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Biomedical subjects

E Hahn

Publications and source records attributed to E Hahn.

At least 37 records · Page 2Linked to original sources
PubMed1994

Development of the emergency physician job satisfaction measurement instrument.

The objective of this study was to develop a valid and reliable instrument to measure the job satisfaction of physicians practicing emergency medicine. A prospective survey involving four separate stages (an item evaluation and reduction stage, a factor analysis stage, a construct validity stage, and a reliability stage) was distributed in Canada to full-time emergency physicians. Three separate survey instruments were administered (an initial draft instrument with 228 items, a pilot instrument with 142 items, and the final instrument with 79 items). Construct validity of the final instrument was tested by evaluating the correlation between physician scores on the instrument, and scores on two instruments measuring the same construct, and three measuring different but related constructs. A draft instrument with 228 items and six hypothetical domains was tested on 61 physicians. Evaluation for frequency endorsement, redundancy, and homogeneity reduced the item pool to 157. The remaining 157 items were used as a pilot instrument and tested on 223 physicians. Factor analysis eliminated 66 items from the pilot instrument, creating a final instrument with 79 items, 11 factors, and six domains. Cronbach's coefficient alpha for the final instrument domains is 0.81, and all domain-total correlations are greater than 0.4. All correlations between the final instrument and the construct validity instruments were statistically significant (P < .001), but not so high that they appeared to be measuring the same thing. Correlations between instruments measuring the same construct were higher than those measuring related but different constructs. Correlations between the final instrument and the CES-D scale, emotional exhaustion, and depersonalization subscales of the Maslach Burnout Inventory were negative. A test-retest reliability study on 42 physicians showed Pearson's correlation coefficients for individual domains were all greater than 0.7 and greater than 0.8 for the final instrument. This study has produced a valid and reliable instrument for measuring emergency physician job satisfaction, which is both internally consistent and stable.

Canada↗
PubMed1993

Bird feathers as bioindicators in areas of the German Environmental Specimen Bank--bioaccumulation of mercury in food chains and exogenous deposition of atmospheric pollution with lead and cadmium.

Feathers of selected bird species are used as pollution integrating biomonitors in areas of the German Environmental Specimen Bank. Lead, cadmium and mercury are analysed by Zeeman Solid Sampling AAS in feather vanes of selected bird species with different ecologies. In feather vanes there are quite different distribution patterns of lead and cadmium on the one hand and mercury on the other: lead and cadmium show strong gradients with respect to feather parts with high exposure to atmospheric influences. In contrast to this, mercury is distributed homogeneously. These different distribution patterns of lead and cadmium in feather vanes, in contrast to mercury, show that there are quite different incorporation paths. Cadmium and lead are deposited exogenously and indicate atmospheric pollution. Mercury in feathers is caused endogenously by food and physiology. Most of the mercury analysed in bird's feathers is in the ecotoxic methylated form and the contents in feathers depend on bioaccumulation in food chains. Feathers are suitable indicators for monitoring heavy metal pollution and give us information about incorporation paths and ecotoxic effects.

Aging↗
PubMed1993

Bedside cardiovascular examination in patients with severe chronic heart failure: importance of rest or inducible jugular venous distension.

OBJECTIVES: The aim of this study was to determine the sensitivity, specificity and utility of the cardiovascular examination in predicting cardiac hemodynamics in patients with advanced chronic congestive heart failure. BACKGROUND: Although the physical signs of acute left heart failure have been shown to correlate relatively well with cardiac hemodynamics, their reliability in estimating hemodynamics in patients with chronic heart failure has recently been questioned. METHODS: We prospectively recorded the history, cardiovascular physical signs present at bedside examination and the hemodynamic measurements obtained at right heart catheterization in 52 patients with chronic congestive heart failure undergoing in-hospital evaluation for possible heart transplantation. In addition, we obtained chest radiographs and multigated nuclear scans for the evaluation of left ventricular function. RESULTS: Pulmonary rales, a left ventricular third heart sound, jugular venous distension and the abdominojugular test, when positive, indicated higher right heart pressures and lower measures of cardiac performance. The presence of jugular venous distension, at rest or inducible, had the best combination of sensitivity (81%), specificity (80%) and predictive accuracy (81%) for elevation of the pulmonary capillary wedge pressure (> or = 18 mm Hg). Furthermore, in this population sample, the probability of an elevated wedge pressure was 0.86 when either variable was present. CONCLUSIONS: The bedside cardiovascular examination in the patient with chronic heart failure is extremely useful in identifying patients with elevation of right and left heart pressures. Examination for jugular venous distension at rest or by the abdominojugular test is simple and highly sensitive and specific in assessing left heart pressures in these patients.

