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Biomedical subjects

C Ohmann

Publications and source records attributed to C Ohmann.

At least 91 records · Page 5Linked to original sources
PubMed1995

Evaluating four diagnostic methods with acute abdominal pain cases.

Contemporary work in medical decision support is characterized by a multitude of methods. To investigate their relative strengths and weaknesses, we built four diagnostic expert systems based on different methods (Bayes, case-based classification, heuristic classification) for analysis of the same set of 1254 cases of acute abdominal pain previously documented in a prospective multicenter study. The results of the comparative evaluation indicate that differences in overall performance are relatively small (statistically not significant). The performance depends more on the quality of the knowledge base and the case data than on the inference methods of the expert systems. Methods relying exclusively on empirical knowledge (Bayes, case-based classification) tend to have slightly higher overall performance scores due to a diagnostic bias toward ordinary and common diseases. By contrast, methods operating with expert knowledge (e.g., heuristic classification) perform slightly worse overall, but are more sensitive toward uncommon (serious) diseases.

Abdominal Pain↗
PubMed1995

[Surgical therapy of uncomplicated ulcer: results of a prospective epidemiologic study. DUSUK Study Group].

In a prospective, multicenter and interdisciplinary study (DUSUK I) the present position of elective surgery in uncomplicated peptic duodenal and gastric ulcers was evaluated. Ten Düsseldorf hospitals (surgery and internal medicine) participated in the study. The investigation focussed on the proportion of operated patients related to hospitals and clinical disciplines, the operative procedure and results and possible selection criteria for the indication of operation. In the study period a total of 1030 patients with uncomplicated peptic ulcer was documented, an incidence of indoor patients with uncomplicated peptic ulcers of 180/100,000 inhabitants/year and an incidence of elective ulcer surgery of 7.5/100,000 inhabitants/year was calculated. Patients primarily admitted to surgical units were operated in 27% of cases (39/146) in contrast to 0.5% (4/884) of patients primarily admitted to internal units. The majority of hospitals perform rare or no elective peptic ulcer surgery at all. There is a considerable difference between the hospitals and clinical disciplines. The collective of operated patients concentrated on young patients with positive ulcer history. In the long run a negative effect on surgical training and results is apprehended.

Adult↗
PubMed1995

Diagnostic scores for acute appendicitis. Abdominal Pain Study Group.

OBJECTIVE: To assess the value of predictive scores in the diagnosis of acute appendicitis. DESIGN: Multicentre evaluation with a prospective database. SUBJECTS: 1254 patients with acute abdominal pain. SETTING: 6 departments of surgery, Germany. INTERVENTIONS: To measure the performance of 10 scores on one database using standardised criteria and to compare the results with published data. MAIN OUTCOME MEASURES: The ability of a score to fulfill standardised criteria: an initial negative appendicectomy rate of 15% or less, a potential perforation rate of 35% or less, an initial missed perforation rate of 15% or less, and a missed appendicitis rate of 5% or less. RESULTS: Reevaluation of the published data showed that the Alvarado score fulfilled all four criteria and the Lindberg, the Fenyö and the Christian scores fulfilled two criteria each. If applied to our database (acute abdominal pain, suspected appendicitis), none of the scores fulfilled any of the given criteria, even if the cut-off point was varied systematically. There were significant differences among the scores. CONCLUSIONS: The original published data seemed to comply with our standardised criteria but evaluation of the scores on our database resulted in poor performances for all of them. Published data seem to be optimistically biased whereas our evaluation gives more realistic estimates of the routine performance in different clinical environments. Further well designed large scale trials are needed to investigate the clinical benefit of diagnostic scoring in acute appendicitis.

Abdominal Pain↗
PubMed1995

[The intensive care gallbladder--a transient phenomenon or a problem requiring therapy?].

