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P Neumann

Publications and source records attributed to P Neumann.

At least 73 records · Page 4Linked to original sources
PubMed1998

First International Pharmacoeconomic Conference on Alzheimer's Disease: report and summary.

The First International Pharmacoeconomic Conference on Alzheimer's Disease (AD) was held in Amsterdam in July 1998. The meeting was held under the auspices of the International Working Group for Harmonization of Dementia Drug Guidelines (http://dementia.ion.ucl.ac.uk/harmon), bringing together academics, clinicians, purchasers, and representatives from industry. Presentations were given on the methodology of pharmacoeconomic studies in AD, particularly focusing on caregiver burden, quality of life (QOL), and resource utilization. Three economic models of AD were presented based on data from the United States, Canada, and the United Kingdom. In two studies, these data were then used to model the cost-effectiveness and effect on cost of treatment with donepezil. Both studies suggested a possible cost advantage for the use of donepezil, when compared with no placebo or treatment, particularly when donepezil is used appropriately in mild-to-moderate AD. These data need to be interpreted with care, as none of the cost or utility information were collected during the clinical trials. Additional data from a 2-year clinical trial of selegiline and vitamin E suggest that cognitive measures may be poor predictors of economic outcome, which is better measured directly. Both economic models of donepezil rely on short-term cognitive data to predict long-term outcome, a methodf that may not be useful in predicting economic savings. The issues facing pharmacoeconomists, researchers, clinicians, and families in the future were addressed in a series of workshops using a method of strategic futuring. The workshops attempted to see 7 years into the future for a range of areas, including consumer and caregiver use of pharmacoeconomic data; early detection and prevention; Japanese perspectives; activities of daily life and what will be daily life activities; caregiver burden; QOL at the end of life; new uses for new information and communication technology in clinical research; and physicians' use of pharmacoeconomic data. A range of exciting futures were predicted, although common themes that arose when considering barriers to achieving these futures included cost, education, political will, confidentiality, privacy, and ethics. The first conference was deemed to have been a success, having attracted more than 160 delegates and many distinguished speaker. A second conference is planned for the year 2000. Over the next 2 years, research needs to be broadened particularly in the methodological areas of resource utilization, QOL, and caregiver burden. Data from clinical trials with relevant economic and QOL outcomes will be needed by purchasers if drug treatments for dementia are to gain widespread use. It is also hoped that the models described at the meeting may become more freely available to politicians, purchasers, clinicians, and caregivers to help them make better decisions about treatment.

Aged↗
PubMed1998

Dynamics of lung collapse and recruitment during prolonged breathing in porcine lung injury.

Oleic acid (OA) injection, lung lavage, and endotoxin infusion are three commonly used methods to induce experimental lung injury. The dynamics of lung collapse and recruitment in these models have not been studied, although knowledge of this is desirable to establish ventilatory techniques that keep the lungs open. We measured lung density by computed tomography during breath-holding procedures. Lung injury was induced with OA, lung lavage, or endotoxin in groups of six mechanically ventilated pigs. After a stabilization period, repetitive computed tomography scans of the same slice were obtained during prolonged expirations with and without positive end-expiratory pressure and during prolonged inspirations after 5 and 30 s of expiration. Lung collapse and recruitment occurred mainly within the first 4 s of breath-holding procedures in all three lung injury models, and some collapse and recruitment occurred even within 0.6 s. OA-injured lungs were significantly more unstable than lungs injured by bronchoalveolar lavage or endotoxin infusion. In this experimental setting, expiration times <0.6 s are required to avoid cyclic alveolar collapse during mechanical ventilation without extrinsic positive end-expiratory pressure.

Animals↗
PubMed1998

Effect of different pressure levels on the dynamics of lung collapse and recruitment in oleic-acid-induced lung injury.

The effects of different inspiratory and expiratory airway pressures (Paw) on the dynamics of lung collapse and recruitment were studied in 14 anesthetized, mechanically ventilated, pigs with oleic-acid-induced lung injury. Repetitive CT scans of the same slice were obtained every 0.8 s during different inspiration and expiration hold procedures. The mean lung density and amount of atelectasis were measured in each scan. Inspiration to a Paw of 15 cm H2O above PEEP resulted in recruitment of collapsed lung tissue, mainly within 1.4 s. During expiration lung density increased rapidly and at an almost even rate within the first 1.4 s, whereas a rapid increase of atelectasis occurred after an initial delay period of 0.6 s with PEEP = 10 or 15 cm H2O. PEEP of 20 or 25 cm H2O almost prevented lung collapse during expiration. Thus, in order to avoid cyclic alveolar collapse during mechanical ventilation in oleic-acid-induced lung injury, a PEEP level >= 20 cm H2O or an expiration time <= 0.6 s is required. Long inspiratory time intervals, as used in inverse ratio ventilation, seem to be of minor importance for the recruitment of collapsed lung tissue in this experimental model.

