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Biomedical subjects

K Ulm

Publications and source records attributed to K Ulm.

At least 19 recordsLinked to original sources
PubMed2003

Estimation of the general threshold limit values for dust.

In 1997 the German MAK Commission set new general threshold limit values for dust. The procedure has recently been assessed (McLaughlin et al. 2001). One of the points raised was the use of inappropriate statistical methods. We want to address this point to a greater extent by discussing several alternatives implied by the already established threshold models, and we present results from a new approach that has been refined in the meantime: the use of the additive isotonic model. The underlined assumption of monotonicity regarding the dose-response relationship has been extensively investigated. One very flexible model, based on smoothing splines, shows in some of the samples a decline in the risk over a certain range of the exposure compared to the risk at baseline. Another approach with fractional polynomials and segmented regression lines shows that this result can be explained by chance. These methods show an increasing risk with increasing exposure. Additionally, permutation tests are used to prove the trend within the isotonic framework. The results from the additive isotonic model confirm previous assessments of the general threshold limit value.

Dose-Response Relationship, Drug↗
PubMed2003

[The use of muscle relaxants for routine induction of anesthesia in Germany].

The aim of this study was to evaluate the use of muscle relaxants during induction of anesthesia in patients without risk of aspiration of stomach contents. Of the 2,996 questionnaires sent out, 2,054 (68.6%) could be analysed and the results show that succinylcholine is used regularly in 13.6% of anesthesia departments. The next most commonly used muscle relaxants are atracurium, vecuronium and mivacurium, followed by cis-atracrium, rocuronium and pancuronium. Alcuronium is the least frequently used muscle relaxant. During induction of an elective anesthesia procedure, a priming technique is used by 19% of anesthesiologists, 22% utilize precurarization, and a timing technique is performed in 7.1%. The use of muscle relaxants for on-going relaxation follows the same pattern as for induction of neuromuscular blockade and succinylcholine is used in 1.4% if further relaxation is needed. The desire for specific qualities of muscle relaxants is correlated with higher use of the specific substance: short onset time for rocuronium, good controllability with mivacurium, no side-effects with cisatracurium and economical aspects with alcuronium. Of the participants 76.6% voiced the desire for a non-depolarizing replacement for succinylcholine.Private practices use mivacurium more often than hospitals, level one hospitals use rocuronium and cisatracurium more often. This survey could not show a definite standard of use in terms of muscle relaxants for an elective case.Precurarization, priming and timing are used frequently in patients not at risk of aspiration. This should be reduced by on-going teaching.

Anesthesia↗
PubMed2003

[Application of muscle relaxants in Germany. A survey of German anaesthesia departments].

AIM: The aim of this study was to evaluate the use and application of muscle relaxants and neuromuscular monitoring in Germany. METHODS: A total of 2,996 questionnaires were sent out to the heads of German anaesthesia departments and private anaesthesia practices. The questions covered frequency of muscle relaxants used,how they were used, and neuromuscular monitoring. Influences on the way muscle relaxants were used could be derived from the desire for specific properties of a muscle relaxant, the desire for different monitoring conditions and from the size of the institution. We correlated these features with application practice using logistic regression analyses. RESULTS: Of the 2,996 questionnaires 2,058 could be analysed (68.6%). Amongst those were 102 level one hospitals (5%) and 903 private practices (44%). The replies from 350 (17%) departments were based on surveyed data, 1,613 (78.5%) were based on estimations. The desire for certain properties of muscle relaxants correlated with the use in practice, as were the desire for a non-depolarizing replacement for succinylcholine, the size of the department and the frequency of use of neuromuscular monitoring. Over 50% of all German anaesthesia departments limited the use of muscle relaxants to three. The use of laryngeal masks reduced the use of muscle relaxants. CONCLUSIONS: The survey regarding use of muscle relaxants in Germany could for the first time give an overview on the use of anaesthesia-specific substances in Germany. From the different frequencies of use and use modalities,conclusions could be drawn towards a standard of application for the year 2000. Changes in this standard would raise the need for further trend surveys. The methods of statistical analysis and survey evaluation can be used as a base for further surveys.

Anesthesia↗
PubMed2003

[Application of muscle relaxants for rapid-sequence induction of anaesthesia].

