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Biomedical subjects

C Ohmann

Publications and source records attributed to C Ohmann.

At least 55 records · Page 3Linked to original sources
PubMed1998

Diagnosis of acute appendicitis in two databases. Evaluation of different neighborhoods with an LVQ neural network.

The use of an artificial neural network system was studied in the diagnosis of acute abdominal pain, especially acute appendicitis, with patients from Finland and Germany. Separate Learning Vector Quantization (LVQ) neural networks were trained with a training set from each database and also with a combined database. Each neural network was evaluated separately with a test set of cases from each database. With the combined database different neighborhood methods were compared to find the optimal choice for this decision-making problem. The acute appendicitis cases of the Finnish test data set were classified well with all the networks, but the cases of the German test set were difficult to classify for the Finnish network. The use of larger neighborhoods increased the sensitivity of the classification by nearly 10%. The differences in the results of the Finnish and German databases suggest that there are differences in the data collection or patient populations between centers. Therefore, care must be taken when using decision-support systems which have been developed in other centers. Neural networks offer a method to evaluate differences between databases. With the use of larger neighborhoods, the effects of the differences on the accuracy of the classification can be partly diminished.

Abdominal Pain↗
PubMed1998

[Cause-oriented prevention of nosocomial pneumonia: the HI-LO EVAC tube].

Surgical high-risk patients were studied in a prospective randomized trial regarding nosocomial pneumonia (NP) using a subglottic lavage (SL). A total of 100 patients were investigated, in whom the primary infection was localized in the oropharynx. Independent of the kind of stress ulcer prophylaxis, intermittent subglottic lavage reduces the incidence of NP drastically to 3%, which is however, without statistical significance.

Critical Care↗
PubMed1998

[Is ultrasound examination in acute appendicitis dispensable? Acute Abdominal Pain Study Group].

In a prospective multicenter observational trial, the performance and clinical benefit of ultrasound of the appendix was evaluated in the clinical routine. Ultrasound of the appendix was performed in 870 of 2280 patients (38%); the overall sensitivity was 55% (range: 13 to 90%), specificity 95%, positive and negative predictive value 81 and 85%. There was no correlation between the frequency or accuracy of ultrasound and the accuracy of the clinician, the negative appendectomy or perforation rate.

Abdomen, Acute↗
PubMed1998

[The diagnostic value of rectal examination of patients with acute appendicitis].

The results of rectal digital examinations performed on 477 patients upon admission with histopathologically proven acute appendicitis from a total of 2280 patients with acute abdominal pain were analyzed. Although 13.7% of the patients experienced pain on the right side and 7.4% pain in the pouch of Douglas during rectal examination, none of the rectal examination parameters was statistically significant for the diagnosis of acute appendicitis. There are well established and statistically significant clinical indications, such as guarding, rigidity, rebound tenderness or abdominal distention that actually make the unpleasant rectal-digital examination superfluous for patients with suspected appendicitis.

Abdomen, Acute↗
PubMed1997

Safety of a low-dosage Filgrastim (rhG-CSF) treatment in non-neutropenic surgical intensive care patients with an inflammatory process.

OBJECTIVE: To evaluate the effect and safety of a low dose Filgrastim treatment in surgical intensive care patients. DESIGN: Prospective, clinical study. SETTING: Surgical intensive care unit (ICU) in a university hospital. PATIENTS: Ten patients with the systemic inflammatory response syndrome (SIRS) and ten patients with sepsis were included in the study. INTERVENTIONS: Filgrastim was given intravenously at 1.0 microgram/kg for 3 days, followed by 0.5 microgram/kg for 4 days. MEASUREMENTS AND RESULTS: Filgrastim treatment increased leukocyte counts and plasma levels of G-CSF. Cytokine levels (IL-6 and IL-8) decreased in the first 3 days of treatment. None of the SIRS patients developed sepsis or multiple organ failure and none of the patients died. In the sepsis group four patients died. No adverse side effects were observed, especially no attenuation of lung injury. CONCLUSIONS: Low-dosage Filgrastim treatment in ICU patients is safe. Whether the observed changes of the inflammatory response can be attributed to Filgrastim has to be clarified in further randomized trials.

Cytokines↗
PubMed1997

Which peptic ulcers bleed? Results of a case-control study. DUSUK Study Group.

