Download RTC MODS 2 - The American Association for the Surgery of

Multiorgan Dysfunction
Syndrome
Justin Chandler
Oct 27, 2010
Epidemiology

Exact incidence is not known

In one study of 938 consecutive SICU pt,
about 50% had MODS
 Mortality

was 30%
Infection related severe sepsis is estimated at
~750,000 cases/yr nationally
 If
non-infectious causes is included (trauma,
pancreatitis), the rate doubles
 Mortality is about 28% or 215,000 deaths/yr
Mechanism

Clinical picture is of generalized systemic
inflammatory response (SIRS)


Typically in response to infection or uncontrolled
inflammation (severe trauma, pancreatitis)
“Can be viewed as a systemic process involving
the excessive stimulation of certain inflammatory
responses mediated by circulating factors whose
effects contribute to injury or dysfunction in
organs not involved in the initial insult”1
SIRS Criteria

Requires two of the following:
Current Concepts

Earliest reports of postinjury MODS identified occult
intraabdominal infection as the etiology in half of the
cases



However, we know now 50%–70% of MOF do not have an
identifiable infectious focus
Therefore uncontrolled infection is not the universal cause of
MODS
It was then realized the host’s own response to tissue
injury or shock could result in a noninfectious sepsis

The immunoinflammatory response to infection, injury, necrotic
tissue, or shock was similar led to the hypotheses that immune
cell products contributed to MODS
Current Concepts

Concept of an excessive immunoinflammatory response from
activated macrophages and other immune cells led to cytokinemediated tissue injury (and thereby SIRS and MODS)

Supported by several experimental and clinical observations


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

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Cytokine levels were increased in trauma patients
Administration of (TNF-α) to humans elicited a clinical response similar to
SIRS
Preclinical animal studies documented that TNF- α neutralization improved
survival after receiving a lethal dose of endotoxin
However, there have been multiple clinical trials of anti-inflammatory
agents that have failed along with more complex preclinical animal
studies
It is now recognized that cytokines have many beneficial functions, such
as the control of infection
Elevated cytokine levels appear to be more markers or predictors of the
host response than inducers
Diagnosis


Term “MODS” was introduced in 1991 by a
consensus of the American College of Chest
Physicians (ACCP) and the Society of Critical
Care Medicine (SCCM)
Concept that there exists a continuous spectrum
from mild to full-blown dysfunction

Several MODS scoring systems have been
established


grade the severity of MODS
Most correlate, on a patient population level, with mortality
and morbidity
Scoring Systems for MOF
SOFA
Scoring

Beneficial in critically ill patients.
Use in the daily clinical evaluation of a
patient’s response
 Epidemiologic studies
 Assessment of new therapies in clinical


Although systems use slightly different
parameters the clinical utility of these
scoring systems is comparable
Management

No cure…

Treatment is largely symptomatic and
dedicated to supporting organs and systems
that have failed
Resuscitation

Central goal: restoration of an effective blood volume, optimization
of microcirculatory blood flow (and hence tissue perfusion), and the
prevention/limitation of ischemia-reperfusion injury


Increasing emphasis on the adequacy of volume resuscitation
Primary endpoint of resuscitation, however, remains controversial



Blood pressure and urine output may not reflect the adequacy of volume
resuscitation
Base deficit, lactate, oxygen delivery, gastric intramucosal pH (pHi), and
pulmonary artery catheters have all been used
patients who cleared their base deficient or lactate levels within 48
hours had a reduced incidence of ARDS and MODS plus a higher
survival rate

resuscitative goal should be to reduce base deficit below –2 mmol/l and/or
lactate less than 1.5 mEq/l.
Resuscitation - Fluids

Choice of resuscitative fluid has become more
controversial



Ringers lactate is proinflammatory
Large-volume resuscitation with crystalloids contributes to
abdominal compartment syndrome
Attention has refocused on the early resuscitation of trauma
patients with hypertonic (7.5%) saline




Has demonstrated similar survival, but decreased complications
(renal failure and ARDS) with hypertonic saline
Not enough data to determine if hypertonic saline resuscitation is
superior to standard crystalloid resuscitation
Splanchnic-directed antioxidant therapy helps prevents MODS in
trauma patients
investigations into novel resuscitation fluids with pharmacologic
actions (i.e., gut-protective, immune modulatory) continues
Resuscitation - Fluids

Blood is immune-suppressive and that blood
transfusions are an independent predictor of
MODS


TRICC trial showed a significant reduction in severity
of organ dysfunction when transfusion withheld until
Hb <7 g/dl
Two general conclusions


Prophylactic transfusions to raise the hemoglobin above 7
g/dl does not improve tissue oxygen consumption
consistently
Prophylactic transfusion is not associated with improvements
in outcome, and may result in worse outcomes in several
subgroups
Resuscitation - Fluids

Attempts to identify optimal hemodynamic values


Tissue-specific resuscitation endpoints

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Gastric pH (tonometry)
Early studies suggested supranormal CO and DO2 for increased
oxygen demands improved survival



Cardiac index, oxygen delivery, and oxygen consumption
Refuted by numerous prospective randomized trials
Use of prophylactic blood transfusions, inotropes, and large volumes of
crystalloids may be deleterious
Some data suggesting low gastric mucosal pHs have a worse
outcome

