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M Weiss

Publications and source records attributed to M Weiss.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Necessity and problems with case-related costing for intensive care patients].

To evaluate whether a German refined diagnosis-related groups (GR-DRGs)-based reimbursement of hospitals/departments covers costs per case, total cost per case accounting is necessary. The aim of the present paper is to delineate the necessity and problems with costs per case accounting for intensive care medicine. The new performance category 8-980 "complex intensive care treatment", in force from 2005 onwards, was integrated into the OPS catalogue to document intensive care work. Whether this will lead to more achievement-oriented cost accounting, has to be demonstrated by the calculations of the institute for reimbursement in hospitals. Basic financing of hospital allowance on a daily basis should be supplemented by extra charges due to analytical concepts of personnel share and to cost-consuming organ replacement procedures. This might lead to a more achievement-oriented cost accounting per case in the ICU.

Costs and Cost Analysis↗
PubMed2005

Nitrous oxide diffusion into the cuffs of disposable laryngeal mask airways.

The aim of this study was to investigate cuff pressure changes found in disposable size 3 laryngeal mask airways (LMAs) from different manufacturers during nitrous oxide exposure and to compare the results with the re-usable Classic LMA. In an in vitro experiment, laryngeal mask airway cuff pressures starting from a baseline pressure of 40 cm H(2)O were recorded using a pressure transducer for 60 min with the laryngeal mask airway cuff exposed to 66% N(2)O in oxygen. Cuff pressure increases within 5 min of nitrous oxide exposure were > 250% in the Classic LMA and were not significantly different from those found in the Marshall laryngeal mask airway. However, they were significantly greater than those in the Soft Seal, the Unique, the AMBU, and Intersurgical laryngeal mask airways, all of which demonstrated stable cuff pressure levels within the first 5 min. The cuff pressure increase following 60 min of nitrous oxide exposure was 13.0 +/- 1.1 and 14.6 +/- 0.7 cm H(2)O in the Intersurgical and Unique laryngeal mask airways, respectively, which was significantly lower than the cuff pressure increase in the Soft Seal and in the Ambu laryngeal mask airways (28.3 +/- 2.9 and 30.9 +/- 1.2 cm H(2)O, respectively). Unlike the re-usable Classic LMA and the disposable Marshall laryngeal mask airway, which have silicone cuffs, the disposable Ambu, Intersurgical, Portex Soft Seal and Unique laryngeal mask airways have cuffs constructed from PVC, which seems to be less susceptible to hyperinflation caused by nitrous oxide diffusion.

Anesthetics, Inhalation↗
PubMed2005

Performance of automated air tonometry under hypothermia.

Intestinal tonometry is used during hypothermic cardio-pulmonary bypass surgery to assess splanchnic perfusion. In an in vitro set-up the performance of automated air tonometry (TONOCAP) was tested for normo- and hypothermia. A 14-FG tonometry catheter was built into a testing chamber (100 cm(3)) perfused with blood from a cardio-pulmonary bypass circuit with P(a)co(2) held at 5.6-5.8 kPa (alpha-stat). P(r)co(2) from the balloon of the tonometry catheter was measured at intervals of 10 min at 37 degrees C and at 25 degrees C by the TONOCAP. Bias (precision) of P(r)co(2) - P(a)co(2 alpha-stat) and P(r)co(2) -P(a)co(2 pH-stat) at 37 degrees C blood temperature were low at 0.23 kPa (0.21) each. Tonometrically measured P(r)co(2) at 25 degrees C significantly differed from P(a)co(2 alpha-stat) bias (precision) of 2.00 kPa (0.11) but was similar to P(a)co(2 pH-stat) (0.30 kPa (0.11)). P(r)co(2) values as measured by the TONOCAP represent pH-stat approach. Identical blood gas management (pH- or alpha-stat) should be used for calculation of mucosal-arterial CO(2) difference (P(r-a)co(2) gap) or calculation of intramucosal pH.

Air↗
PubMed2005

Outer diameter and shape of paediatric tracheal tube cuffs at higher inflation pressures.

