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Search Results: 1 - 10 of 1329 matches for " Dietrich Henzler "
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What on earth is APRV?
Dietrich Henzler
Critical Care , 2011, DOI: 10.1186/cc9419
Abstract: Airway pressure release ventilation (APRV) was described more than 20 years ago [1] as a mode that allows spontaneous breathing throughout the ventilation cycle. APRV is a time-cycled alternant between two levels of positive airway pressure, with the main time on the high level and a brief expiratory release to facilitate ventilation. As such, APRV may be considered a partial ventilatory support modality that has the ability to deliver the full work of breathing if needed. Although it seems that APRV is well defined, the characteristics are surprisingly unspecific, as is the way APRV is used.Different perceptions of this mode may exist around the globe. While 'APRV' is common to users in North America, a very similar mode, biphasic positive airway pressure (BIPAP), was introduced in Europe [2]. The term APRV has also been used in American journals where, from the ventilation characteristics, BIPAP would have been the more adequate terminology [3]. To further confusion, BiPAP? (with a small 'i') is a registered trade-mark for a noninvasive ventilation mode in a specific ventilator (Respironics Inc.). Other names (BILEVEL, DUOPAP) have been created for legal reasons. Although similar in modality, these terms share the same shortcomings: they describe how a mode is intended to inflate the lung, rather than defining the characteristics of synchronization or the way spontaneous breathing efforts are supported.The perceived differences between APRV and BIPAP have been described previously [4,5]. Essentially, APRV has a longer time phase on the high pressure level, while BIPAP usually does not exceed an inspiration:expiration time ratio of 1:1 [5]. Expiratory lung collapse is prevented in APRV by creating intrinsic positive end-expiratory pressure (PEEP) during the short expiration, while in BIPAP the PEEP is directly set with the lower pressure level. BIPAP can be applied in different ways: with unsynchronized, unsupported interfacing of spontaneous breaths ('genuine' BIP
Partial Ventilatory Support Modalities in Acute Lung Injury and Acute Respiratory Distress Syndrome—A Systematic Review
Sarah M. McMullen,Maureen Meade,Louise Rose,Karen Burns,Sangeeta Mehta,Robert Doyle,Dietrich Henzler
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040190
Abstract: The efficacy of partial ventilatory support modes that allow spontaneous breathing in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is unclear. The objective of this scoping review was to assess the effects of partial ventilatory support on mortality, duration of mechanical ventilation, and both hospital and intensive care unit (ICU) lengths of stay (LOS) for patients with ALI and ARDS; the secondary objective was to describe physiologic effects on hemodynamics, respiratory system and other organ function.
Effects of different fibrinogen concentrations on blood loss and coagulation parameters in a pig model of coagulopathy with blunt liver injury
Oliver Grottke, Till Braunschweig, Dietrich Henzler, Mark Coburn, Rene Tolba, Rolf Rossaint
Critical Care , 2010, DOI: 10.1186/cc8960
Abstract: Coagulopathy was induced in 18 anaesthetized pigs (32 ± 1.6 kg body weight) by replacing 80% of blood volume with hydroxyethylstarch 130/0.4 and Ringer's lactated solution, and re-transfusion of erythrocytes. Animals were randomly assigned to receive either 70 mg kg-1 (F-70) or 200 mg kg-1 (F-200) fibrinogen or placebo before inducing blunt liver injury using a force of 225 ± 26 Newton. Haemodynamics, coagulation parameters and blood loss were monitored for 2 hours. After death, histological examination of internal organs was performed to assess the presence of emboli and the equality of liver injury.Plasma dilution caused severe coagulopathy. Measured by thromboelastography fibrinogen restored coagulation dose-dependently. Total blood loss was significantly lower and survival better in both fibrinogen groups as compared to controls (P < 0.05). Between the F-70 (1317 ± 113 ml) and the F-200 group (1155 ± 232 ml) no significant difference in total blood loss could be observed, despite improved coagulation parameters in the F-200 group (P < 0.05). Microscopy revealed even injury pattern and no (micro) thrombi for either group.Restoring fibrinogen with 70 or 200 mg kg-1 after severe dilutional coagulopathy safely improved coagulation and attenuated blood loss after experimental blunt liver trauma. The higher dosage of fibrinogen was not associated with a further reduction in blood loss.Traumatised and surgical patients with massive haemorrhage are predisposed to develop coagulopathy, as a result of multiple mechanisms including acidosis, hypothermia, anaemia, hyperfibrinolysis and hypotension-induced inflammation, as well as consumption and dilution of coagulation factors [1]. Dilutional coagulopathy may occur after massive blood loss, as crystalloid and colloid solutions are infused for fluid resuscitation. The degree of coagulopathy depends on the type and volume of the fluids infused [2]. Resuscitation with colloid plasma expanders may lead to a functional fibrinoge
