Focused Ultrasound: Revolutionizing Shock Diagnosis and Management in Clinical Practice

Focused Ultrasound Assisting Clinicians in the Diagnosis and Management of Shock
Shock is a clinical syndrome in which there is inadequate cellular and tissue oxygenation due
to circulatory failure [1 ]. Hypotension is the cardinal feature of shock in which the systolic
blood pressure is less than 90 mmHg or the mean arterial pressure is less than 65 mmHg as
suggested by the latest international consensus definitions for sepsis and septic shock [2].
There are four varied categories of shock as per underlying pathophysiology which are
cardiogenic shock, hypovolemic shock, distributive shock, obstructive shock (Richards and
Wilcox, 2014). Marx, Walls and Hockberger (2013) adds a fifth category to it which is the
shock related to poisoning of cells. These shocks need to be diagnosed and managed urgently
by the clinicians to save the precious lives.The correct cause and the differential diagnosis in
a symptomatic non traumatic, undifferentiated hypotension is often very difficult and
challenging.The initial diagnosis of shock etiology is correct only in 50% of patients [3]
The evidence shows that the in-hospital mortality rate in such types of hypotensive patients
equals or exceeds the mortality rate of other critical conditions like acute myocardial
infarction, pulmonary embolism, or penetrating chest trauma. [4,5. 6,7,8]. Urgent strategies
and special protocols are followed world wide to diagnose and treat the shocked patients [9].
Focused Ultrasound in non traumatic Hypotension
Focused ultrasound is a thermoblative procedure which has been studied for more than 60
years [10]. It has been utilized for various treatments of shocks [11]. A land mark study
(Jones et al CCM 2004), done on non traumatic shock patients, in which the systolic B.P. was
less than 100 and the shock index SI >1, showed the importance of the early use of the
focused ultrasound. Focused echo and FAST ultrasound were used at 15 and 30 minutes
intervals from the time of arrival.
At 15 minutes interval, only 50% of the cases had correct diagnosis and differential diagnosis
in the clinical assessment group, as compared to the 80% correct diagnosis in the ultrasound
assessment group.
Focus ultrasound or point of care ultrasound POCUS is now an important bedside tool in
emergency medicine and critical care .POCUS means that the portable ultrasound can be
used anywhere in the ambulance, in the emergency departments or any other critical settings,
wherever the patient is located.
PoCUS assists the emergency physicians for a rapid and accurate differentiation between the
major shock types in the undifferentiated hypotensive patients presenting to the ED in a very
a short period of time (average of 6 minutes) [3].
As compared to the traditional imaging it is non invasive , more safe and rapid [12].Early
recognition and appropriate treatment of shock have been shown to decrease mortality
[13,14].

The paper by Atkinson et al. (2009) finds that protocols for focused ultrasound assessment
for the patients of non- traumatic hypotension have been proposed in terms of the Shock
protocol which includes the Abdominal and Cardiac Evaluation with Sonography. In fact,
there are various ways to focus ultrasound. These can be done through a curved transducer, a
lens, a phased array or a combination of any of the three mentioned. When the septic shock
is considered, the focused cardiac ultrasound would identify the required sonographic
findings associated with the decrease in the size of LV (Left Ventrical) which is usual in
hypovolemia throughout the cardiac cycle but substantially decreases in hyperdynamic states.
These findings can possibly help the clinicians in adapting suitable treatments to varied
stages of septic shock.
Reflecting a trend to integrate ultrasound early into the care of the critically ill patient,
multiple resuscitation protocols such as ACES,FATE, FEEL and RUSH have been recently
developed [15—19]. Each of these protocols combines many of the same core ultrasound
elements, differing mainly in the priority of the exam sequence for the assessment of the
heart, lungs, the vena cava, and a focused assessment of the abdomen to find free fluid.The
diagnosed findings of of the shock guide for the early resuscitation strategies such as fluid
versus vasopressor support and the other therapeutic procedures such as pericardiocentesis
and laparotomy.
Summary of POCUS protocols for medical shock assessment

Rapid Ultrasound in shock RUSH exam is an easy and quick shock ultrasound protocol
[17].
The RUSH exam consists of 3-part bedside physiologic assessments .
Step 1: The Pump. First step is the sonographic evaluation of the cardiac status of the patient
in shock which is called “the pump.” Focused echocardiogram includes four classical views:
parasternal long and short axis, sub- xiphoid, and apical (figure 1).
global left ventricular contractility and pericardial effusion are detected in this step and right
to left ventricular ratio is used for massive pulmonary embolism.
Step 2: The Tank. The second part is called “the tank”.It determines the effective
intravascular volume status in inferior vena cava and peritoneal and pleural cavities for free
fluid (figure 2).
Step 3: The Pipes. This part is termed “the pipes,” (figure 3).It is used for the quick
diagnosis the life threatening and catastrophic causes of hypotension , like dissection of the
thoracic aorta , abdominal aortic aneurysm AAA of the abdominal aorta , and the deep
venous thrombosis of the lower extremities. The survival of such patients is often crusual and
is measured in minutes.

Figure 1: The RUSH exam. step 1. Evaluation of “the pump” [18]
Figure 2. The RUSH exam. Step 2: Evaluation of “the tank” [18].