Search PubMed⌕ Search

Biomedical subjects

Antoine Vieillard-Baron

Publications and source records attributed to Antoine Vieillard-Baron.

At least 19 recordsLinked to original sources
PubMed2006

Bedside echocardiographic evaluation of hemodynamics in sepsis: is a qualitative evaluation sufficient?

OBJECTIVE: Transesophageal echocardiography (TEE) has proven its efficiency in assessing hemodynamics in patients by its ability to evaluate cardiac function and fluid responsiveness. Classically, it requires quantitative measurements, whereas in routine practice TEE is used in our unit especially as a qualitative procedure. We assessed the accuracy of this qualitative central hemodynamic evaluation obtained by TEE at the bedside. DESIGN AND SETTING: Prospective study conducted in a medical ICU between September 2004 and April 2005. All TEE examinations performed in consecutive patients hospitalized for septic shock and mechanically ventilated for an associated acute lung injury were eligible for evaluation. Intensivists trained in echocardiography were asked to classify (a) respiratory changes in the superior vena cava (SVC), (b) left ventricular (LV) systolic function, (c) right ventricular (RV) end-diastolic size, and (d) shape and kinetics of the interventricular septum (IVS). A post-hoc quantitative evaluation was then performed by a trained investigator unaware of the patients' status. RESULTS: We evaluated 83 examinations in 30 patients. Qualitative evaluation was easily able to distinguish patients with significant or nonsignificant SVC respiratory changes, normal, moderately or markedly depressed LV systolic function, and nondilated or dilated right ventricle. Acute cor pulmonale was also well recognized. CONCLUSION: By its ability accurately to evaluate hemodynamic status qualitative TEE could be useful for intensivists in managing circulatory failure in septic shock, rendering the more time-consuming quantitative evaluation useless.

Aged↗
PubMed2006

[Circulatory failures].

To treat circulatory failures and recognize their mechanisms, we need to understand circulatory physiology. What determines systemic venous return? How does the right ventricle feed the pulmonary circulation? Where is the left ventricular preload reserve located? Four types of circulatory failure are conventionally recognized: hypovolemic, obstructive, vasoplegic and cardiogenic. One or more of these mechanisms may account for circulatory failure in septic shock. Treatment of circulatory failure requires admission to a specialized unit and continuous or discontinuous hemodynamic monitoring. Prognosis is highly dependent on rapid treatment and correction of circulatory impairment.

Algorithms↗
PubMed2006

Effects of levosimendan on right ventricular afterload in patients with acute respiratory distress syndrome: a pilot study.

OBJECTIVE: Acute respiratory distress syndrome (ARDS) is frequently associated with increased pulmonary vascular resistance and thus with systolic load of the right ventricle. We hypothesized that levosimendan, a new calcium sensitizer with potential pulmonary vasodilator properties, improves hemodynamics by unloading the right ventricle in patients with ARDS. DESIGN: Prospective, randomized, placebo-controlled, pilot study. SETTING: Twenty-two-bed multidisciplinary intensive care unit of a university hospital. PATIENTS: Thirty-five patients with ARDS in association with septic shock. INTERVENTIONS: Patients were randomly allocated to receive a 24-hr infusion of either levosimendan 0.2 microg/kg/min (n = 18) or placebo (n = 17). Data from right heart catheterization, cardiac magnetic resonance, arterial and mixed venous oxygen tensions and saturations, and carbon dioxide tensions were obtained before and 24 hrs after drug infusion. MEASUREMENTS AND MAIN RESULTS: At a mean arterial pressure between 70 and 80 mm Hg (sustained with norepinephrine infusion), levosimendan increased cardiac index (from 3.8 +/- 1.1 to 4.2 +/- 1.0 L/min/m) and decreased mean pulmonary artery pressure (from 29 +/- 3 to 25 +/- 3 mm Hg) and pulmonary vascular resistance index (from 290 +/- 77 to 213 +/- 50 dynes/s/cm(5)/m(2); each p < .05). Levosimendan also decreased right ventricular end-systolic volume and increased right ventricular ejection fraction (p < .05). In addition, levosimendan increased mixed venous oxygen saturation (from 63 +/- 8 to 70 +/- 8%; p < .01). CONCLUSIONS: This study provides evidence that levosimendan improves right ventricular performance through pulmonary vasodilator effects in septic patients with ARDS. A large multiple-center trial is needed to investigate whether levosimendan is able to improve the overall prognosis of patients with sepsis and ARDS.

Aged↗
PubMed2006

Echocardiographic measurement of fluid responsiveness.