Adult↗
PubMed1992

Superiority of a vertical sternal lead for detection of arrhythmias during ambulatory electrocardiographic monitoring.

In a preliminary study comparing 7 sets of bipolar leads with standard modified V1 and V5 leads, a vertical sternal lead system with the negative lead just below the suprasternal notch, and the positive lead over the xiphoid had the greatest P-wave area. In the current study, the vertical sternal and modified V1 leads were obtained simultaneously using 2-channel ambulatory electrocardiographic recorders in 50 consecutive patients undergoing diagnostic ambulatory electrocardiography for suspected arrhythmias. The vertical sternal lead provided tracings with a larger P-wave area compared with that of the modified V1 (0.58 +/- 0.44 vs 1.23 +/- 0.69 mm2; p less than 0.0001), and a greater QRS complex (9.23 +/- 4.16 vs 11.78 +/- 4.90 mm; p = 0.006). During premature atrial contractions and supraventricular tachycardia, P-wave visibility was significantly better in the sternal lead than in V1 (p less than 0.001). Furthermore, sternal lead tracings were superior with regard to overall quality and noise level. It is suggested that the vertical sternal lead replace the currently used modified V1 during ambulatory electrocardiographic monitoring. This lead system in conjunction with the standard modified V5 lead should be useful in the differential diagnosis of atrial arrhythmias.

Adolescent↗
PubMed1992

Dissociation of atrioventricular conduction and refractoriness following application of radiofrequency energy to the canine atrioventricular node: acute and chronic observations.

The electrophysiology of AV nodal modification induced by radiofrequency energy (n = 5) or a sham procedure (n = 5) was studied in ten dogs. The five dogs that received radiofrequency energy had an AH prolongation > 100% from baseline values and this prolongation persisted throughout the 2-month study. The AV nodal functional refractory period was prolonged only acutely. These data indicate a dissociation between the effects on AV nodal conduction and refractoriness that was induced by this procedure. The five sham treated controls showed no acute or chronic electrophysiological changes. In the dogs that received radiofrequency energy, there was fibrosis of the approaches to the AV node and the region of the AV node itself. It is concluded that chronic modification of AV nodal conduction without concomitant changes in refractoriness can be induced by radiofrequency energy delivered in the proximal portion of the AV node. It would be anticipated that this procedure would not decrease the ventricular response to atrial fibrillation or flutter, may be effective in preventing AV nodal reentrant tachycardia by interfering with conduction either in the AV node or perinodal region. Since the AV node itself suffers at least moderate pathological damage, there may be an appreciable incidence of the late development of complete heart block after this procedure.

Animals↗
PubMed1992

Evaluation of electrocardiographic leads for detection of atrial activity (P wave) in ambulatory ECG monitoring: a pilot study.

The usual lead systems for ambulatory ECG monitoring (AECG) used in the evaluation of arrhythmias is a modified bipolar V-1 and V-5. A comparison of various lead systems to enhance the detection of atrial activity (p waves) has not been reported. We evaluated various surface lead systems in 12 subjects comparing p waves recorded at 20 mm/mV and 50 mm/sec. We compared p wave area, amplitude, and duration from modified bipolar V1 and V5 as well as seven nonstandard leads recorded on a AECG monitor. Of the seven nonstandard leads, a vertical sternal lead, with the negative pole just below the suprasternal notch and the positive pole at the xiphoid process, had the largest area (1.46 +/- 0.65 mm2), and also had a greater area than the standard V1 (0.88 +/- 0.45 mm) and V5 (1.06 +/- 0.49 mm2) lead system (P less than 0.01). We conclude that the bipolar vertical sternal lead system provides a larger p wave area than seven nonstandard bipolar lead systems and the two standard lead systems currently used in AECG monitoring. Replacement of the modified bipolar V1 lead with a vertical sternal lead should improve the recognition of atrial activity and, therefore, enhance the diagnosis of cardiac arrhythmias.