The present study evaluates the use of muscle relaxants for rapid-sequence induction (RSI) and different application techniques (pre-curarisation, priming, timing) as a part of a nationwide survey in Germany. In 86.8% of anaesthesia departments succinylcholine is used for RSI and an average of 56.5% of respondents used only succinylcholine for RSI. Of all non-depolarising muscle relaxants rocuronium is the most frequently used alternative. Of the anaesthesia departments 2.6% use rocuronium regularly in patients with increased risk for aspiration of stomach contents; level one centres significantly more than others, 12.9% answered that pre-curarisation techniques were never used, whereas 45.6% use non-depolarising neuromuscular blocking drugs before giving succinylcholine in 80-100% of cases. Priming is not used by 64.4% of respondents, as opposed to 9.8% who utilise this technique regularly. The statements regarding timing are 71.1% and 5.4%, respectively. Alcuronium is used for RSI in departments in which the financial aspect is the primary decision criteria. Despite ist known side-effects and the on-going discussion over the past years, succinylcholine is still the most frequently used muscle relaxants for RSI. Priming is often declined by anaesthetists in Germany, most probably due to the absence of clear advantages and the possibility of severe complications. It is the opinion of the authors that timing but also drugs with a slow onset (e.g., alcuronium and Pancuronium) are obsolete in the context of RSI.

Alcuronium↗
PubMed2003

[The use of neuromuscular monitoring in Germany].

AIM: As there are no reliable epidemiological data for the use of muscle relaxants in Germany,we conducted a mailing study. The aim of the study was to compare the use of muscle relaxants between German anaesthesia departments. In the present part of the presentation we focused on neuromuscular monitoring (NMM) and management of residual paralysis. METHODS: A total number of 2,996 questionnaires were sent to all registered anaesthesiological facilities in Germany and the return was 68.6% (2054 questionnaires). RESULTS: In 574 of the returned questionnaires (28%) the regular use of NMM was confirmed. Intraoperative monitoring of neuromuscular block and assessment of neuromuscular recovery were the most frequent applications of NMM, i.e. 25% and 18% of returned questionnaires, respectively. Clinical signs, however, are still the most popular way to estimate the degree of neuromuscular blockade. Moreover, routine reversal at the end of surgery with a neostigmin/atropine mixture was not practiced in 75% of the anaesthesia departments. CONCLUSIONS: This survey revealed that NMM is still very rarely used in daily clinical practice. Especially the seldom use of NMM to assess residual paralysis has to be improved.

Anesthesiology↗
PubMed2002

Cardiovascular function of workers exposed to carbon disulphide.

OBJECTIVES: The aim of the study was to verify that exposure to carbon disulphide (CS(2)) up to 10 ppm results in a negative inotropic effect on cardiovascular function. METHODS: In a cross-sectional study a total of 325 workers exposed to CS(2) in the rayon-producing industry and 179 controls from the same plants were examined. The exposure assessment was based on personal air sampling and biological monitoring (2-thiothiazolidine-4-carboxylic acid (TTCA) in urine) for all persons. The examination consisted of a standardised questionnaire, physical examination, assessment of body fat mass, ergometric test with the determination of work capacity at heart rates of 100, 130, 150 and 170 beats/min, and electrocardiography. RESULTS: The mean external exposure was 6.04 ppm CS(2) (range: 0.03-91.08); the mean internal exposure was 1.14 mg TTCA/g creatinine (range: 0.02-11.50). The workers exposed to CS(2) showed better physical fitness. The diameters of the left heart chamber of the exposed persons were not significantly different when compared with occupationally non-exposed workers, but there was a tendency of increasing diameters for the exposed employees. In the multiple linear regression the diameters showed physiologically plausible correlations with the body mass index, body fat mass, alcohol consumption, and physical fitness, but not, however, with the exposure, neither with the exposure group in all persons nor with the internal or external exposure within the exposed workers. CONCLUSIONS: In this study, differences in the heart chamber diameters between exposed persons and controls could not be confirmed. Differences in physical fitness and constitution can explain differences in heart chamber diameters.

Adult↗
PubMed2002

Accuracy of endoscopic ultrasonography in upper gastrointestinal submucosal lesions: a prospective multicenter study.