Acute acalculous cholecystitis (AAC) is a well-known complication in postoperative and severely traumatized patients. Existing data of AAC originate from retrospective analyses and episodic case reports. In a prospective study 45 polytraumatized patients admitted to our intensive care unit between January 1, 1989 and June 30, 1990 were clinically and sonographically screened for this condition at defined time-intervals. A clinical and sonographical follow-up was performed annually (1991-1993). Trauma scoring was performed according to the Injury Severity Score (ISS) and Polytrauma Score (PTS). AAC was defined as a combination of hydrops of the gallbladder, an increased mural thickness (> 3.5 mm) and the demonstration of sludge. We were able to demonstrate this diagnostic triad in 8 out of 45 patients (18%). As a consequence early elective cholecystectomy was performed in one patient. The remaining patients were treated conservatively. Incidence of AAC in severely traumatized patients is probably higher than figures so far published suggest. The systematic search for this condition using serial sonographic examinations and defined sonomorphological criteria may select individual cases for elective cholecystectomy. Ultrasound is a reliable method of early detection and follow-up of this complication. Trauma and following intensive care therapy induce a lithogenetic factor, developing gallstone disease in 27% of patients within an 2-3-year interval.

Acute Disease↗
PubMed1995

[Quality assurance from the theoretical viewpoint].

The process of quality assurance is related to all measures and actions used to achieve the required quality. There is agreement about the aim and benefit of quality assurance, but the appropriate way is a matter of discussion. This paper deals from a theoretical viewpoint with basic problems of quality assurance that have not been evaluated adequately so far: a) criteria for measuring quality, b) measuring quality with adjustment for case-mix and c) evaluation of the effects of quality assurance. During the last years tools and study designs have been developed, which could contribute to the solution of these problems by a more sensible analysis, more complete and quality-controlled data and more useful evaluation studies. Further improvements in external quality assurance in surgery are to be expected, if these aspects are taken into consideration.

Diagnosis-Related Groups↗
PubMed1995

[Diagnostic score for acute appendicitis].

Scoring systems seem to be ideal for supporting diagnosis of acute appendicitis because they are non invasive, require no special equipment and can be used in clinical routine. Several scores for appendicitis have been developed with good results in the original publications. Unfortunately these good results could not be reproduced on a German data base. Therefore we developed a new score using multivariate statistics and a quality controlled prospective data base. The score covers 8 variables: tenderness, rebound tenderness, micturition, type of pain, leucocytes, age, relocation of pain, rigidity. Independent evaluation of the score on a Dutch database resulted in a negative appendicectomy rate of 21% and a missing appendicitis rate of 2%. The results are encouraging, so that further testing and clinical application can be recommended.

Acute Disease↗
PubMed1995

Transhiatal oesophagectomy compared with transthoracic resection and systematic lymphadenectomy for the treatment of oesophageal cancer.

OBJECTIVE: To compare the results of transhiatal oesophagectomy with those of transthoracic resection with systematic two field en bloc lymphadenectomy in the treatment of carcinoma of the oesophagus. DESIGN: Prospective open (non-random) study. SETTING: University hospital, Germany. SUBJECTS: 87 patients with carcinoma of the oesophagus of whom 46 underwent transhiatal, and 41 transthoracic resection. MAIN OUTCOME MEASURES: Morbidity and short and long term mortality. RESULTS: The type of operation was chosen on clinical grounds, and the groups were comparable except for site and type of tumour, and nodal stage. The hospital mortality was 7/46 (15%) in the transhiatal group and 4/41 (10%) in the transthoracic group. The most common complication was anastomotic leak (23/46, 50%, compared with 10/41, 24%, p = 0.014), followed by major pulmonary complications (16/46, 35%, compared with 12/41, 29%), and cardiac complications (12/46, 26% compared with 11/41, 27%). Median survival was 350 days in the transhiatal group and 378 days in the transthoracic group. The percentage survival after one, two, and three years in the two groups was 48 and 55, 26 and 18, and 21 and 17, respectively. There were no significant differences in short or long term mortality. CONCLUSION: We have been unable to show that the oncologically more radical procedure (transthoracic resection with systematic two field en bloc lymphadenectomy) results in longer survival, but we have shown that it can be done with similar morbidity and short term mortality. Because it is possible to stage the disease exactly with a transthoracic resection, and because published reports from other centres have hinted at improved prognosis after it, we shall continue to do the operation for suitable patients.