Adult↗
PubMed1991

Comorbidities and perioperative complications among patients with surgically treated benign prostatic hyperplasia.

We address the question of whether or not age and comorbidity are related to intra- and postoperative complications after a transurethral resection. The data are derived from a retrospective, population-based study conducted in Hagen, Germany, which included all patients with an initial prostatectomy for benign prostatic hyperplasia (N = 621) during the five-year period 1984-1988. Seventy-seven percent of the patients had at least one of the following preoperative risk factors: heart disease, hypertension, smoking, chronic obstructive lung disease, and diabetes. There was no intraoperative death. The risk of intraoperative circulatory complications was found to be related to age only for patients without a history of heart diseases or hypertension. The incidence of major complications was 3.1 percent and was significantly higher in the oldest age group. Three patients (0.54%) died postoperatively in the hospital. Infections were the most frequent postoperative complications. The relationship of age and overall postoperative complications was not statistically significant either for patients with (p = 0.121) or without any comorbidity (p = 0.651). Based on this study it seems reasonable to conclude that age is not a clinically relevant risk factor for perioperative complications in patients who have a transurethral resection for benign prostatic hyperplasia.

Age Factors↗
PubMed1991

Factors associated with binocular single vision in microtropia/monofixation syndrome.

We reviewed the charts of 398 patients with microtropia/monofixation syndrome to determine what factors influence the level of binocularity attained. Most patients (82%) exhibited some degree of stereoacuity. Patients with a later age at presentation of the initial deviation were more likely to exhibit stereoacuity (p less than 0.001). Patients with smaller initial deviations were also more likely to exhibit stereoacuity (p = 0.016), as were those with smaller manifest deviations on final testing (p less than 0.001). Patients with amblyopia on final testing were less likely to demonstrate stereoacuity (p = 0.0001). Generally, the more intervention required in the form of optical or surgical correction, the poorer the level of binocularity.

Adolescent↗
PubMed1990

Age-related prognosis after acute myocardial infarction (the Multicenter Diltiazem Postinfarction Trial).

The basis for the excess mortality with age after acute myocardial infarction (AMI) is not clear, nor is it known whether the mode of death is altered with age. Age-related factors predictive of mortality and age-related mechanisms of the 333 deaths were examined in 2,466 patients who were enrolled in a placebo-controlled trial to determine the effect of diltiazem on mortality and reinfarction after AMI. There were 3 age groups with increasing mortality rates: ages 25 to 49 (n = 499), 50 to 64 (n = 1,228) and 65 to 75 years (n = 739). There was a significant age-related increase in the proportion of patients with baseline risk factors. These baseline characteristics did not differ by treatment (placebo vs diltiazem). However, multivariate survivorship analysis still identified age as an independent risk factor for cardiac death. The proportion of arrhythmic and myocardial failure deaths did not differ by treatment or age group.

Adult↗
PubMed1990

The prognostic significance of first myocardial infarction type (Q wave versus non-Q wave) and Q wave location. The Multicenter Diltiazem Post-Infarction Research Group.

The prognostic significance of the type of first acute myocardial infarction (Q wave versus non-Q wave) and Q wave location (anterior versus inferoposterior) was determined from a multicenter data base involving 777 placebo-treated patients who were participants in the Multicenter Diltiazem Post-Infarction Trial. There were 224 patients (29%) with a non-Q wave infarction, 326 (42%) with an inferoposterior Q wave infarction and 227 (29%) with an anterior Q wave infarction. Mean left ventricular ejection fraction was significantly (p less than 0.001) lower in patients with an anterior Q wave infarction than in the other two groups (anterior Q wave 0.39; inferior Q wave 0.52; non-Q wave 0.53). Nevertheless, the total cardiac mortality rate during the follow-up period (average 25 months per patient) was only marginally higher (p = 0.42) in the anterior Q wave group (8.4%) than in the other two groups (inferoposterior Q wave 7.1%; non-Q wave 6.3%). The total first recurrent cardiac event was somewhat higher (p = 0.08) in the anterior Q wave group (18.1%) than in the other two groups (inferoposterior Q wave 11.7%; non-Q wave 15.6%). Survivorship analyses extending over 3 years revealed that electrocardiographic classification of the type of first infarction and Q wave location did not make significant independent contributions to the risk of postinfarction cardiac death or first recurrent cardiac event, either before or after adjustment for baseline clinical variables.

