liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
BETA
Bergkvist, Max
Publications (5 of 5) Show all publications
Bergkvist, M. (2019). Studies on Polarised Light Spectroscopy. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Studies on Polarised Light Spectroscopy
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis project focuses on measurements of dermal microcirculation during vascular provocations with polarised light spectroscopy. This is done with a non-invasive method commercially available as Tissue viability imaging (TiVi) which measures concentration and oxygenation of red blood cells in the papillary dermis. Three studies were done with human subjects and one with an animal model, to validate and compare the TiVi technique with laser Doppler flowmetry, which is an established method of measuring dermal microcirculation.

The TiVi consists of a digital camera with polarisation filters in front of the flash and lens, with software for analysis of the picture. When taking a picture with the TiVi, the polarised light that is reflected on the skin surface is absorbed by the second filter over the lens (which is perpendicular to the first filter) but a portion of light penetrates the surface of the skin and is scattered when it is reflected on tissue components. This makes the light depolarised, passes the second filter, and produces a picture for analysis. The red blood cell (RBC) has a distinct absorption pattern that differs between red and green colour compared to melanin and other components of tissue. This difference is used by the software that calculates differences in each picture element and produces a measure of output which is proportional to the concentration of red blood cells. The oxygenation of RBC can also be calculated, as there is a difference in absorption depending on oxygen state.

The first paper takes up possible sources of error such as ambient light, and the angle and distance of the camera. The main experiment was to investigate how the local heating reaction is detected with TiVi compared to LDF.

In the second paper arterial and venous stasis are examined in healthy subjects with TiVi.

The Third paper is an animal study where skin flaps were raised on pigs, and the vascular pedicle is isolated to enable control of inflow and outflow of blood.The measurements were made during partial venous, total venous, and total arterial occlusion. The TiVi recorded changes in the concentration of RBC, oxygenation and heterogeneity and the results were compared with those of laser Doppler flowmetry.

In the fourth paper oxygenation and deoxygenation of RBC: s was studied. Studies were made on the forearms of healthy subjects who were exposed to arterial and venous occlusion. Simultaneous measurements were made with TiVi and Enhanced perfusion and oxygen saturation or EPOS, which is a new device that combines laser Doppler flowmetry and diffuse reflectance spectroscopy in one probe.

With TiVi, one can measure RBC concentration and oxygenation in the area of an entire picture or in one or multiple user defined regions of interest (ROI). Methods such as laser Doppler flowmetry makes single point measurements, which is a potential source of error both because of the heterogeneity of the microcirculation, and that the circulation be insufficient in the margins of the investigated area. TiVi has been able to measure venous stasis more accurately than laser Doppler flowmetry, and venous stasis is the more common reason for flaps to fail.

The TiVi is an accurate way to measure the concentration of RBC and trends in oxygenation of the dermal microcirculation. It has interesting possible applications for microvascular and dermatological research, monitoring of flaps, and diagnosis of peripheral vascular disease. Future clinical studies are needed as well as development of the user interface.  

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2019. p. 48
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1689
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:liu:diva-159084 (URN)10.3384/diss.diva-159084 (DOI)9789176850428 (ISBN)
Public defence
2019-09-02, Belladonnasalen, Campus US, Linköping, 13:00 (English)
Opponent
Supervisors
Available from: 2019-07-23 Created: 2019-07-23 Last updated: 2019-09-18Bibliographically approved
Bergkvist, M., Zötterman, J., Henricson, J., Iredahl, F., Tesselaar, E. & Farnebo, S. (2017). Vascular Occlusion in a Porcine Flap Model: Effects on Blood Cell Concentration and Oxygenation.. Plastic and reconstructive surgery. Global open, 5(11), Article ID e1531.
Open this publication in new window or tab >>Vascular Occlusion in a Porcine Flap Model: Effects on Blood Cell Concentration and Oxygenation.
Show others...
2017 (English)In: Plastic and reconstructive surgery. Global open, ISSN 2169-7574, Vol. 5, no 11, article id e1531Article in journal (Refereed) Published
Abstract [en]

Background: Venous congestion in skin flaps is difficult to detect. This study evaluated the ability of tissue viability imaging (TiVi) to measure changes in the concentration of red blood cells (CRBC), oxygenation, and heterogeneity during vascular provocations in a porcine fasciocutaneous flap model.

Methods: In 5 pigs, cranial gluteal artery perforator flaps were raised (8 flaps in 5 pigs). The arterial and venous blood flow was monitored with ultrasonic flow probes. CRBC, tissue oxygenation, and heterogeneity in the skin were monitored with TiVi during baseline, 50% and 100% venous occlusion, recovery, 100% arterial occlusion and final recovery, thereby simulating venous and arterial occlusion of a free fasciocutaneous flap. A laser Doppler probe was used as a reference for microvascular perfusion in the flap.

Results: During partial and complete venous occlusion, increases in CRBC were seen in different regions of the flap. They were more pronounced in the distal part. During complete arterial occlusion, CRBC decreased in all but the most distal parts of the flap. There were also increases in tissue oxygenation and heterogeneity during venous occlusion.

