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Biomedical subjects

C Ohmann

Publications and source records attributed to C Ohmann.

At least 109 records · Page 6Linked to original sources
PubMed1991

Diagnostic emergency endoscopy in upper gastrointestinal bleeding--do we have any decision aids for patient selection?

The benefit of emergency endoscopy and therapeutic policies based on certain stigmata of bleeding has recently been demonstrated in patients with peptic ulcer hemorrhage. Applying a simple method of computer-aided diagnosis to a set of prospective data (n = 571) we investigated the question as to whether information on the history (28 variables) and clinical examination (8 variables) could be used to predict ulcer bleeding or certain stigmata of bleeding, with a view to deciding when to perform an emergency endoscopy in patients with upper gastrointestinal bleeding. The patients were assigned to either a high-risk group (probability greater than 0.50 for ulcer bleeding, arterial bleeding, etc.) or a low-risk group (p less than 0.50), and the prediction was compared with the actual findings at endoscopy. The results were disappointing, with an overall accuracy of 71% for the prediction of bleeding peptic ulcer and 71% for the prediction of a bleeding or non-bleeding visible vessel. Despite a relative risk of 2.8 for "bleeding ulcer" and 2.5 for "visible vessel" in the high-risk group, only 72% of all "bleeding ulcer" patients, and 69% of the "visible vessel" patients could be identified by the model. These results indicate that neither a bleeding ulcer nor stigmata of bleeding can be reliably predicted by the patient's history and clinical examination. Emergency endoscopy should therefore be performed in all patients with gastrointestinal bleeding.

Diagnosis, Computer-Assisted↗
PubMed1990

Prognostic scores in oesophageal or gastric variceal bleeding.

Numerous scoring systems have been developed for the prediction of outcome of variceal bleeding; however, only a few have been evaluated adequately. The object of this study was to improve the classical Child-Pugh score (CPS) and to test other scores from the literature. Patients (n = 82) with endoscopically confirmed variceal bleeding and long-term sclerotherapy were included in the study. Linear logistic regression (LR) was applied to different sets of prognostic variables with regard to 30-day mortality. In addition, scores from the literature were evaluated on the data set. Performance was measured by the accuracy and receiver-operating characteristic curves. The application of LR to all five CPS variables (accuracy, 80%) was superior to the classical CPS (70%). LR with selection from the CPS variables or from other sets of variables resulted in no improvement. Compared with CPS only three scores from the literature, mainly based on subsets of the CPS variables, showed an improved accuracy. It is concluded that CPS is still a good scoring system; however, it can be improved by statistical analysis using the same variables.

Esophageal and Gastric Varices↗
PubMed1989

[The effect of preoperative parenteral nutrition on the perioperative course in patients with esophageal cancer].

In 35 consecutive patients who underwent esophagectomy for malignancy the nutritional status was evaluated. 15 patients were estimated to be malnourished and were therefore treated by total parental nutrition (TPN) for 7 days. In the control group (n = 20, no TPN) the nutritional status was normal. TPN corrected abnormal serum parameters with short half-life time. Therefore the nutritional status of both groups was equal at time of operation. The postoperative clinical outcome of both groups was as follows: In TPN-treated patients postoperative hospital stay for 26 days was shorter compared to 32 days in controls, no patients died (vs n = 4), no patient developed sepsis (vs n = 4), no patient developed acute renal failure (vs n = 3). These differences did not reach levels of significance due to the small patient groups. In conclusion our study shows that patients with esophageal cancer and regarded as well nourished seemed to suffer from nutritional deficits. Assessment of the nutritional status by commonly used nutritional parameters does not reveal these deficits.

Adult↗
PubMed1989

Preventing recurrent postoperative adhesions: an experimental study in rats.

A peritoneal lavage model, cyclic intraperitoneal lavage (CIPL), and other adhesion preventing methods with and without fibrinolytic agents were compared to a control group without treatment in an animal study. The adhesion-preventing effect was evaluated at the site of a standardized peritoneal defect (free peritoneal grafting, P) and at the laparotomy wound (L) of 60 rats (12 escape) after surgical lysis of primary adhesions during relaparotomy In five test groups with different treatments and in a control group without treatment recurrent adhesions were investigated during relaparotomy according to an adhesion grading scale with increasing severity (O-III). In the control group only severe adhesions grade II and III were observed. The five test groups showed different distributions of grade 0-II adhesions: compared to the control group a significant difference of the preventing effect was seen after CIPL with 1.36% glucose solution (as used for peritoneal dialysis) and after CIPL with Ringer's solution at the sites P and L, after a one-time irrigation with Ringer's solution only at the peritoneal graft P. Fibrinolytic agents used in CIPL or as single dose application failed to show an improvement compared to the control group.

Animals↗
PubMed1989

[Computer-assisted documentation in upper gastrointestinal endoscopy: experiences with routine use at 3 clinics].