PURPOSE OF REVIEW: Fluid responsiveness is a relatively new concept. It enables the efficacy of volume expansion to be predicted before use, rather than assessed afterwards, thus avoiding inappropriate fluid infusion. Echocardiography is a fantastic noninvasive tool which can directly visualize the heart and assess cardiac function. Its use was long limited by the absence of accurate indices to diagnose hypovolemia and predict the effect of volume expansion. In the last few years, several French teams have used echocardiography to develop new parameters of fluid responsiveness, taking advantage of its ability to monitor cardiac function beat by beat during the respiratory cycle. RECENT FINDINGS: In mechanically ventilated patients perfectly adapted to the respirator, respiratory variations in superior and inferior vena cava diameters and in left ventricular stroke volume have been validated as parameters of fluid responsiveness. In our opinion, the collapsibility index of the superior vena cava is the most reliable of these parameters, but does require transesophageal echocardiography. SUMMARY: Echocardiography has been widely demonstrated to predict fluid responsiveness accurately. This is now a complete and noninvasive tool able to accurately determine hemodynamic status in circulatory failure.

Cardiac Output↗
PubMed2006

Cardiac function during intraperitoneal CO2 insufflation for aortic surgery: a transesophageal echocardiographic study.

The effect of laparoscopy on cardiac function is controversial. We hypothesized that cardiac dysfunction related to increased afterload could be predominant in patients undergoing elective abdominal aortic repair. To test this hypothesis, we conducted a transesophageal echocardiographic study in 15 patients during laparoscopic aortic surgery. We systematically assessed left ventricular (LV) and right ventricular (RV) functions. Measurements were obtained in the supine position without pneumoperitoneum and with an intraabdominal pressure of 14 mm Hg. Then, patients were turned to the right lateral position without pneumoperitoneum and intraabdominal pressure was increased to 7 mm Hg and to 14 mm Hg. Pneumoperitoneum induced a 25% arterial blood pressure increase and a 38% increase in LV systolic wall stress. A 25% decrease in LV ejection fraction and an 18% decrease in LV stroke volume were observed, associated with an increase in LV end-systolic volume. LV diastolic function impairment was observed without change in LV end-diastolic volume. Respiratory alterations in superior vena cava diameter were never observed, suggesting that volume status remained optimal. Respiratory changes in RV stroke volume were increased according to intraabdominal pressure and body position, reflecting an increase in RV afterload. In conclusion, peritoneal CO2 insufflation in patients scheduled for laparoscopic aortic surgery could impair LV and RV systolic functions as a consequence of increased afterload.

Adult↗
PubMed2005

Early veno-venous haemodiafiltration for sepsis-related multiple organ failure.

INTRODUCTION: We conducted a prospective observational study from January 1995 to December 2004 to evaluate the impact on recovery of a major advance in renal replacement therapy, namely continuous veno-venous haemodiafiltration (CVVHDF), in patients with refractory septic shock. METHOD: CVVHDF was implemented after 6-12 hours of maximal haemodynamic support, and base excess monitoring was used to evaluate the improvement achieved. Of the 60 patients studied, 40 had improved metabolic acidosis after 12 hours of CVVHDF, with a progressive improvement in all failing organs; the final mortality rate in this subgroup was 30%. In contrast, metabolic acidosis did not improve in the remaining 20 patients after 12 hours of CVVHDF, and the mortality rate in this subgroup was 100%. The crude mortality rate for the whole group was 53%, which is significantly lower than the predicted mortality using Simplified Acute Physiology Score II (79%). CONCLUSION: Early CVVHDF may improve the prognosis of sepsis-related multiple organ failure. Failure to correct metabolic acidosis rapidly during the procedure was a strong predictor of mortality.

Acid-Base Imbalance↗
PubMed2005

Recurrent pulmonary embolism with non-mobile thrombus in a patient with leiomyosarcoma of the left renal vein.

We describe the case of a man who suffered recurrent pulmonary embolisms despite well-conducted oral anticoagulant therapy. Echocardiography and helical computed tomography revealed a non-mobile right atrial mass related to a leiomyosarcoma of the left renal vein. The prognosis of such a disease is bad and the patient died at 1-year follow-up. Recurrent pulmonary embolism with well-conducted oral anticoagulant therapy requires further appropriate investigations, because of high suspicion of neoplastic process.

Anticoagulants↗
PubMed2005

Incidence, causes and prognosis of hypotension related to meprobamate poisoning.

OBJECTIVE: Meprobamate self-poisoning has been reported as potentially inducing hypotension. We examined the incidence and causes of hypotension induced by this poisoning and its prognosis. DESIGN AND SETTING: Retrospective observational study conducted in a medical ICU between June 1997 and October 2003. Seventy-four patients admitted for meprobamate poisoning and needing mechanical ventilation were included. Demographic, clinical, and laboratory data were compared between patients with and without hypotension. All echocardiograms recorded in patients with hypotension were reviewed, and left ventricular (LV) and right ventricular (RV) functions were assessed. RESULTS: Twenty-nine (40%) patients exhibited hypotension without any significant difference in age, gender, cardiac history, or meprobamate concentration in blood when compared to patients without hypotension. Base excess was significantly lower in patients with hypotension. Echocardiography demonstrated a hypokinetic state, associating decreased LV ejection fraction (45+/-15%) and cardiac index (2+/-0.7 l min(-1) m(-2)), and increased inferior vena cava diameter. Most patients with hypotension received inotropic drugs by infusion, and were ventilated for significantly longer. CONCLUSIONS: Meprobamate self-poisoning induces hypotension, notably related to cardiac failure, in about 40% of cases. This has important therapeutic consequences, as frequent inotropic drug infusion. The mechanisms of cardiac toxicity remain largely unknown, and no predictive factor could be isolated.

