الفهرس 
Definitions and epidemiology of Septic shock
Recent suspects in pathophysiology of septic shockOnly 14 pages are availabe for public view
Abstract
Sepsis is a clinical syndrome characterized by systemic
inflammation and widespread tissue injury due to infection. There
is a continuum of illness severity ranging from sepsis to severe
sepsis and septic shock. When infection is absent, the clinical
syndrome is termed systemic inflammatory response syndrome
(SIRS).
A review of studies evaluating the epidemiology of sepsis
shows a very high prevalence, both among all hospitalized
patients (one third) and among those admitted to ICUs (over
50%). More than half of all septic patients develop severe sepsis
and a quarter develops septic shock; thus, 10-15% of all patients
admitted to ICUs develop septic shock. This show how valuable
to assess the medical & economical burden of such a problem.
Sepsis is the culmination of complex interactions between the
infecting microorganism and the host immune, inflammatory, and
coagulation responses. Both the host responses and the
characteristics of the infecting organism influence the outcome of
sepsis.
The vascular endothelium has a central role in the control of
microvascular tone which is damaged in septic shock producing
multi organ dysfunction; evidenced by the increasing number of
circulating endothelial cells in septic shock.septic shock there is a disturbance of procoagulant –
anticoagulant balance with increase in procoagulant factors &
decrease of anticoagulant factors which is a key feature in
pathogenesis of septic shock.
In shock there is an imbalance between oxygen supply and
demand, which results in a systemic clinical syndrome
characterized by hypotension and hypoperfusion leading to
cellular dysfunction. Sepsis is a systemic response to infection,
and septic shock is sepsis with hypotension and abnormalities in
perfusion.
Septic shock is associated with 3 major pathophysiological
effects within the cardiovascular system which are vasodilatation,
maldistribution of blood flow and myocardial depression.
Appropriate monitoring of patients with septic shock is
imperative, with specific consideration given to detecting changes
in perfusion and tissue oxygenation. Basic monitoring should
include pulse oximetry, electrocardiography, and invasive blood
pressure monitoring. Central venous pressure monitoring or
pulmonary artery catheterization, along with measurements of
venous oxygen saturation (mixed [S¯vO2] or central venous
[ScvO2]), may be useful in evaluating cardiovascular status if a
patient is refractory to initial volume resuscitation or if
oxygenation indices will be used as the end point of resuscitation.Initial management is aimed at securing the airway and
correcting hypoxemia. Intubation and mechanical ventilation may
be required.
Once the patient’s respiratory status has been stabilized, the
adequacy of perfusion should be assessed. Hypotension is the
most common indicator that perfusion is inadequate. However,
critical hypoperfusion can also occur in the absence of
hypotension, especially during early sepsis. Common signs of
hypoperfusion include cool, vasoconstricted skin due to
redirection of blood flow to core organs (although warm, flushed
skin may be present in the early phases of sepsis), restlessness,
oliguria or anuria, and lactic acidosis.
Once it has been established that hypoperfusion exists, early
restoration of perfusion is necessary to prevent or limit multiple
organ dysfunction, as well as reduce mortality. Tissue perfusion
should be promptly restored using intravenous fluids,
vasopressors, red blood cell transfusions, and inotropes. It is
recommended for patients to be managed with therapy aimed at
achieving a central (or mixed) venous oxygen saturation ≥70
percent within six hours of presentation. It is reasonable to
simultaneously aim for a central venous pressure 8 to 12 mmHg,
mean arterial pressure (MAP) ≥65 mmHg, and urine output ≥0.5
mL per kg per hour.Prompt identification and treatment of the culprit site of
infection are essential. Antibiotics should be administered
immediately after appropriate cultures have been obtained. Start
empiric broad spectrum antibiotics when a definite source of
infection can not be identified. Antifungal therapy should be
added if the patient fails to respond or there is clinical suspicion of
fungal infection.
Glucocorticoid therapy, nutritional support, and glucose
control are additional issues that are important in the management
of patients with severe sepsis or septic shock.
Reduce the risk of renal failure through aggressive hydration
and minimization of hypotension. Recently, continuous renal
replacement therapy is a way to restore the kidney functions back
in such critical situations which is accompanied with acute renal
failure, fluid retention or severe sepsis by the continuous
hemodiafiltration.
The primary goal of the anaesthetist during the intraoperative
period is to provide safe and optimal care for critically ill septic
patients so that they may benefit maximally from the surgical or
radiological source control procedure. The majority of surgical
source control procedures are optimally carried out in the
operating theatre under general anaesthesia.
The anaesthetist should choose the technique which they
believe best fits with their assessment of the individual patient’s risk factors and co-morbidities, and their own experience and
expertise. Patients undergoing source control procedures are in an
inherently unstable cardiovascular state due to the combined
effects of sepsis, anaesthesia, intravascular volume loss, bleeding,
and surgical stress.
There is no evidence to suggest an outcome benefit when
anaesthesia is maintained by the inhalation or i.v. route. Options
for maintaining anaesthesia include inhalation agents, i.v. agents,
and opioids, the anaesthetist should choose the technique which
they believe best fits with their assessment of the individual
patient’s risk factors and co-morbidities, and their own experience
and expertise.
Throughout the surgical procedure, cardiovascular
parameters (heart rate, cardiac filling pressures, inotropic state,
and systemic arterial pressure) can be adjusted to optimize tissue
oxygen delivery rather than to achieve set values of cardiac output
or arterial pressure. The adequacy of global oxygen delivery may
be assessed by serum lactate <2 mmol litre−1 and mixed-venous
O2 saturation >70%.
Postoperative care overlaps with ongoing management of
the severe sepsis syndrome patient in the intensive care unit.