Analysis of Variance↗
PubMed1998

Evaluation of respiratory inductive plethysmography in controlled ventilation: measurement of tidal volume and PEEP-induced changes of end-expiratory lung volume.

STUDY OBJECTIVE: To determine the accuracy of respiratory inductive plethysmography (RIP) with a respiratory monitor (Respitrace Plus; NIMS Inc., Miami) operating in the DC-mode for the measurement of tidal volumes (VT) and positive end-expiratory pressure (PEEP)-induced changes of end-expiratory lung volume (deltaEELV) in patients with normal pulmonary function, acute lung injury (ALI), and COPD during volume-controlled ventilation. DESIGN: Prospective comparison of RIP with pneumotachography (PT) for assessment of VT and with multibreath nitrogen washout procedure (N2WO) for determination of deltaEELV as reference methods. SETTING: Mixed ICU at a university hospital. PATIENTS: Thirty-one sedated and paralyzed patients: 12 patients with normal pulmonary function mechanically ventilated after major surgery, 10 patients with respiratory failure due to ALI, and 9 patients with a known history of COPD ventilated after surgery or because of respiratory failure due to bronchopulmonary infection. INTERVENTIONS: Stepwise increase of PEEP from 0 to 5 to 10 cm H2O and reduction to 0 cm H2O again. On each PEEP level, N2WO was performed. MEASUREMENTS AND MAIN RESULTS: The baseline drift of RIP averaged 25.4+/-29.1 mL/min but changed over a wide range even in single patient measurements. Determination of VT for single minutes revealed that 66.5% and 90.0% of all values were accurate within a range of +/-10% and +/-20%, respectively. The deviation for VT measurements between RIP and PT in patients with COPD was significantly (p<0.05) higher compared to patients with ALI or normal pulmonary function. The difference of deltaEELV between RIP and N2WO was 11.6+/-174.1 mL with correlation coefficients of 0.77 (postoperative and COPD patients) and 0.86 (ALI patients). However, just 25.8% and 46.2% were precise within +/-10% and +/-20%, respectively. deltaEELV determination in COPD patients differed more between RIP and N2WO than in the other groups, but this was not significant. CONCLUSION: In a mixed group of patients undergoing controlled ventilation, RIP using the Respitrace Plus monitor was not consistently precise enough for quantitative evaluation of VT and EELV when compared to our reference methods. This was most evident in patients with COPD. For long-term volume measurements, a better control of the baseline drift of RIP should be achieved.

Aged↗
PubMed1997

Ondansetron, droperidol and their combination for the prevention of post-operative vomiting in children.

In this study the antiemetic effects of droperidol, ondansetron and their combination were evaluated in 160 ASA Grade I and II children undergoing surgery for strabismus, who were randomly assigned to one of four groups: Group D received droperidol 75 micrograms kg-1, group O ondansetron 0.1 mg kg-1, group D+O received both droperidol 75 micrograms kg-1 and ondansetron 0.1 mg kg-1, and group N NaCl as placebo. Emesis within the first 24 h occurred in 95.0% of the children with placebo medication, compared with 32.5% (D), 40.0% (O) and 45.0% (D+O) in the groups with antiemetic prophylaxis. The differences between group N and all other groups were significant (P < 0.001). However, there were no statistically significant differences between the groups D, O and D+O. It is concluded that droperidol (75 micrograms kg-1) and ondansetron (0.1 mg kg-1) both significantly reduce PONV in children undergoing surgery for strabismus. Neither ondansetron, nor the combination D+O were superior to droperidol alone.

Adolescent↗
PubMed1997

Assessment of physical work load in epidemiologic studies: common measurement metrics for exposure assessment.

There are many possible means of determining exposure ranging from self-reports of physical exposure to measures of muscle activations and estimated spinal loads. In epidemiologic studies, issues of validity make instrumented measures preferable, however issues of cost and practicability tend to force investigators to less costly but less valid and less reliable measures of exposure, such as self-report questionnaires. This paper presents a method by which estimates of exposure from self-report questionnaires, expert observers, work sampling, video analysis and electromyograms can be reported in a common metric, Newtons of force on a tissue, and show, as an example of its application, estimation of spinal compression on auto workers. A common metric allows a flexible approach to selection of measurement methods in occupational settings: no matter which instrument is used the results can be combined to provide an overall picture of exposure. This approach to exposure assessment for the low back allows for comparability across studies and settings.