Respiratory compliance but not gas exchange correlates with changes in lung aeration after a recruitment maneuver: an experimental study in pigs with saline lavage lung injury
Dietrich Henzler, Paolo Pelosi, Rolf Dembinski, Annette Ullmann, Andreas H Mahnken, Rolf Rossaint, Ralf Kuhlen
Critical Care , 2005, DOI: 10.1186/cc3772
Abstract: In eight anesthetized and mechanically ventilated pigs, acute lung injury was induced by saline lavage and a recruitment maneuver was performed by inflating the lungs three times with a pressure of 45 cmH2O for 40 s with a constant positive end-expiratory pressure of 10 cmH2O. The association of gas exchange and lung mechanics parameters with the amount and the changes in aerated and nonaerated lung volumes induced by this specific recruitment maneuver was investigated by multi slice CT scan analysis of the whole lung.Nonaerated lung correlated with shunt fraction (r = 0.68) and respiratory system compliance (r = 0.59). The arterial partial oxygen pressure (PaO2) and the respiratory system compliance correlated with poorly aerated lung volume (r = 0.57 and 0.72, respectively). The recruitment maneuver caused a decrease in nonaerated lung volume, an increase in normally and poorly aerated lung, but no change in the distribution of a tidal breath to differently aerated lung volumes. The fractional changes in PaO2, arterial partial carbon dioxide pressure (PaCO2) and venous admixture after the recruitment maneuver did not correlate with the changes in lung volumes. Alveolar recruitment correlated only with changes in the plateau pressure (r = 0.89), respiratory system compliance (r = 0.82) and parameters obtained from the pressure-volume curve.A recruitment maneuver by repeatedly hyperinflating the lungs led to an increase of poorly aerated and a decrease of nonaerated lung mainly. Changes in aerated and nonaerated lung volumes were adequately represented by respiratory compliance but not by changes in oxygenation or shunt.Severe impairment of oxygenation in acute lung injury and in the acute respiratory distress syndrome (ARDS) is caused by an inhomogenous ventilation-perfusion distribution () and an increase in shunt fraction. The amount of aerated lung is markedly reduced due to alveolar collapse and flooding [1,2]. Mechanical ventilation has been shown to further a
Analysis of Sigmoidal Equations To Describe the Pulmonary Pressure- Volume Curve in Acute Respiratory Distress Syndrome
Sandra Orfao, Nadine Hochhausen, Ralf KuhlenDietrich Henzler
The Open Critical Care Medicine Journal , 2008, DOI: 10.2174/1874828700801010054]
Abstract: Pulmonary pressure-volume curves (P-V curves) of patients with acute lung injury are commonly analyzed using a parametric algorithm with symmetrical properties. Some of the aspects observed after performing nonlinear regression for two models capable of fitting symmetric, respectively asymmetric data are discussed. One analyzed aspect was the algebraic complexity of the asymmetric model that does not allow for an estimation of the boundaries of the zone of maximal compliance directly from the parameter estimates in contrast to the symmetric model. Moreover, mathematical evidence is provided. Using a sigmoid equation for analysis of P-V curves a systematic deviation caused by asymmetrical distribution was encountered, leading to non-robust definitions of lower and upper inflection points. Increasing the number of parameters to fit asymmetric data does not increase physiological expression. We conclude that some of the drawbacks in using P-V curves may be attributed to imprecise analysis tools. To increase the value of P-V curves other forms of mathematical analysis should be investigated.
A new LEED Instrument for Quantitative Spot Profile Analysis
U. Scheithauer,G. Meyer,M. Henzler
Physics , 2015, DOI: 10.1016/0039-6028(86)90321-3
Abstract: A new instrument for spot profile analysis of electron diffraction - SPA-LEED - has been set up. The instrument works either with a transparent phosphor screen for visual inspection of the pattern or in its main mode with a channeltron for the measurement of the intensity. The diffraction pattern is recorded with a fixed channeltron position by scanning the beam over the channeltron aperture using two sets of electrostatic deflection plates. The scanning range covers about 30{\deg}. The intensity may vary over five orders of magnitude. The SPA-LEED system was checked with the Si 111 7 x 7 surface. A full width at half maximum of 0.3% of the normal reflex distance corresponding to a transfer width of 110 nm is reproducibly obtained. Under optimum conditions the transfer width rose up to about 200 nm. Initial high resolution measurements have been performed on the system Pb on Cu 111. The results demonstrate the possibilities of the new instrument for qualitative and quantitative analysis.