Conclusions: TiVi measures regional changes in CRBC in the skin of the flap during arterial and venous occlusion, as well as an increase in oxygenated hemoglobin during venous occlusion that may be the result of reduced metabolism and impaired delivery of oxygen to the tissue. TiVi may provide a promising method for measuring flap viability because it is hand-held, easy to-use, and provides spatial information on venous congestion.

Place, publisher, year, edition, pages
Wolters Kluwer, 2017
National Category
Radiology, Nuclear Medicine and Medical Imaging Surgery
Identifiers
urn:nbn:se:liu:diva-145391 (URN)10.1097/GOX.0000000000001531 (DOI)29263951 (PubMedID)2-s2.0-85038559789 (Scopus ID)
Available from: 2018-02-27 Created: 2018-02-27 Last updated: 2019-07-23Bibliographically approved
Zötterman, J., Bergkvist, M., Iredahl, F., Tesselaar, E. & Farnebo, S. (2016). Monitoring of partial and full venous outflow obstruction in a porcine flap model using laser speckle contrast imaging. Journal of Plastic, Reconstructive & Aesthetic Surgery, 69(7), 936-943
Open this publication in new window or tab >>Monitoring of partial and full venous outflow obstruction in a porcine flap model using laser speckle contrast imaging
Show others...
2016 (English)In: Journal of Plastic, Reconstructive & Aesthetic Surgery, ISSN 1748-6815, E-ISSN 1532-1959, Vol. 69, no 7, p. 936-943Article in journal (Refereed) Published
Abstract [en]

Background: In microsurgery, there is a demand for more reliable methods of postoperative monitoring of free flaps, especially with regard to tissue-threatening obstructions of the feeding arteries and draining veins. In this study, we evaluated laser speckle contrast imaging (LSCI) and laser Doppler flowmetry (LDF) to assess their possibilities to detect partial and full venous outflow obstruction, as well as full arterial occlusion, in a porcine flap model. Methods: Cranial gluteal artery perforator flaps (CGAPs) were raised, and arterial and venous blood flow to and from the flaps was monitored using ultrasonic flow probes. The venous flow was altered with an inflatable cuff to simulate partial and full (50% and 100%) venous obstruction, and arterial flow was completely obstructed using clamps. The flap microcirculation was monitored using LSCI and LDF. Results: Both LDF and the LSCI detected significant changes in flap perfusion. After partial (50%) venous occlusion, perfusion decreased from baseline, LSCI: 63.5 +/- 12.9 PU (p = 0.01), LDF 31.3 +/- 15.7 (p = 0.64). After 100% venous occlusion, a further decrease in perfusion was observed: LSCI 54.6 +/- 14.2 PU (p amp;lt; 0.001) and LDF 16.7 +/- 12.8 PU (p amp;lt; 0.001). After release of the venous cuff, LSCI detected a return of the perfusion to a level slightly, but not significantly, below the baseline level 70.1 +/- 11.5 PU (p=0.39), while the LDF signal returned to a level not significant from the baseline 36.1 +/- 17.9 PU (p amp;gt; 0.99). Perfusion during 100% arterial occlusion decreased significantly as measured with both methods, LSCI: 48.3 +/- 7.7 (PU, pamp;lt;0.001) and LDF: 8.5 +/- 4.0 PU (pamp;lt;0.001). During 50% and 100% venous occlusion, LSCI showed a 20% and 26% inter-subject variability (CV%), respectively, compared to 50% and 77% for LDF. Conclusions: LSCI offers sensitive and reproducible measurements of flap microcirculation and seems more reliable in detecting decreases in blood perfusion caused by venous obstruction. It also allows for perfusion measurements in a relatively large area of flap tissue. This may be useful in identifying areas of the flap with compromised microcirculation during and after surgery. (C) 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2016
Keywords
Free flaps; Venous occlusion; Arterial occlusion; Laser Doppler; Laser speckle contrast imaging
National Category
Surgery
Identifiers
urn:nbn:se:liu:diva-130059 (URN)10.1016/j.bjps.2016.02.015 (DOI)000377698600010 ()27026039 (PubMedID)
Note

Funding Agencies|county of Ostergotland

Available from: 2016-07-06 Created: 2016-07-06 Last updated: 2017-06-21
Bergkvist, M., Henricson, J., Iredahl, F., Tesselaar, E., Sjöberg, F. & Farnebo, S. (2015). Assessment of microcirculation of the skin using Tissue Viability Imaging: A promising technique for detecting venous stasis in the skin. Microvascular Research, 101, 20-25
Open this publication in new window or tab >>Assessment of microcirculation of the skin using Tissue Viability Imaging: A promising technique for detecting venous stasis in the skin
Show others...
2015 (English)In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 101, p. 20-25Article in journal (Refereed) Published
Abstract [en]

