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M Radespiel-Tröger

Publications and source records attributed to M Radespiel-Tröger.

At least 19 recordsLinked to original sources
PubMed2006

Association between split selection instability and predictive error in survival trees.

OBJECTIVES: To evaluate split selection instability in six survival tree algorithms and its relationship with predictive error by means of a bootstrap study. METHODS: We study the following algorithms: logrank statistic with multivariate p-value adjustment without pruning (LR), Kaplan-Meier distance of survival curves (KM), martingale residuals (MR), Poisson regression for censored data (PR), within-node impurity (WI), and exponential log-likelihood loss (XL). With the exception of LR, initial trees are pruned by using split-complexity, and final trees are selected by means of cross-validation. We employ a real dataset from a clinical study of patients with gallbladder stones. The predictive error is evaluated using the integrated Brier score for censored data. The relationship between split selection instability and predictive error is evaluated by means of box-percentile plots, covariate and cutpoint selection entropy, and cutpoint selection coefficients of variation, respectively, in the root node. RESULTS: We found a positive association between covariate selection instability and predictive error in the root node. LR yields the lowest predictive error, while KM and MR yield the highest predictive error. CONCLUSIONS: The predictive error of survival trees is related to split selection instability. Based on the low predictive error of LR, we recommend the use of this algorithm for the construction of survival trees. Unpruned survival trees with multivariate p-value adjustment can perform equally well compared to pruned trees. The analysis of split selection instability can be used to communicate the results of tree-based analyses to clinicians and to support the application of survival trees.

Algorithms↗
PubMed2004

Readmissions and adverse drug reactions in internal medicine: the economic impact.

BACKGROUND: Recent studies show that nearly half of the hospitalized patients are readmitted within 6 months from discharge. No data exist about the relationship between adverse drug reactions (ADRs) and readmittance to a department of internal medicine. OBJECTIVES: The primary aims of the study were to determine if ADRs could be used as predictors for recurrent hospitalizations in internal medicine and to evaluate the economic impact of ADRs on hospitalization costs. DESIGN AND SETTING: A cohort-based, prospective, 18-month pharmacoepidemiological survey was conducted in the Department I of Internal Medicine at the University Hospital of Erlangen. All patients were intensively monitored for ADRs by a pharmacoepidemiological team. ADRs were evaluated for their offending drugs, probability, severity, preventability and classified by WHO-ART. During a 6-month period ADR-positive patients were matched to non-ADR patients applying diagnosis-related group categorization in order to measure the impact of ADRs on the duration and frequency of hospitalization. RESULTS: Of 1000 admissions 424 patients had single admissions and 206 patients had recurrent readmissions (min 1, max 9). The prevalence of readmissions was 37% (n = 370). In 145 (23%) of 630 patients, 305 ADRs were observed. The ADR incidence was similar in first admissions and readmissions. ADRs were not found to predict further readmissions and lack of ADRs did not preclude readmissions. ADRs caused hospitalizations in 6.2% of first admissions and in 4.2% of readmissions. According to the Schumock algorithm 135 (44.3%) ADRs were found to be preventable. The occurrence and numbers of ADRs per admission were found to prolong hospitalization period significantly (r = 0.48 and 0.51, P < 0.001, n = 135). Of 9107 treatment days 20% were caused by in-house (1130 days) and community-acquired ADRs (669 days). In admissions and readmissions 11% (>973 days) of all treatment days were judged to be preventable. CONCLUSIONS: Intensified drug monitoring supported by information technology in internal medicine is essential for early detecting and prevention of ADRs and saving hospital resources.

Adolescent↗
PubMed2004

A simulation model for small-area cancer incidence rates.

OBJECTIVES: Cancer epidemiologists are often asked by members of the interested public about possible associations between suspected carcinogens and apparently increased small-area cancer incidence rates. Frequently, no systematic incidence differences can be demonstrated. Nevertheless, it is necessary to address public concerns about suspected cancer clusters. To facilitate explanations about the large random variation of small-area tumor incidence, we implemented a software simulation tool in R. METHODS: Under the assumption of no cancer causes other than chance, the tool simulates a small village population with an average number of five inhabitants per house and allows graphical visualisation of ten streets with 100 houses. Published age-specific incidence and mortality data are used for event sampling based on the binomial distribution. Program parameters include sample size, age distribution, cancer incidence, and mortality rates. RESULTS: On average, 22 percent (2.2/10) of all houses per street have been inhabited by at least one cancer patient during the last five years in our simulated small village. A situation where all (10) houses in a street have been inhabited by at least one cancer patient during the last five years appears to be very rare (less than one in a million streets). CONCLUSIONS: Our software tool can be used effectively for numerical and graphical visualisation of small-area tumour incidence and prevalence rates due to chance alone. The explanation of basic epidemiological concepts to members of the public can help to increase public motivation and support for population-based cancer registration. Our simulation tool can be used to support this goal.

