Firms in an R&D race actively manage rivals' beliefs by disclosing and concealing information on ... more Firms in an R&D race actively manage rivals' beliefs by disclosing and concealing information on their cost of investment. The firms' disclosure strategies affect their incentives to invest in R&D, and to acquire information. We compare equilibria under voluntary disclosure with those under mandatory disclosure in a model where the firms' cost of investment are identically independently distributed. Under voluntary disclosure firms conceal bad news, and disclose good news only if little knowledge spills over to their rival. Under mandatory disclosure firms expect higher profits for given information acquisition investments, but they may acquire less information.
The feasibility of three mathematical models to extrapolate the tail of thermodilution curves, wh... more The feasibility of three mathematical models to extrapolate the tail of thermodilution curves, when flectures are present in the descending limb, was tested in anesthetized pigs. The models were a local random walk model (LDRW), a log-normal distribution, and a two-compartment model. First, the accuracy of the extrapolation of the tail by each model was tested on two undisturbed curves by taking the truncation at five different points on the descending limb. The extrapolated curve area obtained from each model was compared with total area of the undisturbed curve. Next, dilution curves obtained during inspiratory hold maneuvers and characterized by deflection points were analyzed, taking the truncation just before deflection. The estimates of cardiac output by the models were compared with electromagnetically measured flow in the pulmonary artery. The area of the dilution curve was estimated more accurately when more information on the descending limb was available. The LDRW model a...
I study the incentives of Cournot duopolists to share their technologies with their competitor in... more I study the incentives of Cournot duopolists to share their technologies with their competitor in markets where intellectual property rights are absent and imitation is costless. The trade-off between a signaling effect and an expropriation effect determines the technology-sharing incentives. In equilibrium at most one firm shares some of its technologies. For similar technology distributions, there exists an equilibrium in which nobody shares. If the technology distributions are skewed towards efficient technologies, then there may exist equilibria in which one firm shares all technologies, only the best technologies, or only intermediate technologies. No other equilibria can exist.
We examine the persistence of monopolies in markets with innovations when the outcome of research... more We examine the persistence of monopolies in markets with innovations when the outcome of research is uncertain. We show that for low success probabilities of research, the incumbent can seldom preempt the poten-tial entrant. Then the efficiency effect outweighs the replacement effect. It is vice versa for high probabilities. Moreover, the incumbent special-izes in "safe" research and the potential entrant in "risky" research. We also show that the probability of entry is an inverted U-shape in the success probability. Since even at the peak entry is rather unlikely, the persistence of the monopoly is high., as well as seminar participants at the Max Planck Institute for Research on Collective Goods in Bonn, the Summer School on Contract Theory in Bronnbach, and the University of Bonn for helpful comments and sugges-tions.
We studied the effect of forced inflation at different alveolar volumes (VA) on carbon monoxide d... more We studied the effect of forced inflation at different alveolar volumes (VA) on carbon monoxide diffusing capacity (DLCO) in anaesthetized, paralysed and mechanically ventilated healthy pigs. An inspiratory pause procedure (equivalent of the single-breath technique) consisting of a pause between an inflation and expiration, both at a constant flow rate, was used. The procedure was computer-controlled and could easily be standardized. In five pigs, VA was varied at constant inflation volume by increasing positive end-expiratory pressure (PEEP) from 2 to 10 cmH2O. Inspiratory pause time was varied from 1 to 8 s to verify whether the decay of CO was exponential. In nine pigs, DLCO was estimated at four different VA values by inflating with 15-30 ml kg-1 at 2 cmH2O PEEP. An exponential decay of CO was always obtained. With increasing VA by either an increase in PEEP or inflation volume, DLCO remained constant. Since the diffusing capacity of the pulmonary membrane is expected to increase with increasing VA, the constant DLCO may be attributed to a decrease in capillary blood volume.
