| 1. |
- Adjeiwaah, Mary, 1980-
(författare)
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Quality assurance for magnetic resonance imaging (MRI) in radiotherapy
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Magnetic resonance imaging (MRI) utilizes the magnetic properties of tissues to generate image-forming signals. MRI has exquisite soft-tissue contrast and since tumors are mainly soft-tissues, it offers improved delineation of the target volume and nearby organs at risk. The proposed Magnetic Resonance-only Radiotherapy (MR-only RT) work flow allows for the use of MRI as the sole imaging modality in the radiotherapy (RT) treatment planning of cancer. There are, however, issues with geometric distortions inherent with MR image acquisition processes. These distortions result from imperfections in the main magnetic field, nonlinear gradients, as well as field disturbances introduced by the imaged object. In this thesis, we quantified the effect of system related and patient-induced susceptibility geometric distortions on dose distributions for prostate as well as head and neck cancers. Methods to mitigate these distortions were also studied.In Study I, mean worst system related residual distortions of 3.19, 2.52 and 2.08 mm at bandwidths (BW) of 122, 244 and 488 Hz/pixel up to a radial distance of 25 cm from a 3T PET/MR scanner was measured with a large field of view (FoV) phantom. Subsequently, we estimated maximum shifts of 5.8, 2.9 and 1.5 mm due to patient-induced susceptibility distortions. VMAT-optimized treatment plans initially performed on distorted CT (dCT) images and recalculated on real CT datasets resulted in a dose difference of less than 0.5%. The magnetic susceptibility differences at tissue-metallic,-air and -bone interfaces result in local B0 magnetic field inhomogeneities. The distortion shifts caused by these field inhomogeneities can be reduced by shimming. Study II aimed to investigate the use of shimming to improve the homogeneity of local B0 magnetic field which will be beneficial for radiotherapy applications. A shimming simulation based on spherical harmonics modeling was developed. The spinal cord, an organ at risk is surrounded by bone and in close proximity to the lungs may have high susceptibility differences. In this region, mean pixel shifts caused by local B0 field inhomogeneities were reduced from 3.47±1.22 mm to 1.35±0.44 mm and 0.99±0.30 mm using first and second order shimming respectively. This was for a bandwidth of 122 Hz/pixel and an in-plane voxel size of 1×1 mm2. Also examined in Study II as in Study I was the dosimetric effect of geometric distortions on 21 Head and Neck cancer treatment plans. The dose difference in D50 at the PTV between distorted CT and real CT plans was less than 1.0%.In conclusion, the effect of MR geometric distortions on dose plans was small. Generally, we found patient-induced susceptibility distortions were larger compared with residual system distortions at all delineated structures except the external contour. This information will be relevant when setting margins for treatment volumes and organs at risk. The current practice of characterizing MR geometric distortions utilizing spatial accuracy phantoms alone may not be enough for an MR-only radiotherapy workflow. Therefore, measures to mitigate patient-induced susceptibility effects in clinical practice such as patient-specific correction algorithms are needed to complement existing distortion reduction methods such as high acquisition bandwidth and shimming.
