par De Backer, Daniel
Editeur scientifique De Backer, Daniel ;Cholley, B.;Slama, Michel;Vieillard-Baron, Antoine;Vignon, P.
Référence Hemodynamic monitoring using echocardiography in the critically ill, Springer Verlag, Milano, Berlin, Heidelberg, New York, page (79-86)
Publication Publié, 2011
Partie d'ouvrage collectif
Résumé : Assessment of the left ventricular (LV) function is a very important step in the hemodynamic evaluation, not only for its contribution to diagnosis in heart and respiratory failure, but also for the guidance of therapeutic interventions. Many indices have been developed, from eyeball evaluation of ejection fraction to very complex computations. Each has its strengths and limitations. In routine clinical practice, LV ejection fraction (transthoracic approach, four-chamber view) or fractional area change should be measured (transesophageal or transthoracic echocardiography, short-axis view, midpapillary muscle level). Eyeball evaluation is sufficient in most cases for trained operators. If available, automated border detection may be used to facilitate measurements and reduce inter- and intraobserver variability. It should be noted that this measurement does not just estimate contractility: it is preload- and afterload sensitive. As such, it should be considered as the means to assess whether the left ventricle is adapted to the current loading conditions, with its intrinsic contractility. This measurement is, therefore, one of the most interesting indices of LV function for the intensivist. In patients with mitral regurgitation and severe aortic regurgitation, noninvasive dP/dt measurements on regurgitant mitral flow can be used. Though less so than with other methods, these measurements are still affected by loading conditions and hence represent mostly LV contractility. For research purposes, one may consider other indices of contractility (velocity of circumferential fiber shortening coupled with wall-stress measurement, LV hydraulic power), which are minimally affected by loading conditions. The significance of end-systolic elastance and the speckle-tracking method remains to be determined. © 2011 Springer-Verlag Berlin Heidelberg.