A new thermodilution method for frequent (near continuous) estimation of cardiac output, without ... more A new thermodilution method for frequent (near continuous) estimation of cardiac output, without manual injection of £uid into the blood, was tested. The method utilizes a pulmonary artery catheter equipped with a £uid ¢lled heat exchanger. The technique is based on cyclic cooling of the blood in the right atrium and measurement of the temperature changes in the pulmonary artery. Using this technique, a new estimate of cardiac output can be obtained every 32 s. Cardiac output estimates, obtained for a running mean of three measurements with this method, were compared to the mean of three conventional thermodilution measurements. The measurements were obtained during short periods of stable respiration and circulation. In six pigs, we made 46 paired measurements of conventional thermodilution (TD) and near continous (TDc) thermodilution. The cardiac output (CO TD) ranged from 2.41 3.7 l/min (mean 5.4 l/min). The best linear ¢t through the paired data points was CO TDc = À0.57 + 1.01 CO TD. The mean di¡erence between the methods was À0.50 l/min (S.D. = 0.39). The mean coe¤cient of variation of repeated measurements with the near continuous thermodilution was 3.6%. Considering changes of more than 0.25 l/min to be signi¢cant, all changes in cardiac output measured by conventional thermodilution were followed by the running mean of three near continuous thermodilution estimates. This study demonstrates the feasibility of the new method to monitor cardiac output, and to detect all changes greater than 0.25 l/min.
Journal of Clinical Monitoring and Computing, 2002
A novel algorithm for real-time detection and prediction of the dicrotic notch from aortic pressu... more A novel algorithm for real-time detection and prediction of the dicrotic notch from aortic pressure waves was evaluated in arrhythmic aortic pressure signals from heart failure patients. A simplified model of the arterial tree was used to calculate real-time aortic flow from aortic pressure. The dicrotic notch was detected at the first negative dip from the calculated flow, prediction of
This paper studies the incentives for production cost disclosure in an asymmetric Cournot duopoly... more This paper studies the incentives for production cost disclosure in an asymmetric Cournot duopoly. Whereas the efficient firm (consumers) prefers information sharing (concealment) when the firms choose accommodating strategies in the product market, the firm (consumers) may prefer information concealment (sharing) when it can exclude its competitor from the market. Hence, the rankings of expected profit and consumer surplus can be reversed if exit of the inefficient firm is possible. Although the efficient firm has stronger incentives to share information when it shares strategically, there remain cases in which the firm conceals information in equilibrium to induce exit.
Objective To examine the effects of short-term cyclic stretch on apoptosis in alveolar type II ce... more Objective To examine the effects of short-term cyclic stretch on apoptosis in alveolar type II cells (A549). To study in vitro the direct influence of alveolar type II cells on mechanical stretch. Methods A549 were treated with different doses of lipopolysaccharide (LPS), 0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, and then A549 were lengthened 5%, 15%, 30% using a FLEXCELL tension unit 4000, a vacuum-driven device that applies strain to cells, which were cultured in six-well plates coated with collagen-I, and 12 cycles/min for 4 hours. Apoptosis was measured using the flow cytometry method that measures annexin V and propidium iodide (PI) staining. The morphological changes of apoptotic cells were observed by transmission electron microscope. Results Apoptosis could be induced in alveolar type II cells (A549) by mechanical stretch. The percentage of annexin V + PI cells increased after being treated with cyclic stretch for 4 hours by 5%, 15%, 30% in all groups. The morphological features of apoptotic cells demonstrated by transmission electron microscope were as follows: shrinkage of the cell, chromatin condensation and aggregation under the nuclear membrane as a crescent or lump, membrane-encapsulated nuclear fragment or cell organ formed by invagination of the cell membrane, and apoptotic body formation followed by vacuolization. Conclusion Apoptosis induced by mechanical stretch and LPS is dose dependent. Mechanical stretch aggravates apoptosis especially in cells treated with LPS. Annexin V and PI double staining is a specific, sensitive, and quantitative method for analyzing apoptotic cells. It is also helpful to clarify the protective mechanism of low-volume ventilation in ARDS. Acknowledgement The study was funded by the 'One Hundred People' project of Shanghai Sanitary Bureau (03-77-20).