BACKGROUND: The incidence of ulcer bleeding has not decrease despite effective medical treatment of peptic ulcer disease. Numerous studies have been performed on risk factors for ulcer bleeding, but only a few studies have related the risk of developing ulcer bleeding to the risk of developing uncomplicated ulcer disease. METHODS: This study was performed as a multicenter interdisciplinary case-control study and was based on diagnosis by endoscopy, prospective data collection, and multivariate analysis. To every study patient with ulcer bleeding (case) one patient with uncomplicated peptic ulcer proven at endoscopy (control) was assigned with regard to sex, ulcer localization, and age (+/-5 years). The controls were randomly taken from three sources: inpatients, outpatients, and patients treated by a private physician. RESULTS: Owing to strict inclusion and exclusion criteria, 209 matched pairs were available for evaluation out of 401 patients with peptic ulcer bleeding. In univariate analysis the duration of ulcer pain and the number of previous ulcer treatments proved to be protective factors for ulcer bleeding. The intake of non-steroidal anti-inflammatory drugs (NSAID) as a whole, acetylsalicylic acid (aspirin), and paracetamol gave an increased risk for ulcer bleeding. Multivariate analysis identified four risk factors for peptic ulcer bleeding: lung disease, NSAID intake, no pretreatment with H2 blockers, and acetylsalicylic acid intake. CONCLUSIONS: The following patient groups represent a risk for peptic ulcer bleeding: multimorbid patients, receiving NSAID and/or aspirin, and patients with no previous ulcer history.

Aged↗
PubMed1997

Integration of a knowledge-based system and a clinical documentation system via a data dictionary.

This paper describes the design and realisation of a knowledge-based system and a clinical documentation system linked via a data dictionary. The software was developed as a shell with object oriented methods and C++ for IBM-compatible PC's and WINDOWS 3.1/95. The data dictionary covers terminology and document objects with relations to external classifications. It controls the terminology in the documentation program with form-based entry of clinical documents and in the knowledge-based system with scores and rules. The software was applied to the clinical field of acute abdominal pain by implementing a data dictionary with 580 terminology objects, 501 document objects, and 2136 links; a documentation module with 8 clinical documents and a knowledge-based system with 10 scores and 7 sets of rules.

Abdominal Pain↗
PubMed1997

Collection of data in clinical studies via Internet.

This paper describes a system enabling data collection in multicenter clinical trials via WWW and Internet. The form-based data entry is based on HTML documents with JavaScript linked to a relational database (mSQL) via a cgi program (w3-msql). The design has been applied to a multi-national study in acute abdominal pain, for which eight clinical forms have been developed. The system is now in test use and experiences with this approach are presented.

Abdominal Pain↗
PubMed1997

A systematic approach to the assessment of user satisfaction with health care systems: constructs, models and instruments.

In this paper an overview is given about research in the field of user satisfaction with health care systems and a new systematic model is set up. The model distinguishes between system-independent and system-dependent factors, the latter characterised by satisfaction with the content, the interface and the organisation. Evaluated instruments for assessing user satisfaction are classified according to the model and recommendation for an appropriate use are given.

Computer Simulation↗
PubMed1997

Prognostic modelling in peritonitis. Peritonitis Study Group of the Surgical Infection Society Europe.

OBJECTIVE: To develop and to evaluate a new score to aid management in peritonitis. DESIGN: Prospective, multicentre study. SETTING: 18 departments of surgery in Germany. Austria, and Switzerland. SUBJECTS: 355 patients with peritonitis confirmed at laparotomy. INTERVENTIONS: Computation of four different prognostic systems: APACHE II; APACHE II and successful operation; APACHE II, successful operation and Goris score on the first postoperative day: and multivariate analysis. Predictions were evaluated according to the following criteria: specificity with a fixed sensitivity at 80%, receiver operating characteristic (ROC-) curve, and predictive value. MAIN OUTCOME MEASURE: The ability to predict hospital death and infective complications. RESULTS: Multivariate analysis was superior to APACHE II: APACHE II and successful operation: and APACHE II, successful operation, and Goris score. From the analysis a new prognostic model was derived from which it was possible to identify patients early in the postoperative period who are at high risk of developing further complications (prognostic peritonitis model: PPM). CONCLUSIONS: None of the existing scores was of particular use for therapeutic decision making in peritonitis. The new prognostic model should be the focus of further trials in the management of peritonitis.

APACHE↗
PubMed1997

[Significance of lymph node metastases of differentiated thyroid gland carcinomas and C-cell carcinomas for prognosis--a meta-analysis].

Surgical therapy of differentiated thyroid cancer (DTC) includes thyroidectomy plus central lymph node dissection and postoperative radioiodine therapy. In cases of lymph node metastasis, T3/T4 tumors and C-cell-carcinoma (after thyroidectomy) uni- or bilateral modified radical lymph node dissection of the neck (neck dissection) and of the mediastinum is recommended. The importance of lymph node metastasis for prognosis of survival in papillary, follicular and C-cell-carcinoma is discussed controversial, however. Even the kind of surgical radicality is questioned. Thus a metaanalysis of 35 studies in 29 independent publications from a pool of 2186 studies was performed. Univariate analysis demonstrates lymph node metastasis as a negative prognostic factor in papillary carcinoma with a 3.25/2.97, in follicular carcinoma with a 7.62/4.0 and in C-cell-carcinoma with a 3.33/3.37 higher probability of mortality 5 and 10 years after operation. Modification of the present surgical therapy can therefore only be accepted after univariate and multivariate analysis of all prognostic factors (age, sex, cell type, tumor extent, lymph node- and distant metastasis) and after it has proven superiority to the present strategy in prospective randomised trials.

