Shock Core Lecture Series Shock Daniel J Riskin MD by wuzhengqin

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									Core Lecture Series -
Shock


       Daniel J. Riskin, MD
       September 9, 2007
Outline
 Definition
 Epidemiology
 Physiology
 Classes of Shock
 Clinical Presentation
 Management
 Controversies
Definition
 A physiologic state characterized by
   Inadequate tissue perfusion



 Clinically manifested by
   Hemodynamic disturbances
   Organ dysfunction
Epidemiology
 Mortality
   Septic shock – 35-40% (1 month mortality)
   Cardiogenic shock – 60-90%
   Hypovolemic shock – variable/mechanism
Pathophysiology
 Imbalance in oxygen supply and demand
 Conversion from aerobic to anaerobic
  metabolism
 Appropriate and inappropriate metabolic and
  physiologic responses
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
Physiology

  Characterized by three stages
      Preshock (warm shock, compensated shock)
      Shock
      End organ dysfunction
Physiology

  Compensated shock
      Low preload shock – tachycardia,
       vasoconstriction, mildly decreased BP
      Low afterload (distributive) shock – peripheral
       vasodilation, hyperdynamic state
Pathophysiology
 Shock
   Initial signs of end organ dysfunction


      Tachycardia
      Tachypnea
      Metabolic acidosis
      Oliguria
      Cool and clammy skin
Physiology
 End Organ Dysfunction
   Progressive irreversible dysfunction


      Oliguria or anuria
      Progressive acidosis and decreased CO
      Agitation, obtundation, and coma
      Patient death
Classification
 Schemes are designed to simplify complex
  physiology
 Major classes of shock
     Hypovolemic
     Cardiogenic
     Distributive
Hypovolemic Shock

  Results from decreased preload
  Etiologic classes
      Hemorrhage - e.g. trauma, GI bleed, ruptured
       aneurysm
      Fluid loss - e.g. diarrhea, vomiting, burns, third
       spacing, iatrogenic
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    Conf used   Lethargic




 Crit Care. 2004; 8(5): 373–381.
Cardiogenic Shock

  Results from pump failure
       Decreased systolic function
       Resultant decreased cardiac output
  Etiologic categories
    Myopathic
    Arrhythmic
    Mechanical
    Extracardiac (obstructive)
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)
Distributive Shock

  Other causes
      Systemic inflammation – pancreatitis, burns
      Toxic shock syndrome
      Anaphylaxis and anaphylactoid reactions
      Toxin reactions – drugs, transfusions
      Addisonian crisis
      Myxedema coma
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
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
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
Treatment

  Manage the emergency
  Determine the underlying cause
  Definitive management or support
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?
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
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
Determine the Cause

  What if you’re wrong?


  85 y/o M 4 hours postop S/P sigmoid resection
   for perforated diverticulitis is hypotensive on a
   monitored bed at 70/40

  Likely causes
  Best actions for the first 5 minutes?
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
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
Cases

								
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