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| 2. |
- Andersson, Sofia, 1972-
(författare)
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Vård i livets slutskede på särskilt boende för äldre personer : närstående och vårdpersonals skattade och berättade erfarenheter
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bakgrund I Europa, blir det allt vanligare att äldre personer dör på särskilt boende i stället för på sjukhus. Särskilda boenden spelar därför en viktig roll när det gäller vård i livets slutskede. Målet med palliativ vård för personer med livshotande sjukdom och deras närstående är att öka livskvaliteten och lindra lidande. Strukturerade vårdplaner såsom Liverpool Care Pathway for care of the dying (LCP) kan vara ett sätt att öka vårdkvaliteten. Det saknas dock forskning om vård i livets slutskede på särskilda boenden när en strukturerad vårdplan har använts.Syfte Det övergripande syftet med avhandlingen var att beskriva vård i livets slutskede på särskilt boende för äldre personer utifrån närstående och vårdpersonals skattade och berättade erfarenheter.Metod Avhandlingen baseras på två kvantitativa (I, II) och två kvalitativa (III, IV) studier. Studie I baseras på frågeformuläret Views of Informal Carers – Evaluation of Services (VOICES) som har besvarats av närstående (n = 189) efter att en anhörig har dött. Data har därefter analyserats med beskrivande och jämförande statistik. Studie II baseras på data om alla förväntade dödsfall (n = 22 855) som registrerats i Svenska palliativregistret (SPR). Dödsfallsenkäten har besvarats av vårdpersonal och svaren har sedan analyserats med beskrivande statistik och univariat och multipel logistisk regressionsanalys. Studie III baseras på fokusgruppsintervjuer och enskilda intervjuer med vårdpersonal. Studie IV baseras på enskilda intervjuer med närstående. Data från studie III och IV har analyserats med hjälp av kvalitativ innehållsanalys.Resultat Resultatet i studie I visar att majoriteten av de närstående skattade att den äldre personen fick tillräcklig hjälp såväl med personlig vård (78,5 %) som med sjukvård (93,0 %) de sista tre dagarna i livet. De närstående (86,2 %) rapporterade att de var informerade om att det var sannolikt att den äldre personen skulle avlida och majoriteten (94,1 %) av de äldre hade avlidit på önskad plats. Resultatet visade dock på hög förekomst av smärta (46,5 %) och andnöd (55,9 %). Det var ingen skillnad mellan åldersgrupperna när det gällde smärta men de äldre < 85 år hade signifikant högre förekomst av andnöd (70,6 %) jämfört med de äldre äldre, ≥ 85 år, (47,5 %). De äldre, < 85 år, hade signifikant oftare symtomlindring för andnöd (53,1 %) jämfört med äldre äldre, ≥ 85 år, (31,8 %).Resultatet i studie II visar hög förekomst av smärta (68,8 %) och ångest (44,0 %). Faktorer associerade med symtomlindring av smärta, illamående, ångest och andnöd var dels att validerat smärtskattningsinstrument hade använts, dels att munhälsan var bedömd. Starkast samband var det mellan symtomlindring av tre symtom (smärta, andnöd och ångest) och att injektioner var förskrivna vid behov.Resultatet i studie III visar att vårdpersonalen upplevde sig tryggare efter implementeringen av LCP genom att de hade fått ett gemensamt förhållningssätt, kände stöd att skräddarsy vården utifrån den döende personens individuella behov, kände stöd att involvera närstående i beslut och i vården samt hade blivit mer medvetna om vårdmiljön.Resultatet i studie IV visar att närstående upplevde sig tryggare i en välbekant och varm atmosfär, att vara kontra inte vara involverad i vård i livets slutskede och att bli tröstade genom att bevittna vårdpersonalens strävan att lindra lidande.Konklusion Resultatet från studierna i den här avhandlingen pekar på hög vårdkvalitet i livets slutskede på särskilt boende genom god omvårdnad, men resultatet pekar också mot förekomst av inadekvat symtomlindring och hög förekomst av smärta, andnöd och ångest de sista dagarna i livet. Det framkom ett tydligt samband mellan ordinerade injektioner vid behov och symtomlindring av smärta, illamående och ångest. Resultatet indikerar även vikten av att använda smärtskattningsinstrument och göra munhälsobedömningar för symtomlindring vid vård i livets slutskede. Således kan ett sätt att öka vårdkvaliteten för döende personer vara att det finns ordinerade injektionsläkemedel vid behov mot vanliga symtom, att använda validerade smärtskattningsinstrument och att göra munhälsobedömningar. Det framkom också att användandet av en standardiserad vårdplan såsom LCP kan vara ett sätt att förbättra vården för de äldre personerna i livets slutskede. Såväl vårdpersonalen som de närstående upplevde stöd av den struktur för bedömningar och vårdaktiviteter som LCP ger. Vårdpersonalen upplevde också stöd i att involvera närstående i vården och i vårdrelaterade beslut.
