by:dawit ayele md,internist. definition epidemiology physiology classes of shock clinical...
TRANSCRIPT
Shock
By:Dawit AyeleMD,Internist
Definition Epidemiology Physiology Classes of Shock Clinical Presentation Management Controversies
Outline
A physiologic state characterized by◦ Inadequate tissue perfusion
Clinically manifested by◦ Hemodynamic disturbances◦ Organ dysfunction
Definition
Mortality◦ Septic shock – 35-40% (1 month mortality)
◦ Cardiogenic shock – 60-90%
◦ Hypovolemic shock – variable/mechanism
Epidemiology
Imbalance in oxygen supply and demand
Conversion from aerobic to anaerobic metabolism
Appropriate and inappropriate metabolic and physiologic responses
Resultant systemic physiology:-◦ Cell death and end organ dysfunction◦ MSOF and death
Pathophysiology
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
Physiology
Shock◦ Initial signs of end organ dysfunction:
◦ Tachycardia
◦ Tachypnea
◦ Metabolic acidosis
◦ Oliguria
◦ Cool and clammy skin
Pathophysiology
End Organ Dysfunction◦ Progressive irreversible dysfunction
◦ Oliguria or anuria
◦ Progressive acidosis and decreased CO
◦ Agitation, obtundation, and coma
◦ Patient death
Physiology
Schemes are designed to simplify complex physiology
Major classes of shock◦ Hypovolemic
◦ Cardiogenic
◦ Distributive
Classification
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
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.
Results from pump failure◦ Decreased systolic function◦ Resultant decreased cardiac output
Etiologic categories◦ Myopathic◦ Arrhythmic◦ Mechanical◦ Extracardiac (obstructive)
Cardiogenic 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
Distributive Shock
Septic ShockSIRS 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 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
Clinical Presentation
Done in parallel with treatment! Hx&P/E – helpful to distinguish type of shock Full laboratory evaluation (including H&H,
cardiac enzymes, ABG) Basic studies – CxR, EKG, U/A Basic monitoring – V/S, UOP, CVP, A-line Imaging if appropriate – FAST, CT Echo vs. P/A catheterization
◦ CO, PAS/PAD/PAW, SVR, SvO2
Evaluation
Manage the emergency
Determine the underlying cause
Definitive management or support
Treatment
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
Manage the Emergency
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
Thanks