BACKGROUND: Endoscopic ultrasonography (EUS) is commonly agreed to be the best imaging method for diagnosing and differentiating between submucosal lesions in the gastrointestinal tract. However, most of the current evidence for this derives from retrospective multicenter studies. A prospective multicenter analysis of the performance of EUS in diagnosing submucosal lesions in everyday practice was therefore conducted. METHODS: Over a 2-year period, this study included 150 patients (52% men, mean age 59.8 years) from 23 centers who had a presumptive diagnosis of a submucosal lesion on upper gastrointestinal endoscopy. The patients' symptoms and EUS results were recorded. Endoscopic and endosonographic findings regarding lesion size, layer of origin, and the presumptive diagnosis (benign or malignant) were recorded. The reference methods used were surgery, biopsy, other imaging tests, and a follow-up period of 6 months. RESULTS: Of the 150 patients, 102 had an intramural lesion (84 tumors, 18 other lesions such as cysts, aberrant pancreas, etc.), and 48 had an extraluminal compression--in most cases (n = 35) by normal organs or structures. For differentiating between a submucosal and an extraluminal compression, the sensitivity and specificity of endoscopy were 87% and 29%, whereas those of EUS were 92% and 100%. However, the sensitivity and specificity of EUS for differentiating between malignant and benign submucosal tumors were only 64% and 80%, respectively. CONCLUSIONS: The accuracy of EUS in differentiating between submucosal tumors and extraluminal compressions is substantially superior to that of endoscopy, but EUS is still inadequate for differential diagnosis between benign and malignant submucosal tumors. However, EUS is still the best method of visualizing submucosal lesions precisely. The influence of EUS on the further management in these patients remains to be examined in subsequent studies.

Adolescent↗
PubMed2001

Neoadjuvant chemotherapy followed by tumor debulking prolongs survival for patients with poor prognosis in International Federation of Gynecology and Obstetrics Stage IIIC ovarian carcinoma.

BACKGROUND: Patients with advanced ovarian carcinoma of International Federation of Gynecology and Obstetrics (FIGO) Stage IIIC should be treated by radical surgical tumor debulking with the goal of complete tumor resection. Prolonged median survival can be achieved in those patients entirely free of tumor after surgery by the administration of postsurgical platinum/taxane-based chemotherapy regimens. However, residual tumor is present in the majority of patients, which limits survival prognosis. Different therapy approaches should be utilized to improve prognosis in these patients. Neoadjuvant chemotherapy could induce "downstaging" of the tumor and thus improve operability. Here, evidence of large ascites volume (>500 mL) can be used to identify those patients who could benefit from neoadjuvant chemotherapy. METHODS: In a prospective, nonrandomized Phase II study, 31 patients with advanced FIGO Stage IIIC ovarian carcinoma and large ascites volume (>500 mL) received 3 cycles of platinum/taxane-based combination chemotherapy, followed by tumor debulking surgery and 3 additional cycles of platinum/taxane-based combination chemotherapy. During the same period, 32 patients with advanced FIGO Stage IIIC ovarian carcinoma and large ascites volume (>500 mL) received conventional therapy (tumor debulking surgery followed by 6 cycles of platinum/taxane-based combination chemotherapy). The two groups were investigated and compared with respect to tumor resection rates, blood transfusion requirements, morbidity, and mortality during surgery, duration of surgery, and median survival. RESULTS: The tumor resection rate in the patient group receiving neoadjuvant chemotherapy was significantly higher (P = 0.04) than that of the conventionally treated group; the median survival time of 42 months versus 23 months also was significantly longer (P = 0.007). Time spent in surgery, blood transfusion requirements, morbidity, and mortality during surgery were not significantly different. CONCLUSIONS: Patients with advanced ovarian carcinoma of FIGO Stage IIIC who will benefit only marginally from conventional therapy can be identified by evidence of large ascites volume. Higher tumor resection rates and longer median survival can be achieved in these patients by the use of neoadjuvant chemotherapy. A prospective randomized multicenter study currently is being performed by the Society for Gynecological Oncology in Germany to confirm these findings.

Aged↗
PubMed2001

Restenosis after coronary placement of various stent types.

Coronary stent implantation is being performed in an increasing number of patients with a wide spectrum of clinical and lesion characteristics. A variety of stent designs are now available and continuous efforts are being made to improve the stent placement procedure. The objective of this study was to perform a comprehensive analysis of the relation between clinical, lesion, and procedural factors, and restenosis after intracoronary stenting in a large and unselected population of patients. A consecutive series of 4,510 patients with coronary stent placement was analyzed. Exclusion criteria were only a failed procedure and an adverse outcome within the first month after the intervention. Follow-up angiography was performed in 80% of patients at 6 months. Clinical, lesion, and procedural data from all 3,370 patients (4,229 stented lesions) with follow-up angiography were analyzed in a logistic regression model for restenosis (> or =50% diameter stenosis). Clinical factors contributed to the predictive power of the model much less than lesion and procedural factors. The strongest risk factor for restenosis was a small vessel size, with a 79% increase in the risk for a vessel of 2.7 mm versus a vessel of 3.4 mm in diameter. Stent design was the second strongest factor; the incidence of restenosis ranged from 20.0% to 50.3% depending on the stent type implanted. In conclusion, this study demonstrates the predominant role of lesion and procedural factors in determining the occurrence of restenosis after coronary stent placement. Among these factors, stent design appears to play a particularly important role in the hyperplastic response of the vessel wall.

