How to tell the difference between hypovolemia and hypovolemic shock?


by healthquest
Tags: hypovolemia, hypovolemic shock
healthquest
healthquest is offline
#1
Sep9-13, 09:15 AM
P: 2
How you can tell (from symptoms or signs) that someone has either hypovolemia or he or she has already gone into a hypovolemic shock?

I understand the difference between compensated and decompensated shock - in the later, the blood pressure falls.

But what is the deciding symptom/sign between hypovolemia and compensated shock? For example, a severely dehydrated person probably has hypovolemia, but not every severely dehydrated person is in the hypovolemic shock. So, is it tachycardia, pale or sweaty skin or capillary refill time that can tell the difference? I'm not asking about precise moment when hypovolemia becomes a shock, but about the judging symptom/sign
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SW VandeCarr
SW VandeCarr is offline
#2
Sep9-13, 02:56 PM
P: 2,490
Quote Quote by healthquest View Post
How you can tell (from symptoms or signs) that someone has either hypovolemia or he or she has already gone into a hypovolemic shock?

I understand the difference between compensated and decompensated shock - in the later, the blood pressure falls.

But what is the deciding symptom/sign between hypovolemia and compensated shock? For example, a severely dehydrated person probably has hypovolemia, but not every severely dehydrated person is in the hypovolemic shock. So, is it tachycardia, pale or sweaty skin or capillary refill time that can tell the difference? I'm not asking about precise moment when hypovolemia becomes a shock, but about the judging symptom/sign
http://www.med.muni.cz/patfyz/pdf/anj/shockanj.pdf

Circulatory shock is an incompatibility between blood volume and circulatory capacity. In hypovolemic shock, there is a relative or absolute decrease in blood volume leading to vasoconstriction to maintain blood pressure. Dehydration alone is a rare cause of progressive shock. Blood loss is a much more common form of progressive hypovolemic shock. Progressive shock occurs when the compensatory mechanisms fail to maintain adequate cardiac output and end organs start to fail, including the heart itself. This phase can still be treated with oxygen and aggressive fluid replacement. At some point however, depending on the individual, progressive shock proceeds to refractory shock. At this point, end organ damage (heart, kidneys, brain) is beyond recovery. Since recovery depends on getting oxygen to the tissues and the heart itself is failing, there is a progressive downward spiral. The signal for this critical refractory point is when blood pressure continues to fall despite oxygen, fluid replacement and in some cases the insertion of cardiac assist devices (by way of femoral artery insertion).

For the lay person, the signs are basically what you described, weak and thready pulse with pale clammy cool skin (cold shock). These people need immediate treatment. Warm shock occurs mostly with gram negative bacterial infections where bacterial toxins dilate the blood vessels.


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