| 1. |
- Ridderstolpe, Lisa, et al.
(författare)
-
Superficial and deep sternal wound complications : Incidence, risk factors and mortality
- 2001
-
Ingår i: European Journal of Cardio-Thoracic Surgery. - : Oxford Academic. - 1010-7940 .- 1873-734X. ; 20:6, s. 1168-1175
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: Sternal wound complications often have a late onset and are detected after patients are discharged from the hospital. In an effort to catch all sternal wound complications, different postdischarge surveillance methods have to be used. Together with this long-term follow-up an analysis of risk factors may help to identify patients at risk and can lead to more effective preventive and control measures.Methods: This retrospective study of 3008 adult patients who underwent consecutive cardiac surgery from January 1996 through September 1999 at Link÷ping University Hospital, Sweden, evaluated 42 potential risk factors by univariate analysis followed by backward stepwise multivariate logistic regression analysis.Results: Two-thirds of the 291 (9.7%) sternal wound complications that occurred were identified after discharge. Of the 291 patients, 47 (1.6%) had deep sternal infections, 50 (1.7%) had postoperative mediastinitis, and 194 (6.4%) had superficial sternal wound complications. Twenty-three variables were selected by univariate analysis (P<0.15) and included in a multivariate analysis where eight variables emerged as significant (P<0.05). Preoperative risk factors for deep sternal infections/mediastinitis were obesity, insulin-dependent diabetes, smoking, peripheral vascular disease, and high New York Heart Association score. An intraoperative risk factor was bilateral use of internal mammary arteries, and a postoperative risk factor was prolonged ventilator support. Risk factors for superficial sternal wound complications were obesity, and an age of
|
|
| 2. |
- Ridderstolpe, Lisa, et al.
(författare)
-
Canonical correlation analysis of risk factors and clinical outcomes in cardiac surgery
- 2005
-
Ingår i: Journal of medical systems. - : Springer. - 0148-5598 .- 1573-689X. ; 29:4, s. 357-377
-
Tidskriftsartikel (refereegranskat)abstract
- Assessment of the association between risk factors and outcomes in cardiac surgery is a complex problem. The aim of this study was to explore the relationship between possible risk factors and several clinical outcomes in cardiac surgery by using canonical correlation analysis (CCA). This retrospective study of 2605 consecutive adult patients who underwent cardiac surgery, evaluated 74 potential risk factors and up to 12 outcomes by canonical correlation analysis. For three serious outcomes, sternal wound complications/mediastinitis, cerebral complications, and perioperative myocardial infarctions, CCA was preceded by univariate analyses and backward stepwise multivariate logistic regression analyses. The CCA suggests that the major risk factors for complications in these models are intraoperative and postoperative risk factors. The power of risk prediction models developed with multivariate regression analysis can be enhanced by application of canonical correlation analysis, thereby offering new ways of analyzing and interpreting sets of potential risk factors in relation to sets of clinical outcomes.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Petersson, Håkan, 1972-, et al.
(författare)
-
A variance-based measure of inter-rater agreement in medical databases
- 2002
-
Ingår i: Journal of Biomedical Informatics. - 1532-0464 .- 1532-0480. ; 35:5-6, s. 331-342
-
Tidskriftsartikel (refereegranskat)abstract
- The increasing use of encoded medical data requires flexible tools for data quality assessment. Existing methods are not always adequate, and this paper proposes a new metric for inter-rater agreement of aggregated diagnostic data. The metric, which is applicable in prospective as well as retrospective coding studies, quantifies the variability in the coding scheme, and the variation can be differentiated in categories and in coders. Five alternative definitions were compared in a set of simulated coding situations and in the context of mortality statistics. Two of them were more effective, and the choice between them must be made according to the situation. The metric is more powerful for larger numbers of coded cases, and Type I errors are frequent when coding situations include different numbers of cases. We also show that it is difficult to interpret the meaning of variation when the structures of the compared coding schemes differ.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Razavi, Amir Reza, 1973-, et al.