Cuffed tracheal tubes are becoming increasingly popular in paediatric anaesthesia and intensive care medicine. To avoid cuff related complications and airway morbidity, a thorough understanding of cuff volume/pressure behaviour and management is required. In this study, the outer cuff diameter and form stability of the cuff at high cuff pressure were assessed in a series of different paediatric cuffed tracheal tubes with internal diameter of between 3.0 and 5.0 mm. The main findings were that small amounts of inflated air led to a rapid increase in cuff pressure and volume and that the outer cuff diameters increased to 2-2.5 times the age-corresponding internal tracheal diameter following inadvertent syringe inflation. Careful cuff inflation under cuff pressure monitoring and/or automatic cuff pressure release is recommended in paediatric tracheal tube cuffs to prevent airway damage caused by manual inflation, pilot balloon compression and nitrous oxide diffusion.

Air Pressure↗
PubMed2005

Is genome size influenced by colonization of new environments in dipteran species?

Genome size differences are usually attributed to the amplification and deletion of various repeated DNA sequences, including transposable elements (TEs). Because environmental changes may promote modifications in the amount of these repeated sequences, it has been postulated that when a species colonizes new environments this could be followed by an increase in its genome size. We tested this hypothesis by estimating the genome size of geographically distinct populations of Drosophila ananassae, Drosophila malerkotliana, Drosophila melanogaster, Drosophila simulans, Drosophila subobscura, and Zaprionus indianus, all of which have known colonization capacities. There was no strong statistical differences between continents for most species. However, we found that populations of D. melanogaster from east Africa have smaller genomes than more recent populations. For species in which colonization is a recent event, the differences between genome sizes do not thus seem to be related to colonization history. These findings suggest either that genome size is seldom modified in a significant way during colonization or that it takes time for genome size of invading species to change significantly.

Analysis of Variance↗
PubMed2005

Fit and seal characteristics of a new paediatric tracheal tube with high volume-low pressure polyurethane cuff.

BACKGROUND: To evaluate a new paediatric tracheal tube (Microcuff, Weinheim, Germany) with an ultrathin high volume-low pressure polyurethane cuff. METHODS: With approval of the Hospital Ethics Committee tracheas of children undergoing general anaesthesia were intubated using a Microcuff tube. Tube sizes were selected according to: internal diameter (mm) = age/4 + 3.5 in children aged > or = 2 years. In newborns (> or = 3 kg) < or = 1 year, ID 3.0-mm tubes, and in children from 1 to 2 years, internal diameter 3.5-mm tubes were used. Tubes were classified too large if no air leakage was obtained at an airway pressure of 20 cm H2O with the cuff not inflated. Sealing pressure was assessed by auscultation. Post-extubation croup requiring therapy was noted. RESULTS: Five-hundred children were studied. In eight children the tubes were too large. Sealing pressure was 9.7 +/- 2.5 cm H2O (4-20). In two patients postextubation croup required singular short-term therapy. CONCLUSIONS: Microcuff paediatric tracheal tubes provided tracheal sealing with cuff pressures considerably lower than usually accepted. The rate of tube exchange was very low (1.6%), as was the rate of airway morbidity (croup requiring therapy; 0.4%).

Adolescent↗
PubMed2005

Nitrous oxide diffusion into tracheal tube cuffs--efficacy of a new prototype cuff pressure release valve.

BACKGROUND: The aim of this study was to evaluate the performance of a new cuff pressure release valve (CPRV), in which the release pressure can be adjusted from 10 to 25 cmH2O, particularly intended to control pressure in paediatric cuffed tracheal tubes and to avoid cuff hyperinflation caused by N2O diffusion. METHODS: In vitro: the PRV was set to 10, 15, 20 or 25 cmH2O release pressure and connected to a cuffed tube placed into a box flushed with 66% N2O in O2. The cuff pressure was monitored with and without CPRV for 60 min. Experiments were performed four times using two different CPRVs. In vivo: with Institutional Review Board approval, CPRV was studied in 50 children undergoing general anaesthesia with tracheal intubation and standardized anaesthesia technique (including 66% N2O in O2) and ventilator settings. Patients were randomized into two groups (with and without CPRV). The cuff pressure baseline was 20 cmH2O and CPRV was set to 25 cmH2O. If the cuff pressure exceeded 25 cmH2O, it was manually released to 20 cmH2O. The numbers of deflations in both groups were noted and compared by Mann-Whitney U-test (P<0.05). RESULTS: In vitro: the cuff pressure exceeded 50 cmH2O after 60 min without CPRV, but did not exceed the settings with CPRV. In vivo: there was no need to manually deflate the cuff in the CPRV group but, in every patient in the control group, three (two to seven) deflating manoeuvres were required within the first hour of anaesthesia (P<0.0001). CONCLUSION: The CPRV allows reliable cuff pressure release at various pressure levels and reliably prevents cuff pressure increases caused by N2O.