The imperfect appropriability of revenues from innovation affects the incentives of firms to inve... more The imperfect appropriability of revenues from innovation affects the incentives of firms to invest, and to disclose information about their innovative productivity. It creates a free-rider effect in the competition for the innovation that countervails the familiar business-stealing effect. Moreover, it affects the disclosure incentives such that full disclosure emerges for extreme revenue spillovers (e.g., full protection and no protection of intellectual property), but either partial disclosure or full concealment emerges for intermediate spillovers. I analyze the implications of imperfect appropriability and strategic disclosure for the firms' profits and the probability of innovation.
By using general information structures and precision criteria based on the dispersion of conditi... more By using general information structures and precision criteria based on the dispersion of conditional expectations, we study how oligopolists' information acquisition decisions may change the effects of information sharing on the consumer surplus. Sharing information about individual cost parameters gives the following trade-off in Cournot oligopoly. On the one hand, it decreases the expected consumer surplus for a given information precision, as the literature shows. On the other hand, information sharing increases the firms' incentives to acquire information, and the consumer surplus increases in the precision of the firms' information. Interestingly, the latter effect may dominate the former effect.
Pfl�gers Archiv European Journal of Physiology, 1996
A double indicator dilution technique for determining the mean cross-sectional area (CSA) of a bl... more A double indicator dilution technique for determining the mean cross-sectional area (CSA) of a blood vessel in vivo is presented. Analogous to the thermodilution method, dilution of hypertonic saline was measured by an electrical conductance technique. Because the change in conductance rather than absolute conductance was used to calculate CSA, pulsatile changes in shear rate of blood and conductance of surrounding tissues had no effect on the data. To calculate CSA from an ion mass balance, cardiac output was needed and estimated from the thermodilution curve using the same "cold" (hypertonic) saline injection. The mean CSA, obtained from this double indicator dilution method (CSA GD), was compared with the CSA obtained from the intravascular ultrasound method (IVUS) in 44 paired observations in six piglets. The regression line is close to the line of identity (CSAGD =-1.83 + 1.06-CSAivus, r = 0.96). The difference between both CSAs was independent of the diameter of the vessel, on average-0.99 mm 2 + 2.64 mm2 (mean CSAGD = 46.84 ± 8.21 mm 2 , mean CSA,vus = 47.82 ± 9.08 mm 2) and not significant. The results show that the double indicator dilution method is a reliable technique for estimating the CSA of blood vessels in vivo.
We tested the hypothesis that during high-frequency oscillatory ventilation, the oscillatory pres... more We tested the hypothesis that during high-frequency oscillatory ventilation, the oscillatory pressure ratio (OPR) is minimal at the optimal mean airway pressure (Paw). OPR is defined as the ratio of pressure swings at the distal end and the proximal opening of the endotracheal tube. Optimal Paw was assumed to be the lowest Paw at which the physiological shunt fraction was below 0.1. Acute lung injury was produced by saline lung lavage of pigs who were then subjected to a stepwise increase of Paw to impose underinflation, optimal inflation, and overdistention (inflation phase), followed by a stepwise decrease of Paw (deflation phase). OPR reached a minimum of 0.10 +/- 0.01 at Paw = 31 +/- 4 cm H(2)O during the inflation phase and a minimum of 0.04 +/- 0.01 at Paw = 18 +/- 1 cm H(2)O during the deflation phase. Optimal Paw was 31 +/- 4 cm H(2)O on the inflation limb and 14 +/- 2 cm H(2)O on the deflation limb. Paw at the minimal OPR was not significantly different from the optimal Paw during the inflation phase, and slightly but significantly higher (4.1 +/- 1.6 cm H(2)O) during the deflation phase. In conclusion, a consistent relationship was found between OPR and Paw, with a minimum in all animals. The minimal OPR coincides fairly well with the Paw where oxygenation is optimal.