Adolescent↗
PubMed2003

Comparison of tree-based methods for prognostic stratification of survival data.

Tree-based methods can be used to generate rules for prognostic classification of patients that are expressed as logical combinations of covariate values. Several splitting algorithms have been proposed for generating trees from survival data. However, the choice of an appropriate algorithm is difficult and may also depend on clinical considerations. By means of a prognostic study of patients with gallbladder stones and of a simulation study, we compare the following splitting algorithms: log-rank statistic adjusted for measurement scale with (AP) and without (AU) pruning, exponential log-likelihood loss (EP), Kaplan-Meier (KP) distance of survival curves, unadjusted log-rank statistic (LP), martingale residuals (MP), and node impurity (ZP). With the exception of the AU algorithm (based on a Bonferroni-adjusted p-value driven stopping rule), trees are pruned using the measure of split-complexity, and optimally-sized trees are selected using cross-validation. The integrated Brier score is used for the evaluation of predictive models. According to the results of our simulation study and of the clinical example, we conclude that the AU, AP, EP, and LP algorithm may yield superior predictive accuracy. The choice among these four algorithms may be based on the required parsimonity and on medical considerations.

Algorithms↗
PubMed2002

Small bowel resection in the rat: the effect upon bone and mineral metabolism.

BACKGROUND AND AIMS: We analyzed bone and mineral metabolism after long-segment small bowel resection in the rat to detect functional and morphological alterations and to determine the development of osteopathy. METHODS: Twelve-week-old male Lewis rats were randomized into short (8-week) or long (16-week) follow-up groups. Sham operation, resection of the proximal third of the small bowel, resection of the distal third of the bowel and resection of the entire jejunum and ileum were carried out. Nineteen days before the end of the experiment the animals were transferred into a metabolic cage to analyze weight gain/loss, food intake, and fecal excretion/24 h. At the end of the experiment the animals were killed; blood samples and bowel and bone specimens were collected, length, weight, volume, density, mineral content, and fracturing energy were determined, and bone histology was examined. The calcium/phosphorus ratio, nonmineralized tissue content and the ratio fracturing energy/mean bone density were calculated. RESULTS: After 8 weeks there were significant differences to the control group in body weight, weight gain, food efficiency, femur length, weight, volume, mineral content, mineral density, fracturing energy per bone volume, and bone density but not in bone calcium or magnesium. After 16 weeks there were differences in body weight, weight gain, food efficiency, femur length, weight, volume, bone mineral content and density, bone minerals, and nonmineralized tissue but not in fracturing energy; the average values of all these parameters were lower in the resected groups, and lowest in the group after resection of the entire jejunum and ileum. Bone histology showed a reduction in trabecular bone mass after long-segment small bowel resection. CONCLUSIONS: Long-segment small bowel resection causes a significant loss of body weight despite of a comparable mean chow ingestion resulting in a significant decreased food efficiency. We conclude that there is no inverse relationship of bone calcium content and the fracture risk, and that there is no severe mineralization defect after long-segment small bowel resection.

Animals↗
PubMed2002

Traffic hypoglycaemias and accidents in patients with diabetes mellitus treated with different antidiabetic regimens.