Adolescent↗
PubMed2005

[Radiation exposure of patients undergoing nuclear medicine procedures in Germany between 1996 and 2000. Multicenter evaluation of age and gender-specific patient data].

UNLABELLED: The aim of this study was to estimate both the frequency and effective dose of nuclear medicine procedures performed in Germany between 1996 and 2000 for different subgroups of patients. METHODS: Electronically archived data from 14 hospitals and 10 private practices were restored and statistically analyzed. The effective dose per examination was calculated according to ICRP publication 80 using the tissue weighting factors given in ICRP publication 60. Based on the data collected, statistical parameters were computed to characterize the frequency and effective dose of the various nuclear medicine procedures. RESULTS: In total, 604,771 nuclear medicine procedures performed in 433,709 patients were analyzed. On average, 1.4 examinations were carried out per patient and year. The median effective dose was 1.7 [5.-95. percentile; mean: 0.4-8.5; 2.9] mSv per examination and 2.3 [0.5-11.2; 3.5] mSv per patient. Interestingly, the mean effective dose per examination, but not the number of examinations per year increased with the age of the patients. Most frequent were examinations of the thyroid (36.7%), the skeleton (27.1%) and the cardiovascular system (11.1%), which were associated with a median effective dose of 0.5 [0.5-1.1; 0.7] mSv, 3.4 [2.9-5.1; 3.6] mSv and 7.3 [3.2-21.0; 9.5] mSv, respectively. Over the five-year period examined, the total annual number of PET procedures (222.3%) as well as of examinations of thyroid (24.5%), skeleton (17.9%), and the cardiovascular system (14.9%) increased markedly, whereas a decrease was observed for brain (-39.3%), lung (-20.2%) and renal (-15.0%) scans. CONCLUSION: The age- and gender-specific data presented in this study provide detailed public health information on both the current status and recent trends in the practice of diagnostic nuclear medicine examinations.

Adolescent↗
PubMed2005

[Lymph kinetics with technetium-99m labeled radiopharmaceuticals. Animal studies].

UNLABELLED: Aim of this study was to characterize suitable technetium-99m labeled tracers for lymphoscintigraphy by comparative animal tests. ANIMALS, METHODS: To evaluate the influence of the particle size and the organ tracer-uptake on lymphtransport animal experiments were performed on six different agents (including one control group). Activity distributions were examined in Sprague-Dawley-rats by lymphoscintigraphy; the maximum uptake (count-rate) of the whole body and in lymph nodes were analyzed by regions-of-interest-technique, respectively. Additionally, for characterization of lymphatic and extralymphatic traceruptake an intra-individual relative count-rate ratio of the liver, lung, kidneys, and spleen has been calculated following organ extraction. RESULTS: Organ specific differences of distribution were clearly demonstrated. Our results indicate that the kinetics of lymphoscintigraphic (99m)Tc-bound agents substantially depends on particle size. Reliable transport from the interstitium to initial lymph vessels and lymph node uptake suggested for tracers suited for lymphoscintigraphy a median size of about <100 nm. CONCLUSION: Our data could improve standardization of diagnostic methods and lead to an objective consideration of therapeutic procedures.

Animals↗
PubMed2005

Interstitial nephritis and high titers of PR3-ANCA: an unusual manifestation of ANCA-associated disease.