Adult↗
PubMed1995

Integration of a data dictionary and a clinical database in an expert system for acute abdominal pain.

Despite promising results, computer-aided diagnosis in acute abdominal pain is rarely used in the clinic. We therefore developed an expert system for acute abdominal pain to be used in clinical routine. The system is based on a new approach integrating a data dictionary, a clinical database and the knowledge base. A data dictionary editor has been developed (C++, WINDOWS, IBM-compatible PC) and a data dictionary for acute abdominal pain has been built up. The clinical database has been linked to a documentation program providing three modes of data entry. The documentation program has been evaluated extensively by clinicians. The integrated approach clearly separates clinical data from knowledge, but guarantees high consistency of data.

Abdominal Pain↗
PubMed1994

Quality assurance in gastroenterology: the Telegastro project.

The goal of this Telegastro project is to improve standards of care in gastroenterology by establishing and circulating a 'consensus' view of several aspects of 'good practice' in specific areas of gastroenterology. The background for the study is described, followed by the detailed goals of the project and the modus operandi designed to achieve these goals. Finally, the problems of implementing such a package are discussed along with progress in the first 18 months and schedules for future activities.

Computer Communication Networks↗
PubMed1994

[Significance of anamnesis and clinical findings for diagnosis of acute appendicitis. Acute Abdominal Pain Study Group].

UNLABELLED: Acute appendicitis raises considerable diagnostic difficulties. This is proven by rates of negative appendectomies that sometimes extent 30%. In order to find reasons for this we tested 211 patients findings for diagnostic relevance. METHOD: Within the European Community--Acute Abdominal Pain Survey, a study to support diagnosis in acute abdominal pain, 1254 patients were seen in the six participating German hospitals. 16.8% had appendicitis. History data and physical findings were tested for positive and negative predictive value (PPV/NPV), sensitivity and specificity (SEN/SPE). RESULTS: We had 15% negative appendectomies and 16% perforated appendicies. Only few of the parameters tested show a PPW significantly higher than the prior probability of appendicitis: (PPV/NPV/SEN/SPE in %) rebound tenderness 39/63/91/80, tenderness in the right lower quadrant 36/82/95/70, pain right lower quadrant at presentation 34/77/94/70, onset of pain right lower quadrant 29/49/88/75, rigidity 28/9/84/95, guarding 26/43/87/76. All other parameters had a lower PPV. The combination of three parameters leads to maximal PPV of 85%. CONCLUSION: Very few symptoms are helpful in diagnosing appendicitis: the pain related symptoms (spontaneous pain, tenderness and rebound tenderness, guarding) and the history of the pain hint at an appendicitis. A structured and complete medical history and physical examination focussing on these few symptoms, a systematic combination of these and possibly ultrasonography will improve diagnostic accuracy.

Abdomen, Acute↗
PubMed1993

[Computer-assisted surgery documentation in clinical routine practice].

In surgery, computer support is still of minor importance. It is the aim of this publication to outline the concept of a computer-assisted documentation system for surgical procedures, to describe the realization of the concept and to discuss the results of the evaluation. Planning of the system started in 1988 with an analysis of existing computer support at our clinic, definition of the parameters to be documented and determination of the classifications to be used, followed by a design for the system's use and a decision on hardware and software. The system is run on an IBM-compatible personal computer with three terminals, and the software used is MEDOS. The surgical procedures are documented with a four-level hierarchical classification related to the VESKA code and the internal university codes. After extensive training of the doctors, routine use commenced in 1991. Up to now 9837 operations have been documented by 35 surgeons. The system produces all necessary statistics and supports scientific studies and inquiries from individual doctors. A prospective evaluation of 300 consecutive operations demonstrated good compliance of the doctors and high data quality. To achieve optimal benefit from the use of computers it is recommended that departmental communication and documentation systems be gradually built up in surgical departments.

Attitude of Health Personnel↗
PubMed1993

Prospective evaluation of prognostic scoring systems in peritonitis. Peritonitis Study Group.