OBJECTIVES: Insulin-treated patients with diabetes are at a higher risk than the general population in causing traffic accidents due to hypoglycaemias. Preceding investigations focused on insulin-treated patients and hypoglycaemia-induced accidents as "end-points". We studied the incidence of symptomatic hypoglycaemia and hypoglycaemia-induced accidents during driving and put it in relation to the different treatment modes of insulin therapy (Conventional Insulin Treatment = CT, Intensified Conventional Insulin Treatment = ICT, Continuous Subcutaneous Insulin Infusion = CSII) as well as to patients treated with oral hypoglycaemia-inducing agents and the two main types of diabetes mellitus. DESIGN SUBJECTS AND SETTING: We investigated 450 patients (122 treated with sulphonylureas, 151 with CT, 143 with ICT and 34 with CSII) by an anonymous questionnaire at different locations to avoid bias. A total of 176 persons had type 1 diabetes, 243 persons had type 2 diabetes, 31 subjects could not be classified. RESULTS: Symptomatic hypoglycaemias during driving were rare events with an occurrence of 0.19-8.26 (minimal and maximal mean, depending on the mode of treatment), if given as hypoglycaemias per 100 000 km on one treatment regimen, or 0.02-0.63, if given as events per year driven. Their incidence increased significantly with the degree of "strictness" between the treatment groups, except between the patients treated with ICT and CSII. Hypoglycaemia-induced accidents are rare with 0.01-0.49, if given as events per 100 000 km and 0.007-0.01, if given as events per year driven. These differences were not significant. Significant confounders influencing the traffic safety of the patients were age, duration of diabetes and concomitant antihypertensive medication. Analysing the data in accordance with the type of diabetes revealed a significantly higher rate of hypoglycaemic events in patients with type 1 diabetes. The number of hypoglycaemia-induced accidents was considerably higher in this group, but failed slightly to reach statistical significance. CONCLUSIONS: Hypoglycaemias during driving are rare events, their occurrence is significantly influenced by the treatment regimen and type of diabetes. Hypoglycaemia-induced accidents are extremely rare, presumably as a positive effect of patient education in our group.

Accidents, Traffic↗
PubMed2002

Vascularization of the area between free grafts and irradiated graft beds in the neck in rats.

Inflammatory lesions of the vascular endothelium after preoperative radiotherapy often cause healing-delayed healing of free flaps in the irradiated graft bed. We investigated changes in neovascularization in the transition area between grafted tissues and irradiated tissues of the graft bed. We irradiated the neck(30 and 50 Gy total dose) in 102 Wistar rats and then grafted a free myocutaneous gracilis flap to the irradiated region of the neck 4 weeks later. We examined histologically the tissues of the graft, the transition area between the graft and the irradiated graft bed, and the graft bed. In contrast to control rats, the tissues in the irradiated animals showed a qualitatively reduced and a more irregular capillary distribution, with substantial fibrosis in the irradiated graft bed. We also found significant differences in vascularization and mean capillary lumen in the transitional zone between graft and graft bed in the irradiated rats compared with controls (P = 0.004 and P < 0.001, respectively). Both number and diameter of capillaries were reduced in the irradiated graft bed tissue. The graft failed to improve vascularization in the transitional zone between graft and irradiated tissue, so we conclude that it is the vascularization status of the bed tissue rather than that of the transplant tissue that is the limiting factor for graft healing.

Animals↗
PubMed2002

Tele-endoscopy: influence of data compression, bandwidth and simulated impairments on the usability of real-time digital video endoscopy transmissions for medical diagnoses.

BACKGROUND AND STUDY AIMS: Real-time digital video transmission (rtDVT) at an acceptable quality through networks has been possible for several years. This technique can be used for telemedical applications, such as tele-endoscopy. The hypotheses of the present study were that the quality of real-time DVT depends on the technical equipment used, and that the resulting image quality influences the usability of the system for diagnostic purposes. MATERIALS AND METHODS: An experimental network was established between two German referral endoscopy centers, using the Asynchronous Transfer Mode (ATM) protocol. At first, rtDVTs of routine gastrointestinal video endoscopies were transferred through the network for prospective evaluation of the feasibility of the technical equipment and its usability for diagnostic tele-endoscopy, based on the video image quality. Secondly, the image quality and usability for correct telemedical diagnosis were evaluated prospectively in a double-blind experimental setting in relation to variations in the methods of data compression used, transmission bandwidths, and simulated transmission errors. Fourteen endoscopists evaluated 27 variations of an endoscopic video sequence. RESULTS: Compression with the Moving Picture Expert Group 2 (MPEG2 [4 : 2 : 2]) standard, the ATM protocol, and a bandwidth of 40 megabits per second (Mb/s) were used successfully in 40 routine tele-endoscopies for practical evaluation. Doctors were able to handle the system with ease, and its availability was 100%. There were no detectable differences between the original video image and the transferred image, and the images were usable for diagnosis in all cases. The set-up used clinically was therefore considered to provide the optimal conditions for comparisons in the experimental part of the study. Experimentally, any technical variation was found to cause a reduction in the overall image quality and hence a reduction in diagnostic usability: compression algorithm (MPEG2 [4 : 2 : 2] vs. others: P = 0.001), bandwidth (> or = 8 vs. < 8 Mb/s: P = 0.001), and error rate (10 (-8) vs. 10 (-7): P = 0.001). CONCLUSIONS: rtDVT using MPEG2 [4 : 2 : 2] compression and a bandwidth of 40 Mb/s did not effectively differ from the original video images in routine tele-endoscopy. The qualitative requirements in diagnostic video endoscopy, however, are obviously much higher than previously assumed, since experienced endoscopists detected a loss of image quality and a reduction in diagnostic usability with any reduction in the technical specification. Modern methods of data compression, broadband networks and a network protocol with good quality-of-service guarantees are therefore prerequisites for diagnostic rtDVT.