(författare)
-
An approach for generating fuzzy rules from decision trees
- 2006
-
Ingår i: Ubiquity. - : IOS Press. - 9781586036478 ; , s. 581-586
-
Konferensbidrag (refereegranskat)abstract
- Identifying high-risk breast cancer patients is vital both for clinicians and for patients. Some variables for identifying these patients such as tumor size are good candidates for fuzzification. In this study, Decision Tree Induction (DTI) has been applied to 3949 female breast cancer patients and crisp If-Then rules has been acquired from the resulting tree. After assigning membership functions for each variable in the crisp rules, they were converted into fuzzy rules and a mathematical model was constructed. One hundred randomly selected cases were examined by this model and compared with crisp rules predictions. The outcomes were examined by the area under the ROC curve (AUC). No significant difference was noticed between these two approaches for prediction of recurrence of breast cancer. By soft discretization of variables according to resulting rules from DTI, a predictive model, which is both more robust to noise and more comprehensible for clinicians, can be built.
|
|
| 9. |
- Razavi, Amir Reza, 1973-, et al.
(författare)
-
Canonical correlation analysis for data reduction in data mining applied to predictive models for breast cancer recurrence
- 2005
-
Ingår i: The XIXth International Congress of the European Federation for Medical Informatics,2005. - Amsterdam : IOSPress. ; , s. 175-180
-
Konferensbidrag (refereegranskat)abstract
- Data mining methods can be used for extracting specific medical knowledge such as important predictors for recurrence of breast cancer in pertinent data material. However, when there is a huge quantity of variables in the data material it is first necessary to identify and select important variables. In this study we present a preprocessing method for selecting important variables in a dataset prior to building a predictive model. In the dataset, data from 5787 female patients were, analysed. To cover more predictors and obtain a better assessment of the outcomes, data were retrieved from three different registers: the regional breast cancer, tumour markers, and cause of death registers. After retrieving information about selected predictors and outcomes from the different registers, the raw data were cleaned by running different logical rules. Thereafter, domain experts selected predictors assumed to be important regarding recurrence of breast cancer. After that, Canonical Correlation Analysis (CCA) was applied as a dimension reduction technique to preserve the character of the original data. Artificial Neural Network (ANN) was applied to the resulting dataset for two different analyses with the same settings. Performance of the predictive models was confirmed by ten-fold cross validation. The results showed an increase in the accuracy of the prediction and reduction of the mean absolute error.
|
|
| 10. |
- Razavi, Amir Reza, 1973-, et al.
(författare)
-
Data Mining Approach to Analyze Non-compliance with a Guideline for the Treatment of Breast Cancer
- 2007
-
Ingår i: MEDINFO 2007: PROCEEDINGS OF THE 12TH WORLD CONGRESS ON HEALTH (MEDICAL) INFORMATICS, PTS 1 AND 2. - : IOS Press. - 9781586037741 ; , s. 591-595
-
Konferensbidrag (refereegranskat)abstract
- Postmastectomy radiotherapy (PAMT) is prescribed in order to reduce the local recurrence of breast cancer and improve overall survival. A guideline supports the trade-off between benefits and adverse effects of PMRT However, this guideline is not always followed in practice. This study tries to find a method for revealing patterns of noncompliance between the actual treatment and the PMRT guideline.Data from breast cancer patients admitted to Linkoping University Hospital between 1990 and 2000 were analyzed in this study. Cases that were not treated in accordance with the guideline were selected and analyzed by decision tree induction (DTI). Thereafter, four resulting rules, as representations for groups of patients, were compared to the guideline.Finding patterns of non-compliance with guidelines by means of rules can be an appropriate alternative to manual methods, i.e. a case-by-case comparison when studying very large datasets. The resulting rules can be used in a knowledge base of a guideline-based decision support system to alert when inconsistencies with the guidelines may appear.
|
|
| 11. |
- Ridderstolpe, Lisa, et al.