Background: : Venous occlusion in the skin is difficult to detect by existing measurement techniques. Our aim was to find out whether Tissue Viability Imaging (TiVi) was better at detecting venous occlusion by comparing it with results of laser Doppler flowmetry (LDF) during graded arterial and venous stasis in human forearm skin. Methods: : Arterial and venous occlusions were simulated in 10 healthy volunteers by inflating a blood pressure cuff around the upper right arm. Changes in the concentration of red blood cells (RBC) were measured using TiVi, while skin perfusion and concentration of moving red blood cells (CMBC) were measured using static indices of LDF during exsanguination and subsequent arterial occlusion, postocclusive reactive hyperaemia, and graded increasing and decreasing venous stasis. Results: : During arterial occlusion there was a significant reduction in the mean concentration of RBC from baseline, as well as in perfusion and CMBC (p less than 0.008). Venous occlusion resulted in a significant 28% increase in the concentration of RBC (p = 0.002), but no significant change in perfusion (mean change -14%) while CMBC decreased significantly by 24% (p = 0.02). With stepwise increasing occlusion pressures there was a significant rise in the TiVi index and reduction in perfusion (p = 0.008), while the reverse was seen when venous flow was gradually restored. Conclusion: : The concentration of RBC measured with TiVi changes rapidly and consistently during both total and partial arterial and venous occlusions, while the changes in perfusion, measured by LDF, were less consistent This suggests that TiVi could be a more useful, non-invasive clinical monitoring tool for detecting venous stasis in the skin than LDF.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Tissue viability imaging; Laser Doppler flowmetry; Post-occusive hyperaemia; Venous occlusion; Arterial occlusion
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-121302 (URN)10.1016/j.mvr.2015.06.002 (DOI)000360028500004 ()26092681 (PubMedID)
Note

Funding Agencies|County Council of Ostergotland, Sweden [2014JZ0004]

Available from: 2015-09-16 Created: 2015-09-14 Last updated: 2019-07-23Bibliographically approved
Orwelius, L., Bergkvist, M., Nordlund, A., Simonsson, E., Nordlund, P., Bäckman, C. & Sjöberg, F. (2012). Physical effects of trauma and the psychological consequences of preexisting diseases account for a significant portion of the health-related quality of life patterns of former trauma patients. Journal of Trauma and Acute Care Surgery, 72(2), 504-512
Open this publication in new window or tab >>Physical effects of trauma and the psychological consequences of preexisting diseases account for a significant portion of the health-related quality of life patterns of former trauma patients
Show others...
2012 (English)In: Journal of Trauma and Acute Care Surgery, ISSN 2163-0755, E-ISSN 2163-0763, Vol. 72, no 2, p. 504-512Article in journal (Refereed) Published
Abstract [en]

Background: Health-related quality of life (HRQoL) is known to be significantly affected in former trauma patients. However, the underlying factors that lead to this outcome are largely unknown. In former intensive care unit (ICU) patients, it has been recognized that preexisting disease is the most important factor for the long-term HRQoL. The aim of this study was to investigate HRQoL up to 2 years after trauma and to examine the contribution of the trauma-specific, ICU-related, sociodemographic factors together with the effects of preexisting disease, and further to make a comparison with a large general population.

Methods: A prospective 2-year multicenter study in Sweden of 108 injured patients. By mailed questionnaires, HRQoL was assessed at 6 months, 12 months, and 24 months after the stay in ICU by Short Form (SF)-36, and information of preexisting disease was collected from the national hospital database. ICU-related factors were obtained from the local ICU database. Comorbidity and HRQoL (SF-36) was also examined in the reference group, a random sample of 10,000 inhabitants in the uptake area of the hospitals.

Results: For the trauma patients, there was a marked and early decrease in the physical dimensions of the SF-36 (role limitations due to physical problems and bodily pain). This decrease improved rapidly and was almost normalized after 24 months. In parallel, there were extensive decreases in the psychologic dimensions (vitality, social functioning, role limitations due to emotional problems, and mental health) of the SF-36 when comparisons were made with the general reference population.

Conclusions: The new and important finding in this study is that the trauma population seems to have a trauma-specific HRQoL outcome pattern. First, there is a large and significant decrease in the physical dimensions of the SF-36, which is due to musculoskeletal effects and pain secondary to the trauma. This normalizes within 2 years, whereas the overall decrease in HRQoL remains and most importantly it is seen mainly in the psychologic dimensions and it is due to preexisting diseases

Place, publisher, year, edition, pages
Lippincott Williams & Wilkins, 2012
Keywords
Multiple trauma, follow-up, critical care, comorbidity
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-17827 (URN)10.1097/TA.0b013e31821a416a (DOI)000300781000051 ()
Note

On the day of the defence date the title of this article was "Pre-existing disease is an important contributor to reduced health related quality of life after critical care in Swedish trauma patients".

Funding agencies|Health Research Council in the South-East of Sweden (FORSS)| F2004-204 |County Council of Ostergotland, Sweden||

Available from: 2009-04-22 Created: 2009-04-22 Last updated: 2017-12-13Bibliographically approved
Organisations

Search in DiVA

Show all publications