Author
Marc Zelter
Bio: Marc Zelter is an academic researcher from University of Paris-Sud. The author has contributed to research in topics: Pulmonary artery catheter & Cardiac output. The author has an hindex of 2, co-authored 3 publications receiving 102 citations.
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TL;DR: The bedside determination of the ΔPpao/ΔPpa ratio should identify the cases in which Ppao measurements are not valid more reliably than lateral chest x-ray film, thus avoiding misleading interpretations of P pao during PEEP ventilation.
87 citations
TL;DR: Norepinephrine, epinephrine, and dopamine at doses commonly used in humans increase pulmonary venous tone in sheep and Elevation of cardiac output alone could not account for these findings since the increase in cardiac output induced by fluid infusion did not change the pressure differences.
Abstract: OBJECTIVE To assess the effects of various catecholaminergic agents on pulmonary venous tone. DESIGN Prospective, randomized, controlled, experimental study. SETTING Physiology laboratory of a university hospital. SUBJECTS Thirty anesthetized, mechanically ventilated adult sheep. INTERVENTIONS Four groups of six animals received 1-hr infusions of norepinephrine (0.5 microg/kg/min), epinephrine (0.5 microg/kg/ min), dopamine (10 microg/kg/min), or dobutamine (10 microg/kg/min). MEASUREMENTS AND MAIN RESULTS A 7-Fr pulmonary artery catheter was placed in a proximal location to measure cardiac output and pressure in a large pulmonary vein (Ppw) after balloon inflation. Another catheter wedged in a small pulmonary artery measured pressure in a small pulmonary vein (Pdw). A third catheter measured left atrial pressure (PLA ). This method was able to detect the pulmonary venoconstrictive effects of histamine in a separate group of six animals. Pdw-PLA increased from a mean of 2.0+/-1.7 to 3.0+/-1.5 (SD) cm H2O (p < .01), 2.3+/-1.6 to 4.4+/-1.3 cm H2O (p < .01), and 1.7+/-1.0 to 3.5+/-2.2 cm H2O (p < .05) with norepinephrine, epinephrine, and dopamine, respectively. All of these drugs increased Pdw-Ppw, but only norepinephrine and epinephrine increased Ppw-PLA . No change in either pressure difference was observed with dobutamine. Elevation of cardiac output alone could not account for these findings since the increase in cardiac output induced by fluid infusion did not change the pressure differences. CONCLUSION Norepinephrine, epinephrine, and dopamine at doses commonly used in humans increase pulmonary venous tone in sheep.
15 citations
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TL;DR: As compared with conventional ventilation, the protective strategy was associated with improved survival at 28 days, a higher rate of weaning from mechanical ventilation, and a lower rate of barotrauma in patients with the acute respiratory distress syndrome.
Abstract: Background In patients with the acute respiratory distress syndrome, massive alveolar collapse and cyclic lung reopening and overdistention during mechanical ventilation may perpetuate alveolar injury. We determined whether a ventilatory strategy designed to minimize such lung injuries could reduce not only pulmonary complications but also mortality at 28 days in patients with the acute respiratory distress syndrome. Methods We randomly assigned 53 patients with early acute respiratory distress syndrome (including 28 described previously), all of whom were receiving identical hemodynamic and general support, to conventional or protective mechanical ventilation. Conventional ventilation was based on the strategy of maintaining the lowest positive end-expiratory pressure (PEEP) for acceptable oxygenation, with a tidal volume of 12 ml per kilogram of body weight and normal arterial carbon dioxide levels (35 to 38 mm Hg). Protective ventilation involved end-expiratory pressures above the lower inflection poin...
3,323 citations
TL;DR: It was concluded that in mechanically ventilated patients with acute circulatory failure related to sepsis, analysis of DeltaPp is a simple method for predicting and assessing the hemodynamic effects of VE, and that DeltaP p is a more reliable indicator of fluid responsiveness than DeltaPs.
Abstract: In mechanically ventilated patients with acute circulatory failure related to sepsis, we investigated whether the respiratory changes in arterial pressure could be related to the effects of volume expansion (VE) on cardiac index (CI). Forty patients instrumented with indwelling systemic and pulmonary artery catheters were studied before and after VE. Maximal and minimal values of pulse pressure (Pp(max) and Pp(min)) and systolic pressure (Ps(max) and Ps(min)) were determined over one respiratory cycle. The respiratory changes in pulse pressure (DeltaPp) were calculated as the difference between Pp(max) and Pp(min) divided by the mean of the two values and were expressed as a percentage. The respiratory changes in systolic pressure (DeltaPs) were calculated using a similar formula. The VE-induced increase in CI was >/= 15% in 16 patients (responders) and < 15% in 24 patients (nonresponders). Before VE, DeltaPp (24 +/- 9 versus 7 +/- 3%, p < 0.001) and DeltaPs (15 +/- 5 versus 6 +/- 3%, p < 0.001) were higher in responders than in nonresponders. Receiver operating characteristic (ROC) curves analysis showed that DeltaPp was a more accurate indicator of fluid responsiveness than DeltaPs. Before VE, a DeltaPp value of 13% allowed discrimination between responders and nonresponders with a sensitivity of 94% and a specificity of 96%. VE-induced changes in CI closely correlated with DeltaPp before volume expansion (r(2) = 0. 85, p < 0.001). VE decreased DeltaPp from 14 +/- 10 to 7 +/- 5% (p < 0.001) and VE-induced changes in DeltaPp correlated with VE-induced changes in CI (r(2) = 0.72, p < 0.001). It was concluded that in mechanically ventilated patients with acute circulatory failure related to sepsis, analysis of DeltaPp is a simple method for predicting and assessing the hemodynamic effects of VE, and that DeltaPp is a more reliable indicator of fluid responsiveness than DeltaPs.
1,178 citations
TL;DR: It is demonstrated that cardiac filling pressures are poor predictors of fluid responsiveness in septic patients and their use as targets for volume resuscitation must be discouraged, at least after the early phase of sepsis has concluded.
Abstract: Objective:Values of central venous pressure of 8–12 mm Hg and of pulmonary artery occlusion pressure of 12–15 mm Hg have been proposed as volume resuscitation targets in recent international guidelines on management of severe sepsis. By analyzing a large number of volume challenges, our aim was to t
609 citations
TL;DR: Analysis of respiratory changes in aortic blood velocity is an accurate method for predicting the hemodynamic effects of volume expansion in septic shock patients receiving mechanical ventilation who have preserved left ventricular systolic function.
547 citations
TL;DR: The dDown component of the systolic pressure variation is a sensitive indicator of the response of cardiac output to volume infusion in patient with sepsis‐induced hypotension who require mechanical ventilation.
Abstract: BackgroundMonitoring left ventricular preload is critical to achieve adequate fluid resuscitation in patients with hypotension and sepsis. This prospective study tested the correlation of the pulmonary artery occlusion pressure, the left ventricular end-diastolic area index measured by transesophage
523 citations