The introduction of powerful and inexpensive personal computers (PC) enabled us to develop a documentation system for upper gastrointestinal endoscopy. The system was programmed using the database management system dBASE III. It works on-line, and no computer knowledge or additional staff is needed to run the system. It is now routinely used in the endoscopic units of three different hospitals. Features of performance are a menu-driven data input, automatic report generation and record retrieval, listing according to different criteria as well as other dBASE III facilities. This paper deals with the quality, time effort and user acceptance of the PC-aided system in clinical routine. The analysis showed a good data quality with respect to completeness and adequate use of terminology. Reliability and validity of the documentation were satisfactory considering the methodological problems encountered at their determination. The system was generally judged useful, but time effort was increased compared to conventional documentation.

Documentation↗
PubMed1989

[Various strategies in the diagnosis and therapy of thyroid gland cancer. Results of a survey].

In a questionnaire we compared generally adviced therapeutical and technical procedures in patients with thyroid carcinomas with the actually favorized strategy of the clinically active surgeons. At present, sonography and cytology are not favored as preoperative diagnostic tools by the questioned surgeons. Hemithyreoidectomy as primary procedure in suspicious nodules is performed only seldomly. In the treatment of thyroid carcinoma total thyroidectomy is the accepted procedure and the possibility of restricted radicality in the treatment of papillary thyroid carcinomas has gained wide acknowledgement. Most surgeons prefer to visualize the recurrent nerve and at least one or two parathyroid glands. Autotransplantation of parathyroid glands with insufficient blood supply is considered only seldomly.

Adenocarcinoma↗
PubMed1988

Prediction of risk for pseudoallergic reactions and histamine release in patients undergoing anaesthesia and surgery: a computer-aided model using independence-Bayes.

A computer-aided model for the prediction of pseudoallergic reactions was developed using prospective data collected from 581 patients in a controlled clinical trial examining pseudoallergic reactions to the plasma substitute Haemaccel (outdated formulation). The multivariate analysis of 22 proposed risk factors was performed using Bayes theorem. This enabled the accurate prediction of 86% of the patients who had a systemic reaction. The clinical use of such system would enable a selection of patients to receive the effective prophylactic measure of pretreatment with H1 plus H2-receptor antagonists.

Anesthesia↗
PubMed1988

Do the stigmata of recent haemorrhage have additional prognostic value in patients with bleeding duodenal ulcer?

To assess the additional prognostic value of endoscopic stigmata of recent haemorrhage (SRH) in addition to clinical data, a pilot study was conducted on 207 duodenal ulcer patients from the OMGE survey. The incidence of SRH was compared in 145 patients who settled and 62 who re-bled. Only active bleeding emerged as significantly commoner in the latter group. Two computer-assisted predictions of further bleeding (before and after addition of the stigmata to a clinical database) were compared with the final outcome. Little improvement, in terms of prognosis for further bleeding, was obtained when SRH data were added. Similar findings were observed in a smaller series from Marburg, FRG.

Diagnosis, Computer-Assisted↗
PubMed1988

[Perioperative risk from the viewpoint of the surgeon. Analysis and clinical use].

General definitions are proposed in this paper for the terms of risk and risk factor. Risks are then analysed, with reference to the literature, on the basis of the defined terminology. Possible approaches are then demonstrated for clinical translation of risk analyses into appropriate therapeutic concepts, with reference being made to a study of oesophageal carcinoma. The benefit has been persuasively reflected in reduced lethality.

Colonic Neoplasms↗
PubMed1988

[Computer-assisted diagnosis].

Numerous models of computer-aided diagnosis have been developed. However, only a few are used in the clinical routine. The methodology of computer-aided diagnosis is described briefly in this paper and a survey of clinical applications is given. Standards for evaluating these models are proposed and illustrated by examples. The inadequate assessment of most diagnostic systems is one of the main reasons for their limited clinical use. New methodological and technical developments will lead to more clinical applications, if the systems are evaluated adequately.

Diagnosis, Computer-Assisted↗
PubMed1987

[Biomedical and clinimetric approaches in determining the causes of perioperative risk: developing a German ASA classification].

Perioperative risk research with biomedical (biochemical, physiological) methods must grow up as a main topic in surgical research. However, operative risk has also to be analysed with methods of clinimetrics, such as formal (objective) decision making and epidemiology. Only by this way a convincing practical dimension is added to basic scientific statements. ASA-classification of the preoperative physical status is a global index for estimating the operative risk. It contains objective findings, subjective impressions and the final clinical judgement. For this reason it is so flexible. For a multicentre trial on perioperative risk and histamine an empirical index was constructed using both the ASA-classification and the Mannheim-Munich risk check list.

Germany, West↗
PubMed1987

[Quantifications of perioperative risk].

In this paper standardized and quantitative definitions of perioperative risk and risk factor using probabilities are given. A calculation of risk and risk factors is performed using data from a study on perioperative risk in colon resection and a study on a preoperative risk check in general surgery. The problem of one risk factor, a combination of two risk factors and the use of many risk factors to quantify preoperative risk is discussed. Confidence intervals are recommended as a standard method for presenting statistical results on perioperative risk.

Colonic Diseases↗
PubMed1987

Reliability and practicability of the fluorometric-fluoroenzymatic histamine determination in pathogenetic studies on peptic ulcer: detection limits and problems with specificity.

