Describe the body’s response to sudden and massive blood loss.

Massive blood loss from circulatory shock is a critical condition for a person to find themselves in. According to Kelly, shock is:

(insert kelly quote here)

What are the stages of shock?

There are three stages. Each stage is weighted by the recovery capacity of the person. The light-weight stage is a relatively straightforward and easy stage to recover from. A medium-weight stage is more difficult and the heavy-weight stage is the most difficult. The light-weight stage is called nonprogressive/compenstated/reversible. It is possible to correct the effects of this stage via compensatory mechanisms and through proper instigation of medical knowledge the patient will recover in time. The medium-weight stage is known as progressive. At this stage if the patient does not receive medical attention their condition will get worse and they will die. The heavy-weight stage is referred to as irreversible and it means exactly that. At this stage the patients condition is so dire that it has moved outside the helping ability of medical practitioners. Death is unavoidable.

Hypovolaemic shock is a shock induced by a severe decrease in blood volume. Because of this decrease the the cardiac system struggles to work properly and thus there is a decrease in cardiac output. In most cases the reason for a person to succumb to hypovolaemic shock is due to massive blood loss. The more blood that is lost the more severe the shock. It is extremely important for a medical practitioner to locate where the blood is being lost from and to seal it in the quickest time possible. Furthermore, it is important to note that hypovolaemic shock can occur through major burns due to the critical loss of extra-cellular fluid from the wounds.

A person at the light-weight stage, or non-progessive stage, of hypovolaemic shock would show these symptoms:

Sweat all over body, anxiety, restlessness due to sympathetic nervous system activity
Pale skin and cool hands and feet. The constriction of the blood cells (as mediated via the SNS) pulls blood back into the body, most notably the kidneys, spleen and skin
A lowered urine output and a thirst because of increased aldosterone and anti-diuretic hormones
A rapid pulse due to the SNS increasing the heart rate
A faintness due to reduced blood flow to the brain and
rapid, shallow breathing (increased respiration) due to the homeostatic nature of the body trying to maintain the normal pH levels of the blood

As such, it is understandable that the body's attempt to maintain/restore blood pressure whilst keeping the blood flowing around the vital organs is the main reason for the above listed symptoms. The symptoms try to stop the shock from progressing onwards.

Shock, if not properly dealt with, can breed more shock. The medium-weight stage, otherwise known as progressive shock, is the more dire circumstance one may find themselves in when compared with non-progressive shock. A person suffering from progressive shock will show these symptoms:

Oedema (the capillaries will increase their permeability)
Clammy, pale, cold skin because of the body's reaction that draws the blood away from the extremities
Oliguria due to the lowered amount of blood flowing to the kidneys as well as due to the fact that the kidneys are trying to maintain water
Their pulse will weaken and fall, blood pressure is falling due to huge loss of blood volume in the body
They will most likely be confused, stressed, difficult to control due to restlessness and pain due to the loss of blood to the brain and the increased sympathetic nervous system activity.

It is understood that progressive shock encompasses an awful situation that arises due to vicious cycles of positive feedback. The decrease of the mean arterial pressure leads to a weakening of the cardiac system which then leads to further weakening of said system. This also means that less blood flows to the brain which then also decreased the ability of the cardiac system to function properly. This decrease in blood pressure also means that less blood is pumped throughout the body which drops the blood pH level thus making the body even more unhealthy via a vasodilatory and hypotensive effect. The decrease in blood pressure also leads to the patient's skin turning blue, otherwise known as hypoxia. Finally, the decrease in blood pressure slows the blood down to the point where clots are easily able to form in the blood vessels.

Finally, and most distressing, is irreversible shock. Knowing that there is absolutely nothing medical intervention can do to save this person from their condition is how irreversible shock is defined. A person in this stage of shock will show the following symptoms:

exceedingly low blood pressure
an increased chance of cardiac arrest via tachycardia
oedema (once again, the capillaries increasing their permeability)
anuria (extremely low passing of urine, most likely none in this case)
signs of organ failure
rapid and shallow breathing.

At this stage it is very common for the patient to suffer from multiple organ dysfunction syndrome. This syndrome is characterized by the severe dysfunction of two or more organ systems and the more organs that fail, the higher the chance of death. When two organ systems fail there is a 54% mortality rate, when five organ systems fail, it is a 100% mortality rate.

The mechanism at work which creates the irreversible shock is the breaking down of cells. The cells break down due to lack of nutrients and a build up of waste. The death of the cells then leads to a loss of tissue which leads to organ dysfunction. The body's response system tries to maintain a healthy environment for the cells. The body during the non-progessive shock stage is able to maintain a healthy environment naturally. However, at the progressive shock stage the body is unable to function properly, and we see that as it instigates methods of survival these methods occur in such a way that they actually hasten the death of the cells, the tissue and thus the patient progresses into the stage of irreversible shock.