We study whether a firm that produces and sells access to an excludable public good should face a... more We study whether a firm that produces and sells access to an excludable public good should face a self-financing requirement, or, alternatively, receive subsidies that help to cover the cost of public-goods provision. The main result is that the desirability of a self-financing requirement is shaped by an equity-efficiency trade-off: While first-best efficiency is out of reach with such a requirement, its imposition limits the firm's ability of rent extraction. Hence, consumer surplus may be higher if the firm has no access to public funds.
The time interval between mitral and tricuspid valve closure was measured from M-mode echocardiog... more The time interval between mitral and tricuspid valve closure was measured from M-mode echocardiograms in patients with Ebstein's anomaly. It was found that this time interval demonstrated a range of values within each patient. The use of different transducer positions on the chest wall was found to be the predominant factor. There was no correlation between the measured time interval, its variability, and the moment of measurement during breathing. However, a period of breathholding significantly reduced the variability. This study indicates that a wide range of time intervals might be measured in a single patient. We conclude therefore, that this parameter should be used with great care in the diagnosis of Ebstein's anomaly.
Journal of Cardiothoracic and Vascular Anesthesia, 2011
The authors evaluated the ability of 2 pulse contour cardiac output (CO) techniques to track CO c... more The authors evaluated the ability of 2 pulse contour cardiac output (CO) techniques to track CO changes during passive leg raising (PLR) to assess fluid loading responsiveness. A prospective study. An intensive care unit in a university hospital. Twenty mechanically ventilated postoperative cardiac surgery patients. Thirty-degree PLR. The authors estimated CO by 3 techniques: thermodilution (COtd), arterial pulse power (Coli; LiDCO, London, UK), and pulse contour method (Com; FMS, Amsterdam, The Netherlands) based on uncalibrated Modelflow. The authors measured heart rate (HR), central venous pressure, arterial pulse pressure (PP), systolic pressure (SP), and mean arterial pressure (MAP). Stroke volume (SV), SP, PP, and SV variation (PPV and SVV, respectively) were calculated over 5 breaths. SVV was measured by both LiDCO (SVVli) and Modelflow (SVVm) devices. PLR-induced changes in COtd correlated with COli (p < 0.001) and COm (p < 0.001). Preload dependence was predicted with an area under the ROC curve of 0.968 for ΔCOm, 0.841 for ΔCOli, 0.825 for SVVm, 0.873 for SVVli, 0.808 for PPV, 0.778 for ΔSP, 0.714 for ΔPP, and 0.873 for ΔMAP. Changes in COm, COli, SVV, and PPV track COtd changes during PLR with a high degree of accuracy in sedated, ventilated, postoperative cardiac surgery patients. Changes in pulse contour CO after PLR can be used to predict fluid loading responsiveness.
Journal for European Environmental & Planning Law, 2012
This section briefly describes the significant political initiatives and acts of legislation in t... more This section briefly describes the significant political initiatives and acts of legislation in the environmental field adopted from 1 July 2011 until 29 February 2012.
Development of a stable model of respiratory distress in pigs with oleic acid, fulfilling clinica... more Development of a stable model of respiratory distress in pigs with oleic acid, fulfilling clinical criteria of the adult respiratory distress syndrome (ARDS). Design: Eight pigs (9.1 _ 0.7 kg) were anesthetized with pentobarbital, paralyzed with tubocurarine and mechanically ventilated with an Fio 2 of 0.6, an I: E ratio of 2: 3 and a PEEP of 0.2 kPa. Oleic acid (dissolved 1:1 in 96% alcohol) was administered in a series of multiple injections of 0.1 ml until P~o2 was lower than 8 kPa. Measurements and results: Careful titration of the oleic acid injections on guidance of the PaQ established a reproducible respiratory distress (P, o2 = 7.3 _+ 0.8 kPa), in which gas exchange and hemodynamic variables were stable for at least 4 h. The number of oleic acid injections (22 + 11, mean and SD) varied between the animals. Conclusions: With the use of multiple injections of oleic acid, a stable model of early respiratory distress in pigs can be achieved, in spite of individual differences in sensitivity. Such a stable model allows for a diversity of studies on early respiratory distress.