Histamine, among various "biologic-physiologic" abnormalities, is considered as a pathogenetic factor in chronic duodenal ulcer disease. The 10-30 per cent difference between its concentration in gastric and duodenal mucosa of patients compared to healthy controls, however, has to be demonstrated to be specific for the disease. It has to be shown to be neither a methodological artefact nor a common effect, concomitant factor or consequence. This study, after a series of pathogenetic trials examines systematic errors (biases) in the fluorometric-fluoroenzymatic histamine assay under the conditions of field studies including tests on specificity over a time period of 10 years. It concentrates on sensitivity (detection limits) and specificity of a standard technique described herein. A modified Shore procedure for large scale assays in human biopsies was developed including reference luminescence values for all reagents, cleaning material and glassware, reduction of OPD concentration to 0.05%, purification of n-heptan, omission of centrifugation steps in the extraction procedure and use of 2 ml 1 M HClO4 in the homogenization step to prevent losses of histamine due to adherence to the mechanical homogenizer. This assay was sensitive enough to measure histamine without difficulty in any biopsy taken. The detection limit was 3 ng/biopsy, but the smallest quantities of the amine ever obtained were 10.6 and 18.3 ng/biopsy (depending on both histamine content and biopsy weight). A series of problems had to be solved both in achieving and demonstrating specificity. It had to be defined not only for the assay in general, but also for assessing the difference in histamine content between ulcer patients and healthy controls. Exogenous more than endogenous fluorescing material interfering with the determination had to be excluded. A series of pitfalls were detected which had to be overcome in demonstrating the specificity of the assay by physicochemical and enzymatic tests. The specificity of the identification tests was more often impaired than the histamine assay itself. Fluorescing material interfering with the assay occurred in the homogenization, extraction and condensation steps, was found in water, OPD, the organic solvents, the cleaning material and in all kinds of plastic vessels. Plasticizers were shown by physicochemical characteristics including fluorescence spectra to be most likely responsible for this interfering material. Rules were developed to exclude such hazards in specificity in longterm pathobiochemical studies. Enzymatic identification test were applied to exclude endogenous fluorecing substances interfering with the standard technique. Simil

Biopsy↗
PubMed1987

[Principles of risk research in surgery: definition, calculation and clinical use in the problem of upper gastrointestinal hemorrhage].

In surgery, risk research is of great importance at the present time but is controversely discussed with contradictory definitions, calculations and applications. In this paper standardized and quantitative definitions of risk and risk factors using probabilities are given. A calculation of risk, risk factors and risk rates is performed using data from studies on bleeding duodenal ulcers. Possible applications of risk and risk factor research (risk analysis) in suitable treatment policies are demonstrated using data from patients with bleeding duodenal ulcers. The utility of this type of approach, using decision tree analysis, clearly manifests itself in the reduction of lethality. Objective and quantitative surgical risk research and its application as risk analysis using probabilities can improve patient care in standard surgical situations.

Duodenal Ulcer↗
PubMed1986

[Principles of surgical indications: aids in decision making].

Several types of clinical studies provide important decision aids for surgical indications. They include quantitative data on outcomes and utility analysis, graphic illustration of the various possibilities for decisions by decision trees, controlled clinical trials with data used in decision trees and--if these trials fail for several reasons--carefully conducted and documented prospective and retrospective trials. Items for defining the term "surgical indication" were illustrated by constructing a decision tree for treatment of chronic duodenal ulcer.

Diagnosis↗
PubMed1985

Thyroid function after surgery for autonomous and non-autonomous nodular endemic goitre--effect of iodide-substitution.

The aim of this study was to evaluate the influence of postoperative iodide-substitution on the function of thyroid remnants of different quality and quantity in order to define the appropriate prophylaxis (iodide or thyroid hormone) to prevent recurrent goitre. In a prospective, randomized clinical trial, the following patients were examined: group I: simple, non-autonomous nodular goitre, bilateral thyroidectomy (n = 40); group II: simple, non-autonomous nodular goitre, "selective" (unilateral) thyroidectomy (n = 40); group III: autonomous nodular goitre, bilateral thyroidectomy (n = 40); group IV: autonomous nodular goitre, "selective" (unilateral) thyroidectomy (n = 35). The following parameters were measured 6 and 12 weeks postoperatively. Serum-total-T4, -T3, -TSH, TRH-test, 99mTc-Thyroid-Uptake (TcTU). Six weeks postoperatively the 4 groups were separately randomized into controls and treatment groups, who received 200 micrograms iodide/day orally. Six weeks postoperatively, patients in group I had lower T4 levels and both basal and stimulated TSH were higher than in the other groups, however no significant differences were observed in T3, T4/T3 ratio and TcTU. Twelve weeks postoperatively patients from groups I, II and III, who had been treated with iodide, had lower T3 and TcTU values but higher T4 and T4/T3 than the appropriate controls. Basal and stimulated TSH showed no differences between controls and iodide-treated patients in these groups. In group IV, T4 and T3 showed a tendency to elevation (n.s.), and basal and stimulated TSH as well as TcTU were lower in patients with iodide.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