four types of shock
hypovolemic shock cardiogenic shock distributive shock obstructive shock
hypovolemic shock
caused by blood loss, burns, blood loss, diarrhea
cardiogenic shock
caused by reduced output, pump failure (MI)
distributive shock
caused by anaphylaxis, septic shock, neurogenic shock, all of these cause excessive vasodilation need volume
obstructive shock
caused by pulmonary embolism cardiac tamponade tension pneumothorax (collapsed lung)
shock
circulatory insufficiency that creates imbalance between tissue O2 supply and demand causing reduction in effective tissue perfusion and suboptimal substage
which hormone is produced at higher levels during shock
epinephrine reinforces adrenergic tone early stages, then it is reduced after BP is restored
first compensatory mechanism in shock
increase cardiac output in response to insufficient oxygen supply
if increased CO is inadequate… (shock)
amount of O2 extracted from Hg by tissues is increased, decreased SVO2
6 main steps in shock response
3 stages of shock
pre shock shock end organ dysfunction
edema
accumulation of fluid in interstitial tissues ex: pleural effusion and ascites results from disturbance of ECF circulation bt capillaries and interstitial space
factors that regulate edema
capillary hydrostatic pressure
force pushing fluid from capillaries into extracellular space
capillary permeability
determines ease of fluid flow through capillary endothelium
osmotic pressure
water attracting proper exerted by proteins in blood that attract fluid from interstitial space back to the capillaries
lymphatic channels
collect fluid forced out of capillaries by hydrostatic pressure and return fluid to circulation
pathogenesis of edema
arterial thromboembolic dx main cause
injury to vessel wall via arteriosclerosis ulceration and rupture of cholesterol plaque
cardioembolic sources of a clot
within atrial appendages (potential space) surface of heart valves (valve vegetation/endocarditis) wall motion defect (mural thrombus caused by MI or Afib)
thrombus
intravascular clot occurring at site of tissue injury can occur at any vessel (arterial or venous)
emboli
detached clot or cholesterol plaque carried into pulmonary or systemic circulation plugs smaller vessel, blocking blood flow and causing necrosis
Virchow’s triad
what might form emboli besides blood
malignancy, fat, air, amniotic fluid, foreign particles, sepsis