Firms in an R&D race actively manage rivals' beliefs by disclosing and concealing information on ... more Firms in an R&D race actively manage rivals' beliefs by disclosing and concealing information on their cost of investment. The firms' disclosure strategies affect their incentives to invest in R&D, and to acquire information. We compare equilibria under voluntary disclosure with those under mandatory disclosure in a model where the firms' cost of investment are identically independently distributed. Under voluntary disclosure firms conceal bad news, and disclose good news only if little knowledge spills over to their rival. Under mandatory disclosure firms expect higher profits for given information acquisition investments, but they may acquire less information.
The feasibility of three mathematical models to extrapolate the tail of thermodilution curves, wh... more The feasibility of three mathematical models to extrapolate the tail of thermodilution curves, when flectures are present in the descending limb, was tested in anesthetized pigs. The models were a local random walk model (LDRW), a log-normal distribution, and a two-compartment model. First, the accuracy of the extrapolation of the tail by each model was tested on two undisturbed curves by taking the truncation at five different points on the descending limb. The extrapolated curve area obtained from each model was compared with total area of the undisturbed curve. Next, dilution curves obtained during inspiratory hold maneuvers and characterized by deflection points were analyzed, taking the truncation just before deflection. The estimates of cardiac output by the models were compared with electromagnetically measured flow in the pulmonary artery. The area of the dilution curve was estimated more accurately when more information on the descending limb was available. The LDRW model a...
I study the incentives of Cournot duopolists to share their technologies with their competitor in... more I study the incentives of Cournot duopolists to share their technologies with their competitor in markets where intellectual property rights are absent and imitation is costless. The trade-off between a signaling effect and an expropriation effect determines the technology-sharing incentives. In equilibrium at most one firm shares some of its technologies. For similar technology distributions, there exists an equilibrium in which nobody shares. If the technology distributions are skewed towards efficient technologies, then there may exist equilibria in which one firm shares all technologies, only the best technologies, or only intermediate technologies. No other equilibria can exist.
We examine the persistence of monopolies in markets with innovations when the outcome of research... more We examine the persistence of monopolies in markets with innovations when the outcome of research is uncertain. We show that for low success probabilities of research, the incumbent can seldom preempt the poten-tial entrant. Then the efficiency effect outweighs the replacement effect. It is vice versa for high probabilities. Moreover, the incumbent special-izes in "safe" research and the potential entrant in "risky" research. We also show that the probability of entry is an inverted U-shape in the success probability. Since even at the peak entry is rather unlikely, the persistence of the monopoly is high., as well as seminar participants at the Max Planck Institute for Research on Collective Goods in Bonn, the Summer School on Contract Theory in Bronnbach, and the University of Bonn for helpful comments and sugges-tions.
We studied the effect of forced inflation at different alveolar volumes (VA) on carbon monoxide d... more We studied the effect of forced inflation at different alveolar volumes (VA) on carbon monoxide diffusing capacity (DLCO) in anaesthetized, paralysed and mechanically ventilated healthy pigs. An inspiratory pause procedure (equivalent of the single-breath technique) consisting of a pause between an inflation and expiration, both at a constant flow rate, was used. The procedure was computer-controlled and could easily be standardized. In five pigs, VA was varied at constant inflation volume by increasing positive end-expiratory pressure (PEEP) from 2 to 10 cmH2O. Inspiratory pause time was varied from 1 to 8 s to verify whether the decay of CO was exponential. In nine pigs, DLCO was estimated at four different VA values by inflating with 15-30 ml kg-1 at 2 cmH2O PEEP. An exponential decay of CO was always obtained. With increasing VA by either an increase in PEEP or inflation volume, DLCO remained constant. Since the diffusing capacity of the pulmonary membrane is expected to increase with increasing VA, the constant DLCO may be attributed to a decrease in capillary blood volume.
