By:Dawit Ayele MD,Internist

 Definition  Epidemiology  Physiology  Classes of Shock  Clinical Presentation  Management  Controversies

 A physiologic state characterized by ◦ Inadequate tissue perfusion  Clinically manifested by ◦ Hemodynamic disturbances ◦ Organ dysfunction

 Mortality ◦ Septic shock – 35-40% (1 month mortality) ◦ Cardiogenic shock – 60-90% ◦ Hypovolemic shock – variable/mechanism

 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

 Characterized by three stages ◦ Preshock (warm shock, compensated shock) ◦ Shock ◦ End organ dysfunction

 Compensated shock ◦ Low preload shock – tachycardia, vasoconstriction, mildly decreased BP ◦ Low afterload (distributive) shock – peripheral vasodilation, hyperdynamic state

 Shock ◦ Initial signs of end organ dysfunction: ◦ Tachycardia ◦ Tachypnea ◦ Metabolic acidosis ◦ Oliguria ◦ Cool and clammy skin

 End Organ Dysfunction ◦ Progressive irreversible dysfunction ◦ Oliguria or anuria ◦ Progressive acidosis and decreased CO ◦ Agitation, obtundation, and coma ◦ Patient death

 Schemes are designed to simplify complex physiology  Major classes of shock ◦ Hypovolemic ◦ Cardiogenic ◦ Distributive

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

 Hemorrhagic Shock ParameterIIIIIIIV Blood loss (ml)<750750– –2000>2000 Blood loss (%)<15%15–30%30–40%>40% Pulse rate (beats/min)<100>100>120>140 Blood pressureNormalDecreased Respiratory rate (bpm)14–2020–3030–40>35 Urine output (ml/hour)>3020–305–15Negligible CNS symptomsNormalAnxiousConfusedLethargic 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)

 Results from a severe decrease in SVR ◦ Vasodilation reduces afterload ◦ May be associated with increased CO  Etiologic categories ◦ *Sepsis ◦ *Neurogenic / spinal ◦ Other (next page)

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

 Septic Shock

Clinical presentation varies with type and cause, but there are features in common:-  Hypotension (SBP 40)  Cool, clammy skin (exceptions – early distributive, terminal shock)  Oliguria  Change in mental status  Metabolic acidosis

 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

 Manage the emergency  Determine the underlying cause  Definitive management or support

 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?

 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

 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