Transesophageal Echocardiography: A New Monitoring Technique

ISBN-13: 9783211826508 / Angielski / Miękka / 1995 / 157 str.

N. Kolev; Nikolai Kolev; Ga1/4nter Huemer

Opis

"Everything should be as simple as can be, but not simpler. " Albert Einstein The past decade has been marked by a trend from invasive to noninvasive intraoperative monitoring. As far as respiratory monitoring is concerned, initial experience with transcutaneous gas analysis laid the foundation for widespread clinical use of pulse oximetry and end-tidal gas analysis. It has been long recognized that echo cardiography might become an equally useful adjunct to cardiovascular monitoring. The fundamental purpose of cardiac monitoring is to warn the anesthesiologist of existing or impending cardiac abnormalities, so they can be corrected or prevented before the patient is harmed. Forces wi thin and ou tside of medicine are pressuring our specialty to improve cardiovascular monitoring. For instance, the average age of the population is increasing, resulting in more elderly patients presenting for major surgical procedures. At the same time, the medical-legal establishment stands ready to hold anesthesiologists accountable for almost any adverse outcome associated with anesthesia or surgery. In an effort to deal with this pressure, anesthesiologists have often resorted to invasive cardiovascular monitoring. However, invasive procedures are expensive, and even in the most experienced hands, they sometimes result in complications. In the past few years, with the development of modern computerized medical ultrasonics, anesthesiologists have recognized the usefulness of trans esophageal echocardiography (TEE) as a new monitoring technique. TEE is the most complex, sophisticated, and potent cardiovascular monitor ever introduced."

Spis treści

1 Introduction.- References.- 2 General theory, history and development.- Principles of two-dimensional echocardiography.- Principles of Dopper echocardiography.- Digital cine loop technology.- History and development of transesophageal echocardiography.- Characteristics of transesophageal systems.- References.- 3 Standard transesophageal imaging and planes.- General considerations.- Cardiac examination.- Transgastric views.- Midesophageal views.- Basal esophageal views.- References.- 4 On-line and off-line determinations of ventricular preloads and volumes.- Preload - clinical relevance.- Off-line echocardiography estimations of preload.- Prolate ellipse method, area-length approach.- Simpson’s rule method.- On-line assessment of preload: acoustic quantification technique.- References.- 5 Assessment of afterload.- Clinical relevance.- Echocardiographic estimation of afterload.- References.- 6 Contractility.- Contractility indices revisited.- Cardiac output.- Two-dimensional method.- Doppler echocardiography method.- Theory.- Cardiac output by sampling the aortic valve.- Cardiac output by sampling the pulmonic valve.- Fundamental sources of error.- Comparison with other methods of cardiac measurement.- Uses of Doppler cardiac output in anesthesiology.- Ejection fraction.- Mean velocity of circumferential fiber shortening (Vcf).- Two-dimensional Doppler echocardiographic estimation of isovolumic phase indexes.- Peak rate of change of left ventricular pressure (dP/dt).- Isovolumic contraction time (IVCT).- Frank-Starling principle and end-systolic performance curves.- References.- 7 Perioperative myocardial ischemia.- Cardiac risk.- References.- Myocardial ischemia: pathophysiology and effects of the inhalational anesthetics.- References.- Left ventricular segmental wall motion analysis.- Experimental and clinical studies.- Standard TEE monitoring position.- General considerations.- Reference systems.- Methods for calculating the central reference (centroid) for an individual frame.- Systolic wall thickening analysis.- Biplane and multiplane TEE imaging.- Cine loop and SWMA.- Methodological problems.- References.- Automated on-line wall motion analysis.- Principles of border identification.- Principles of the internal “centroid” reference systems.- Wall motion versus wall thickening.- Conclusion.- References.- Myocardial ischemia and Doppler transmural diastolic flow.- Recording techniques and parameters of Doppler transmitral inflow.- Practical remarks on measurement of Doppler transmitral parameters.- Relation between mitral flow characteristic and hemodynamics.- Doppler transmitral flow for intraoperative diagnosis of acute myocardial ischemia.- References.- Myocardial perfusion by contrast echocardiography: new trend in ischemia detection (scenario of the year 2000).- Principles of contrast echocardiography.- Quantitative analysis of myocardial contrast two-dimensional echocardiography.- a) Assessment of the perfusion territory of regional myocardial perfusion mapping.- b) Qualification of regional myocardial blood flow.- Conclusion.- References.