Adult↗
PubMed2005

Diagnosis of right ventricular dysfunction in acute pulmonary embolism using helical computed tomography.

Forty-six consecutive patients with pulmonary embolism (PE) who underwent pulmonary angiography, helical computed tomography (CT), and echocardiography in the investigators' emergency department were studied. It was determined that the CT right ventricular (RV)/left ventricular (LV) end-diastolic area ratio was correlated with PE obstruction and echocardiography. A CT RV/LV area ratio >1 had a sensitivity of 88% and a specificity of 88% in diagnosing significant PE. The present study suggests that helical CT may be used as a triage tool in acute PE for selecting high-risk patients, using calculation of the RV/LV area ratio to detect RV dysfunction.

Adult↗
PubMed2005

Monitoring of right-sided heart function.

PURPOSE OF REVIEW: Because the right side of the heart supplies blood to the pulmonary circulation, its integrity is required for both adequate respiratory and circulatory function. By reducing pulmonary perfusion, right-sided heart failure may compromise arterial oxygenation and left ventricular filling, and monitoring of right-sided heart function at the bedside in critically ill patients is fundamental. Two recent clinical commentaries have focused on the invaluable help provided by echocardiography for this purpose. RECENT FINDINGS: Bedside echocardiography has supplanted invasive procedures as the best tool to evaluate right-sided heart function. Although not recent, this technique, previously reserved for cardiologists, has recently gained a larger acceptance in respiratory intensive care units. Echocardiographic examination detects excessive right ventricular afterload, visualized by septal dyskinesia, and its usual consequence, right ventricular enlargement, which impairs left ventricular filling. SUMMARY: Monitoring of right-sided heart function is essential in a clinical setting associated with hemodynamic instability, such as severe sepsis or acute coronary artery obstruction, and also in that it is associated with increased pulmonary vascular resistance, as in massive pulmonary embolism or acute respiratory failure. Moreover, use of mechanical ventilation requires regular evaluation of its effects on the right side of the heart.

Atrial Function, Right↗
PubMed2004

Prone position improves mechanics and alveolar ventilation in acute respiratory distress syndrome.

OBJECTIVE: We tested the hypothesis that ventilation in the prone position might improve homogenization of tidal ventilation by reducing time-constant inequalities, and thus improving alveolar ventilation. We have recently reported in ARDS patients that these inequalities are responsible for the presence of a "slow compartment," excluded from tidal ventilation at supportive respiratory rate. DESIGN: In 11 ARDS patients treated by ventilation in the prone position because of a major oxygenation impairment (PaO(2)/FIO(2)</=100 mm Hg) we studied mechanical and blood gas changes produced by a low PEEP (6+/-1 cm H(2)O), ventilation in the prone position, and the two combined. RESULTS: Ventilation in the prone position significantly reduced the expiratory time constant from 1.98+/-0.53 s at baseline with ZEEP to 1.53+/-0.34 s, and significantly decreased PaCO(2) from 55+/-11 mm Hg at baseline with ZEEP to 50+/-7 mm Hg. This improvement in alveolar ventilation was accompanied by a significant improvement in respiratory system mechanics, and in arterial oxygenation, the latter being markedly increased by application of a low PEEP (PaO(2)/FIO(2) increasing from 64+/-19 mm Hg in supine position with ZEEP to 137+/-88 mm Hg in prone with a low PEEP). CONCLUSION: In severely hypoxemic patients, prone position was able to improve alveolar ventilation significantly by reducing the expiratory time constant.

Analysis of Variance↗
PubMed2004

Superior vena caval collapsibility as a gauge of volume status in ventilated septic patients.

OBJECTIVE: In mechanically ventilated patients inspiratory increase in pleural pressure during lung inflation may produce complete or partial collapse of the superior vena cava. Occurrence of this collapse suggests that at this time external pressure exerted by the thoracic cavity on the superior vena cava is greater than the venous pressure required to maintain the vessel fully open. We tested the hypothesis that measurement of superior vena caval collapsibility would reveal the need for volume expansion in a given septic patient. DESIGN AND SETTING: Prospective data collection for 66 successive patients in septic shock admitted in a medical intensive care unit and mechanically ventilated for an associated acute lung injury. MEASUREMENTS AND RESULTS: We simultaneously measured superior vena caval collapsibility by echocardiography and cardiac index by the Doppler technique at baseline and after a 10 ml/kg volume expansion by 6% hydroxyethyl starch in 30 min. The threshold superior vena caval collapsibility of 36%, calculated as (maximum diameter on expiration-minimum diameter on inspiration)/maximum diameter on expiration, allowed discrimination between responders (defined by an increase in cardiac index of at least 11% induced by volume expansion) and nonresponders, with a sensitivity of 90% and a specificity of 100%. CONCLUSIONS: Superior vena cava measurement should be systematically performed during routine echocardiography in septic shock as it gives an accurate index of fluid responsiveness.

Adult↗