Shock Flashcards
(46 cards)
Definition of shock:
acute circulatory failure with inadequate or inappropriately distributed tissue perfusion resulting in generalized tissue hypoxia
Name the 6 types of shock:
1) hypovolemic 2) cardiogenic 3) distributive (septic, anaphylactic) 4) neurogenic 5) traumatic 6) obstructive
What is the pathophysiology of shock in general?
tissue hypoperfusion causing a cellular energy deficit; supply/demand imbalance resulting in neuroendocrine and inflammatory responses
What are the 4 stages of shock?
1 initial 2 compensatory 3 progressive 4 refractory
What are the characteristics of the initial stage of shock?
Hypo-perfusion, tissue hypoxia, lactic acidosis
What are the characteristics of the compensatory stage of shock?
Cytokine release, hyperventilation for CO 2 removal, endogenous catecholamine release (norepinephrine and epinephrine)
What are the characteristics of the progressive stage of shock?
Failing compensatory mechanisms, worsening capillary leakage and metabolic acidosis, increased blood viscosity, micro-sludging, worsening organ dysfunction (MODS)
What are the characteristics of the refractory stage of shock?
Irreversible organ damage, cell death, degradation of ATP to adenosine
4 different categories of hemodynamic shock?
hypovolemic, cardiogenic, distributive, obstructive
Possible causes of hypovolemic shock?
hemorrhagic, GI/UT volume loss, third spacing
Cause of cardiogenic shock?
myocardial pump failure
Causes of distributive shock?
sepsis, anaphylaxis, spinal cord injury, corticosteroid insufficiency
Possible causes of obstructive shock?
tamponade, tension pneumothorax, PE all lead to equalization of diastolic pressures with filling pressures
What is the mortality of shock?
hypovolemic - variable cardiogenic - 60-90% spetic - 35-40%
What are the determinants of shock?
Loss of circulating intravascular volume • Inadequate capillary and tissue perfusion (micro circulation) • Disturbed cell metabolism • Mismatch of oxygen delivery and oxygen demand
The body’s systemic physiological reaction to shock:
– Progressive vasoconstriction – Increased blood flow to vital organs: Shunt of skin, acral regions, splanchnic system – Increase in CO/CI – Increase in respiratory rate and tidalvolume – Reduced urine production – Reduction gastric and intestinal activity
What does shock do to the kidneys?
Acute kidney injury: tubular necrosis and subsequent kidney failure
What does shock do to the liver?
congestion with elevated liver enzymes and coagulopathy
What does shock do to the GI tract?
Gastrointestinal ischemia: GI hemmorhage, peritonitis
Definition of cardiogenic shock:
Protracted severe malperfusion of tissues due to an acute, critical reduction in myocardial pump capacity Need to exclude other correctible factors: hypovolemia, arterial hypoxia, vasovagal rxn
What percent of MI pt end up with cardiogenic shock?
5-10% and Cardiogenic shock is considered the cause of death in 50-90% of these patients
What are the clinical signs of cardiogenic shock?
• Signs of centralized circulation and organ dysfunction • Agitation • Pale, cool, clammy skin • Oliguria (< 20ml/h) • RV dysfuntion (e.g. PE, RCA MI) : – Elevated venous pressures, jugular distention • LV dysfunction (e.g. LAD/Cx MI, acute AI/MR): – Pulmonary edema
The etiology of cardiogenic shock can be one of two categories:
myocardial or mechanical
Pathophysiology of ischemic cardiogenic shock?
inadequate myocardial perfusion (decreased duration of diastole) excessive increase in myocardial oxygen consumption (tachycardia and increse wall tension) metabolic derangement (lactic acidosis)
