Frédéric Michard

PURPOSE: Second-generation FloTrac software has been shown to reliably measure cardiac output (CO) in cardiac surgical patients. However, concerns have been raised regarding its accuracy in vasoplegic states. The aim of the present multicenter study was to investigate the accuracy of the third-generation software in patients with sepsis, particularly when total systemic vascular resistance (TSVR) is low. METHODS: Fifty-eight septic patients were included in this prospective observational study in four university-affiliated ICUs...

INTRODUCTION: A new system has been developed to assess global end-diastolic volume (GEDV), a volumetric marker of cardiac preload, and extravascular lung water (EVLW) from a transpulmonary thermodilution curve. Our goal was to compare this new system with the system currently in clinical use. METHODS: Eleven anesthetized and mechanically ventilated pigs were instrumented with a central venous catheter and a right (PulsioCath; Pulsion, Munich, Germany) and a left (VolumeView™; Edwards Lifesciences, Irvine, CA, USA) thermistor-tipped femoral arterial catheter...

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No abstract text is available yet for this article.

BACKGROUND: The arterial pulse pressure variation induced by mechanical ventilation (deltaPP) has been shown to be a predictor of fluid responsiveness. Until now, deltaPP has had to be calculated offline (from a computer recording or a paper printing of the arterial pressure curve), or to be derived from specific cardiac output monitors, limiting the widespread use of this parameter. Recently, a method has been developed for the automatic calculation and real-time monitoring of deltaPP using standard bedside monitors...

INTRODUCTION: Several studies have shown that maximizing stroke volume (or increasing it until a plateau is reached) by volume loading during high-risk surgery may improve post-operative outcome. This goal could be achieved simply by minimizing the variation in arterial pulse pressure (deltaPP) induced by mechanical ventilation. We tested this hypothesis in a prospective, randomized, single-centre study. The primary endpoint was the length of postoperative stay in hospital. METHODS: Thirty-three patients undergoing high-risk surgery were randomized either to a control group (group C, n = 16) or to an intervention group (group I, n = 17)...

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In anesthetized patients without cardiac arrhythmia the arterial pulse pressure variation (PPV) induced by mechanical ventilation has been shown the most accurate predictor of fluid responsiveness. In this respect, PPV has so far been used mainly in the decision-making process regarding volume expansion in patients with shock. As an indicator of the position on the Frank-Starling curve, PPV may actually be useful in many other clinical situations. In patients with acute lung injury or with acute respiratory distress syndrome, PPV can predict hemodynamic instability induced by positive end-expiratory pressure and recruitment maneuvers...

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OBJECTIVES: To review the advantages and limitations of dilution methods to assess extravascular lung water (EVLW) at the bedside and to discuss the clinical value of EVLW measurements. DATA SOURCE: Experimental and clinical studies were searched in PUBMED by using "extravascular lung water" and "dilution method" as keywords and further selected as studies investigating either the reliability or the clinical usefulness of dilution methods to assess EVLW. Related articles and the reference lists of selected studies were scanned for additional relevant references...

In order to turn a fluid challenge into a significant increase in stroke volume and cardiac output, 2 conditions must be met: 1) fluid infusion has to significantly increase cardiac preload and 2) the increase in cardiac preload has to induce a significant increase in stroke volume. In other words, a patient can be nonresponder to a fluid challenge because preload does not increase during fluid infusion or/and because the heart (more precisely, at least 1 of the ventricles) is operating on the flat portion of the Frank-Starling curve...

OBJECTIVE: The purpose of this study was to compare dP/dt(max) estimated from a femoral artery pressure tracing to left ventricular (LV) dP/dt(max) during various alterations in myocardial loading and contractile function. PARTICIPANTS: Seventy patients scheduled for elective coronary artery bypass surgery. METHODS: All patients were instrumented with a high-fidelity LV catheter, a pulmonary artery catheter, and a femoral arterial catheter...

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Mechanical ventilation induces cyclic changes in vena cava blood flow, pulmonary artery blood flow, and aortic blood flow. At the bedside, respiratory changes in aortic blood flow are reflected by "swings" in blood pressure whose magnitude is highly dependent on volume status. During the past few years, many studies have demonstrated that arterial pressure variation is neither an indicator of blood volume nor a marker of cardiac preload but a predictor of fluid responsiveness. That is, these studies have demonstrated the value of this physical sign in answering one of the most common clinical questions, Can we use fluid to improve hemodynamics?, while static indicators of cardiac preload (cardiac filling pressures but also cardiac dimensions) are frequently unable to correctly answer this crucial question...

OBJECTIVE: To investigate factors that may influence the estimation of extravascular lung water (EVLW) with a single (cold) indicator compared with assessment using two indicators (thermo-dye dilution). DESIGN: Post hoc analysis of an electronic hemodynamic database. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: Forty-eight critically ill patients monitored by the thermo-dye dilution technique in the postoperative period...

OBJECTIVE: To investigate whether the respiratory variation in inferior vena cava diameter (DeltaD(IVC)) could be related to fluid responsiveness in mechanically ventilated patients. DESIGN: Prospective clinical study. SETTING: Medical ICU of a non-university hospital. PATIENTS: Mechanically ventilated patients with septic shock (n=39). INTERVENTIONS: Volume loading with 8 mL/kg of 6% hydroxyethylstarch over 20 min...

STUDY OBJECTIVE: To assess the value of the global end-diastolic volume (GEDV) evaluated by transpulmonary thermodilution as an indicator of cardiac preload. DESIGN: Prospective clinical study. SETTING: Medical ICU of a university hospital (20 beds). PATIENTS: Thirty-six patients with septic shock. INTERVENTIONS: Volume loading and dobutamine infusion. MEASUREMENTS AND RESULTS: Hemodynamic parameters were evaluated in triplicate by the transpulmonary thermodilution technique: (1) before and after 66 fluid challenges in 27 patients, and (2) before and after 28 increases in dobutamine infusion rate in 9 patients...

STUDY OBJECTIVE: To identify and critically review the published peer-reviewed, English-language studies investigating predictive factors of fluid responsiveness in ICU patients. DESIGN: Studies were collected by doing a search in MEDLINE (from 1966) and scanning the reference lists of the articles. Studies were selected according to the following criteria: volume expansion performed in critically ill patients, patients classified in two groups (responders and nonresponders) according to the effects of volume expansion on stroke volume or on cardiac output, and comparison of responder and nonresponder patients' characteristics before volume expansion...

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