OBJECTIVE: To assess the accuracy of the APACHE II score, the Mannheim Peritonitis Index (MPI), and the Peritonitis Index Altona (PIA) II in the prediction of outcome of patients with peritonitis. DESIGN: Prospective, multicentre study. SETTING: 12 Departments of Surgery in Europe. SUBJECTS: 271 Patients with peritonitis confirmed at laparatomy. INTERVENTIONS: Computation of the three scores on one set of data for each patient. MAIN OUTCOME MEASURES: The ability to predict death or survival within 30 days of operation with each of the three scores. The prediction were evaluated according to the following criteria: discriminatory ability (areas under the receiver-operator characteristic (ROC) curves relating sensitivity to specificity); sharpness (level of confidence that was associated with a prediction); and reliability (agreement between predicted and observed mortality within equidistant intervals on the scale). RESULTS: APACHE II was superior to both the MPI and PIA II in its discriminatory ability and reliability, but the MPI and PIA II made more "sharp" predictions. CONCLUSIONS: None of the three scores is of any use for predicting the outcome for individual patients. APACHE II is the current standard for assessing the severity of peritonitis.

Adult↗
PubMed1992

[Cholecystectomy through laparotomy].

Laparotomy cholecystectomy is the "gold standard operation". Its mortality is almost nil. Its morbidity dramatically decreased while digestive surgery was improving. Alternative therapies are to be compared to it. Indications of laparotomy cholecystectomy remain frequent today but will decrease promptly due to the functional and cosmetic benefits of coelioscopic cholecystectomy.

Cholecystectomy↗
PubMed1992

Peptic ulcer bleeding: medical and surgical point of view. Results of a prospective interdisciplinary multicenter observational study. DUSUK Study Group.

Various treatment policies and clinical disciplines compete for the treatment of bleeding peptic ulcer. In a prospective multicenter and interdisciplinary study performed during a 1-year period at ten hospitals in Düsseldorf, all patients admitted for peptic ulcer bleeding were recorded. The characteristics of patients admitted to surgical and to medical departments, the distribution of endoscopic treatment, indications for surgery, type of surgical procedures, and outcome were investigated. In the study period 387 bleeding peptic ulcers were recorded. Of these patients 82% were primarily admitted to medical and 18% to surgical departments. No differences in terms of severity of ulcer disease or bleeding activity were noted between the groups of medical and surgical patients. However, accompanying or underlying diseases were detected more often in patients admitted to medical departments. Endoscopy treatment was performed in the majority of patients with arterial spurting bleeding (88%) or a visible vessel (80%). Injection therapy with epinephrine or polidocanol was mainly used (78%). In 16% of cases the patients underwent operation; 44% of the patients primarily admitted to a surgical department were operated (medical departments, 10%). About half of the operated patients underwent emergency surgery; in the majority of cases resections were performed (gastric ulcer, 76%; duodenal ulcer, 56%). Overall mortality was 11%, with no difference between surgical and medical patients. A high mortality was observed in the subgroup of patients with late recurrent bleeding (27%). It is concluded that for optimal treatment of peptic ulcer bleeding intensive cooperation between physicians and surgeons is necessary, and that agreed and evaluated treatment policies are needed.

Aged↗
PubMed1992

[Sonomorphology of stress cholecystitis].

Acute acalculous cholecystitis is a well-known complication in postoperative and particularly in severely traumatized unit patients. All that is known so far of "stress"-cholecystitis is based on episodic case reports and retrospective analyses. An incidence between 0.5 and 4.2%, a complicated clinical course and a lethality up to 75% have been reported. In intensive-care unit patients a clinical diagnosis of suspected acute cholecystitis is rarely reliable; greater reliance is placed on the ultrasound findings as seen in our prospective study. According to the literature, the established ultrasound criteria of cholecystitis include: hydrops, thickening of the gallbladder wall, sludge, subserosal oedema, pericholecystic fluid collection and fragmentation of the gallbladder wall. Other factors, however, may also lead to morphological changes of the gallbladder, and hence there is no agreement about the definitive sonomorphology of this entity. The variability of sonomorphological criteria is reviewed and compared to the results of a series of our own.

Acute Disease↗