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Biomedical subjects

F Jardin

Publications and source records attributed to F Jardin.

At least 19 recordsLinked to original sources

[Quantitative two-dimensional echocardiography in acute pulmonary embolism].

Emergency two-dimensional echocardiography was carried out in 61 patients admitted to an intensive care unit for suspected pulmonary embolism, in order to find out whether signs of acute cor pulmonale (ACP) were present or absent. Pulmonary angiography was subsequently performed to confirm or infirm the diagnosis of pulmonary embolism. Only 7 out of 13 patients with normal echocardiography had no pulmonary embolism. All other patients who showed echocardiographic signs of ACP had pulmonary embolism. Thus, the finding of normal echocardiographic results does not necessarily exclude a diagnosis of pulmonary embolism. Conversely, the presence of echocardiographic signs of ACP in a suggestive context provides a near-certain diagnosis of pulmonary embolism.

Acute Disease

Combined thermodilution and two-dimensional echocardiographic evaluation of right ventricular function during respiratory support with PEEP.

In ten patients requiring respiratory support for an episode of acute respiratory failure (ARF), the best therapeutic level of PEEP was determined by measurement of changes in lung and chest wall compliance (CT) during a PEEP challenge from 0 to 20 cm H2O. During this challenge, hemodynamic monitoring combined with thermodilution measurement of right ventricular (RV) ejection fraction (EF) and two-dimensional echocardiographic measurement of RV size permitted assessment of the effects of increasing levels of PEEP on RV function. RV preload, as reflected by RV end-diastolic volume (EDV) and two-dimensional RV end-diastolic area (EDA), remained unchanged and RV diastolic compliance progressively decreased. On the other hand, RV systolic function, as assessed by RVEF and two-dimensional RV fractional area contraction (FAC), was progressively depressed. Substantial deleterious effects of PEEP were noted at high levels of PEEP including reduced CT and augmented pulmonary vascular resistance. Inadequate increase in RV preload to compensate for increased RV afterload resulted in depressed RV systolic function and contributed to the reduction in cardiac output. Finally, two-dimensional echocardiography proved to be more sensitive than fast-response thermodilution to evaluate change in RV function.

Echocardiography

Comparison of the effects of intravenous almitrine and positive end-expiratory pressure on pulmonary gas exchange in adult respiratory distress syndrome.

The effects of almitrine on pulmonary gas exchange and haemodynamics were compared to those of positive end-expiratory pressure (PEEP) in 10 patients with a severe adult respiratory distress syndrome (ARDS) who required continuous mechanical ventilation. Haemodynamic and gas exchange measurements were made before and after 30 min of PEEP at a level of 10 cmH2O, then 30 min later, before and at the end of the intravenous infusion of almitrine at a dose of 0.25 mg.kg-1 in 30 min. There was no significant difference between baseline gas exchange and haemodynamic parameters. PEEP and almitrine increased Pao (p = 0.001) from 10.9 to 12.6 kPa and from 10.6 to 12.6 kPa (1 kPa = 7.5 mmHg), respectively, and ratio of venous admixture to total blood flow (Qs/Qt) decreased (p less than 0.001) from 34 to 29% and from 33 to 29%, respectively, the effects of PEEP and almitrine being not significantly different. Neither PEEP nor almitrine caused a significant change in arterial carbon dioxide tension (PaCO2). The haemodynamic parameters did not change significantly with almitrine, whereas mean systemic arterial pressure decreased from 85.4 to 81.1 mmHg (p less than 0.05) with PEEP. These results are consistent with the hypothesis that both treatments improve ventilation/perfusion (VA/Q) distributions, by an increase in functional residual capacity in the case of PEEP and a redistribution of pulmonary perfusion in the case of almitrine.

Adult

Reevaluation of hemodynamic consequences of positive pressure ventilation: emphasis on cyclic right ventricular afterloading by mechanical lung inflation.

To examine the cyclic changes in right ventricular (RV) function induced by controlled ventilation, right heart catheterization and two-dimensional echocardiography were combined in a group of 20 patients requiring respiratory support for an episode of acute respiratory failure. Simultaneous measurements of RV pressure (using a modified pulmonary artery catheter), RV stroke output (thermodilution), and RV dimensions (two-dimensional echocardiography), permitted a beat to beat evaluation of RV function throughout the mechanical respiratory cycle. When compared with expiration, lung inflation produced an increase in RV systolic pressure and volume, an increase in RV diastolic volume with an unchanged RV diastolic pressure, and a marked decrease in RV ejection fraction. It is concluded that controlled ventilation altered RV function primarily by increasing RV afterload during the lung inflation period.

Acute Disease

Sepsis-related cardiogenic shock.

