Exsanguination is technically defined as the loss of blood to a degree sufficient to cause death.
There are three main signs characterizing exsanguination, hypothermia, coagulopathy, and acidosis. Hypothermia is due to the reduced quantity of blood flowing through the body, which fails to provide the several body parts with a sufficient amount of calories necessary to preserve and maintain the temperature. This, then, begins to decrease substantially from the average of 36.5-37.5°C , until it gets to highly dangerous low levels. Hypothermia might in turn bring about other injuries, like shivering or muscle miscoordination  . Coagulopathy, the impaired ability of the body to clot and coagulate , is due by the imbalance of the plasma proteins regulating coagulation and blood clotting, after the decrease of blood plasma. Acidosis, instead, comes as additional dangerous factor which induces, among other signs, tremors and dysfunction of the cerebrum .
It is important to remember that many of the episodes of exsanguination result in death because of several factors like lack of knowledge on how to stop bleeding or the intense pain which prevents patients from realizing the presence of a serious wound and the hemorrhage, especially when these happen in critical conditions such as an evil incident. Therefore, people who might be at risk of experiencing a traumatic accident are strongly recommended to get training on how to deal with this type of circumstances.
Apart from a general physical examination, the diagnosis of exsanguination and hemorrhagic shock can be also performed with laboratory tests. These analyses allow clinicians to measure and check key factors like hemoglobin and hematocrit values, metabolic acidosis, platelet function, electrolytes, as well as calcium and creatinine levels.
Imagine studies, instead, are very useful to detect the source of bleeding, which is not always an easy task especially when the patient is in bad condition. Radiography is particularly useful when the site of hemorrhage lies within the thoracic and abdominal cavity, where bleeding might be very difficult to reveal. CT scan, instead, is much more expensive but provides with high-quality imagines. Other imagine studies used in the diagnosis of ES include esophagogastroduodenoscopy, colonoscopy, ultrasound, and angiography.
The most important thing to cope with exsanguination and a hemorrhagic shock is to control the source of bleeding, avoid profuse blood loss and transfuse the required blood to the suffered body. In other words, the basic procedures to treat a serious episode of hemorrhagic hock are homeostasis control and blood transfusion. Homeostasis control can be done with fluid treatment, to restore radial pulse and blood pressure. The treatment should be continued until the patient’s hemodynamic balance is restored. PRBCs (Packed Red Blood Cells) should be provided only when the conditions of the patient remain unstable, as too large quantities might be toxic without no evident favorable clinical outcome . In certain critical conditions surgery might be performed, such as acute life-threatening bleeding in the abdominal and chest cavity.
The prognosis of exsanguination is usually good, if the hemorrhagic shock is early recognized and promptly treated. In any case, this has to happen before the body loses 25% of its blood, because this limit is considered the threshold behind which the shock becomes irreversible causing severe physiological damages or death. The typical complication caused by severe episodes include stroke, heart attack, liver failure, kidney failure, and gangrene of extremities.
One of the most common causes of exsanguination is trauma in accidental situations, such as car accidents, sport injuries, domestic falls, or simply work accidents. In many of these situations the bleeding is often ignored, as the patients simply do not realize the problem due to the severe pain for a fracture in some other part of the body or a dislocation of a major joint. Injuries frequently occur in the upper extremities, with the laceration or tear of subclavian or brachial arteries causing profuse bleeding and continuous blood loss.
Another frequent cause of exsanguination is suicidal attempts, when many individuals seek death by for example cutting radial artery at their wrist or the brachial artery at their elbows. A loss of blood of 25-30% is already sufficient to cause loss of consciousness and drowsiness, which further favor bleeding and additional plasma loss. The loss of blood by cut of radial artery might slow down because of the possible collapse of arterial walls, something which rarely happens with the brachial artery.
Gunshot injury, instead, can be extremely dangerous, because it might also cause internal bleeding. Patients often do not realize the presence of the internal bleeding, especially when this is due to laceration or tear of major blood vessels like aorta, subclavian artery in the chest, mesentery artery in abdomen and iliac artery in pelvis. For example, internal bleeding can be frequently caused by rupture of aneurysm in elderly patients, when the think weak arterial wall eventually ruptures because of the blood pressure it can no longer control, causing internal bleeding. Another cause of exsanguination is a surgical complication, where the laceration or tear of an artery is caused by a surgical trauma, or an infection and a sepsis which can cause the ulceration of blood vessel walls and their final rupture. Cancer can also cause exsanguination, especially when it occurs in chest and abdomen in the terminal stages, with the cancer cells reaching major blood vessels and causing the rupture of their walls.