Measuring gastric mucosal pH has not been shown to be as effective as
base deficit or lactate as markers resuscitation
Operative Intervention

Judicious use of damage-control laparotomy to limit both
acute and delayed MODS


Prolonged attempts at definitive control can result in
hemodynamic instability, acidosis, and coagulopathy
Morbidity and mortality of damage-control laparotomies is
significant

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Incidence of MODS appears to be reduced and survival increased
A planned reoperation is safer and easier

Occurs after pts have been warmed, resuscitated, and had their
acidosis and coagulopathy corrected
Operative Intervention

A second example



reduce the incidence of ARDS and MODS with early
fixation of long-bone fractures
Compared with delayed fracture fixation is associated
with lower rates of renal, respiratory, and liver failure
and death
Early fracture fixation in the presence of major
thoracic or head injury is controversial



Early fixation have shown no added morbidity with either
chest or head injury
Others cite increases in secondary brain injury and ARDS
Overall, most evidence supports early fracture fixation
as an effective method
ICU

MOF can be prevented through:
Continued resuscitation
 Management of infectious complications

 Early
empiric abx in suspected pneumonia has
been shown to reduce pneumonia mortality
 Selective decontamination of the digestive tract
(SDD) reduces infectious complications as well as
mortality in trauma and surgical pts

Early nutritional and specific organ support
Prevention

SDD
Gut is a major reservoir for organisms causing
pneumonias and bacteremias
 By controlling intestinal bacterial flora,
including upper GI, incidence of infections
and hence mortality will be reduced
 The failure to employ SDD appears to relate
to the labor intensiveness
 Has only recently been shown by metaanalyses to improve survival

Activated Protein C

With the exception of activated protein C,
immunomodulatory agents have been
disappointing


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APC is both anticoagulant and anti-inflammatory
activity, thereby protecting the microcirculation as well
as limiting the inflammatory response
More rapid resolution of cardiovascular, respiratory,
and hematologic dysfunction in severe sepsis
Improved 28-day survival
Steroids

Low-dose steroids


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Effective therapy in patients with pressor-refractory
septic shock and impaired response to ACTH
stimulation
Trials have documented in this pt group the
administration of 50 mg of hydrocortisone every 6
hours and 50 mcg of fludrocortisone improves
survival
Surviving sepsis recommends 300 mg/day divided
doses, with mineralocorticoid being superfluous
Other Therapies
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Other beneficial interventions include
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Early enteral alimentation


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Based on limiting atrophy to limit gut-origin sepsis by loss of
barrier funct
Effectively reduces infectious complications, ICU, and total
hospital length of stay, but does not improve survival
Glucose control

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Elevated serum glucose is associated with an increased
incidence of infectious complications and poorer outcomes
Excessively tight glucose control has been shown to increase
complications and mortality for most subsets
Ventilator Therapies
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Ventilator-induced lung injury (VILI)
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Reduced vent volumes and pressures
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outcomes with ALI or ARDS are similar whether lower or higher
PEEP levels are used
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end-inspiratory plateau pressure under 30 cm of water
While oxygenation is maintained with low tidal volumes,
permissive hypercapnia and increased CO2 levels may develop

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High volumes and increased pressures cause, rather than prevent,
lung injury by inducing lung inflammation
does not appear to be harmful
Other ventilatory strategies have either failed to show consistent
benefit (such as inhaled nitric oxide) or remain to be proven
beneficial (such as prone ventilation or high-frequency
ventilation).
Other Therapies

Other beneficial interventions include

Elevation of the head of the bed
 In
ventilated patients reduces the incidence of
pneumonia and helps to preserve pulmonary
function

Daily cessation of sedative infusions
 Reduces
ICU length of stay and morbidity
Renal Support

Renal support


Prophylactic use of low-dose dopamine, have not been found to
be effective
Best way to limit renal failure


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Once renal failure occurs, continuous venovenous hemodialysis
(CVVHD) appears to be superior to hemodialysis


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Avoid underresuscitation
Promptly diagnose and treat infectious complications
Avoids the need for systemic anticoagulation
Less likely to cause hypotension
Renal replacement therapy

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Allows regulation of fluid and electrolytes
Has the potential to remove toxins and circulating mediators of
inflammation
Abdominal Compartment
Syndrome

Recently recognized and treatable cause of MODS

As the intra-abdominal pressure rises

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Pts at highest risk include:

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Abdominal visceral perfusion decreases
Ventilation is impaired
Cardiac output declines
Polytrauma
Massive hemorrhage
Prolonged operations with massive volume resuscitation
Massive hemorrhage requiring intra-abdominal packing
Diagnosis



Clinical signs: decreasing urine output, inadequate ventilation associated w/
elevated peak airway pressures, and hypotension
Made or confirmed by measuring the abdominal pressure through a Foley
catheter placed in the bladder (> 25 mm Hg), progressive organ dysfunction
(UO < 0.5 ml/kg/hr, PaO2/FIO2 < 150, PIP 45 cm H2O or cardiac index <3
L/min/m2 despite resuscitation)
Improved organ function after surgical abdominal decompression
Prevention Strategies
References
Current Therapy of Trauma and Surgical
Critical Care
 http://www.medicalcriteria.com
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