Automobiles↗
PubMed1997

Endothelial barrier dysfunction and p42 oxidation induced by TNF-alpha are mediated by nitric oxide.

We tested the hypothesis that nitric oxide (.NO) mediates tumor necrosis factor-alpha (TNF-alpha)-induced alterations in permeability and actin of pulmonary artery endothelial monolayers (PAEM). The permeability of PAEM was assessed by the clearance rate of albumin labeled with Evans blue dye. The PAEM Triton-soluble ("cytoskeletal-nonassociated") and -insoluble ("cytoskeletal-associated") lysates were analyzed by Western blot for actin and oxidized protein using polyclonal antibodies to the COOH terminus of actin and dinitrophenylhydrazone (DNP), respectively. PAEM were incubated with TNF-alpha (100 U/ml) for 4 h. Incubation of PAEM with TNF-alpha resulted in increases in 1) the .NO oxidation product nitrite (NO2-), 2) nitrotyrosine immunofluorescence, 3) the oxidation of p42 (tentatively identified as actin), and 4) permeability to Evans blue dye-albumin. The .NO synthase inhibitor aminoguanidine (100 microM) prevented the TNF-alpha-induced increase in NO2-, nitrotyrosine immunofluorescence, oxidized p42, and permeability. Coincubation with L-arginine (200 microM) or the .NO mimic spermine-NO (1 microM) prevented the ablation of the response to TNF-alpha by aminoguanidine. The data indicate that TNF-alpha-induced increases in endothelial permeability and oxidized protein are mediated by .NO in PAEM.

Actins↗
PubMed1997

[Possibilities and limits of mammography with special reference to breast carcinoma--a comparison of clinical, mammography and histologic diagnoses].

This paper informs about the diagnostical accuracy of clinical examination and mammography at the women's Hospital of the Städtische Klinikum Zwickau from 1989 to 1992 when pathological changes of breasts are diagnosed. A total of 508 diagnostical biopsies was performed during this study period. The histological examination resulted in 276 benign breast lesions and in 232 breast cancers. In 432 cases there was a lump palpable in the breast that was noticed at first by more than 60% of women themselves. 288 (56.7%) correct and 220 (43.3%) false diagnoses were established following the clinical examination. This resulted in a sensitivity of 100% with a specificity of 20.3% and an overall accuracy of 56.7%. However, with the help of mammography 386 (76.6%) pathological changes of breasts were found to be correct. 118 mammograms proved to be false. Out of these 90 (17.8%) had a false-positive diagnosis and 28 (5.6%) a false-negative one. The overall accuracy of mammography was 76.6% (sensitivity 87.9%, specificity 67%).

Biopsy↗
PubMed1996

Flexion-distraction injury of the lumbar spine: influence of load, loading rate, and vertebral mineral content.

The biomechanical response of the lumbar spine to combined flexion-shear loading was determined experimentally. The injury model simulated flexion-distraction trauma to the lumbar spine. Forty-eight lumbar functional spinal units (FSUs) were subjected to dynamic loading to injury with six different load types. The reactive forces and moments and resulting deformity were determined. Static physiologic loading was performed before and after the injurious loading to assess residual injury. The biomechanical response of FSUs was dependent on the amount of load and loading rate. The vertebral bone mineral content explained most of the biologic variation of the results. An osteoporotic or severely degenerated spine will be more easily rendered unstable after trauma with lower deformity. Injury at high loading rates will create instability with lower deformity. In vitro experiments should be performed on entire spinal units and with combined loads.

Acceleration↗
PubMed1996

[Prevention of postoperative nausea and vomiting with single and repeat administration of ondansetron--review of the literature on different administration forms].