A new thermodilution method for frequent (near continuous) estimation of cardiac output, without ... more A new thermodilution method for frequent (near continuous) estimation of cardiac output, without manual injection of £uid into the blood, was tested. The method utilizes a pulmonary artery catheter equipped with a £uid ¢lled heat exchanger. The technique is based on cyclic cooling of the blood in the right atrium and measurement of the temperature changes in the pulmonary artery. Using this technique, a new estimate of cardiac output can be obtained every 32 s. Cardiac output estimates, obtained for a running mean of three measurements with this method, were compared to the mean of three conventional thermodilution measurements. The measurements were obtained during short periods of stable respiration and circulation. In six pigs, we made 46 paired measurements of conventional thermodilution (TD) and near continous (TDc) thermodilution. The cardiac output (CO TD) ranged from 2.41 3.7 l/min (mean 5.4 l/min). The best linear ¢t through the paired data points was CO TDc = À0.57 + 1.01 CO TD. The mean di¡erence between the methods was À0.50 l/min (S.D. = 0.39). The mean coe¤cient of variation of repeated measurements with the near continuous thermodilution was 3.6%. Considering changes of more than 0.25 l/min to be signi¢cant, all changes in cardiac output measured by conventional thermodilution were followed by the running mean of three near continuous thermodilution estimates. This study demonstrates the feasibility of the new method to monitor cardiac output, and to detect all changes greater than 0.25 l/min.
Journal of Clinical Monitoring and Computing, 2002
A novel algorithm for real-time detection and prediction of the dicrotic notch from aortic pressu... more A novel algorithm for real-time detection and prediction of the dicrotic notch from aortic pressure waves was evaluated in arrhythmic aortic pressure signals from heart failure patients. A simplified model of the arterial tree was used to calculate real-time aortic flow from aortic pressure. The dicrotic notch was detected at the first negative dip from the calculated flow, prediction of
This paper studies the incentives for production cost disclosure in an asymmetric Cournot duopoly... more This paper studies the incentives for production cost disclosure in an asymmetric Cournot duopoly. Whereas the efficient firm (consumers) prefers information sharing (concealment) when the firms choose accommodating strategies in the product market, the firm (consumers) may prefer information concealment (sharing) when it can exclude its competitor from the market. Hence, the rankings of expected profit and consumer surplus can be reversed if exit of the inefficient firm is possible. Although the efficient firm has stronger incentives to share information when it shares strategically, there remain cases in which the firm conceals information in equilibrium to induce exit.
Objective To examine the effects of short-term cyclic stretch on apoptosis in alveolar type II ce... more Objective To examine the effects of short-term cyclic stretch on apoptosis in alveolar type II cells (A549). To study in vitro the direct influence of alveolar type II cells on mechanical stretch. Methods A549 were treated with different doses of lipopolysaccharide (LPS), 0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, and then A549 were lengthened 5%, 15%, 30% using a FLEXCELL tension unit 4000, a vacuum-driven device that applies strain to cells, which were cultured in six-well plates coated with collagen-I, and 12 cycles/min for 4 hours. Apoptosis was measured using the flow cytometry method that measures annexin V and propidium iodide (PI) staining. The morphological changes of apoptotic cells were observed by transmission electron microscope. Results Apoptosis could be induced in alveolar type II cells (A549) by mechanical stretch. The percentage of annexin V + PI cells increased after being treated with cyclic stretch for 4 hours by 5%, 15%, 30% in all groups. The morphological features of apoptotic cells demonstrated by transmission electron microscope were as follows: shrinkage of the cell, chromatin condensation and aggregation under the nuclear membrane as a crescent or lump, membrane-encapsulated nuclear fragment or cell organ formed by invagination of the cell membrane, and apoptotic body formation followed by vacuolization. Conclusion Apoptosis induced by mechanical stretch and LPS is dose dependent. Mechanical stretch aggravates apoptosis especially in cells treated with LPS. Annexin V and PI double staining is a specific, sensitive, and quantitative method for analyzing apoptotic cells. It is also helpful to clarify the protective mechanism of low-volume ventilation in ARDS. Acknowledgement The study was funded by the 'One Hundred People' project of Shanghai Sanitary Bureau (03-77-20).