Algorithms↗
PubMed2001

Dendritic hypertrophy of Stach type VI neurons within experimentally altered ileum of pigs.

Myenteric neurons were investigated morphometrically to answer the question if type-specific somal hypertrophy of type VI neurons in mechanically stressed ileum of pigs, which was known from an earlier study, is correlated with an increased dendritic arborization, that is, with dendritic hypertrophy. Muscular hypertrophy was induced in the ileum of two juvenile pigs by narrowing the gut circumference (mechanical stenosis) and by reversing a loop of ileum which results in an antiperistaltic segment (functional stenosis), respectively. After a survival time of 6 weeks, wholemounts from the pre- and poststenotic ileal regions, from the antiperistaltic segment as well as from an age matched control animal, were silver impregnated. Dendritic parameters of Stach types IV and VI neurons were recorded using a computer-aided morphometric program and analysed statistically. Type IV neurons showed no change of dendritic parameters, neither within control nor within stenosed ileal segments. In contrast, the type VI neurons displayed increased dendritic parameters within zones of muscular hypertrophy such as total dendritic length, numbers of dendrites, of dendritic branching points and of dendritic endings. We suggest that type VI neurons may participate as descending nitrergic interneurons or motorneurons in the control of muscular function, thus, undergoing plastic changes in case of experimental muscular hypertrophy. Type IV neurons which are involved in the regulation of mucosal processes were not affected by muscular hypertrophy.

Animals↗
PubMed2001

Critical illness polyneuropathy: clinical findings and cell culture assay of neurotoxicity assessed by a prospective study.

OBJECTIVE: First, to evaluate the role of typical intensive care-related conditions like sepsis, prolonged ventilation, drug effects and metabolic disorders in the pathogenesis of critical illness polyneuropathy (CIP); second, to investigate the possible significance of patient serum neurotoxicity assessed by an in vitro cytotoxicity assay with respect to CIP development. DESIGN: Prospective study. SETTING: Neurological intensive care unit. PATIENTS AND PARTICIPANTS: Twenty-eight patients who were on mechanical respiratory support for at least 4 days during a 21-month study period. RESULTS: Diagnosis of CIP was established by clinical and electrophysiological examination in 16 (57%) of 28 patients. Patients were investigated on days 4, 8 and 14 of mechanical ventilation. Two of 16 CIP patients had clinical signs of polyneuropathy at initial examination. Factors that correlated significantly with the development of CIP were: the multiple organ failure score on day 8 of ventilation, the total duration of respiratory support, the presence of weaning problems and the manifestation of complicating sepsis and/or lung failure. The in vitro toxicity assay showed serum neurotoxicity in 12 of 16 CIP patients. Electrophysiological investigations yielded false positive results of the toxicity assay in six patients (not developing CIP) and false negative results in four patients (developing clinical and electrophysiological signs of CIP). Statistical analysis did not reveal a significant correlation between the diagnosis of CIP and the finding serum neurotoxicity. CONCLUSION: The results support the hypothesis of a multi-factorial aetiopathogenesis of CIP. We observed serum neurotoxicity in the majority of CIP patients, indicating the possible involvement of a so far unknown, low-molecular-weight neurotoxic agent in CIP pathogenesis.

Adrenal Cortex Hormones↗
PubMed2001

Morbidity of harvesting of chin grafts: a prospective study.

