I. Circulatory Shock
Circulatory Shock is an acute circulatory crisis marked by hypotension and decreased peripheral blood flow. It is caused by Hemorrhaging (hypovolemia) or damage to heart.
A. Shock – acute circulatory crisis
1. Hypotension
2. Decreased peripheral blood flow
B. Causes
1. Hemorrhaging (hypovolemia)
2. Damage to heart
C. Symptoms
1. Systolic pressure < 90 mmHg (hypotension)
2. Pale, cool, clammy skin
a. peripheral vasoconstriction
b. Sympathetic Nervous System (SNS) – activity of sweat glands
3. Disorientation – decreased blood flow to brain
4. Tachycardia, rapid weak pulse
5. Cessation of urination
6. Acidosis
a. lactic acid – hypoxic tissue
D. Homeostatic Adjustments
1. Short and long-term mechanisms
2. Loss of 35% of blood volume -decreased blood pressure — decreased
venous return — inadequate CO
3. Central Ischemic Response
a. massive vasoconstriction, except cerebral vessels
b. last-ditch effort
c. kidney, liver, heart ——lose function
4. Circulatory Collapse
a. arterioles and precapillary sphincters — no contraction
b. general vasodilation
c. capillary pressure so low — collapse