(författare)
-
Risk factor analysis of early and delayed cerebral complications after cardiac surgery
- 2002
-
Ingår i: Journal of Cardiothoracic and Vascular Anesthesia. - : Elsevier. - 1053-0770 .- 1532-8422. ; 16:3, s. 278-285
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To report the incidence, severity, and possible risk factors for early and delayed cerebral complications.Design: Retrospective study.Setting: Linköping University Hospital, Sweden.Participants: Consecutive patients who underwent cardiac surgery in the period July 1996 through June 2000 (n = 3,282).Interventions: A standard cardiopulmonary bypass (CPB) technique was used for most patients. Postoperative anticoagulant treatment included heparin or anti-Xa dalteparin. Patients undergoing coronary artery bypass graft surgery received acetylsalicylic acid, and patients undergoing valve surgery received warfarin.Measurements and Main Results: Cerebral complications occurred in 107 patients (3.3%). Of these, 60 (1.8%) were early, and 33 (1.0%) were delayed, and in 14 (0.4%) patients the onset was unknown. There were 37 variables in univariate analysis (p < 0.15) and 14 variables in multivariate analysis (p < 0.05) associated with cerebral complications. Predictors of early cerebral complications were older age, preoperative hypertension, aortic aneurysm surgery, prolonged CPB time, hypotension at CPB completion and soon after CPB, and postoperative arrhythmia and supraventricular tachyarrhythmia. Predictors of delayed cerebral complications were female gender, diabetes, previous cerebrovascular disease, combined valve surgery and coronary artery bypass graft surgery, postoperative supraventricular tachyarrhythmia, and prolonged ventilator support. Early cerebral complications seem to be more serious, with more permanent deficits and a higher overall mortality (35.0% v 18.2%).Conclusion: Most cerebral complications had an early onset. The results of this study suggest that aggressive antiarrhythmic treatment and blood pressure control may imfurther prove the cerebral outcome after cardiac surgery.
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
- Wigertz, Ove, 1934-, et al.
(författare)
-
Teaching medical informatics to medical students
- 1990
-
Ingår i: Int Conference on Medical Informatics and Medical Education IMIA,1990. - : Elsevier Science Publ. ; , s. 41-
-
Konferensbidrag (refereegranskat)
|
|
| 16. |
- Wigertz, Ove, 1934-, et al.
(författare)
-
Teaching medical informatics to medical students
- 1991
-
Ingår i: IMIA Int Conference on Medical Informatics and Medical Education,1990. - Amsterdam : Elsevier Science Publishers. ; , s. 41-
-
Konferensbidrag (refereegranskat)
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Hanberger, Håkan, 1954-, et al.
(författare)
-
Low antibiotic resistance rates in Staphylococcus aureus, Escherichia coli and Klebsiella spp but not in Enterobacter spp and Pseudomonas aeruginosa : A prospective observational study in 14 Swedish ICUs over a 5-year period
- 2007
-
Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 51:7, s. 937-941
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Intensive care units (ICUs) are hot zones for emergence and spread of antibiotic resistance because of frequent invasive procedures, antibiotic usage and transmission of bacteria. We report prospective data on antibiotic use and bacterial resistance from 14 academic and non-academic ICUs, participating in the ICU-STRAMA programme 1999-2003. Methods: The quantity of antibiotics delivered to each ICU was calculated as defined daily doses per 1000 occupied bed days (DDD1000). Specimens for culture were taken on clinical indications and only initial isolates were considered. Species-related breakpoints according to the Swedish Reference Group for Antibiotics were used. Antibiotic resistance was defined as the sum of intermediate and resistant strains. Results: Mean antibiotic use increased from 1245 DDD1000 in 1999 to 1510 DDD1000 in 2003 (P = 0.11 for trend). Of Staphylococcus aureus, 0-1.8% were methicillin resistant (MRSA). A presumptive extended spectrum beta-lactamase (ESBL) phenotype was found in <2.4% of Escherichia coli, based on cefotaxime susceptibility, except a peak in 2002 (4.6%). Cefotaxime resistance was found in 2.6-4.9% of Klebsiella spp. Rates of resistance among Enterobacter spp. to cefotaxime (20-33%) and among Pseudomonas aeruginosa to imipenem (22-33%) and ciprofloxacin (5-21%) showed no time trend. Conclusion: MRSA and cefotaxime-resistant E. coli and Klebsiella spp strains were few despite high total antibiotic consumption. This may be the result of a slow introduction of resistant strains into the ICUs, and good infection control. The cause of imipenem and ciprofloxacin resistance in P. aeruginosa could reflect the increased consumption of these agents plus spread of resistant clones. © 2007 The Authors.