In a prospective study, 20 patients who underwent harvesting of chin grafts as outpatients, were followed up for 12 months (3 further patients with incomplete follow-up data were excluded from the study). Preoperatively and 7 days, 1, 3, 6 and 12 months postoperatively, follow-up data were assessed. Evaluation of the superficial sensory function of the inferior alveolar nerve was determined by the Pointed-Blunt Test and the Two-Point-Discrimination Test. Sensory disturbances were objectively assessed by testing thermal sensitivity with the "Pain and Thermal Sensitivity" Test (PATH Test). In addition, evaluation of the pulp sensitivity of teeth 35-45 was carried out by cold vitality testing. One week postoperatively, 8 patients were affected by superficial sensory impairment. 8 nerve territories showed hypoaesthetic reactions and 5 showed hyperaesthetic reactions. After 12 months, two patients still suffered from hypoaesthesia of one side of the chin. There was a statistically significant sensitivity impairment of the chin for all patients comparing the preoperative data of the Two-Point-Discrimination Test (left/right median: 8.17/8.17 mm, interquartile range (IQR) 1.00/2.00 mm) with the first postoperative measurement (left/right median 9.00/8.33 mm, IQR 1.67/2.66 mm). Comparing the latter to the last postoperative measurement there was significant tendency for regeneration of a nerve function (left/right median 8.00/7.84 mm, IQR 0.66/2.00 mm). In the PATH Test all hypoaesthetic areas could be identified by a reduction of thermal sensitivity. After the first postoperative examination 21.6% (n=38/176) of the examined teeth had lost their pulp sensitivity. After 12 postoperative months 11.4% (n=20/176) still did not react sensitively. Many of these were canines (n=8/20). Comparing the preoperative to the first postoperative examination, there was a significant reduction of pulp sensitivity. However, statistically significant recovery until the last postoperative follow-up could not be detected. The assessed data show that patients have to be informed extensively about disturbances of the inferior alveolar nerve function lasting longer than 12 months. Moreover, the loss of pulp sensitivity is a very frequent event which has always to be taken into account. Considering the high rate of complications with harvesting of chin grafts, more prospective trials should be done to find out whether there are other donor sites for autogenous bone which put less strain on patients.

Ambulatory Surgical Procedures↗
PubMed2001

Quantitative testing of liver function in patients with cirrhosis due to chronic hepatitis C to assess disease severity.

BACKGROUND/AIMS: Quantitative testing of liver function (QTLF) may allow a prognostic assessment of patients with various liver diseases. However, there are insufficient data about patients with liver cirrhosis due to hepatitis C. PATIENTS/METHODS: 86 consecutive patients (58 males, 28 females, age: 48.3 +/- 11.7 years) with chronic hepatitis C (HCV RNA pos.) underwent sonographically guided liver biopsy to confirm the diagnosis of cirrhosis. QTLF included aminopyrine breath test (microsomal liver function), galactose elimination capacity (cytosolic liver function), sorbitol clearance (liver plasma flow) and indocyanine green clearance (liver perfusion). Values were correlated with the Child-Pugh classification. RESULTS: 55% of the patients (n=47) had cirrhosis of Child-Pugh grade A, 28% of grade B (n=24) and 17% of grade C (n=15). QTLF showed a steady decrease from Child-Pugh grade A to grade B and to grade C. Contrary to markedly reduced tests of metabolic liver function in Child-Pugh grade patients, surrogate tests of hepatic perfusion were at the lower normal limit. All QTLF were significantly reduced in Child-Pugh grade B and C patients compared to healthy controls. Differences between the three Child grades were significant. CONCLUSION: In patients with cirrhosis due to hepatitis C, QTLF correlated inversely with Child-Pugh grades. Since in cirrhosis of grade A, surrogate tests of hepatic perfusion remained at the lower normal limit, whereas those of metabolic function were decreased, QTLF may be a tool to predict prognosis or complications in early cirrhosis due to chronic hepatitis C.

Aminopyrine↗
PubMed2001

Adverse drug reactions in patients with gastroenterological diseases: does age increase the risk?