We present the case of a 75-year-old female with weight loss, anemia, systemic signs of inflammation, mild renal insufficiency, microscopic hematuria, mixed glomerular and tubular proteinuria, and high titers of PR3-ANCA. Renal biopsy demonstrated interstitial nephritis with some sclerosed but otherwise normal glomeruli. Extensive work-up showed no signs of granulomatous inflammation or other vasculitic organ involvement. We presumed this to be a rare renal manifestation of ANCA-associated disease with the presence of sclerosed glomeruli suggesting a previous history of glomerular involvement. In view of the absence of active vasculitic or granulomatous disease, treatment was limited to low-dose corticosteroids with good response.

Aged↗
PubMed2004

Expression of DARC, CXCR3 and CCR5 in giant cell arteritis.

OBJECTIVES: Leucocyte infiltration is the hallmark of vasculitis, chemokines being mainly responsible for leucocyte migration into inflamed tissues. The objective was to evaluate the local expression of chemokines and chemokine receptors in biopsies of patients with giant cell arteritis (GCA) compared with arteries from patients with polymyalgia rheumatica (PMR). We studied the expression of CCR5, CXCR3 and that of the Duffy antigen/receptor of chemokine (DARC), a chemokine internalizing receptor (interceptor), in parallel to the expression of the CCR5 ligand RANTES/CCL5. METHODS: Paraffin-embedded tissue sections from six patients with GCA and five patients with PMR were available for immunohistological analysis of chemokine receptor expression. RANTES/CCL5 mRNA was detected in tissue sections by in situ hybridization. RESULTS: In patients with biopsy-proven giant cell arteritis, CCR5 and CXCR3 were highly expressed by infiltrating leucocytes in involved tissue sections. Predominant clustering of CCR5+ and CXCR3+ leucocytes was found in the adventitia and was co-localized with the expression of CCL5/RANTES mRNA. Interestingly, we found marked expression of DARC on adventitial high endothelial venules in vasculitis lesions of patients with GCA, while in arteries from patients with PMR DARC was only expressed on a low number of vessels with flat lining endothelium. CONCLUSIONS: The co-localization of infiltrating CCR5+ and CXCR3+ leucocytes together with CCL5/RANTES and DARC in vasculitis lesions suggests a role for these chemokine receptors in leucocyte infiltration, possibly supported by DARC-mediated vascular presentation of chemokines.

Biomarkers↗
PubMed2004

Appropriate placement of intubation depth marks in a new cuffed paediatric tracheal tube.

BACKGROUND: The aim of this study was to evaluate the appropriateness of intubation depth marks on the new Microcuff paediatric tracheal tube. METHODS: With local Institutional Ethics Committee approval and informed parental consent, we included patients from birth (weighing > or =3 kg) to 16 yr who were undergoing general anaesthesia requiring orotracheal intubation. Tracheal intubation was performed using direct laryngoscopy, the intubation depth mark was placed between the vocal cords, and the tube was taped to the lateral corner of the mouth. The distance between the tube tip and the tracheal carina was assessed by flexible bronchoscopy with the patients in supine, and their head in neutral positions. Tube sizes were selected according to the formula: internal diameter (ID; mm)=(age/4)+3.5 in children > or =2 yr. In full-term newborns (> or =3 kg) to less than 1 yr ID 3.0 mm tubes were used and in children from 1 to less than 2 yr ID 3.5 mm tubes were used. Endoscopic examination was performed in 50 size ID 3.0 mm tubes, and in 25 tubes of each tube size from ID 3.5 to 7.0 mm. Tracheal length and percentage of the trachea to which the tube tip was advanced were calculated. RESULTS: 250 patients were studied (105 girls, 145 boys). The distance from the tube tip to the carina ranged from 1.4 cm in a 2-month-old infant (ID 3.0 mm) to 7.7 cm in a 14-yr-old boy (ID 7.0 mm). Mean tube insertion into the trachea was 53.2% (6.3) of tracheal length with a minimum of 40% and a maximum of 67.6%. CONCLUSIONS: The insertion depth marks of the new Microcuff paediatric tracheal tube allow adequate placing of the tracheal tube with a cuff-free subglottic zone and without the risk for endobronchial intubation in children from birth to adolescence.