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| 3. |
- Brunström, Mattias, 1988-
(författare)
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Effect of antihypertensive treatment at different blood pressure levels
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundHigh blood pressure is associated with an increased risk of cardiovascular disease and premature death. The shape of association between blood pressure and the risk of cardiovascular events is debated. Some researchers suggest that the association is linear or log-linear, whereas others suggest it is J-shaped. Randomized controlled trials of antihypertensive treatment have been successful in hypertension, but ambiguous in the high normal blood pressure range. Previous systematic reviews have not found any interaction between baseline systolic blood pressure and treatment effect, with beneficial effects at systolic blood pressure levels well below what is currently recommended. These reviews, however, use a method to standardize treatment effects and study weights according to within-trial blood pressure differences that may introduce bias.MethodsWe performed two systematic reviews to assess the effect of antihypertensive treatment on cardiovascular disease and mortality at different blood pressure levels. The first review was limited to people with diabetes mellitus. The second review included all patient categories except those with heart failure and acute myocardial infarction. Both reviews were designed with guidance from Cochrane Collaborations Handbook for Systematic Reviews of Interventions, and are reported according to PRISMA guidelines. We included randomized controlled trials assessing any antihypertensive agent against placebo or any blood pressure targets against each other. Results were combined in random-effects meta-analyses, stratified by baseline systolic blood pressure. Non-stratified analyses were performed for coronary heart disease trials and post-stroke trials. Interaction between blood pressure level and treatment effect was assessed with Cochran’s Q in the first review, and multivariable-adjusted metaregression in the second review.The third paper builds on data from the second paper, and assesses the effect of standardization according to within-trial blood pressure differences on the results of meta-analyses. We performed non-standardized analyses, analyses with standardized treatment effects, and analyses with standardized treatment effects and standard errors. We compared treatment effect measures and heterogeneity across different methods of standardization. We also compared treatment effect estimates between fixed-effects and random-effects meta-analyses within each method of standardization. Lastly, we assessed the association between number of events and study weights, using linear regression.ResultsForty-nine trials assessed the effect of antihypertensive treatment in people with diabetes mellitus. Treatment effect on cardiovascular mortality and myocardial infarction decreased with lower baseline systolic blood pressure. Treatment reduced the risk of death and cardiovascular disease if baseline systolic blood pressure was 140 mm Hg or higher. If baseline systolic blood pressure was below 140 mm Hg, however, treatment increased the risk of cardiovascular death by 15 % (0-32 %).Fifty-one trials assessed the effect of antihypertensive treatment in primary prevention. Treatment effect on cardiovascular mortality, major cardiovascular events, and heart failure decreased with lower baseline systolic blood pressure. If baseline systolic blood pressure was 160 mm Hg or higher treatment reduced the risk of major cardiovascular events by 22 % (95 % confidence interval 13-30 %). If systolic blood pressure was 140-159 mm Hg treatment reduced the risk by 12 % (4-20 %), whereas if systolic blood pressure was below 140 mm Hg, treatment effect was neutral (4 % increase to 10 % reduction). All-cause mortality was reduced if systolic blood pressure was 140 mm Hg or higher, with neutral effect at lower levels.Twelve trials compared antihypertensive treatment against placebo in people with coronary heart disease. Mean baseline systolic blood pressure was 138 mm Hg. Treatment reduced the risk of major cardiovascular events by 10 % (3-16 %), whereas the effect on mortality was neutral (7 % increase to 11 % reduction).Standardization of treatment effects resulted in more extreme effect estimates for individual trials. This caused increased between-study heterogeneity, and different results with fixed- and random-effects model. Standardization of standard errors shifted weights from trials with many events to trials with large blood pressure differences. This caused biased overall effect estimates. Standardization of standard errors also resulted in wider confidence intervals, masking the previously increased heterogeneity. This reduced the possibility to find different treatment effects at different blood pressure levels.Conclusion The effect of antihypertensive treatment depends on blood pressure level before treatment. Treatment reduces the risk of death and cardiovascular disease if baseline systolic blood pressure is 140 mm Hg or higher. Below this level, treatment is potentially harmful in people with diabetes, has neutral effect in primary prevention, but might offer additional protection in people with coronary heart disease. Standardization should generally be avoided in meta-analyses of antihypertensive treatment. Previous meta-analyses using standardized methods should be interpreted with caution.
