1. Progressive Shock
Low Cardiac Output decreases arterial pressure and
reduces transport of nutrients to tissues
Blood pH then decreases because of lactic & carbonic
acid buildup.
Waste products lead to blood agglutination. Smaller
vessels may become blocked, further decreasing
nutrient transport
2. HYPOVOLEMIA
“Hemorrhagic Shock”
Diminished blood volume and cardiac
output as a result of hemorrhage
Commonly associated with major trauma
and obstetrical situations
Affects the central nervous, cardiac, and
renal systems
5. Dehydration and Shock – Form or Cause?
Some texts refer to Dehydration as “a form of shock”, however
the terms are not synonymous.
Dehydration is the result of total body water loss
Hypovolemic shock results from loss of blood volume and MAY
result from dehydration as well as other alternate or
contributing factors.
Forms of Shock:
Hypovolemic (inadequate blood volume)
Neurogenic (nervous system damage)
Anaphylactic (allergic reaction)
Septic (infections/bacterial spread)
Cardiogenic (heart problems)
6. Dehydration is the result of losing water from the body faster than it can be moved
from other locations within the body (interstitial spaces) or replaced through intake
and absorption. Therefore, the rate of fluid loss is as important as the amount of
fluid loss.
Fluid Loss is primarily from Vascular spaces:
Sweat glands move fluid from the blood to the skin
Kidneys move fluid from the blood to the urine
(highest contributor to fluid loss)
Fluid may also be lost through breathing as well as
vomiting or diarrhea (lost fluid originally
from blood within gut walls).
This fluid loss may CAUSE hypovolemic shock.
Rapid and high fluid loss will cause shock (e.g. hemorrhage)
Rapid and moderate fluid loss may lead to symptoms (e.g. fainting after whole
blood donation, only 0.5-l); however may eventually be compensated for
Slow and high fluid loss will gradually increase symptoms until shock
eventually occurs (see Chart).
Slow and moderate fluid loss may be compensated for by body without
symptoms
7. Fluid Loss and Shock
% Dehydration Examination Findings
<5 History of fluid loss, but no findings on
physical examination
5 Dry oral mucous membranes, but no panting or
pathological tachycardia
7 Mild to moderate decreased skin turgor, dry
oral mucous membranes, slight tachycardia,
and normal pulse pressure
10 Moderate to marked degree of decreased skin
turgor, dry oral mucous membranes,
tachycardia, and decreased pulse pressure.
12 Marked loss of skin turgor, dry oral mucous
membranes, and significant signs of shock
FLUID AND ELECTROLYTE THERAPY
(http://www.cvmbs.colostate.edu/clinsci/wing/fluids/fluids.htm)
Wayne E. Wingfield, MS, DVM
