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- Lindblad, Marie, 1966-
(författare)
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Pathogen colonisation, transmission and infection control measures in burn patients
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Burn patients are susceptible to infections due to impaired natural defences when the epidermal barrier is damaged. Moreover, the trauma affects the patient's immune system through local and systemic inflammatory reactions. Adding to that, the need for intensive care treatment with multiple surgical interventions increases the risk of infection. The need for vascular, airway, etc. catheterisations further strains the burned patient. Microbes, especially those with extraordinary survival properties in the healthcare environment, are essential sources of infections in burn wounds.This thesis aimed to investigate microbiological aspects in burn care, including bacterial colonisation, transmission and possible measures to combat this and reduce infection rates.In paper I, we investigated Staphylococcus aureus-colonisation in burn patients. Thirty-nine (48.8%) patients were S. aureus positive, and 41 (51.3%) negative at admission. Whole-genome sequencing of the 53 (39 + 14) S. aureus positive showed that the patients carried unique isolates, most likely due to their flora at admission and not by cross-contamination.In paper II, through a systematic investigation, we showed that higher awareness and education of contamination routes increased healthcare workers' compliance with hand hygiene and dress code. Intensified cleaning procedures of the environment and equipment could successfully be established, which significantly contributed to stopping the further spread of Acinetobacter baumannii in the burn unit.In paper III, we observed that the decontamination-efficacy of Ultraviolet–C (UVC) of bacteria in fabrics in a clinical setting is not as effective as laundering and, thus, it´s not an alternative to UVC decontamination.In paper IV, we established that received UVC dose varied with the device's location when decontaminating a wardroom. The validation of single-use UVC dose indicators showed their usefulness in ensuring adequate decontamination doses. This thesis shows that the patient’s colonisation of S. aureus during the burn treatment is primarily due to the S. aureus carried at admission and not due to transmission. It also shows that a high level of knowledge about transmission routes, infection prevention, and cleaning protocols is essential to burn care. Decontamination using UVC light seems a plausible adjunct to routine cleaning.
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| 2. |
- 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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