Introduktion: Vårdrelaterade infektioner (VRI) har negativ inverkan på folkhälsan med påverkan på mortalitet, morbiditet och livskvalitet. Inom hälso- och sjukvården är VRI en stor utmaning. Den vanligaste VRI i Sverige är vårdrelaterade urinvägsinfektioner (VUVI). För att förebygga VRI är regelbundna mätningar och återkopplingar viktigt. Mätinstrument som idag används på lokal och nationell nivå för att mäta incidens av VRI är bl.a. Markörbaserad journalgranskning och Infektionsverktyget. Syfte: Validera Infektionsverktyget och jämföra incidens av VUVI från Infektionsverktyget mot manuell journalgranskning och Markörbaserad journalgranskning samt studera förekomsten av urinkateter i samband med VUVI. Metod: Under 2017 samlades data in från 143 slumpmässigt utvalda journaler i slutenvården på Södra Älvsborgs sjukhus. Diagnostiserad VUVI och samhällsförvärvad urinvägsinfektion (SUVI) i Infektionsverktyget validerades mot manuell journalgranskning. Incidensen av VUVI i Infektionsverktyget jämfördes även mot VUVI i markörbaserad journalgranskning. Resultat: Incidens av VUVI innan validering var 1.5 % medan den uppskattade incidensen efter manuell journalgranskning och validering var 3.6 %. Markörbaserad journalgranskning visade en incidens på 1.1 %. I 65.6 % av fallen med VUVI fanns en koppling till urinkateter. Den mest förekommande orsaken till inkorrekt registreringen av VUVI var att patienter med urinkateter bedömdes som SUVI. Slutsats: Den rapporterade incidensen av VUVI skiljer sig mellan de mätinstrument som används idag och incidensen är troligtvis högre än vad som idag rapporteras. För att få bra kvalitet på övervakningsdata krävs kunskap och granskning av hög kvalitet. Dock begränsas resultatet från denna studie av att studiepopulationen var relativt liten och därmed begränsar generaliserbarheten. / Introduction: Health care associated infections (HCAIs) have a negative impact on public health, with an impact on mortality, morbidity and quality of life. The most common HCAIs in Sweden are health care associated urinary tract infections (UTI). One important component in preventing HCAIs are regular measurements and feedback to these. Instruments that are currently used for measuring HCAIs at a local and national level in Sweden are marker-based journal review and the Anti-Infection Tool (AIT). Aim:  The aim of this study was to validate the AIT and compare the incidence of health care associated UTI measured with the AIT against both manual journal review and marker-based journal review. The aim was also to study the presence of urinary catheters in conjunction with a healthcare associated UTI. Methods: In 2017, data was collected from 143 records from a random sample of patients admitted to somatic wards at Södra Älvsborg's Hospital. From the AIT, diagnosed health care associated UTI and community-acquired UTI were studied and validated against manual journal review. Also, the incidence of health care associated UTI in the AIT was compared with that found in marker-based journal review. Results: Incidence of health care associated UTI before the validation was 1.5% while the estimated incidence after manual journal review and validation was 3.6%. Marker-based journal review showed an incidence of 1.1%. In 65.6 % of the cases with health care associated UTI, the patient was equipped with urinary catheter. The most common cause of incorrect registration of health care associated UTI was that patients with urinary catheters were assessed as community-acquired UTI.   Conclusion:  The reported incidence of health care associated UTI differs greatly between these instruments. The incidence is probably much higher than what is currently reported using these instruments. To obtain good quality of monitoring data, knowledge and journal reviews of high quality are required. However, the generalizability of the result of this study is limited, due to the relatively small study sample.

This thesis addresses a multi-agent search problem where several agents, equipped with sensors and communication devices, search an unknown area. Lack of information about the search space is modeled as an uncertainty density distribution. A sequential deploy and search (SDS) strategy is formulated where the agents are first deployed to maximize single step search effectiveness. To achieve an optimal deployment, a multi-center objective function defined using the Voronoi cells and the uncertainty distribution is optimized. It is shown that the critical points of this objective function are the centroids of the Voronoi cells. A proportional control law is proposed that makes the agents move to their respective “centroids”. Assuming agents to be first order dynamical systems and using LaSalle's invariance principle, it is shown that the closed-loop system converges globally asymptotically to the critical points. It is also shown that the sequential deploy and search strategy is spatially distributed with respect to the Delaunay graph corresponding to any given agent configuration. Next, a combined deploy and search (CDS) strategy is proposed where, instead of first deploying agents and then performing the search, the agents engage in search operation as they move toward the centroids. This strategy gives rise to shorter agent trajectories compared to the SDS strategy. Then the problem is formulated with practical constraints such as sensor range limits and limit on maximum speed of the agents. A few issues relating to implementation of the proposed search strategies are also addressed. Finally, the assumption of homogeneous agents is relaxed and agents equipped with sensors with heterogeneous capabilities are considered. A generalized Voronoi partitioning scheme is proposed and used to formulate a heterogeneous locational optimization problem. In this problem the agents are deployed in the search space optimizing the sensor effectiveness. As earlier, the two search strategies are proposed. Simulation experiments are carried out to validate the performance of the proposed search strategies. The simulation results indicate that both the proposed search strategies perform quite well even when the conditions deviated from the nominal. It is also shown that the combined deploy and search strategy leads to shorter and smoother trajectories than those of the sequential deploy and search strategy with the same parameters.