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8/14/2019 Shock 2.ppt
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Core Lecture Series -Shock
Daniel J. Riskin, MD
September 9, 2007
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Outline
Definition
Epidemiology
Physiology
Classes of Shock
Clinical Presentation
Management
Controversies
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Definition
A physiologic state characterized by
Inadequate tissue perfusion
Clinically manifested by
Hemodynamic disturbances
Organ dysfunction
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Epidemiology
Mortality
Septic shock – 35-40% (1 month mortality)
Cardiogenic shock – 60-90%
Hypovolemic shock – variable/mechanism
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Pathophysiology
Imbalance in oxygen supply and demand
Conversion from aerobic to anaerobicmetabolism
Appropriate and inappropriate metabolic andphysiologic responses
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Pathophysiology
Cellular physiology
Cell membrane ion pump dysfunction
Leakage of intracellular contents into the
extracellular space Intracellular pH dysregulation
Resultant systemic physiology
Cell death and end organ dysfunction
MSOF and death
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Physiology
Characterized by three stages
Preshock (warm shock, compensated shock)
Shock End organ dysfunction
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Physiology
Compensated shock
Low preload shock – tachycardia,
vasoconstriction, mildly decreased BP Low afterload (distributive) shock – peripheral
vasodilation, hyperdynamic state
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Pathophysiology
Shock
Initial signs of end organ dysfunction
Tachycardia
Tachypnea
Metabolic acidosis
Oliguria Cool and clammy skin
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Physiology
End Organ Dysfunction
Progressive irreversible dysfunction
Oliguria or anuria
Progressive acidosis and decreased CO
Agitation, obtundation, and coma
Patient death
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Classification
Schemes are designed to simplify complex
physiology
Major classes of shock
Hypovolemic
Cardiogenic
Distributive
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Hypovolemic Shock
Results from decreased preload
Etiologic classes
Hemorrhage - e.g. trauma, GI bleed, rupturedaneurysm
Fluid loss - e.g. diarrhea, vomiting, burns, third
spacing, iatrogenic
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Hypovolemic Shock
Hemorrhagic Shock
Parameter I II III IV
Blood loss (ml) <750 750 –1500 1500 –2000 >2000
Blood loss (%) <15% 15 –30% 30 –40% >40%
Pulse rate (beats/min) <100 >100 >120 >140
Blood pressure Normal Decreased Decreased Decreased
Respiratory rate (bpm) 14 –20 20 –30 30 –40 >35
Urine output (ml/hour) >30 20 –30 5 –15 Negligible
CNS symptoms Normal Anxious Confused Lethargic
Crit Care. 2004; 8(5): 373 –381.
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Cardiogenic Shock
Results from pump failure
Decreased systolic function
Resultant decreased cardiac output
Etiologic categories
Myopathic
Arrhythmic Mechanical
Extracardiac (obstructive)
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Distributive Shock
Results from a severe decrease in SVR
Vasodilation reduces afterload
May be associated with increased CO
Etiologic categories
Sepsis
Neurogenic / spinal Other (next page)
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Distributive Shock
Other causes
Systemic inflammation – pancreatitis, burns
Toxic shock syndrome Anaphylaxis and anaphylactoid reactions
Toxin reactions – drugs, transfusions
Addisonian crisis Myxedema coma
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Distributive Shock
Septic Shock
SIRS 2 or more of the following: Temp >38 or <36 HR > 90
RR > 20 WBC > 20K >10% bands
Sepsis SIRS in the presence of suspected or documented infection
Severe Sepsis Sepsis with hypotension, hypoperfusion, or organ dysfunction
Septic Shock Sepsis with hyotension unresponsive to volume resuscitation, and evidence of hypoperfusion or organ dysfunction
MODS Dysfunction of more than one organ
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Clinical Presentation
Clinical presentation varies with type and
cause, but there are features in common
Hypotension (SBP<90 or Delta>40) Cool, clammy skin (exceptions – early
distributive, terminal shock)
Oliguria Change in mental status
Metabolic acidosis
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Evaluation
Done in parallel with treatment!
H&P – helpful to distinguish type of shock
Full laboratory evaluation (including H&H,cardiac enzymes, ABG)
Basic studies – CxR, EKG, UA
Basic monitoring – VS, UOP, CVP, A-line Imaging if appropriate – FAST, CT
Echo vs. PA catheterization
CO, PAS/PAD/PAW, SVR, SvO2
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Treatment
Manage the emergency
Determine the underlying cause
Definitive management or support
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Manage the Emergency
Your patient is in extremis – tachycardic,
hypotensive, obtunded
How long do you have to manage this?
Suggests that many things must be done at
once Draw in ancillary staff for support!
What must be done?
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Manage the Emergency
One person runs the code!
Control airway and breathing
Maximize oxygen delivery
Place lines, tubes, and monitors
Get and run IVF on a pressure bag
Get and run blood (if appropriate) Get and hang pressors
Call your senior/fellow/attending
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Determine the Cause
Often obvious based on history
Trauma most often hypovolemic (hemorrhagic)
Postoperative most often hypovolemic(hemorrhagic or third spacing)
Debilitated hospitalized pts most often septic
Must evaluate all pts for risk factors for MI and
consider cardiogenic
Consider distributive (spinal) shock in trauma
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Determine the Cause
What if you’re wrong?
85 y/o M 4 hours postop S/P sigmoid resectionfor perforated diverticulitis is hypotensive on a
monitored bed at 70/40
Likely causes
Best actions for the first 5 minutes?
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Definitive Management
Hypovolemic – Fluid resuscitate (blood or
crystalloid) and control ongoing loss
Cardiogenic - Restore blood pressure(chemical and mechanical) and prevent
ongoing cardiac death
Distributive – Fluid resuscitate, pressors for
maintenance, immediate abx/surgical control
for infection, steroids for adrenocortical
insufficiency
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Controversies
IVF Resuscitation
Limited resuscitation in penetrating trauma
Use of hypertonic saline resuscitation in trauma Endpoints for prolonged resuscitation
Pressors
Best pressors for distributive shock Monitoring
Most appropriate timing and use for PA
catheterization or intermittent echocardiogram
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Cases