Two-Phase Transplantation (TPTX) Concept: A New Approach for Instant Rehabilitation of Young Children after Avulsion of Central Incisor  [PDF]
Dirk Nolte, Claudia Tschammler, Markus Henzler, Robert Linsenmann, Johannes Angermair Angermair
Open Journal of Stomatology (OJST) , 2017, DOI: 10.4236/ojst.2017.72009
Abstract: Background: To present a new idea for rapid management of tooth avulsion in young children and adolescents (age: 6 to 16) by this case report. Case presentation: A nine-year-old boy presented with loss of upper permanent central incisor in early mixed dentition (6 to 10 years, phase I). The not yet fully resorbed primary canine was used as tooth transplant for the lost incisor. The intentional renounce on endodontic treatment of the primary transplant permits natural exfoliation of the transplant occurring either spontaneously or due to undermining resorption through the adjacent erupting teeth. In the late mixed dentition (10 to 16 years, phase II), the primary tooth transplant is electively removed and replaced by a premolar autotransplant for long-term rehabilitation of the meanwhile adolescent patient. Results: Primary canine autoTX acts as a temporary denture with instant surgical gap closure. Ensuing premolar autoTX in phase II then acts as permanent denture with excellent 10 years survival rates. Patient satisfaction issued by a questionnaire resulted in good to very good school grades for both phases of autotransplantation. Conclusions: The “TPTX” concept is a new surgical approach that immediately restores the patient’s function and aesthetics after tooth loss in early childhood supporting the growth of local bone and soft tissue in the growing adolescent jaw.
The marimba: musical and secret language of the political violence in Guatemala La marimba: lenguaje musical y secreto de la violencia política en Guatemala
América Latina Hoy , 2010,
Abstract: The author reflects the construction of national music while the arise of the nation State in Guatemala. This development begins formally while the first decades of the nineteenth century and has not finished yet. For the myth of the Nation state and those who use it for their project of domination it is crucial that national music can be distinguished externally from musics generated by other nations while it can be applied internally for the aim of national homogenisation. Since the middle of the nineteenth century the music is used in Guatemala for the dissemination of ideologies that help to construct this myth. The vernacular music of the Maya people does not follow this logic. Hence it is considered inferior or incorrect . For the myth of the nation State only the totality of the people as an abstract concept can understand and appreciate the national music, but not the concrete or individual group. Assuming this the music is converted into an important tool of a repressive mechanism and deculturation. The marimba thus is the symbol of the nation State in Guatemala. The dictatorships of the army, who were the main responsible of the genocide of the Maya people, declared the chromatic marimba symbol of the nation. After a long history of violence the marimba desindianizada and therefore ladinizada reached the status of the national instrument. While the period of violence the chromatic marimba never ceased to sound in the nightclubs and the elegant restaurants of the Capital. In the meanwhile the Mayas of the highlands hided their K’ojomes in caves and ca ons to protect them from the army. Therefore the anarchic and rebellious diversity of the k’ojom’s tuning continues to be the vernacular and secret language of groups and individuals who do not belong to the national reality of the chromatic marimba. El autor refleja la construcción de la música nacional en el proceso del devenir del Estado nacional guatemalteco. Este proceso comienza formalmente a principios del siglo XIX, pero no ha concluido aún. Para el mito del Estado nación y para aquellos que lo utilizan para su proyecto de dominación, es de importancia d
Gate Leakage Reduction by Clocked Power Supply of Adiabatic Logic Circuits
Ph. Teichmann,J. Fischer,E. Amirante,St. Henzler
Advances in Radio Science : Kleinheubacher Berichte , 2005,
Abstract: Losses due to gate-leakage-currents become more dominant in new technologies as gate leakage currents increase exponentially with decreasing gate oxide thickness. The most promising Adiabatic Logic (AL) families use a clocked power supply with four states. Hence, the full VDD voltage drops over an AL gate only for a quarter of the clock cycle, causing a full gate leakage only for a quarter of the clock period. The rising and falling ramps of the clocked power supply lead to an additional energy consumption by gate leakage. This energy is smaller than the fraction caused by the constant VDD drop, because the gate leakage exponentially depends on the voltage across the oxide. To obtain smaller energy consumption, Improved Adiabatic Logic (IAL) has been introduced. IAL swaps all n- and p-channel transistors. The logic blocks are built of p-channel devices which show gate tunneling currents significantly smaller than in n-channel devices. Using IAL instead of conventional AL allows an additional reduction of the energy consumption caused by gate leakage. Simulations based on a 90nm CMOS process show a lowering in gate leakage energy consumption for AL by a factor of 1.5 compared to static CMOS. For IAL the factor is up to 4. The achievable reduction varies depending on the considered AL family and the complexity of the gate.
Power supply network design: a case study driven approach
M. Eireiner,S. Henzler,T. Missal,J. Berthold
Advances in Radio Science : Kleinheubacher Berichte , 2007,
Abstract: A study, based on product related scenarios, on power supply integrity issues is conducted. The effectiveness of specific design parameters depends strongly on the expected loading of the power distribution grid. Therefore, the commonly used approach to only use an even current distribution can lead to non-optimal power grid designs. For power grid optimization, a problem reduction from quadratic to linear order is presented. Simulations in a System-on-Chip (SoC) environment show, that power supply integrity mainly depends on the placing of the cores within the SoC die.
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