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C Ohmann

Publications and source records attributed to C Ohmann.

At least 37 records · Page 2Linked to original sources
PubMed2000

[What studies are useful within the scope of quality assurance?].

The necessity for studies in quality assurance is based on the demand for evaluation of quality assurance measures. Whereas investigation of effects of quality assurance measures under controlled conditions is the goal of quality research, quality assurance deals with the improvement and assurance of quality under routine conditions. In quality research a far reaching control of bias and confounding variables should be aimed at. This is only possible with controlled studies, preferably with the randomised study. With methodological demanding randomised studies the effectiveness of specific quality instruments (e.g. guidelines) could be demonstrated. In the evaluation of quality assurance comparison is also the major principle. This can be done in a controlled non-randomised study, in an empiricle comparison between institutions or in a comparison with a given quality standard. It is hoped, that also in Germany methodological adequate studies will play a major role in quality research and quality assurance in the future.

Clinical Trials as Topic↗
PubMed2000

[Previous experiences with evaluation of practice guidelines].

Numerous expectations are associated with the development of guidelines. Referring to the experiences so far it can be stated that despite the large amount of guidelines that have been developed, little attention has been given to dissemination, implementation and evaluation of guidelines. The developed guidelines often do not follow international accepted quality criteria, for example many are not based on scientific evidence or they lack the involvement of all relevant parties. The main problems occur in the process from development to implementation of a guideline. Results from evaluation studies nevertheless show that guidelines can have positive effects on the process and outcome of medical care. More scientifically sound evaluation studies are needed to assess the effects of guidelines. Especially in Germany a lot more needs to be done to improve the quality of guidelines and the amount of evaluation studies.

Evidence-Based Medicine↗
PubMed1999

Clinical benefit of a diagnostic score for appendicitis: results of a prospective interventional study. German Study Group of Acute Abdominal Pain.

HYPOTHESIS: Clinical use of a diagnostic score improves decision making in acute appendicitis. DESIGN: A before-and-after trial comparing a group of patients undergoing standard diagnostic workup with no additional diagnostic support (phase 1) with a group of patients undergoing additional diagnostic support with a score (phase 2). SETTING: Eight departments of surgery in Germany and Austria. PATIENTS: Eight hundred seventy patients with acute abdominal pain in phase 1 (October 1, 1994, to April 30, 1995) and 614 patients in phase 2 (February 1, 1995, to August 15, 1995). INTERVENTIONS: Structured and standardized history and clinical investigation in all patients with computer-based documentation; introduction of the diagnostic score after phase 1 and computer-supported use of the score in phase 2. RESULTS: The 2 groups were comparable with respect to signs, symptoms, and investigations related to acute appendicitis. Diagnostic performance of the final examiner decreased with the score (specificity, 86% vs 78%; positive predictive value, 67% vs 50%; and accuracy, 88% vs 81%). There were no differences in the rates of perforated appendix, appendectomy with normal findings, and complications; however, the delayed appendectomy rate (2% vs 8%) and the delayed discharge rate (11% vs 22%) were significantly lower with diagnostic support by the score (P = .02). CONCLUSIONS: Integration of a score into the diagnostic process may have unforeseen clinical effects. The tested score cannot be recommended as a standard tool for diagnostic decision making in acute appendicitis.

Acute Disease↗
PubMed1999

Ultrasonography for diagnosis of acute appendicitis: results of a prospective multicenter trial. Acute Abdominal Pain Study Group.

A prospective multicenter observational trial was performed to assess the performance and clinical benefit of ultrasonography of the appendix in the routine clinical examination. Included in the study were 2280 patients with acute abdominal pain from 11 surgical departments in Germany and Austria. Ultrasonography of the appendix was performed in 870 (38%) of the patients (range 16-85%). The overall sensitivity of ultrasonography of the appendix was 55% (13-90%), the specificity 95% (range 82-100%), positive predictive value 81% (50-100%), and negative predictive value 85% (68-96%). With respect to single ultrasound scan findings, adequate sensitivity (44%) was achieved only with the target phenomen, not with the other criteria. There were no correlations between the ultrasound findings of the appendix and the diagnostic accuracy of the clinician, the negative appendectomy rate, or the perforated appendix rate. From the study it can be concluded that there is no proven clinical benefit of ultrasound scanning of the appendix in the routine clinical diagnosis.

Abdominal Pain↗
PubMed1999

[Formal decision aids in surgery--results of a survey].

Even though many decision-aids have been developed in the past, the application of these systems in clinical practice is still rare. There are many reasons for this, including the reservations of potential users. A survey in three university surgery clinics was conducted to assess the experience and attitudes towards decision-aids among physicians. Seventy-two of the 102 physicians approached (71%) filled out and returned the short questionnaire that was sent to them. More than half of the 72 survey participants already use decision-aids. Among them, guidelines are used most often (46%), whereas other instruments (algorithms, scores, decision trees) are used less frequently (10-17%). Computer-based decision-aids are hardly used at all (7%). These results are in contrast to the strong request for more decision-aids, especially for computer-based systems (40%). Physicians who already use decision-aids are more interested in additional systems. More than 70% of all participants are interested in more information about the topic. The standardized question about attitudes towards computer-based decision-aids reveals more positive than negative appraisal, whereas the answers to open questions focus more on objections. The substantial differences between the three survey locations in parts of the survey results show that attitudes towards decision-aids are influenced by the way the instruments are introduced and the way the users are informed and involved in the process of implementation. A successful implementation of decision-aids in clinical practice should therefore try to integrate the future users as much as possible.