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| 4. |
- Brynolfsson, Patrik, 1981-
(författare)
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Applications of statistical methods in quantitative magnetic resonance imaging
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Magnetic resonance imaging, MRI, offers a vast range of imaging methods that can be employed in the characterization of tumors. MRI is generally used in a qualitative way, where radiologists interpret the images for e.g. diagnosis, follow ups, or assessment of treatment response. In the past decade, there has been an increasing interest for quantitative imaging, which give repeatable measurements of the anatomy. Quantitative imaging allows for objective analysis of the images, which are grounded in physical properties of the underlying tissues. The aim of this thesis was to improve quantitative measurements of Dynamic contrast enhanced MRI (DCE-MRI), and the texture analysis of diffusion weighted MRI (DW-MRI).DCE-MRI measures perfusion, which is the delivery of blood, oxygen and nutrients to the tissues. The exam involves continuously imaging the region of interest, e.g. a tumor, while injecting a contrast agent (CA) in the blood stream. By analyzing how fast and how much CA leaks out into the tissues, the cell density and the permeability of the capillaries can be estimated. Tumors often have an irregular and broken vasculature, and DCE-MRI can aid in tumor grading or treatment assessment. One step is crucial when performing DCE-MRI analysis, the quantification of CA in the tissue. The CA concentration is difficult to measure accurately due to uncertainties in the imaging, properties of the CA, and physiology of the patient. Paper I, the possibility of using two aspects of the MRI data, phase and magnitude, for improved CA quantification, is explored. We found that the combination of phase and magnitude information improved the CA quantification in regions with high CA concentration, and was more advantageous for high field strength scanners.DW-MRI measures the diffusion of water in and between cells, which reflects the cell density and structure of the tissue. The structure of a tumor can give insights into the prognosis of the disease. Tumors are heterogeneous, both genetically and in the distribution of cells, and tumors with high intratumoral heterogeneity have poorer prognosis. This heterogeneity can be measured using texture analysis. In 1973, Haralick et al. presented a texture analysis method using a gray level co-occurrence matrix, GLCM, to gauge the spatial distribution of gray levels in the image. This method of assessing texture in images has been successfully applied in many areas of research, from satellite images to medical applications. Texture analysis in treatment outcome assessment is studied in Paper II, where we showed that texture can distinguish between groups of patients with different survival times, in images acquired prior to treatment start.However, this type of texture analysis is not inherently quantitative in the way it is calculated today. This was studied in Paper III, where we investigated how texture features were affected by five parameters related to image acquisition and pre-processing. We found that the texture feature values were dependent on the choice of these imaging and preprocessing parameters. In Paper IV, a novel method for calculating Haralick texture features was presented, which makes the texture features asymptotically invariant to the size of the GLCM. This method allows for comparison of textures between images that have been analyzed in different ways.In conclusion, the work in this thesis has been aimed at improving quantitative analysis of tumors using MRI and texture analysis.