Every individual is at risk for traumatic injury. The etiology of traumatic injury varies according to the lifestyles and social backgrounds of individuals, going from episodes of interpersonal violence to motor vehicle crashes. There are no precise epidemiological data indicating in how many of these cases people die because of intense blood losses. However, exsanguination is a relatively uncommon cause of death among human beings, apart from the scenarios of war and military combats where exsanguination is frequently responsible of the death of soldiers or civilians after gunshot and bomb wounds.
As previously said, patients suffering from exsanguination ultimately die for hemorrhagic shock , the condition of severely decreased blood volume and plasma, which results in a reduced tissue perfusion and inadequate delivery of oxygen and nutrients to the main organs necessary to maintain cellular functions.
The main aspect of the pathophysiology of exsanguination is the systematic deviation of circulating blood away from non-vital organ systems. This response is very understandable, as the lack of blood requires the body to keep the little blood left in the vital organ systems. After a serious loss of blood the cardiac output and pulse pressure decrease, and these changes are detected by the baroreceptors in the aortic arch and atrium which send a signal to the central nervous system. This in turn, as response, increases heart rate and vasoconstriction, and redistributes the blood flow to the detriment of non-vital organs, like skin, gastrointestinal tract, and kidneys.
Then, as system of multi-hormonal response is activated to face the hemorrhage. The response actually sets in motion a series of hormones, such as corticotropin-releasing hormone, glucocorticoid, beta-endorphin, and vasopressin, to regulate key functions like water retention, arterial pressure, aldosterone level, plasma glucose level, and sodium and water resorption, with the aim of coping with the loss of blood. In any case, the organs cannot tolerate this situation for long periods of time, and normal conditions have to be restored before major damages occur.
Unfortunately, in many occasions exsanguination and hemorrhagic shock cannot be prevented, as they frequently occur in traumatic incidents. So, no prevention can be suggested, apart from simple measures to help balance minerals and organic compounds in the blood plasma, such as taking commercial hydration solutions.
It is not necessary for an individual to lose all the blood of the body to die, but just a part of it. The exact quantity of blood lost leading to death depends on many factors, such as age, health, and the general conditions of the individual, but in general a loss of at least half the blood of the body can be fatal. This condition could occur in situations such as accidents, where the cut of a vein or artery after a trauma can cause the loss of an abundant quantity of blood. In any case, exsanguination is a relatively uncommon cause of death in human beings, happening when the bleeding from a wound is not promptly controlled or in military combats.
The classical situations in which exsanguination can occur include gunshots, stab wounds, motor vehicle crashes, suicide by artery cut especially on wrists, or partial/total amputation of limbs after contact with operating machinery or saws. Exsanguination can also be caused by serious internal hemorrhages, when it can take place without the appearance of clear signs of distress.
The main consequence of exsanguination is hemorrhagic shock, the physiological state of decreased volume of blood and blood plasma, which finally leads to death. Human body is able to compensate for a substantial loss of blood, even though within certain limits behind which it is necessary to intervene with medical treatment, to restore normal conditions and avoid further fatal complications and damages.
Exsanguination consists in the loss of blood to an amount sufficient enough to cause severe damages to main organs and finally death. The human body is able to compensate of a loss up to one-third of the entire quantity of blood flowing in the circulatory system. However, if the loss is higher than this threshold hemorrhagic shock occurs. Exsanguination is the consequence of accidental traumatic situations, like suicidal attempts, car accidents, sport injuries, or domestic falls. These situations also include gunshot injuries, which appear to be particularly dangerous since they cause internal hemorrhages difficult to detect.
The hemorrhage sets in motion a serious of physiological changes to try to cope with the difficult situation. The major change consists in the deviation of blood away from non-vital organs, to try to protect vital ones. However, this condition cannot last for long, as after a while organs no longer receiving a sufficient blood supply begin to seriously damage. The major signs of the condition are a reduced body temperature, an impaired capacity of the body to coagulate, and an increased level of acidity in the blood plasma.
The main goals of the treatment are to control bleeding and transfuse new blood to replace the lost one. This can be achieved through fluid treatment and blood transfusion. The treatment should be continued until normal conditions are restored. In certain critical conditions surgery might be performed, such as acute life-threatening bleeding in the abdominal and chest cavity.
Unfortunately, in many occasions exsanguination and hemorrhagic hock cannot be prevented, as they frequently occur in traumatic incidents. So, no prevention can be suggested, apart from simple measures to help balance minerals and organic compounds in the blood plasma, such as taking commercial hydration solutions. Although very dangerous, exsanguination is very rare as source of death.