Analysis of Variance↗
PubMed2001

[Morphological findings and medical insurance aspects in 371 exhumations].

OBJECTIVES: The morphological findings in organ systems following exhumation, form the basis for answering a number of medical insurance issues. The aim of this study was to analyse the development of the number of exhumations performed and the medical insurance relevance over a 31-year-period. METHODS: A total of 371 exhumations, performed between 1967-1998 at the Institute of Pathology, Occupational Associations Hospital, Bochum, for medical insurance reasons were evaluated. RESULTS: The average number of days after burial was 74, ranging from 9 to 47.8. For the first third of the period investigated, the proportion of exhumations was 3.5% of all autopsy cases, for the second third this fell to about 0.4% and rose to 1.5% for the last third. In the first two-thirds, the main reasons for the exhumations were related to the grading and effects of pneumoconioses in connection with the cause of death. In the last third, asbestos-associated diseases were mainly involved. In 99.2% of all cases, the autopsy results revealed important evidence for clarification of the medical insurance issues. The current catalogue of expectations listing the pathomorphological findings which can be expected after certain periods of internment, could be extended by our own results.

Academies and Institutes↗
PubMed2001

Randomized trial of cefotiam prophylaxis in the prevention of postoperative infectious morbidity after elective cesarean section.

A prospective, randomized study was performed in order to evaluate the effect of cefotiam in the prevention of postoperative infectious morbidity in patients undergoing low-risk elective cesarean section. A total of 146 patients were randomly assigned to receive either intraoperative single-shot prophylaxis with 2 g cefotiam (study group, n =76) or no prophylaxis (control group, n=70). Due to a higher rate of urinary tract infections, the incidence of infectious morbidity after cefotiam prophylaxis was higher in the study group than in the control group (16% vs. 9%, P=0.1). Postoperative infectious morbidity following low-risk elective cesarean section cannot be reduced by intraoperative cefotiam prophylaxis.

Adult↗
PubMed2000

Endovascular irradiation from beta-particle-emitting gold stents results in increased neointima formation in a porcine restenosis model.

BACKGROUND: Recent studies have shown that ionizing radiation reduces neointima formation after balloon angioplasty and stent implantation in experimental models of restenosis and first clinical trials. The objective of this study was to determine the dose distribution of a new beta-particle-emitting radioactive gold stent and to evaluate the dose-dependent vascular response in the coronary overstretch pig model. METHODS AND RESULTS: Sixteen Göttinger minipigs underwent placement of 11 nonradioactive and 36 beta-particle-emitting stents with activity levels of 10.4+/-0.6, 14.9+/-2.4, 22.8+/-1.3, 35.8+/-2. 8, and 55.4+/-5.3 microCi of (198)Au. Three months after implantation, the percent area stenosis, neointimal thickness, neointimal area, and vessel injury were analyzed by quantitative histomorphometry. The lifetime radiation doses at a depth of 1 mm were 3.3+/-0.2, 4.7+/-0.5, 7.2+/-0.4, 11.4+/-0.9, and 17.6+/-1.7 Gy for the different activity groups. No dose-response relationship was observed in the radioactive stents with respect to percent area stenosis (P=0.297), mean neointimal thickness (P=0.82), or mean neointimal area (P=0.65). Significantly lower neointima formation and less luminal narrowing was seen in the control group than in the beta-particle-emitting stents (P<0.001). Multilinear regression analysis revealed that only radioactivity made a significant independent contribution to the degree of percent area stenosis (P<0. 001). CONCLUSIONS: Neointima formation in pigs is markedly increased by beta-particle-emitting stents with (198)Au as the radioisotope. This study provides evidence that dosages of 3 to 18 Gy of low-dose-rate beta-particle irradiation via endovascular stents cause pronounced luminal narrowing in the animal model at 3 months.

Animals↗
PubMed2000

Identifying and modelling prognostic factors with censored data.