The imperfect appropriability of revenues from innovation affects the incentives of firms to inve... more The imperfect appropriability of revenues from innovation affects the incentives of firms to invest, and to disclose information about their innovative productivity. It creates a free-rider effect in the competition for the innovation that countervails the familiar business-stealing effect. Moreover, it affects the disclosure incentives such that full disclosure emerges for extreme revenue spillovers (e.g., full protection and no protection of intellectual property), but either partial disclosure or full concealment emerges for intermediate spillovers. I analyze the implications of imperfect appropriability and strategic disclosure for the firms' profits and the probability of innovation.
By using general information structures and precision criteria based on the dispersion of conditi... more By using general information structures and precision criteria based on the dispersion of conditional expectations, we study how oligopolists' information acquisition decisions may change the effects of information sharing on the consumer surplus. Sharing information about individual cost parameters gives the following trade-off in Cournot oligopoly. On the one hand, it decreases the expected consumer surplus for a given information precision, as the literature shows. On the other hand, information sharing increases the firms' incentives to acquire information, and the consumer surplus increases in the precision of the firms' information. Interestingly, the latter effect may dominate the former effect.
Pfl�gers Archiv European Journal of Physiology, 1996
A double indicator dilution technique for determining the mean cross-sectional area (CSA) of a bl... more A double indicator dilution technique for determining the mean cross-sectional area (CSA) of a blood vessel in vivo is presented. Analogous to the thermodilution method, dilution of hypertonic saline was measured by an electrical conductance technique. Because the change in conductance rather than absolute conductance was used to calculate CSA, pulsatile changes in shear rate of blood and conductance of surrounding tissues had no effect on the data. To calculate CSA from an ion mass balance, cardiac output was needed and estimated from the thermodilution curve using the same "cold" (hypertonic) saline injection. The mean CSA, obtained from this double indicator dilution method (CSA GD), was compared with the CSA obtained from the intravascular ultrasound method (IVUS) in 44 paired observations in six piglets. The regression line is close to the line of identity (CSAGD =-1.83 + 1.06-CSAivus, r = 0.96). The difference between both CSAs was independent of the diameter of the vessel, on average-0.99 mm 2 + 2.64 mm2 (mean CSAGD = 46.84 ± 8.21 mm 2 , mean CSA,vus = 47.82 ± 9.08 mm 2) and not significant. The results show that the double indicator dilution method is a reliable technique for estimating the CSA of blood vessels in vivo.
We tested the hypothesis that during high-frequency oscillatory ventilation, the oscillatory pres... more We tested the hypothesis that during high-frequency oscillatory ventilation, the oscillatory pressure ratio (OPR) is minimal at the optimal mean airway pressure (Paw). OPR is defined as the ratio of pressure swings at the distal end and the proximal opening of the endotracheal tube. Optimal Paw was assumed to be the lowest Paw at which the physiological shunt fraction was below 0.1. Acute lung injury was produced by saline lung lavage of pigs who were then subjected to a stepwise increase of Paw to impose underinflation, optimal inflation, and overdistention (inflation phase), followed by a stepwise decrease of Paw (deflation phase). OPR reached a minimum of 0.10 +/- 0.01 at Paw = 31 +/- 4 cm H(2)O during the inflation phase and a minimum of 0.04 +/- 0.01 at Paw = 18 +/- 1 cm H(2)O during the deflation phase. Optimal Paw was 31 +/- 4 cm H(2)O on the inflation limb and 14 +/- 2 cm H(2)O on the deflation limb. Paw at the minimal OPR was not significantly different from the optimal Paw during the inflation phase, and slightly but significantly higher (4.1 +/- 1.6 cm H(2)O) during the deflation phase. In conclusion, a consistent relationship was found between OPR and Paw, with a minimum in all animals. The minimal OPR coincides fairly well with the Paw where oxygenation is optimal.