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| 5. |
- Carlsson, Daniel, 1982-
(författare)
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Effects of cold and hand-arm vibration on the peripheral neurosensory and vascular system : an occupational perspective
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background In Swedish working life, exposure to cold and exposure to hand-arm vibration (HAV) are two common health hazards. Health effects of HAV in the neurosensory, vascular and musculoskeletal systems are collectively denoted hand-arm vibration syndrome (HAVS), and have been thoroughly studied. Effects of cold exposure in terms of effects on the peripheral neurosensory and vascular system are on the contrary limited, especially in an occupational setting. Effects of cold exposure or cold injury have not previously been assessed with quantitative sensory testing (QST). Commonly reported symptoms after exposure to HAV and after cold injuries, includes cold sensitivity and sensation of cold. Cold sensitivity can also occur without previous exposure to vibration or cold and may have a major impact on quality of life. Other possible risk factors for cold sensitivity need to be assessed. Sensation of cold hands could theoretically imply an early manifestation of damage to the neurosensory or vascular system, and therefore be of importance to enable early detection of vascular and neurosensory HAVS. The purpose of this thesis was to increase the knowledge about health effects from cold and HAV on the peripheral neurosensory and vascular system, with an occupational perspective. The aims were: first, to identify and evaluate health effects and sequelae in the peripheral neurosensory and vascular system due to cold injury and cold exposure; second, to investigate if sensation of cold hands is a predictor for future onset of Raynaud's phenomenon or paresthesia; and third, to identify possible risk factors associated with cold sensitivity.Methods A case series on 15 military conscripts with local cold injuries in the hands or feet, involving QST and symptom descriptions, was conducted to investigate the hypothesis that cold injuries can result in similar neurosensory and vascular impairments as in HAVS. To assess health effects of cold exposure, a cohort study on 54 military conscripts in cold winter military training, with cold exposure assessments, was conducted. Possible health effects were assessed after 14 months of military training, containing considerable cold exposure, by means of QST, Finger systolic blood pressure after local cooling (FSBP) and a questionnaire. To investigate if sensation of cold hands is a predictor for vascular or neurosensory HAVS we investigated a cohort of 178 employees at a manufacturing company where HAV was a common exposure. The cohort was followed during 21 years and both vibration exposure and health outcomes were assessed regularly. Questionnaire items were used to assess sensations of cold hands as well as signs of Raynaud’s phenomenon and paresthesia. To identify risk factors for cold sensitivity a case-control study was conducted involving 997iiiparticipants from the general population in northern Sweden. The study was cross-sectional and explored possible risk factors for cold sensitivity.Results Cold injuries and cold exposure were associated with reduced sensibility in QST and increase severity and prevalence of neurosensory and vascular symptoms. Our results did not show any impairment in peripheral blood flow due to cold exposure, detectable by FSBP. The risk of developing Raynaud's phenomenon was increased for workers previously reporting sensation of cold hands (OR 6.3, 95% CI 2.3-17.0). No increased risk for paresthesia in relation to a sensation of cold hands was observed. The identified risk factors for cold sensitivity were frostbite in the hands, rheumatic disease, nerve injury in upper extremities or neck, migraine and vascular disease. When analysing women and men separately, women’s risk factors were frostbite in the hands, rheumatic disease, migraine and cold exposure. Men’s risk factors were frostbite in the hands, vibration exposure and nerve injury in upper extremities or neck. BMI > 25 was a protective factor for both men and women.Conclusion Cold injury and cold exposure are associated with impairments in the neurosensory system, detectable by QST. Symptoms such as sensation of cold hands and white fingers indicate vascular involvement, even though no vascular impairments due to cold exposure could be detected by objective measurements. A sensation of cold hands is a risk factor for development of Raynaud´s phenomenon, but not for paresthesia. At the individual level, reporting cold hands does not appear to be useful information when considering the possibility of a future development of Raynaud’s phenomenon. Frostbite in the hands is a risk factor for cold sensitivity among both women and men. For women rheumatic disease, migraine and cold exposure are also independent risk factors, and for men, exposure to HAV. Being overweight is a protective factor for both women and men.
