[show abstract][hide abstract] ABSTRACT: BACKGROUND: Left ventricular rotation and twist can be assessed noninvasively by speckle tracking echocardiography. We sought to characterize the effects of acute load change and change in inotropic state on rotation parameters as a measure of left ventricular (LV) contractility. METHODS: Seven anesthetised juvenile pigs were studied, using direct measurement of left ventricular pressure and volume and simultaneous transthoracic echocardiography. Transient inflation of an inferior vena cava balloon (IVCB) catheter produced controlled load reduction. First and last beats in the sequence of eight were analysed with speckle tracking (STE) during the load alteration and analysed for change in rotation/twist during controlled load alteration at same contractile status. Two pharmacological inotropic interventions were also included to examine the same hypothesis in additionally conditions of increased and decreased myocardial contractility in each animal. Paired comparisons were made for different load states using the Wilcoxon's Signed Rank test. RESULTS: The inferior vena cava balloon occlusion (IVCBO) load change compared for first to last beat resulted in LV twist increase (11.67degrees +/-2.65degrees vs. 16.17degrees +/-3.56degrees respectively, p < 0.004) during the load alteration and under adrenaline stimulation LV twist increase 12.56degrees +/-5.1degrees vs. 16.57degrees +/-4.6degrees (p < 0.013), and though increased, didn't reach significance in negative inotropic condition. Untwisting rate increased significantly at baseline from 41.7degrees/s +/-41.6degrees/s vs.122.6degrees/s +/-55.8degrees/s (P < 0.039) and under adrenaline stimulation untwisting rate increased (55.3degrees/s +/-3.8degrees/s vs.111.4degrees/s +/-24.0degrees/s (p < 0.05), but did not systematically changed in negative inotropic condition. CONCLUSIONS: Peak systolic LV twist and peak early diastolic untwisting rate are load dependent. Differences in LV load should be included in the interpretation when serial measures of twist are compared.
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Tissue velocity echocardiography is increasingly used to evaluate global and regional cardiac function. Previous studies have suggested that the quantitative measurements obtained during ejection are reliable indices of contractility, though their load-sensitivity has been studied in different settings, but still remains a matter of controversy. We sought to characterize the effects of acute load change (both preload and afterload) and change in inotropic state on peak systolic velocity and strain as a measure of LV contractility. METHODS: Thirteen anesthetized juvenile pigs were studied, using direct measurement of left ventricular pressure and volume and transthoracic echocardiography. Transient inflation of a vena cava balloon catheter produced controlled load alterations. At least eight consecutive beats in the sequence were analyzed with tissue velocity echocardiography during the load alteration and analyzed for change in peak systolic velocities and strain during same contractile status with a controlled load alteration. Two pharmacological inotropic interventions were also included to generate several myocardial contractile conditions in each animal. RESULTS: Peak systolic velocities reflected the drug-induced changes in contractility in both radial and longitudinal axis. During the acute load change, the peak systolic velocities remain stable when derived from signal in the longitudinal axis and from the radial axis. The peak systolic velocity parameter demonstrated no strong relation to either load or inotropic intervention, that is, it remained unchanged when load was systematically and progressively varied (peak systolic velocity, longitudinal axis, control group beat 1- 5.72 +/- 1.36 with beat 8- 6.49 +/- 1.28 cm/sec, 95% confidence interval), with the single exception of the negative inotropic intervention group where peak systolic velocity decreased a small amount during load reduction (beat 1- 3.98 +/- 0.92 with beat 8- 2.72 +/- 0.89 cm/sec). Systolic strain, however, showed a clear degree of load-dependence. CONCLUSIONS: Peak systolic velocity appears to be load-independent as tested by beat-to-beat load reduction, while peak systolic strain appears to be load-dependent in this model. Peak systolic velocity, in a controlled experimental model where successive beats during load alteration are assessed, has a strong relation to contractility. Peak systolic velocity, but not peak strain rate, is largely independent of load, in this model. More study is needed to confirm this finding in the clinical setting.
[show abstract][hide abstract] ABSTRACT: Echocardiography has a key role in the hemodynamic evaluation of cardiac surgical patients, before, during, and after surgery.
Before surgery, it mostly covers indications for cardiac surgery in patients with cardiogenic shock, and in a multidisciplinary
approach it is sound practice to involve cardiologists.
During surgery, the anesthesiologist can continuously monitor the patient with transesophageal echocardiography. This allows
not only general hemodynamic monitoring, as described in other chapters, but also evaluation of the adequacy of surgical repair.
In the postoperative setting, transesophageal echocardiography should be performed when indicated by clinical signs. At this
stage, monitoring using TEE is no longer continuous, even though the probe can often be left in place for some time. After
patient extubation, transthoracic echocardiography can be attempted, but it is often of limited quality and usually restricted
to some views and indices, and it can leave the physician with some uncertainty.
More often than in other settings, cardiac surgical patients in the peri- and early postoperative setting present some specific
alterations that require careful examination, such as tamponade and particularly localized compression (often of the right
heart), dynamic obstruction of the left ventricular outflow tract, and regional hypokinesia (suggesting occlusion of the bypass
[show abstract][hide abstract] ABSTRACT: Transesophageal echocardiography (TEE) uses echographic facilities mounted on a blinded gastroscope. It opens a new window
to the heart and large vessels. The implementation of two-phased-array transducers perpendicular to each other has led to
imaging capabilities in both transverse and longitudinal planes. TEE includes most imaging and Doppler facilities, as in transthoracic
In this chapter, the different views are described as well as their main use in critically ill patients. TEE necessitates
positioning of the probe in different locations in the esophagus and stomach. The transgastric view is used to evaluate left
ventricular contractility, right ventricular dilation, and the left ventricular outflow tract (for cardiac output measurements).
Midesophageal views are used to visualize simultaneously the four cavities of the heart and valves. TEE is also used to measure
the diameter of the left ventricular outflow tract – and hence compute cardiac output in addition to the above Doppler measurements.
The upper esophageal view is particularly useful for evaluating the superior vena cava, which can be predictive of preload
[show abstract][hide abstract] ABSTRACT: Echography has developed as an indispensable tool in diagnosis and subsequent therapy in the critically ill. Although pulmonary and abdominal ultrasounds play a major role in their management, this article will discuss the advantages and indications of echocardiography in the intensive care unit (ICU). The assessment of morphological abnormalities, left or right ventricular malfunction, pulmonary arterial hypertension and valvular dysfunctions is a routine indication of echocardiography. Actually, besides contractility, several preload and even afterload indicators can also be assessed. In short, this bedside tool rapidly provides insight in the haemodynamics without invasive pressure estimations.
Baillière' s Best Practice and Research in Clinical Anaesthesiology 09/2009; 23(3):249-61.