We study whether a firm that produces and sells access to an excludable public good should face a... more We study whether a firm that produces and sells access to an excludable public good should face a self-financing requirement, or, alternatively, receive subsidies that help to cover the cost of public-goods provision. The main result is that the desirability of a self-financing requirement is shaped by an equity-efficiency trade-off: While first-best efficiency is out of reach with such a requirement, its imposition limits the firm's ability of rent extraction. Hence, consumer surplus may be higher if the firm has no access to public funds.
The time interval between mitral and tricuspid valve closure was measured from M-mode echocardiog... more The time interval between mitral and tricuspid valve closure was measured from M-mode echocardiograms in patients with Ebstein's anomaly. It was found that this time interval demonstrated a range of values within each patient. The use of different transducer positions on the chest wall was found to be the predominant factor. There was no correlation between the measured time interval, its variability, and the moment of measurement during breathing. However, a period of breathholding significantly reduced the variability. This study indicates that a wide range of time intervals might be measured in a single patient. We conclude therefore, that this parameter should be used with great care in the diagnosis of Ebstein's anomaly.
Journal of Cardiothoracic and Vascular Anesthesia, 2011
The authors evaluated the ability of 2 pulse contour cardiac output (CO) techniques to track CO c... more The authors evaluated the ability of 2 pulse contour cardiac output (CO) techniques to track CO changes during passive leg raising (PLR) to assess fluid loading responsiveness. A prospective study. An intensive care unit in a university hospital. Twenty mechanically ventilated postoperative cardiac surgery patients. Thirty-degree PLR. The authors estimated CO by 3 techniques: thermodilution (COtd), arterial pulse power (Coli; LiDCO, London, UK), and pulse contour method (Com; FMS, Amsterdam, The Netherlands) based on uncalibrated Modelflow. The authors measured heart rate (HR), central venous pressure, arterial pulse pressure (PP), systolic pressure (SP), and mean arterial pressure (MAP). Stroke volume (SV), SP, PP, and SV variation (PPV and SVV, respectively) were calculated over 5 breaths. SVV was measured by both LiDCO (SVVli) and Modelflow (SVVm) devices. PLR-induced changes in COtd correlated with COli (p < 0.001) and COm (p < 0.001). Preload dependence was predicted with an area under the ROC curve of 0.968 for ΔCOm, 0.841 for ΔCOli, 0.825 for SVVm, 0.873 for SVVli, 0.808 for PPV, 0.778 for ΔSP, 0.714 for ΔPP, and 0.873 for ΔMAP. Changes in COm, COli, SVV, and PPV track COtd changes during PLR with a high degree of accuracy in sedated, ventilated, postoperative cardiac surgery patients. Changes in pulse contour CO after PLR can be used to predict fluid loading responsiveness.
Journal for European Environmental & Planning Law, 2012
This section briefly describes the significant political initiatives and acts of legislation in t... more This section briefly describes the significant political initiatives and acts of legislation in the environmental field adopted from 1 July 2011 until 29 February 2012.
Development of a stable model of respiratory distress in pigs with oleic acid, fulfilling clinica... more Development of a stable model of respiratory distress in pigs with oleic acid, fulfilling clinical criteria of the adult respiratory distress syndrome (ARDS). Design: Eight pigs (9.1 _ 0.7 kg) were anesthetized with pentobarbital, paralyzed with tubocurarine and mechanically ventilated with an Fio 2 of 0.6, an I: E ratio of 2: 3 and a PEEP of 0.2 kPa. Oleic acid (dissolved 1:1 in 96% alcohol) was administered in a series of multiple injections of 0.1 ml until P~o2 was lower than 8 kPa. Measurements and results: Careful titration of the oleic acid injections on guidance of the PaQ established a reproducible respiratory distress (P, o2 = 7.3 _+ 0.8 kPa), in which gas exchange and hemodynamic variables were stable for at least 4 h. The number of oleic acid injections (22 + 11, mean and SD) varied between the animals. Conclusions: With the use of multiple injections of oleic acid, a stable model of early respiratory distress in pigs can be achieved, in spite of individual differences in sensitivity. Such a stable model allows for a diversity of studies on early respiratory distress.
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