الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
There has been a several modifications in the management of septic
shock. Studies such as the early goal-directed therapy (EGDT) advocated
for aggressive fluid management guided by static measures such as the
central venous pressure (CVP). Recently, several studies have
demonstrated that aggressive resuscitation of septic shock patients as well
as an overall positive fluid balance can be harmful and can lead to worst
outcomes. So, it is important to avoid excessive fluid administration in such
cases. Depending on static measurements such as CVP to predict volume
responsiveness has been unreliable by several studies.
In order to predict the response of cardiac output to fluid infusion,
the passive leg raising (PLR) test has been validated. It consists of lifting
the legs passively at 45°and moving the trunk down horizontally, starting
from a semi-recumbent position. By transferring a consistent amount of
venous blood from the legs and the splanchnic compartment towards the
intra-thoracic compartment, it increases the mean systemic pressure, the
cardiac preload and consequently cardiac output in the case of preload
responsiveness of both ventricles. However, it must be coupled with a
direct and real-time measurement of cardiac output, which is often
invasive.
The decision to give fluids must be guided by a reliable prediction
of fluid responsiveness as around 50% of patients respond to fluid
administration by increasing cardiac output. So, recent research started to
study non-invasive maneuvers for assessing volume responsiveness such as
the inferior vena cava (IVC) ultrasound evaluation, as well as more
advanced Doppler applications such as esophageal Doppler monitoring
looking at changes in aortic flow time to guide fluid therapy. Moreover,
some studies have looked at the left ventricular outflow tract (LVOT) velocity time integral (VTI) change with either a passive leg raise or a fluid
bolus as a measure of volume responsiveness and found it to be specific in
predicting fluid responsiveness.
Acquiring an appropriate apical five-chamber view and getting an
adequate window of the LVOT can be challenging. Novice emergency
physicians (EP) are taught to identify the apical 4-chamber and then tilt the
ultrasound upward and slightly counterclockwise to open the 5th chamber,
the aorta. The inability of getting an adequate apical-5 chamber can
underestimate patients’ VTI values. Given that the majority of EPs are
comfortable with apical-4 views and carotid duplex, we sought to
investigate the sensitivity and specificity of mitral valve (MV) velocity
time integral (VTI) as a non-invasive marker of volume responsiveness.