Adolescent↗
PubMed2004

[Microcuff pediatric tracheal tube. A new tracheal tube with a high volume-low pressure cuff for children].

BACKGROUND: Principles and characteristics of the recently introduced Microcuff paediatric tracheal tube (Microcuff, GmbH, Weinheim, Germany) with anatomically based depth markings, cuff-free subglottic tube shaft and short high volume-low pressure cuff with ultrathin cuff membrane are presented. First available tubes (ID 4.0 mm) were evaluated regarding cuff pressures required to seal the trachea and regarding the distance from the tube tip to the carina. METHODS: After obtaining approval of the local ethical committee, 20 children aged 2-4 years, receiving tracheal intubation under general anaesthesia with muscle paralysis, were included. The tubes were placed during direct laryngoscopy and the glottic depth marking placed between the vocal cords. Cuff pressure to prevent audible air leakage at standardised ventilator settings (PIP 20 cm H(2)O/PEEP 5 cm H(2)O/RR20 x min(-1)) was assessed by means of a cuff pressure manometer within 5 min after intubation. Subsequently, the distance from the tube tip to the tracheal carina was measured by means of fibre bronchoscopy. Data are presented as the median (range). RESULTS: Patient age was 3.0 years (2.0-3.9 years), weight 13.5 kg (9.1-19.2 kg) and body length 95 cm (79-105 cm). The lowest cuff pressure required to seal the trachea ranged from 4-14 cmH(2)O (median 10 cm H(2)O), the distance from tube tip to tracheal carina was to 2.9 cm (2.0-4.5 cm). CONCLUSIONS: The new Microcuff paediatric tracheal tube with ultrathin high volume-low pressure cuff required tracheal sealing pressures below tracheal wall pressures usually required with uncuffed tracheal tubes for efficient sealing and ventilation at 20 cm H(2)O peak inspiratory pressure. The distance from the tube tip to carina was in the safe range in all patients.

Anesthesia, General↗
PubMed2004

Erosive separation of organic coatings from fibrous substrates.

The separation of organic coatings from fibrous substrates is a key problem in recycling processes. This problem applies to carpets, technical textiles and automotive interior components. This paper reports about results of laboratory studies involving the application of high-speed liquid jets to solve this problem. Results from high-speed video images are used to qualify the principal erosion process. It is shown that the coating material is first ground by the jet; the generated erosion debris is then pushed through the permeable fibrous fabric of the substrate. It is also found that threshold conditions exist for the coating grinding process and for the debris transportation. These threshold conditions depend on target composition and process parameters. A phenomenological separation model is introduced. The influence of key process parameters, namely jet velocity, exposure time, stand-off distance and impact angle, is also investigated. It is found that high-speed liquid jets are suitable tools for separating organic coatings completely and selectively from fibrous substrates. Recommendations on how to optimise the erosion process are derived from the results.

Automobiles↗
PubMed2004

Air leakage around endotracheal tube cuffs.

BACKGROUND AND OBJECTIVE: To compare the recently introduced Microcuff endotracheal tube with conventional tubes in respect of the cuff pressures required to prevent air leakage. METHODS: The following tubes (ID 7.0mm) were compared: Microcuff HVLP ICU, Mallinckrodt HiLo, Portex Profile Soft Seal, Rüsch Super Safety Clear and Sheridan CF. Fifty patients undergoing endotracheal intubation with a cuffed tube of internal diameter 7.0 mm were studied. Tracheas were intubated using one of the endotracheal tubes in random order. Cuff pressure to prevent air leakage at standardized ventilator setting (peak inspiratory pressure 20 cmH2O/PEEP 5 cmH2O/respiratory rate 15 breaths min(-1)) was assessed by auscultation of audible sounds at the mouth. Patients characteristics and cuff pressures from each brand were compared to the Microcuff group using the Mann-Whitney U-test (P < 0.05 was chosen as the level of statistical significance). RESULTS: Patients' median age (range) was 14.2 (12.0-17.1) yr, body weight 57.5 (40.0-81.9) kg and length 164.9 (146.5-190.0) cm. No significant differences in patients' characteristics were found between groups. Mean cuff pressure (all tubes) required for air sealing was 19.1 (8-42) cmH2O. The Microcuff tube required significantly lower sealing pressures (9.5 (8-12) cmH2O) compared to the other brands of endotracheal tube (P < 0.05, Mann-Whitney U-test). CONCLUSION: The Microcuff endotracheal tube with its ultra-thin polyurethane cuff membrane required the lowest sealing pressure to prevent air leakage. These features are potentially of interest for long-term intubated patients and for cuffed endotracheal tubes in children, allowing tracheal sealing at lower cuff pressures implying less damage to the trachea.