Academic Medical Centers↗
PubMed1999

Risk factors associated with intraabdominal infections: a prospective multicenter study. Peritonitis Study Group.

INTRODUCTION AND METHODS: A prospective observational multicenter study with 18 hospitals was performed to assess preoperative risk, therapeutic management and outcome of patients with peritonitis. Data collection was carried out according to standardized and recommended definitions. Included in the study were 355 patients with macroscopically confirmed peritonitis. RESULTS: In the univariate analysis, the following factors influenced both the mortality and the incidence of postoperative complications: age, presence of certain concomitant disease, site of origin of peritonitis, type of admission and the ability of the surgeon to eliminate the source of infection. In addition, postoperative infective complications were related to the etiology of peritonitis and the exudate. In the multivariate analysis, APACHE II (P<0.001), successful operation (P<0.001), age (P<0.001), liver disease (P<0.03), malignant disease (P<0.04) and renal disease (P<0.05) turned out to be significant with respect to death. Escherichia coli was the predominant organism (51%), following by enterococci (30%) and bacteroides (25%). There was a significantly higher postoperative infection rate in patients with no adequate treatment of enterococci than patients with adequate treatment or no enterococci (P<0.05). CONCLUSION: The study demonstrated the important role of the physiological reserve of the patient and of the surgeon, which is not adequately reflected in existing scoring systems. Further investigations are needed to study the impact of enterococci on the outcome.

APACHE↗
PubMed1999

Perforating appendicitis: is it a separate disease? Acute Abdominal Pain Study Group.

OBJECTIVE: To find out whether perforated and unperforated appendicitis are separate diseases and can be distinguished clinically. DESIGN: Prospective multicentre study. SETTING: 11 departments of surgery in Germany and Austria. SUBJECTS: 519 patients over 6 years old who had histologically confirmed acute appendicitis between October 1994 and March 1996. MAIN OUTCOME MEASURES: Differences in history, clinical findings, lab results, clinical course and outcome. RESULTS: 92 of the 519 patients (18%) had perforated appendicitis. The following variables were shown by univariate analysis to be significantly more common in the group with perforated appendicitis: rigidity, reduced abdominal wall movement, abdominal distension, reduced bowel sounds (all p<0.001), pale skin (p<0.005), generalised abdominal tenderness, severe abdominal tenderness (both p<0.01), WCC > or =10(9)/L (p<0.05). By multivariate analysis the following variables were significantly more common in the group with perforated appendicitis: age over 50 years (p<0.0001); change in bowel habit and rigidity of the abdominal wall (both p = 0.001); generalised tenderness (p<0.01); male sex (p<0.01); and distended abdomen (p<0.05). Rectal examination failed to make the distinction. CONCLUSIONS: Perforated and unperforated appendicitis behave clinically like two different diseases. They can in most cases reliably be distinguished using clinical criteria alone. Although greater diagnostic accuracy may result in a higher rate of perforation, close observation and timely intervention will only marginally affect the outcome.

Adult↗
PubMed1999

Generalisation and extension of a web-based data collection system for clinical studies using Java and CORBA.

Inadequate informatical support of multi-centre clinical trials lead to pure quality. In order to support a multi-centre clinical trial a data collection via WWW and Internet based on Java has been developed. In this study a generalization and extension of this prototype has been performed. The prototype has been applied to another clinical trial and a knowledge server based on C+t has been integrated via CORBA. The investigation and implementation of security aspects of web-based data collection is now under evaluation.

Artificial Intelligence↗
PubMed1999

European and Latin-American countries associated in a networked database of outstanding guidelines in unusual clinical cases (ELCANO).

The aim of ELCANO, an EU-funded project, is to build a virtual multilingual multimedia library of unusual clinical cases related to gastroenterology. Based on a standardisation of the format to report and the representation of clinical information on WWW, the multilingual multimedia case has been developed and till now 350 cases have been included. User satisfaction and user acceptance of ELCANO are under evaluation.

Databases as Topic↗
PubMed1998

[Early stomach carcinoma--pathologic-anatomic findings and prognosis].