A major issue in the analysis of diseases is the identification and assessment of prognostic factors relevant to the development of the illness. Statistical analyses within the proportional hazards framework suffer from a lack of flexibility due to stringent model assumptions such as additivity and time-constancy of effects. In this paper we use tree-based models and varying coefficient models to allow for detectability of prognostic factors with possibly non-additive, non-linear and time-varying impact on disease development. Questions concerning model and smoothing parameter selection are addressed. An analysis of a data set of breast cancer patients demonstrates the ability of these methods to reveal additional insight into the disease influencing mechanisms.

Adult↗
PubMed2000

Influence of stent design on 1-year outcome after coronary stent placement: a randomized comparison of five stent types in 1,147 unselected patients.

The objective of this randomized trial was to assess whether differences in stent design are translated in different clinical outcomes in patients undergoing coronary stent placement. This multicenter randomized trial included 1,147 patients who were randomly assigned to receive one of five types of stainless steel stents: Inflow, MULTI-LINK, NIR, Palmaz-Schatz, and PURA-A stent. Primary endpoint of the study was event-free survival at 1 year. Event-free survival at 1 year was significantly different between the groups (P = 0.014), ranging from 69.4% to 82.4%. Similarly, freedom from myocardial infarction was also significantly different (P = 0.022), with values between 88.2% and 95.2%. Diameter stenosis at 6 months varied from 38.1% +/- 25.0% to 45.6% +/- 27.7% (P = 0. 046), late lumen loss ranged from 1.01 +/- 0.70 mm to 1.20 +/- 0.82 mm (P = 0.085), and the incidence of restenosis varied between 25.3% and 35.9% (P = 0.145). Thus, stent design has a significant impact on the long-term results after coronary stent placement.

Aged↗
PubMed2000

Combined transvaginal B-mode and color Doppler sonography for differential diagnosis of ovarian tumors: results of a multivariate logistic regression analysis.

OBJECTIVE: Transvaginal sonography is limited in its ability to assess early stage cancers of the ovary as well as in distinguishing benign processes. As a method for characterization of tumor vascularization, color-coded Doppler sonography may be able to improve the diagnostic accuracy of B-mode sonography. METHODS: Preoperative transvaginal B-mode and Doppler sonography was performed in 63 patients with unclear adnexal lesions prior to operation. Using multiple logistic regression, the independent variables of each procedure were selected and combined to yield a diagnostic flow chart. The diagnostic accuracy of this decision matrix was tested on 257 patients with unclear adnexal tumors. RESULTS: In the 63 adnexal tumors investigated, the diagnostic impact of isolated sonomorphological assessment with evidence of a "solid area" was 78%. Using Doppler sonography, the best discrimination was achieved by displaying the vascular distribution ("central vascularization"). Combining these independent significant variables of the two procedures raised the diagnostic accuracy to 90% (sensitivity 86%, specificity 93%). The validity achieved by this combination was confirmed by the independent application of this method to the 257 adnexal tumors with unclear malignancy status (diagnostic accuracy 93%, sensitivity 92%, specificity 94%). CONCLUSIONS: The combination of sonography and Doppler sonography achieves high and reproducible diagnostic accuracy in preoperative malignancy status assessment of adnexal tumors. The additional use of Doppler sonography can thus provide significant aid both for differential diagnostics of adnexal lesions and for the choice of surgical route in the case of an existing indication for operative therapy.

Adnexal Diseases↗
PubMed2000

Postpartum curettage in patients with HELLP-syndrome does not result in accelerated recovery.

OBJECTIVE: Our purpose was to examine the impact of immediate postpartum curettage on the recovery of patients with HELLP-syndrome (hemolysis, elevated liver enzymes, and low platelets). SUBJECTS: Between January 1994 and July 1997 all patients who presented with HELLP-syndrome in our institution underwent immediate postpartum curettage (n=24). Their outcome was compared with the recovery of women with HELLP-syndrome who were delivered without postpartum curettage between 1987 and 1993 (n=20). Clinical and laboratory data were analyzed. RESULTS: No significant difference could be found between both groups in terms of normalization of serum glutamic-oxaloacetic transaminase (GOT), serum glutamic-pyruvic transaminase (GPT), lactic dehydrogenase (LDH), and quantitative platelet count. Postpartum hospitalization time was identical in both groups. CONCLUSION: In our retrospective study no benefit is achieved by immediate postpartum curettage in patients with HELLP-syndrome. In order to eliminate the possible bias of retrospective analysis, we now plan a randomized study to further investigate the impact of immediate postpartum curettage.

Adult↗