To further define cardiovascular abnormalities in patients with septic shock, serial conventional hemodynamic measurements combined with two-dimensional echocardiographic studies were performed at the bedside in 21 patients admitted for an acute episode of sepsis-related circulatory failure. Measurements obtained during the first hours of hospitalization revealed a group of six patients (group 1) with markedly depressed left ventricular function, as evidenced by a low cardiac index (CI) (2.2 +/- 0.8 L/min.m2), reduced left ventricular ejection fraction (LVEF) (21 +/- 8%), and an increased arterial-venous oxygen content difference. Right ventricular systolic function was also severely depressed. These patients were characterized as having sepsis-related cardiogenic shock secondary to profound myocardial depression, which was reversible within 24 to 48 h with inotropic support. The 15 remaining patients (group 2) exhibited an initially increased CI (4.9 +/- 1.8 L/min.m2), with a low systemic vascular resistance. In group 2, LVEF remained within the normal range despite abnormally low peripheral vascular resistance. This finding would suggest the presence of slight to moderate depression of left ventricular systolic function. All patients in this series had a normal left ventricular end-diastolic volume, whether profound myocardial depression was present or not.

Adolescent

Relation between transpulmonary pressure and right ventricular isovolumetric pressure change during respiratory support.

Simultaneous recordings of airway pressure, pleural pressure, and right ventricular (RV) pressure were obtained during mechanically controlled ventilation in a group of patients requiring respiratory support. Changes in transpulmonary pressure (calculated as airway pressure minus pleural pressure) were measured at end-expiration and end-inspiration during intermittent positive pressure ventilation with or without the application of a positive end-expiratory pressure, and were related to RV isovolumetric pressure changes at the onset of systole. It was found that any increase in transpulmonary pressure by intermittent positive pressure ventilation, or positive end-expiratory pressure (PEEP), or both, was associated with a proportional increase in RV isovolumetric pressure change. Moreover, when lung volume was progressively increased by incremental increases in tidal volume or PEEP level, transpulmonary pressure and RV isovolumetric pressure changes were strongly and linearly correlated. These results suggest that: 1) RV isovolumetric pressure change might be used as an index of RV output impedance during respiratory support by mechanically controlled ventilation; and 2) lung inflation resulting from the use of a positive airway pressure during respiratory support can increase RV output impedance and thereby contribute to the decrease in RV stroke output.

Cardiac Output

Quantitative two-dimensional echocardiography in massive pulmonary embolism: emphasis on ventricular interdependence and leftward septal displacement.

In 14 patients requiring aggressive therapy for circulatory failure resulting from massive pulmonary embolism, hemodynamic and two-dimensional echocardiographic data were obtained at bedside (acute phase) and again after circulatory improvement (intermediate phase) and during recovery. The acute stage was characterized by a low cardiac output state despite inotropic support (cardiac index 1.9 +/- 0.6 liters/min per m2) associated with increased right atrial pressure (12.4 +/- 4.2 mm Hg), increased right ventricular end-systolic and end-diastolic area (12.4 +/- 3.4 and 15.4 +/- 4.1 cm2/m2, respectively) and reduced right ventricular fractional area contraction (20.1 +/- 8.6%). Two-dimensional echocardiography also revealed interventricular septal flattening at both end-systole and end-diastole and markedly decreased left ventricular end-diastolic dimensions. Left ventricular fractional area contraction remained normal. Hemodynamic improvement occurred during the intermediate phase as shown by restoration of cardiac index (3.3 +/- 0.6 liters/min per m2), decrease in right atrial pressure (8.3 +/- 4.8 mm Hg), reduction in right ventricular end-systolic area (9.0 +/- 3.6 cm2/m2 at the intermediate stage and 6.1 +/- 1.8 cm2/m2 at recovery) and end-diastolic area (10.5 +/- 3.6 cm2/m2 at the intermediate stage and 8.9 +/- 2.9 cm2/m2 at recovery) and improvement in right ventricular fractional area contraction (31.5 +/- 16.4%). The interventricular septum progressively returned to a more normal configuration at both end-systole and end-diastole, and left ventricular diastolic dimension steadily increased. It is concluded that circulatory failure secondary to massive pulmonary embolism was mediated through a profound decrease in left ventricular preload, resulting from both pulmonary outflow obstruction and reduced left ventricular diastolic compliance.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization

Inspiratory impairment in right ventricular performance during acute asthma.