Adenocarcinoma, Follicular↗
PubMed1997

[Surgical epidemiology].

The application of epidemiological principles and methods to problems in surgery (Surgical Epidemiology) still plays a minor role in Germany. Different examples are presented, demonstrating that an increase of intellectual power can be achieved by applying epidemiological methods to surgery. Future developments in surgery can be estimated and the role of surgery in comparison with other clinical disciplines can be clarified and strengthened. Similar to foreign countries, support of Surgical Epidemiology by reference centers is required.

Bias↗
PubMed1997

[Is perforating appendicitis a separate disease picture?].

Large epidemiological studies recently published suggest that perforating appendicitis may represent a separate disease entity. To find out whether perforating and nonperforating appendicitis may be distinguished by clinical features (history and examination, lab tests) data from 519 cases of acute appendicitis (17.7% perforations) were analysed, and significant differences were recorded in various aspects of history and clinical examination. It was concluded that perforating and nonperforating appendicitis may clinically be distinguished reliably in the majority of cases.

Adult↗
PubMed1996

[Clinical standardization in acute abdominal pain].

The correct diagnosis in acute abdominal pain is necessary for adequate treatment. In several clinical studies it has been shown that, despite improvements in laboratory and technology medicine, errors occur in a considerable proportion of cases due to insufficient history-taking and clinical examination. By the introduction of a standardised and structured history and clinical examination, the diagnostic accuracy can be improved by at least 10%. The aim of this publication is to improve history-taking, clinical examination and diagnostic decision-making by exact definition of all relevant parameters. This was performed by a national clinical expert group, international standardisations were taken in consideration. The standardisation was based mainly on these existing international standardisations (World Organisation of Gastroenterology); however, revisions and corrections were necessary. In order to introduce the standardisation into clinical routine, a documentation form and a documentation program can be provided.

Abdomen, Acute↗
PubMed1996

Evaluation of automatic knowledge acquisition techniques in the diagnosis of acute abdominal pain. Acute Abdominal Pain Study Group.

Clinical diagnosis in acute abdominal pain is still a major problem. Computer-aided diagnosis offers some help; however, existing systems still produce high error rates. We therefore tested machine learning techniques in order to improve standard statistical systems. The investigation was based on a prospective clinical database with 1254 cases, 46 diagnostic parameters and 15 diagnoses. Independence Bayes and the automatic rule induction techniques ID3, NewId, PRISM, CN2, C4.5 and ITRULE were trained with 839 cases and separately tested on 415 cases. No major differences in overall accuracy were observed (43-48%), except for NewId, which was below the average. Between the different techniques some similarities were found, but also considerable differences with respect to specific diagnoses. Machine learning techniques did not improve the results of the standard model Independence Bayes. Problem dimensionality, sample size and model complexity are major factors influencing diagnostic accuracy in computer-aided diagnosis of acute abdominal pain.

Abdominal Pain↗
PubMed1996

[Ulcer surgery '96--choice of methods in an emergency].

Understanding of peptic ulcer disease has dramatically changed within the last years. Today ulcer disease can be considered as a chronic infection. Based on this new pathophysiological concept treatment policies for ulcer bleeding and perforation have to be revised. For ulcer bleeding the standard procedure consists of a diagnostic emergency endoscopy and endoscopic treatment based on the bleeding activity. Patients with recurrent bleeding during hospital stay carry an increased risk for death. More than 50% of these patients have to be operated, nearly 25% die during hospital stay. For that reason an early elective operation can be recommended in patients with a high risk for further bleeding. This includes patients with arterial bleeding (Forrest Ia) and with a vissible vessel (Forrest IIa) with an additional risk (e. g. posterior wall of the duodenum, lesser curvature). All other bleeding activities can primarily treated conservatively. Because of an effective medical treatment of the ulcer disease with eradication, the operation should be restricted to ulcer excision and ulcer oversewing in bleeding or perforated gastric ulcer and duodenotomy, ulcer ligation and extraluminal ligature in bleeding duodenum ulcer and excision and oversewing with pyloroplasty in perforated duodenal ulcer. More definite surgery is not reasonable and should be avoided. With treatment policies based on early elective operation in high risk groups and medical treatment in the other patients a mortality of 5% or less can be achieved.

Duodenal Ulcer↗