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| 6. |
- Córdoba Doña, Juan Antonio, 1962-
(författare)
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Withstanding austerity : economic crisis and health inequalities in Spain
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Along with the austerity measures introduced in many countries, the economic crisis affecting Europe since 2008 seems to have impacted many aspects of the health of the Spanish population and has had a negative effect on the provision health services. An increasing body of knowledge has shown a clear impact of the current crisis on suicidal behaviour and mental health, and a less consistent effect on physical health and access to healthcare. However, little is known about the impact of the crisis on social inequalities in health and healthcare access, an area on which the present study seeks to shed light in the context of Spain, and specifically Andalusia, a region hit very hard by the crisis.Objective: To study the impact of the economic crisis starting in 2008 on health, health inequalities and health service utilisation in Spain and Andalusia and the roles of socio-demographic factors in these associations.Methods: Death rates were analysed to study the annual percent change in overall and cause-specific mortality in Spain between 1999 and 2011, and the Longitudinal Database of the Andalusian Population was used to study educational inequalities in overall mortality from 2002 to 2010 (study 1). To calculate suicide attempt rates, information from 2003 to 2012 on 11,494 men and 12,886 women provided by the Health Emergencies Public Enterprise Information System in Andalusia was utilised. The association between unemployment and suicide attempts was studied through linear regression models (study 2). Two waves of the Andalusian Health Survey (2007 and 2011–12) provided data for the third and fourth studies of this thesis. Educational and employment status inequalities in poor mental health in relation with the crisis were analysed through Poisson regression models (study 3). The change in inequalities (pre-crisis–crisis) in health care utilisation outcomes (general practitioner, specialist, hospitalisation and emergency attendance) was measured by the change in horizontal inequality indices. A decomposition analysis of change in inequality between periods was performed using the Oaxaca approach (study 4).Results: Study 1: Overall mortality in Spain decreased steadily during the period, with annual percent changes of -2.44% in men and -2.20% in women. An increase in educational inequality in mortality was observed in men in Andalusia. In women, the inequalities instead remained stable. Suicide mortality showed a downward trend in both sexes in Spain. Study 2: A sharp increase in suicide attempts in Andalusia was detected after the onset of the crisis in both sexes, with adults aged 35 to 54 years being the most affected. Suicide attempts were associated with unemployment rates only in men. Study 3: Poor mental health increased in working individuals with secondary and primary studies during the crisis compared to the pre-crisis period, while it decreased in the university study group. However, in unemployed individuals poor mental health increased only in the secondary studies group. Financial strain could partly explain the crisis effect on mental health among the unemployed. Study 4: Horizontal inequality in utilisation changed to a greater equality or a more pro-poor inequality in both sexes. In the decomposition analysis, socioeconomic position and health status showed greater contributions to the changes in inequalities.Conclusion: This thesis illustrates the complexity of the influences of the current economic crisis on health inequalities in a Southern European region. Specifically, no noticeable effects of the crisis on overall and suicide mortality were detected; instead, increasing educational inequalities in mortality in men and a large increase in suicide attempts in middle aged men and women were observed. The deterioration in poor mental health was mainly detected in those of intermediate educational level. Economic conditions such as unemployment and financial strain proved to be relevant. Finally, in the light of no increased inequalities in healthcare utilisation, the universal coverage health system seems to buffer the deleterious effect of the crisis and austerity policies in this context.