Right ventricular function was investigated in seven asthmatic patients during an acute attack, using simultaneous bedside right heart catheterization and two-dimensional echocardiography (2DE). Hemodynamic and echocardiographic data were compared during four successive periods of the respiratory cycle: inspiration, early expiration, mid-expiration, and late expiration. During inspiration, 2DE showed a significant increase in right ventricular area at both end-systole and end-diastole. This inspiratory right ventricular enlargement coexisted with a significant reduction in 2DE stroke area and pulmonary artery pulse pressure suggesting an inspiratory reduction in right ventricular stroke output. A transient depression of right ventricular function during deep inspiratory effort in asthma was thus strongly suggested. The negative pressure surrounding the right ventricle at inspiration is advocated as the causative factor enabling reduction in the hydraulic force effecting right ventricular ejection. The highly negative pleural pressure probably holds the right ventricular free wall and restrains its systolic inward motion, as suggested by the finding of a concomitant inspiratory reduction in right ventricular developed pressure and 2DE fractional area contraction.

Acute Disease

Two-dimensional echocardiographic evaluation of right ventricular size and contractility in acute respiratory failure.

Right ventricular size and contractility were evaluated using two-dimensional echocardiography during the first days of respiratory support in 23 patients requiring mechanical ventilation for acute respiratory failure. Nine patients had normal echocardiographic right ventricular function, and nine other patients had a slightly enlarged right ventricle with normal systolic function. The remaining five patients had a severely enlarged right ventricle with abnormal contractile pattern. In these five patients, two-dimensional echocardiography also showed a reduction in left ventricular size suggesting detrimental ventricular interdependence. All 23 patients had normal left ventricular systolic function by two-dimensional echocardiography.

Acute Disease

Dobutamine: a hemodynamic evaluation in pulmonary embolism shock.

Intravenous dobutamine was used in ten patients requiring aggressive therapy for massive pulmonary embolism with circulatory failure. Except in one patient who rapidly died, a 30-min dobutamine infusion (8.3 +/- 2.7 micrograms/kg . min) increased both cardiac index (from 1.7 +/- 0.4 to 2.3 +/- 0.6 L/min . m2, p less than .001) and stroke index (from 16.6 +/- 6.7 to 21 +/- 5 ml/m2, p less than .01), and also reduced pulmonary vascular resistance. Additional hemodynamic improvement was observed until weaning from dobutamine, which was successfully completed 3.3 +/- 0.9 days after the start of infusion.

Adult

Right ventricular volumes by thermodilution in the adult respiratory distress syndrome. A comparative study using two-dimensional echocardiography as a reference method.

Measurements of right ventricular ejection fraction and volumes were obtained at bedside by the thermodilution method performed with a fast-response balloon-tipped thermistor in a group of 18 patients undergoing respiratory therapy for the adult respiratory distress syndrome (ARDS). These measurements were compared with right ventricular dimensions simultaneously obtained with two-dimensional echocardiography. A significant correlation was found between right ventricular ejection fraction by thermodilution and two-dimensional echocardiographic fractional area contraction (r = 0.74; p less than 0.001), between right ventricular end-diastolic volume by thermodilution and two-dimensional echocardiographic end-diastolic area (r = 0.70; p less than 0.001), and between right ventricular end-systolic volume by thermodilution and two-dimensional echocardiographic end-systolic area (r = 0.78; p less than 0.001). Right ventricular end-diastolic pressure, a commonly used index of right ventricular preload, did not correlate with two-dimensional echocardiographic end-diastolic area. In conclusion, the thermodilution method allowed reliable measurements of right ventricular ejection fraction and volumes at bedside in critically ill patients. Appraisal of right ventricular end-diastolic volume by this method appeared to be a better predictor of right ventricular preload than were the measurements of pressure.

Adolescent

Influence of lung and chest wall compliances on transmission of airway pressure to the pleural space in critically ill patients.

Nineteen patients with acute respiratory failure were divided into three groups according to their total compliance (CT). Transmission of airway pressure to the pleural space was then evaluated by measurement of esophageal pressure at both end-expiration and end-inspiration, and at three levels of PEEP. Chest wall (CW) and lung complicance (CL) were also calculated from simultaneous measurements of lung volume changes induced by tidal delivery. In group 1 (CT greater than 45 ml/cmH2O), 37 percent of airway pressure was transmitted to pleural space. In group 2 (CT between 45 and 30 ml/cmH2O), 32 percent of airway pressure was transmitted to the pleural space. In group 3 (CT less than 30 ml/cmH2O), only 24 percent of airway pressure was transmitted to the pleural space. These differences are statistically significant (p less than 0.001) and illustrate the influence of a progressive increase in lung stiffness (CL = 100.3 +/- 17.2 ml/cmH2O in group 1, CL = 45.0 +/- 6.3 ml/cmH2O in group 2, and CL = 28.6 +/- 8.9 ml/cmH2O in group 3) on transmission of airway pressure to the pleural space. Despite lesser transmission of airway pressure to the pleural space in the most damaged lungs, no significant difference was found between groups with regard to transmural venous pressure changes throughout the study.

Acute Disease