BACKGROUND: It has been claimed that the risk of adverse drug reactions increases with age. However, only limited data exist for disease-group specific risks and none for patients with liver and gastrointestinal diseases. AIMS: To determine the incidence and characteristics of adverse drug reactions and the physicians' awareness of adverse drug reactions. METHODS: During a 7-month period, a prospective survey of 532 male patients (158 aged 65 years or older; 30%) was conducted on a hepatogastroenterological ward of a tertiary-care university hospital, using intensive bedside and computer-assisted drug surveillance methods. RESULTS: No difference was found in the overall rate of adverse drug reactions between older and younger patients (25.9% vs. 24.2%) during 6213 treatment days. However, a significantly higher risk for developing adverse drug reactions could be shown for the elderly with biliary tract diseases (P < 0.01). Independently of age, patients suffering from gastric ulcers, acute episodes of pancreatitis, cholangitis or inflammatory bowel diseases were at high risk of adverse drug reactions. Adverse drug reaction-associated mortality was encountered in four elderly and none of the younger patients. Secondary pharmacological effects and drug toxicity were the main types of adverse drug reactions for both age groups. Although 75.3% of the adverse drug reactions were predictable, only 37.5% of all adverse drug reactions were recognized by the staff physicians. CONCLUSION: In hepatogastroenterological patients, advancing age was not associated with an overall increased risk of adverse drug reactions except for patients with biliary tract diseases. In the elderly, adverse drug reactions were more severe and carried higher mortality. Guidelines and educational programs should be developed to increase the awareness of adverse drug reactions and their prevention, especially in high risk patients and, thus, to improve patient outcomes.

Age Factors↗
PubMed2001

Interictal cardiac autonomic dysfunction in temporal lobe epilepsy demonstrated by [(123)I]metaiodobenzylguanidine-SPECT.

We studied the post-ganglionic cardiac sympathetic innervation in patients with chronic temporal lobe epilepsy (TLE) by means of [(123)I]metaiodobenzylguanidine-single photon computed tomography (MIBG-SPECT) and evaluated the effects of carbamazepine on cardiac sympathetic innervation. TLE is frequently associated with dysfunction of the autonomic nervous system. Autonomic dysregulation might contribute to unexplained sudden death in epilepsy. Anticonvulsive medication, particularly with carbamazepine, might also influence autonomic cardiovascular modulation. MIBG-SPECT allows the quantification of post-ganglionic cardiac sympathetic innervation, whereas measuring the variability of the heart rate provides only functional parameters of autonomic modulation. Antiepileptic drugs, especially carbamazepine (CBZ), can affect cardiovascular modulation. We determined the index of cardiac MIBG uptake (heart/mediastinum ratio) and heart rate variability (HRV) using time and frequency domain parameters of sympathetic and parasympathetic modulation in 12 women and 10 men (median age 34.5 years) with a history of TLE for 7-41 years (median 20 years). Myocardial perfusion scintigrams were examined to rule out deficiencies of MIBG uptake due to myocardial ischaemia. To assess the possible effects of CBZ on autonomic function, we compared MIBG uptake and HRV in 11 patients who had taken CBZ and 11 patients who had not taken CBZ, and in 16 healthy controls. In order to identify MIBG uptake defects due to myocardial ischaemia, all patients had a perfusion scintigram. Cardiac MIBG uptake was significantly less in the TLE patients (1.75) than in the controls (2.14; P = 0.001), but did not differ between subgroups with and without CBZ treatment. The perfusion scintigram was normal in all patients. Time domain analysis of HRV parameters suggested the predominance of parasympathetic cardiac activity in the TLE patients, but less parasympathetic modulation in the patients treated with CBZ than in those not treated with CBZ (P < 0.05), whereas frequency domain parameters showed no significant difference between the subgroups of patients or between patients and controls. MIBG-SPECT demonstrates altered post-ganglionic cardiac sympathetic innervation. This dysfunction might carry an increased risk of cardiac abnormalities.

3-Iodobenzylguanidine↗
PubMed2001

[Hemodynamics of the lower extremity with pneumatic foot compression. Effect on leg position].