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| 7. |
- Daerga, Laila, 1965-
(författare)
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Att leva i två världar : hälsoaspekter bland renskötande samer
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: There is a gap of knowledge of the health situation among the reindeer herding Sami in Sweden. The Swedish government has also got criticism for not taking responsibility for the Sami health. The aim of this thesis was to get more knowledge to understand the health situation of the reindeer herding Sami in Sweden. Furthermore, gender specific risk factors in the working environment among reindeer herders and their perception of healthcare and social services were investigated.Method: Cross–sectional questionnaires covering different aspects of health such as musculoskeletal disorders, trust for different healthcare providers and work related psychosocial factors was distributed to reindeer herding Sami and non-Sami populations. Interviews with nine reindeer herding Sami about trust in healthcare and social services were carried out and analyzed with thematic analysis. Sixteen discussion meetings with 80 reindeer herders focusing on psychosocial perspectives of working conditions in Sami communities were performed.Result: The prevalence of musculoskeletal symptoms from elbow, hand/wrist and lower back from male reindeer herders were higher compared to blue-collar worker. Psychosocial risk factors for health were identified such as high workload on a few herders, difficulties to get relief and support as well as to get appreciation in work and lack of participation in decisionmaking among women were common in the organization of reindeer husbandry. The trust in healthcare and social services was lower among reindeer herding Sami compared to non-Sami majority population. A hypothesis is that healthcare professionals do not know that the "Reindeer cloud" (metaphor to iCloud) affects all parts in the reindeer herders life. The distrust are influenced by historically traumas, reindeer herding Sami experiences from healthcare professionals and healthcare organization and culturally generated norms.Conclusio: The thesis hypothesized that health disorders, attitude towards healthcare and psychosocial environment are important aspects when trying to understand the health situation among the reindeer herding Sami. There is a need to introduce long-term public health work for all Sami people, to establish ethical guidelines for Sami health research and develop healthcare services that provides access to healthcare for the reindeer herding Sami, on equal terms.
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| 8. |
- D'Ascenzi, Flavio, 1983-
(författare)
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Atrial function and loading conditions in athletes
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Intensive training is associated with hemodynamic changes that typically induce an enlargement of cardiac chamber. Despite LA dilatation in athletes has been interpreted as a benign adaptation, little evidence is available. The aim of this thesis is to demonstrate that LA size changes in response to alterations in loading conditions and to analyse atrial myocardial function in athletes through the application of novel echocardiographic techniques.We found that top-level athletes exhibit a dynamic morphological and functional LA remodelling, induced by training, with an increase in reservoir and conduit volumes, but stable active volume. Training causes an increase in biatrial volumes which is accompanied by normal filling pressures and stiffness. These changes in atrial morphology are not associated with respective electrical changes. Extending the evidence from adult athletes to children, we found that training-induced atrial remodelling can occur in the early phases of the sports career and is associated with a preserved biatrial function. Finally, in a meta-analysis study of the available evidence we demonstrated that atrial function and size are not affected by aging.In conclusions, athlete’s heart is characterized by a physiological biatrial enlargement. This adaptation occurs in close association with LV cavity enlargement, is dynamic and reversible. This increase in biatrial size is not intrinsically an expression of atrial dysfunction. Indeed, in athletes the atria are characterized by a preserved reservoir function, normal myocardial stiffness, and dynamic changes in response to different loading conditions.
