ER

1. Shock
DR HOSAM ATEF

2. Outline
 Definition
 Epidemiology
 Physiology
 Classes of Shock
 Clinical Presentation
 Management
 Controversies

3. Definition
 A physiologic state characterized by
 Inadequate tissue perfusion
 Clinically manifested by
 Hemodynamic disturbances
 Organ dysfunction

4. Epidemiology
 Mortality
 Septic shock – 35-40% (1 month mortality)
 Cardiogenic shock – 60-90%
 Hypovolemic shock – variable/mechanism

5. Pathophysiology
 Imbalance in oxygen supply and demand
 Conversion from aerobic to anaerobic
metabolism
 Appropriate and inappropriate metabolic and
physiologic responses

6. 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

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

8. Physiology
 Compensated shock
 Low preload shock – tachycardia,
vasoconstriction, mildly decreased BP
 Low afterload (distributive) shock – peripheral
vasodilation, hyperdynamic state

9. Pathophysiology
 Shock
 Initial signs of end organ dysfunction
 Tachycardia
 Tachypnea
 Metabolic acidosis
 Oliguria
 Cool and clammy skin

10. Physiology
 End Organ Dysfunction
 Progressive irreversible dysfunction
 Oliguria or anuria
 Progressive acidosis and decreased CO
 Agitation, obtundation, and coma
 Patient death

11. Classification
 Schemes are designed to simplify complex
physiology
 Major classes of shock
 Hypovolemic
 Cardiogenic
 Distributive

12. 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

13. 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.

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

15. 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)

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

17. 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

18. Clinical Presentation
 Clinical presentation varies with type and
cause, but there are features in common
 Hypotension (SBP<90 )
 Cool, clammy skin (exceptions – early
distributive, terminal shock)
 Oliguria
 Change in mental status
 Metabolic acidosis

19. 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

20. Treatment
 Manage the emergency
 Determine the underlying cause
 Definitive management or support

21. Manage the Emergency
 Your patient is in extreme – 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?

22. 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

23. 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

24. 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?

25. 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

26. 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