Postoperative nausea and vomiting (PONV) is still a common perioperative complication and ondansetron has proved to be an effective antiemetic substance in its prevention. The antiemetic effect of single and repetitive application was evaluated in this study. Fifty-one female patients who underwent gynaecological surgical procedures took part in a random double-blind study. Before the start of anaesthesia, 21 patients (group 1) received either a placebo (six patients), 8 mg ondansetron orally (seven patients) or 16 mg orally (eight patients). The remaining 30 patients (group 2), split into subgroups of ten, were given the same preoperative medication as group 1 plus further doses of the same strength 8 and 16 hours after the first intake of the study medication. Metoclopramide was given intravenously if patients had more than one emetic episode or if they asked for it. Nausea and vomiting were documented up to 24 hours after finishing anaesthesia. Metoclopramide had only to be given to patients who had received a placebo. Nausea was felt by 57% (4/7) of the patients after a single dose of 8 mg ondansetron and by 40% (4/10) of the patients after three doses of 8 mg. One patient (14%, 1/7) with a single dose and two patients (20%, 2/10) with a repetitive dose of 8 mg ondansetron vomited. Following a single dose of 16 mg ondansetron, no patient (0/8) had to vomit and 25% (2/8) of the patients had nausea. There were no complications reported by the patients. Ondansetron was shown to be a well-tolerated antiemetic and seems to have a higher reductive effect on PONV when given in a single dose and not repetitively. The prophylaxis of vomiting seems to be more effective than the reduction of nausea. Follow-up studies will have to clarify our findings.

Adult↗
PubMed1996

[Clinical use of antiemetic drugs for prevention and therapy of postoperative nausea and vomiting].

The incidence of postoperative nausea and vomiting (PONV) has not decreased significantly for decades. This study was done to evaluate whether there is a standard method or a preferred substance in German hospitals in the prophylaxis and treatment of PONV. Twenty-one randomly selected hospitals were asked to give details about substances, doses and application times and forms in PONV prophylaxis and treatment. Most of the patients with a high risk of emesis were treated prophylactically with droperidol. Dosage and time of application were different in each hospital. Metoclopramide was the second most frequently used substance for both prophylaxis and treatment. Dimenhydrinate, triflupromaxzine, promethazine and acupuncture were used less commonly in prophylaxis. Alizapride and ondansetron were used to treat PONV in only two hospitals. Summarising, this study found no routine standard in the prophylaxis and therapy of PONV. Droperidol and metoclopramide were the most frequently used antiemetics. An overview of the antiemetics involved is given.

Antiemetics↗
PubMed1995

Traumatic instability of the lumbar spine. A dynamic in vitro study of flexion-distraction injury.

STUDY DESIGN: This in vitro study determined the effect on the lumbar spine of a dynamic flexion-distraction loading simulating a lap seatbelt injury. The proportion by which the forces and the moments contributed to the injury of the lumbar spinal segment in such a situation was analyzed. The remaining stability of the injured lumbar motion segment was determined together with the threshold for lumbar spine instability in such an injury. OBJECTIVES: Based on the experimental results in this study, radiographic guidelines for instability criteria in lumbar and thoracolumbar dislocations in the sagittal plane without concomitant compression fracture of the middle column were proposed. SUMMARY OF BACKGROUND DATA: A number of check-lists and guidelines were suggested for the diagnosis of spinal instability after trauma, but no conclusive system was established. Those systems were mostly based on experiments performed on spinal segments after sequential ablation of ligaments and facet joints followed by static, unidirectional physiologic loading. We believed that there was a need for more profound knowledge of spinal injury and for instability criteria of lumbar spinal injuries based on more realistic experimental data simulating the clinical situation. In our injury model, we decided to study the biomechanic outcome of a flexion-distraction injury similar to seatbelt type injury seen in frontal motor vehicle collisions. METHODS: Twenty lumbar functional spinal units were first loaded statically with a physiologic flexion-shear load to determine angulations and displacements under noninjurous conditions. Dynamic flexion-shear loading to injury with two different load pulses was then applied. Static physiologic load was then again applied to determine any permanent residual deformation. RESULTS: The viscoelastic effect of loading rate on translatory and angular displacements and the values for translatory and angulation displacements at first sign of injury (yield) and at failure were determined. CONCLUSIONS: Radiographic guidelines for instability criteria in lumbar and thoracolumbar fracture-dislocations without concomitant posterior vertebral body compression are proposed: 1. Instability exists if there is a kyphosis of the lumbar motion segment > or = 12 degrees (impending instability) or > or = 19 degrees (total instability) on lateral radiographs. 2. Relative increase in interspinous process distance > or = 20 mm (impending instability), > or = 33 mm (total instability) on anteroposterior radiographs.

Accidents, Traffic↗
PubMed1995

Volunteer low-risk outpatient surgery for uninsured patients in San Francisco. The Ambulatory Surgery Access Coalition.