External pneumatic compression of the foot is being used more and more to increase the venous blood flow in the lower limbs and thus reduce the risk of postoperative deep venous thrombosis. We have investigated the efficacy of the foot pump pneumatic compression device (A-V Impulse, Novamedix, Andover, England) in 10 healthy subjects and in 10 patients undergoing total hip arthroplasty. The velocity of venous blood flow in the common femoral artery was measured in the horizontal, Trendelenburg (head-down, foot-up) and reverse Trendelenburg (head-up and foot-down) positions using a duplex ultrasound unit (Sonoline Elegra, Siemens, Erlangen, Germany) with a 5 MHz linear array probe. Application of the foot pump produced an increase in venous blood flow velocity in all healthy subjects and in all patients. In healthy subjects the mean increase in the horizontal position was 31.18% (SD = 15.86%), and in the Trendelenburg position 20.72 (SD = 15.69%) (right limb). In the reverse Trendelenburg position, the foot pump produced a mean increase of 94.08% (SD = 55.00%). The difference is statistically significant (p < 0.005). In patients with a total hip arthroplasty, the mean increase in the horizontal position was 28.67% (SD = 9.95%), and in the Trendelenburg position 20.34% (SD = 17.85%) (operated limb). In the reverse Trendelenburg, the foot pump produced a mean increase of 91.55% (SD = 42.38%). The difference is statistically significant (p < 0.005). There was no noteworthy difference in results between the controls and patients. Pneumatic compression devices designed to reduce venous stasis are effective in decreasing the rate of deep venous thrombosis after surgery on the lower limb. The results of the present study show that the efficiency of the foot pump in increasing venous return is improved by adopting the reverse Trendelenburg position. This may increase its thromboprophylactic effect.

Adult↗
PubMed2000

Differentiation of Parkinson's disease and multiple system atrophy in early disease stages by means of I-123-MIBG-SPECT.

BACKGROUND: Differential diagnosis between idiopathic Parkinson's disease (PD) and multiple system atrophy (MSA) is often difficult in early disease stages. Since MSA is misdiagnosed as PD in more than 20% of the early stages, there is need for methods refining the differentiation of the two disease entities. In PD postganglionic involvement of the autonomic nervous system (ANS) predominates whereas in MSA the ANS is mainly affected in its preganglionic structures. The functional integrity of postganglionic cardiac sympathetic neurons can be investigated using I-123-metaiodobenzylguanidine-single photon emission computed tomography (MIBG-SPECT). OBJECTIVES: We investigated whether I-123-MIBG-SPECT allows to differentiate between early stages of PD and MSA in patients not yet requiring L-dopa therapy. METHODS: Thirty patients (10 PD and 20 MSA patients) underwent MIBG-SPECT and evaluation of heart rate variability (HRV). Patients on any medication interfering with MIBG-accumulation were excluded from the study. Cardiac perfusion was evaluated by myocardial scintigraphy. RESULTS: The median cardiac MIBG uptake was significantly decreased in PD as well as MSA patients compared to controls (P<0.001). However, in the PD group MIBG uptake was significantly lower than in MSA (P=0.03). Even in PD patients without clinical signs of autonomic failure, MIBG uptake was significantly lower than in MSA patients (P=0.03). Analysis of heart rate parameters did not differentiate between PD and MSA patients. The median coefficient of variation was significantly smaller in PD and MSA patients compared to control subjects. CONCLUSIONS: Our study shows that MIBG-SPECT identifies autonomic cardiac dysfunction in very early stages of both, PD and MSA. More importantly, the technique facilitates differentiation of MSA and PD in the early stages. The different pathology with prominent peripheral, postganglionic sympathetic dysfunction in PD and primarily central and preganglionic lesions in MSA accounts for a lower MIBG uptake in PD compared to MSA patients.

Adult↗
PubMed2000

Peripheral neuropathy in chronic venous insufficiency.

Chronic venous insufficiency (CVI) of the lower legs may cause tissue damage, but involvement of peripheral nerves is uncertain. We examined 30 patients with CVI and 20 healthy controls using motor and sensory nerve conduction studies, vibration testing and thermotesting, quantitative sudomotor axon-reflex test, and laser Doppler flowmetry. Subjects with possible confounding factors for peripheral neuropathies were excluded. Prolongation of distal motor latency of the peroneal nerve (median, 5.4 versus 4.5 ms; P = 0.02), increased limits for warm (9.60 degrees C versus 5.20 degrees C; P = 0.016) and cold detection (3.45 degrees C versus 1.55 degrees C; P = 0.016) and reduced vibration sense (2.8925 versus 1.1075; P < 0.008) were found. The results demonstrate a disturbance of A-alpha fibers, A-beta fibers, A-delta fibers, and thermoafferent-C fibers, possibly induced by ischemia due to venous microangiopathy and increased endoneurial pressure. Analogous to neuropathic ulcers in diabetes, the CVI-associated neuropathy may also be a cofactor in the development of venous ulcers.

Adult↗