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| 9. |
- Diderichsen, Saima, 1981-
(författare)
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It's just a job : a new generation of physicians dealing with career and work ideals
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Today, women constitute about half of medical students. However, women are still underrepresented in prestigious specialties such as surgery. Some suggest that this could be explained by women being more oriented towards work-life balance.Aim: The overall aim of this dissertation was to explore aspects of gender in work-life priorities, career plans, clinical experiences and negotiations of professional ideals among medical students and newly graduated doctors, all in a Swedish setting.Method: We based the analysis on data from two different sources: an extensive questionnaire exploring gender and career plans among medical students (paper I-III) and interviews with newly graduated doctors (study IV).In paper I, four classes of first- and final-year medical (N=507, response rate 85%) answered an open-ended question about their future life, 60% were women. We conducted a mixed methods design where we analyzed the answers qualitatively to create categories that could be analyzed quantitatively in the second stage.In paper II, five classes of final-year medical students were included (N = 372, response rate 89%), and 58% were women. We studied their specialty preference and how they rated the impact that the motivational factors had for their choice. In order to evaluate the independent impact of each motivational factor for specialty preference, we used logistic regression. In paper III, final-year medical students answered two open-ended questions: “Can you recall an event that made you interested of working with a certain specialty?” and “Can you recall an event that made you uninterested of working with a certain specialty?”. The response rate was 62% (N = 250), and 58% were women. The analysis was similar to paper I, but here we focused on the qualitative results.In paper IV, thematic interviews were conducted in 2014 and 2015. We made a purposeful sampling of 15 junior doctors, including nine women and six men from eight different hospitals. Data collection and analysis was inspired by constructivist grounded theory methodology.Results: When looking at the work-life priorities of medical students and junior doctors it is clear that both men and women want more to life than work in their ideal future. The junior doctors renounced fully devoted and loyal ideal and presented a self-narrative where family and leisure was important to cope and stay empathic throughout their professional lives.The specialty preferences and the highly rated motives for choosing them were relatively gender neutral. However, the gender neutrality came to an end when the final-year medical students described clinical experiences that affected their specialty preference. Women were more often deterred by workplace cultures, whereas men were more often deterred by knowledge area, suggesting that it is a male privilege to choose a specialty according to interest.Among the newly graduated doctors, another male privilege seemed to be that men were able to pass more swiftly as real doctors, whereas the women experienced more dissonance between their self-understanding and being perceived as more junior and self-doubting.Conclusions: The career plans and work-life priorities of doctors-to-be were relatively gender neutral. Both female and male doctors, intended to balance work not only with a family but also with leisure. This challenges the health care system to establish more adaptive and flexible work conditions.Gender segregation in specialty choice is not the result of gender-dichotomized specialty preferences starting in medical school. This calls for a re-evaluation of the understanding where gender is seen as a mere background characteristic, priming women and men for different specialties.
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| 10. |
- Doohan, Isabelle, 1985-
(författare)
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Surviving a major bus crash : experiences from the crash and five years after
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Major road traffic crashes (RTCs) can have a significant impact on the survivors, their family, and their friends, as well as on emergency personnel, volunteers, and others involved. However, survivors’ perspectives are rare or missing in research on major RTCs in Sweden. A comprehensive understanding of the survivors and their experiences is also lacking. By studying what it is like to survive a major RTC, the care and support provided to survivors can be adapted and improved.The overall aim is to broaden the understanding of the short- and long-term consequences and experiences of surviving a major bus crash.Methods The contexts are two bus crashes that occurred in Sweden, in February 2007 and December 2014. In total, the participants are 110 out of the 112 survivors, and the data is collected through telephone interviews, official reports, and medical records at one month, three months, and five years after the crashes. Analysis methods include qualitative content analysis, descriptive statistics, thematic analysis, and mixed methods research analysis.Results One month after the crash, most of the survivors were experiencing minor or major physical and/or psychological stress in their everyday lives (Study I). Four main findings were identified regarding their experiences of immediate care (Study II): prehospital discomfort, lack of compassionate care, dissatisfaction with crisis support, and satisfactory initial care and support. The importance of compassion and being close to others was also highlighted. Five years after the bus crash in Rasbo (Study III), survivors were still struggling with physical injuries and mental problems. Other long-term consequences were a lasting sense of connectedness among fellow passengers, a gratitude for life, as well as feelings of distress in traffic, especially in regard to buses. The main findings from study IV indicated that injury severity did not seem to affect mental health, and that social aspects were important to the recovery process. There was an interconnection among survivors in which they seemed to be linked to each other’s recovery.Conclusion A strong need for short- and long-term social and psychological support in terms of compassion and community is evident in all the studies. The survivors ought to be acknowledged as capable and having the resources to contribute to their own and their fellow survivors’ recovery and health. There is a need for greater understanding of how different the survivors are, with each one of them having various physical, psychological, social, and existential needs.
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