg, and the variation in blood flow was measured. Studies III and IV included 42 healthy individuals < 65 years, 38 healthy individuals ≥ 65 years, and 35 patients ≥ 65 years. Study III included between-subject comparisons of blood flow and pressure between individuals in the three study groups lying in supine positions on a standard hospital mattress. Study IV added within-subject comparisons while the individual was lying on four different types of mattress. The studies explored the vascular phenomena pressure-induced vasodilation (PIV) and reactive hyperemia (RH).The most common blood flow response to tissue exposure in this thesis was PIV, although a decrease in blood flow (a lack of PIV) was observed in some individuals. The patients tended to have higher interface pressure during pressure exposure than the healthy groups but no differences in blood flow responses were seen. Our results showed that pressure levels that are normally considered to be harmless could have a significant effect on the microcirculation in different tissue structures. Differences in individual blood flow responses in terms of PIV and RH were seen, and a larger proportion of individuals lacked these responses in the deeper tissue structures compared to more superficial tissue structures.This thesis identified PIV and RH that are important vascular mechanisms for pressure ulcer development and revealed for the first time that PIV and RH are present at different depths under clinically relevant conditions. The thesis also identified a population of individuals not previously identified who lack both PIV and RH and seem to be particularly vulnerable to pressure exposure. Further, this thesis has added a new perspective to the microcirculation in pressure ulcer etiology in terms of blood flow regulation and endothelial function that are anchored in clinically relevant studies. Finally, the evaluation of pressureredistribution support surfaces in terms of mean blood flow during and after tissue exposure was shown to be unfeasible, but the assessment of PIV and RH could provide a new possibility for measuring individual physiological responses that are known to be related to pressure ulcer development.
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| 4. |
- Dini, Francesca, et al.
(författare)
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Volatile Emissions from Compressed Tissue
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- Since almost every fifth patient treated in hospital care develops pressure ulcers, early identification of risk is important. A non-invasive method for the elucidation of endogenous biomarkers related to pressure ulcers could be an excellent tool for this purpose. We therefore found it of interest to determine if there is a difference in the emissions of volatiles from compressed and uncompressed tissue. The ultimate goal is to find a non-invasive method to obtain an early warning for the risk of developing pressure ulcers for bed-ridden persons. Chemical analysis of the emissions, collected in compresses, was made with gas-chromatography – mass spectrometry and with a chemical sensor array, the so called electronic nose. It was found that the emissions from healthy and hospitalized persons differed significantly irrespective of the site. Within each group there was a clear difference between the compressed and uncompressed site. Peaks that could be certainly deemed as markers of the compression were, however, not identified. Nonetheless, different compounds connected to the application of local mechanical pressure were found. The results obtained with GC-MS reveal the complexity of VOC composition, thus an array of non-selective chemical sensors seems to be a suitable choice for the analysis of skin emission from compressed tissues; it may represent a practical instrument for bed side diagnostics. Results show that the adopted electronic noses are likely sensitive to the total amount of the emission rather than to its composition. The development of a gas sensor-based device requires then the design of sensor receptors adequate to detect the VOCs bouquet typical of pressure. This preliminary experiment evidences the necessity of studies where each given person is followed for a long time in a ward in order to detect the insurgence of specific VOCs pattern changes signalling the occurrence of ulcers.
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| 5. |
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| 6. |
- Hagblad, Jimmie, et al.