OBJECTIVE: To provide uncompensated elective low-risk outpatient surgery for uninsured patients through a coalition of volunteer physicians, nurses, and hospitals. DESIGN: Description of the process of establishing the Ambulatory Surgery Access Coalition (ASAC), the political and administrative obstacles encountered, and the clinical results of treatment of the first 25 patients in the pilot project. SETTING: The ASAC includes the Kaiser Foundation Hospital, San Francisco, Calif, the University of California, San Francisco, the San Francisco General Hospital (SFGH), the San Francisco Department of Public Health, the San Francisco Consortium of Community Clinics, the Northern California Chapter of the American College of Surgeons, and the San Francisco Medical Society. A pilot program of uncompensated outpatient surgery was performed at the Kaiser Foundation Hospital. PATIENTS: Twenty-nine patients were referred to the ASAC between January 1 and November 1, 1994. Twenty-six patients were judged to be candidates for surgery, and 25 patients met the criteria for the ASAC program. One patient was referred to SFGH for treatment because of a perceived increased risk for hospitalization after surgery. RESULTS: Twenty-one patients underwent herniorrhaphy; three, excision of large inclusion cysts; and one, anal fistulotomy. Seventeen procedures were done under local anesthesia, seven under general anesthesia, and one under spinal anesthesia. None of the patients required hospital admission. No wound infections occurred. CONCLUSION: The ASAC successfully provided uncompensated low-risk outpatient surgery to 25 low-income uninsured patients in San Francisco. The coalition hopes, first, to include other San Francisco hospitals and surgical specialties, and second, to serve as a model for other communities throughout the country.

Ambulatory Surgical Procedures↗
PubMed1995

Colorimetric analyses of various light sources for the D-15 color vision test.

Colorimetric analyses were performed in both normal trichromatic and dichromatic color spaces to determine whether several light sources were suitable illuminants for the Farnsworth-Munsell Panel D-15 (D-15) color vision test. Results for fluorescent lamps showed that lamps with a correlated color temperature (CCT) of 7200 degrees K and a general color rendering index (GCRI) of at least 90 are acceptable substitutes for illuminant C. Predictions for filtered tungsten light indicated that lights with a color temperature near 5000 degrees K are unsuitable because of nonuniformities in the glass daylight filter transmittance. Conclusions based on these analyses are conservative because, with exception of the GCRI, color adaptation effects were not taken into account.

Adaptation, Ocular↗
PubMed1994

Effect of strain rate and bone mineral on the structural properties of the human anterior longitudinal ligament.

The effect of strain rate and bone mineral content on the biomechanical properties of the human lumbar anterior longitudinal ligament-bone complex was studied. Tensile structural properties were determined for 54 such preparations subjected to distraction rates ranging from 0.1-230 mm/sec. The ultimate load as well as the stiffness of the bone-ligament complex increased more than 50% over this strain rate range. A high correlation between bone mineral and structural properties of the ligament-bone complex was also noted. These findings suggest that, in development and construction of spine models for prediction of injury risks, one should consider the effect of different loading rates as well as the inherent properties (i.e., bone mineral content) of the biological material.

Adult↗
PubMed1994

Aging, vertebral density, and disc degeneration alter the tensile stress-strain characteristics of the human anterior longitudinal ligament.

The mechanical properties of the human lumbar anterior longitudinal ligament were investigated, and the influence of aging, disc degeneration, and vertebral bone density on these properties was determined. Tensile mechanical properties of the vertebra-anterior longitudinal ligament-vertebra complex were determined for 16 segments from cadavera of individuals who had been 21-79 years old (mean, 52.1 years) at the time of death. Regional strain patterns associated with three sites across the width and three sites along the length of the anterior longitudinal ligament were measured with use of a video-based motion analysis system. In the young, normal anterior longitudinal ligament, the elastic moduli of the insertion and substance regions of the ligament were similar (approximately 500 MPa). During aging (21-79 years), the elastic modulus of the substance region increased 2-fold, whereas the elastic modulus of the insertion decreased 3-fold; this resulted in an approximately 5-fold difference in elastic modulus between these regions in the older spine. The strength of the bone-ligament complex decreased approximately 2-fold (from 29 to 13 MPa) over this same age range. The outer portion of the anterior longitudinal ligament consistently had the highest peak tensile strains (11.8 +/- 2.7%) in all of the specimens examined. Preparations with nondegenerated discs and high bone density were significantly stronger (66%) and failed in the ligament substance; in contrast, segments from older individuals with degenerated discs and lower bone density failed in the ligament insertion regions.

Adult↗