Adolescent↗
PubMed2004

Enhanced glucose-dependent glucagon-like peptide-1 and insulin secretion in Crohn patients with terminal ileum disease is unrelated to disease activity or ileal resection.

BACKGROUND: Enhanced secretion of glucagon-like peptide-1 (GLP-1) has been reported in patients with Crohn disease (CD). However, the correlation between the enteropancreatic axis and the activity of CD remains unclear. METHODS: Plasma glucose, insulin, GLP-1 levels and insulin sensitivity were determined before and after oral glucose tolerance tests in 13 patients with CD of the terminal ileum, in 13 patients after resection of the terminal ileum and in 7 healthy controls. Basal and stimulated insulin sensitivities were determined using the homeostasis model assessment (HOMA) and the insulin sensitivity index (ISI) methods, respectively. RESULTS: Basal and stimulated glucose levels were comparable in patients and controls. The peak stimulated GLP-1 secretion was significantly higher in the patient group compared to controls: 12.2 +/- 1.24 pM/L and 8.1 +/- 1.72 pM/L, respectively, P=0.03. This was associated with 52% increased overall insulin secretion in the patients' group as compared to controls (P=0.007) and a higher peak insulin response: 63.5 +/- 9.69 mU/L and 41.5 +/- 6.85 mU/L for patients and controls, respectively, P=0.04. Operated patients had similar GLP-1 levels but higher peak and overall insulin secretions compared with those in non-operated patients (P=0.01). Fasting and stimulated insulin sensitivities were reduced only in patients with ileal resection as compared to controls: P=0.01 and P=0.05, respectively. No correlation was found between the CD activity index and GLP-1 or insulin secretion. CONCLUSIONS: CD of the terminal ileum is associated with enhanced glucose-dependent GLP-1 secretion, which is unrelated to disease activity or ileal resection.

Adult↗
PubMed2004

Shortcomings of cuffed paediatric tracheal tubes.

BACKGROUND: The goal of this investigation was to evaluate adequacy of the design of readily available paediatric cuffed tracheal tubes (CPTT). METHODS: In 15 series of cuffed (11) and uncuffed (four) paediatric tracheal tubes (ID: 2.5-7.0 mm) from four different manufacturers the following dimensions were measured: outer diameter of the tube, position and largest diameter of the tube cuff inflated at 20 cm H(2)O and position of depth markings and compared with age-related dimensions. RESULTS: Outer diameters for tubes with similar IDs varied markedly between manufacturers and between cuffed and uncuffed tracheal tubes from the same manufacturer. Cuff diameters at 20 cm H(2)O cuff pressure and cross-sectional cuff area at 20 cm H(2)O cuff pressure did not always cover maximal internal age-related tracheal diameters and cross-sectional areas. Placing the tube tip in the mid-trachea, the cuffs of cuffed tubes with ID 3.0, 4.0, or 5.0 mm would become positioned within the larynx. If the cuffs were placed 1 cm below the cricoid level, many of the tube tips would be dangerously deep within the trachea. Only five of the 11 cuffed tubes had a depth marking. In many of these tubes the distances from depth marking to tube tip were greater than the age-related minimal tracheal length. CONCLUSION: Most cuffed paediatric tracheal tubes are poorly designed, in particular the smaller sizes. A better design of cuffed tubes with a short high-volume, low-pressure cuff, cuff-free subglottic space and adequately placed depth markings are urgently needed.

Adolescent↗