(författare)
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A technique based on laser Doppler flowmetry and photoplethysmography for simultaneously monitoring blood flow at different tissue depths
- 2010
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Ingår i: Medical and Biological Engineering and Computing. - : Springer Science Business Media. - 0140-0118 .- 1741-0444. ; 48:5, s. 415-422
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to validate a non-invasive optical probe for simultaneous blood flow measurement at different vascular depths combining three photoplethysmography (PPG) channels and laser Doppler flowmeter (LDF). Wavelengths of the PPG were near-infrared 810 nm with source-to-detector separation of 10 and 25 mm, and green 560 nm with source-to-detector separation of 4 mm. The probe is intended for clinical studies of pressure ulcer aetiology. The probe was placed over the trapezius muscle, and depths from the skin to the trapezius muscle were measured using ultrasound and varied between 3.8 and 23 mm in the 11 subjects included. A provocation procedure inducing a local enhancement of blood flow in the trapezius muscle was used. Blood flows at rest and post-exercise were compared. It can be concluded that this probe is useful as a tool for discriminating between blood flows at different vascular tissue depths. The vascular depths reached for the different channels in this study were at least 23 mm for the near-infrared PPG channel (source-to-detector separation 25 mm), 10-15 mm for the near-infrared PPG channel (separation 10 mm), and shallower than 4 mm for both the green PPG channel (separation 4 mm) and LDF.
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| 7. |
- Hallberg, Inger, et al.
(författare)
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A striving for independence: a qualitative study of women living with vertebral fracture
- 2010
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Ingår i: BMC Nursing. - : Springer Science and Business Media LLC. - 1472-6955. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundQuantitative studies using generic and disease-specific health-related quality of life (HRQOL) questionnaires have shown that osteoporosis-related vertebral fractures have a significant negative effect on HRQOL, but there are only few studies that address what it means to live with vertebral fracture from a deeper experiential perspective. How HRQOL and daily life are affected several years after vertebral fracture and how women cope with this are more unclear. This study aimed to describe how HRQOL and daily life had been affected in women with vertebral fracture several years after diagnosis.MethodsThe study design was qualitative. Semi-structured interviews were conducted with ten Swedish women during 2008. Data were analysed using qualitative inductive content analysis.ResultsThe findings of this study revealed three themes related to the influence on HRQOL and daily life: A threatened independence, i.e. back pain, anxiety, negative impact on self-image and consequences in daily life; Strategies for maintaining independence, i.e. coping, self-care and support; and The importance of maintaining independence, i.e. the ability to perform everyday activities, social interaction and having something meaningful to do. The women were striving for independence or maintaining their independence by trying to manage different types of symptoms and consequences in different ways.ConclusionHRQOL and daily life were strongly affected in a negative way by the impact of the vertebral fracture. Information from this study may provide new knowledge and understanding of the women's experiences of living with vertebral fracture from an insider's point of view in order to obtain a deeper understanding of the women's everyday life. However, further evaluation is still needed in larger study groups.
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| 8. |
- Källman, Ulrika, et al.
(författare)
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Different lying positions and their effects on tissue blood flow and skin temperature in older adult patients
- 2013
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Ingår i: Journal of Advanced Nursing. - : Blackwell Publishing. - 0309-2402 .- 1365-2648. ; 69:1, s. 133-144
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Tidskriftsartikel (refereegranskat)abstract
- Aim. To report a study to compare the effects of different lying positions on tissue blood flow and skin temperature in older adult patients. This article reports the evaluation of study design and procedures. Background. To reduce risk of pressure ulcers, repositioning of immobile patients is a standard nursing practice; however, research into how different lying positions effect tissue microcirculation is limited. Design. Descriptive comparative design. Methods. From MarchOctober 2010, 20 inpatients, aged 65 years or older, were included in the study. Tissue blood flow and skin temperature were measured over bony prominences and in gluteus muscle in four supine and two lateral positions. Results. The blood flow over the bony prominence areas was most influenced in the superficial skin and especially in the 30 degrees lateral position, where the blood flow decreased significantly in comparison with the supine positions. There were significant individual differences in blood flow responses, but no common trend was identified among the patients considered at risk for pressure ulcer development. The study procedure worked well and was feasible to perform in an inpatient population. Conclusion. The lying positions seem to influence the tissue blood flow over the bony prominences in different ways in older adult inpatients, but further study is needed to confirm the results and to make recommendations to clinical practice. The study procedure worked well, although some minor adjustments with regard to heat accumulation will be made in future studies.
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