Adult↗
PubMed1990

[Statistical evaluation of 60,000 blood alcohol values from 1964 to 1983. III. Multiple convictions].

Between the years 1964 and 1983, 59,226 blood samples with appropriate blood-alcohol concentrations (BAC greater than 0.1 g/kg) were investigated at the Institute for Forensic Medicine at the University of Tübingen. These originated from 47,416 different "culprits", of whom 38,851 (81.9%) were first offenders and 8,565 (18.1%) multiple offenders. The total number of crimes committed by the latter group reached as many as 13. There were fewer women amongst the recurring offenders, the maximum number of offences in this group was 4. The age of the multiple offenders at the time of their first brush with the law was lower than that of single culprits. Their blood-alcohol level at the first offence was similar to that of single offenders, however it increased slightly with each subsequent time. Homotropic traffic offenders were mainly only represented in the group with the lower crime rate. Most multiple offenders proved to be criminal delinquents who were frequently conspicuous not only for criminal--but also for criminal--and traffic violations. In about half the cases the time intervals between 2 offences was under 3 years.

Accidents, Traffic↗
PubMed1989

Energy metabolism in children with newly diagnosed acute lymphoblastic leukemia.

The effect of tumor burden in acute lymphoblastic leukemia on resting energy expenditure, thermic effect of food, and substrate utilization was investigated with open-circuit indirect calorimetry after an overnight fast. Nine patients (six females, three males) ages 6.5 to 15.8 y were studied. Patients were divided into two groups according to their tumor burden at diagnosis (i.e. white cell count, presence or absence of mediastinal mass, or massive organomegaly). The patients with a greater tumor burden had increased energy expenditure. Their resting energy expenditure returned to normal in response to chemotherapy. These results must be interpreted with caution due to the small patients numbers (high tumor burden n = 3; low tumor burden n = 6). Substrate utilization was altered by chemotherapy with an increase in carbohydrate utilization and a decrease in fat oxidation (p less than 0.009). The magnitude of the thermic effect of food tended to increase on treatment (p less than 0.016). Inasmuch as most chemotherapy programs for children last up to 3 y, we believe it is important that the effects of chemotherapy on intermediary metabolism be studied, particularly in relationship to any possible permanent effects on growth and development.

Adolescent↗
PubMed1988

Discontinuous buffer systems optimized for the agarose gel electrophoresis of subcellular particles.

Discontinuous buffer systems operative between pH 5.7 and 7.4, 0 degrees C, were generated, which are characterized by more rapidly displaced moving boundaries than applied previously. These allow one to resolve subcellular particles relatively rapidly and at relatively low agarose gel concentrations. A commercial mixture of DNA restriction fragments pre-stained with ethidium bromide was found to be a suitable tracking dye for these boundaries.

Buffers↗
PubMed1988

Linear Ferguson plots of polystyrene sulfate size standards for the quantitative agarose gel electrophoresis of subcellular particles.

Accurately standardized commercial polystyrene sulfate particles in agarose gel electrophoresis yield linear Ferguson plots at pH 7.4 over a gel concentration range up to 0.9% agarose which do not exhibit any significant sigmoidal curve elements, using either a discontinuous buffer system or a continuous buffer. Ferguson plots of these standard-sized particles were evaluated using alternatively a linear or convex model, by means of a newly developed set of programs (to be used in conjunction with program M-LAB) which (i) is sufficiently user-friendly to allow for quantitative agarose gel electrophoresis of subcellular-sized spherical particles based on their convex Ferguson plots with the same operational simplicity previously available for linear Ferguson plots only; (ii) simultaneously and interactively analyzes the Ferguson plots of all particles under consideration on the basis of an extended Ogston model.

Electronic Data Processing↗