BACKGROUND: The therapy for early gastric cancer (endoscopy, gastric resection, D1/2 dissection) is controversial. MATERIALS AND METHODS: In a retrospective study (4/86-12/95) we analyzed the prognosis of 57 early gastric cancer patients with respect to pathological findings and surgical therapy. RESULTS: The R0 resection rate was 100%. In 7% multifocal tumor growth was seen. The 5-year survival rate was 70%. LN-metastases were found in 12% of all cases, more often in pT1b than in pT1 a tumors (17 vs 9%) and more often in large carcinomas than in small carcinomas (> 1000 mm2: 27%; < 300 mm2: 0%). Long-term survival was significantly better in pN0 patients than in patients with LN metastasis (P = 0.020). CONCLUSION: Prognosis of early gastric cancer after curative resection is good.

Adolescent↗
PubMed1998

Simple data from history and physical examination help to exclude bowel obstruction and to avoid radiographic studies in patients with acute abdominal pain.

OBJECTIVE: To assess the value of plain abdominal radiographs and of data from the medical history and physical examination in the diagnosis of acute abdominal pain in general and of bowel obstruction in particular. DESIGN: Prospective study. SETTING: 4 university and 2 community hospitals, Germany. SUBJECTS: 1254 patients with acute abdominal pain lasting less than 7 days, and with no history of abdominal injury including surgery. INTERVENTIONS: Standardised and structured medical history and physical examination, study of results of plain abdominal radiographs. MAIN OUTCOME MEASURES: Positive predictive value and sensitivity of clinical variables and abdominal film with respect to the diagnosis at discharge. RESULTS: 48 patients (3.8%) had bowel obstruction. 704 patients (56.1%) had plain abdominal films taken at the time of initial presentation. 111 studies (15.8%) showed important findings leading to diagnosis or immediate treatment, 455 (64.7%) showed unimportant or no findings. In 138 (19.6%) results of films were not reported. 16 of 45 single variables were of help in diagnosing bowel obstruction. The six with the highest sensitivity were distended abdomen, increased bowel sounds, history of constipation, previous abdominal surgery, age over 50, and vomiting. If only patients presenting with any two of these symptoms had had radiographs taken, 300 (42.6%) could have been avoided without loss in diagnostic accuracy. CONCLUSION: A considerable number of plain abdominal films taken for patients with acute abdominal pain could be avoided by focusing on clinical variables relevant to the diagnosis of bowel obstruction.

Abdominal Pain↗
PubMed1998

Impact of early operation on the mortality from bleeding peptic ulcer --ten years' experience.

In 1984, a risk-dependent combined endoscopic and operative approach for the treatment of bleeding peptic ulcer was developed. This treatment policy has as its major feature an early elective operation in patients with arterial bleeding and a visible vessel, providing that endoscopic control of the bleeding could be achieved. Using this concept in a prospective series resulted in a mortality of 5% compared to a mortality of 14% in a historical control group, where an operation was performed only on demand in case of recurrent bleeding. In 1986, the treatment policy was introduced into clinical routine circumstances at the University Hospital of Düsseldorf. In this paper the results of routine clinical application are presented. The treatment policy was followed in 47% of patients treated respectively primarily transferred to the surgical department. Mortality in arterial bleeding and visible vessel in the conservatively treated group was double the mortality in the early elective operated group (14 vs. 7%). The mortality in patients treated primarily in the department of internal medicine was double the mortality of patients treated at the surgical department (18 vs. 9%). The differences in mortality are mainly due to the procedure in the elderly patients. In patients aged 70 years or more, the mortality rate of patients treated in internal medicine was 31% compared to 16% in the surgery department. Younger patients do not seem to benefit from early elective operation. Our study clearly demonstrates the importance of avoiding late recurrent bleeding. Patients at high risk of this complication should therefore be identified as early as possible and early surgical intervention should be considered by agreed interdisciplinary and evaluated treatment concepts.

Adult↗
PubMed1998

Data collection in multi-center clinical trials via Internet. A generic system in Java.

Data collection via Internet is usually performed with an HTML/CGI combination, which has a lot of disadvantages, most important the lack of security features. We therefore have developed a system written entirely in Java, which implements a true client/server application based on TCP/IP. The documents are created using a multi-lingual data dictionary, and the used GUI components are able to perform plausibility checks, which improves quality of the data. The system is designed to be easily extensible so that it can be used in almost any kind of clinical trials. It is based on a three-tier model where client requests are handled and monitored by an application server. We will describe this system and it's implementation and compare it to the HTML/CGI approach. Of special interest are security features, which are possible through the use of Java.

Computer Systems↗
PubMed1998

A data dictionary approach to multilingual documentation and decision support for the diagnosis of acute abdominal pain. (COPERNICUS 555, an European concerted action).

This paper describes the design and development of a multilingual documentation and decision support system for the diagnosis of acute abdominal pain. The work was performed within a multi-national COPERNICUS European concerted action dealing with information technology for quality assurance in acute abdominal pain in Europe (EURO-AAP, 555). The software engineering was based on object-oriented analysis design and programming. The program cover three modules: a data dictionary, a documentation program and a knowledge based system. National versions of the software were provided and introduced into 16 centers from Central and Eastern Europe. A prospective data collection was performed in which 4020 patients were recruited. The software design has been proven to be very efficient and useful for the development of multilingual software.

Abdomen, Acute↗
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↗