|
|
| 24. |
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- Lindholm, P, et al.
(författare)
-
Time components of circulatory transport from the lungs to a peripheral artery in humans
- 2006
-
Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 97:1, s. 96-102
-
Tidskriftsartikel (refereegranskat)abstract
- Blood gas changes occurring in the lung undergo delay and damping on their way to a peripheral artery sampling site. Knowledge of the time components of circulatory transfer is important for the understanding of respiratory control and cardiovascular reflexes in response to blood gas transients. Providing steady state with regard to V̇A/ Q̇ distribution, cardiac output and peripheral blood flow, the relationship between the time courses of small end-tidal and peripheral PO2 changes is determined by the transfer function of the interposed vascular segment. This transfer function, expressed as delay time TD and mean transit time (MTT), was measured in six well-trained subjects, allowing the calculation of arterial time-courses from end-tidal to the reverse. They were studied at rest and during four different dynamic leg exercise intensities in the supine posture. TD and MTT amounted to 15.8 ± 1.7 (mean ± SEM) and 18.3 ± 2.1 s at rest and were shortened to 7.7 ± 0.6 and 11.5 ± 1.8 s during exercise at 170 W. The shortening of TD and MTT did not appear to be simply an inverse function of cardiac output, suggesting that the shortening occurs in the central circulatory segment but not in the arm segment. © Springer-Verlag 2006.
|
|
| 28. |
|
|
| 29. |
|
|
| 30. |
|
|
| 31. |
|
|
| 32. |
- Saeedi, Baharak, 1972-, et al.
(författare)
-
Phene Plate (PhP) biochemical fingerprinting : a screening method for epidemiological typing of enterococcal isolates?
- 2005
-
Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 113:9, s. 603-612
-
Tidskriftsartikel (refereegranskat)abstract
- Pulsed-field gel electrophoresis (PFGE) is currently considered the gold standard for genotyping of enterococci. However, PFGE is both expensive and time-consuming. The purpose of this study was to investigate whether the PhP system can be used as a reliable clinical screening method for detection of genetically related isolates of enterococci. If so, it should be possible to minimize the number of isolates subjected to PFGE typing, which would save time and money. Ninety-nine clinical enterococcal isolates were analysed by PhP (similarity levels 0.90–0.975) and PFGE (similarity levels ≤3 and ≤6 bands) and all possible pairs of isolates were cross-classified as matched or mismatched. We found that the probability that a pair of isolates (A and B) belonging to the same type according to PhP also belong to the same cluster according to PFGE, i.e. p(APFGE=BPFGE • APhP=BPhP), and the probability that a pair of isolates of different types according to PhP also belong to different clusters according to PFGE, i.e. p(APFGE≠BPFGE • APhP≠BPhP), was relatively high for E. faecalis (0.86 and 0.96, respectively), but was lower for E. faecium (0.51 and 0.77, respectively). The concordance which shows the probability that PhP and PFGE agree on match or mismatch was 86%–93% for E. faecalis and 54%–66% for E. faecium, which indicates that the PhP method may be useful for epidemiological typing of E. faecalis in the current settings but not for E. faecium.
|
|
| 33. |
|
|
| 34. |
|
|
| 35. |
|
|
| 36. |
|
|
| 37. |
|
|
| 38. |
|
|
