Hypovolemic shock is a severe circulatory disorder that leads to death if left untreated. The cause is usually a loss of blood or fluid, for example, from severe diarrhea or bleeding after an accident.
What is hypovolemic shock?
In colloquial language, people often talk about shock as a result of a situation involving extreme psychological stress. In medicine, however, the term hypovolemic shock refers to an acute lack of oxygen in vital organs such as the lungs or kidneys. The ratio between oxygen demand and oxygen supply is no longer correct. Due to a lack of volume, there is a centralization of the remaining blood volume and thus a reduced blood flow in the smallest blood vessels (capillaries). The lack of blood flow results in a lack of oxygen and damage to the cells and thus to the entire organ. This can lead to loss of function of the affected structures.
Causes
The cause of hypovolemic shock is volume deficiency. It occurs when blood loss exceeds 20 to 30 percent of total blood volume, as well as other fluid losses. Hypovolemic shock caused by blood loss is also referred to as hemorrhagic shock. Injuries to vessels, for example, from cuts or from the rupture of an aneurysm, which is a vascular outpouching of the aorta, can result in massive blood loss and thus cause hypovolemic shock. Bleeding in the gastrointestinal tract, for example due to gastric ulcers or tumors in the intestines, can also be so massive that the volume of blood is no longer sufficient to supply the body completely. Another source of heavy bleeding is acute severe inflammation of the pancreas (pancreatitis). Other causes of severe bleeding that can trigger hypovolemic shock are fractures of bones with a good blood supply, such as a pelvic fracture or a femoral fracture. Rupture of the spleen, for example after an accident, or accidental injury to other organs can also lead to bleeding into the abdomen and thus to a loss of volume that cannot be compensated for. Similarly, complications during childbirth or during surgery carry the risk of life-threatening blood loss. However, not only the loss of blood, but also the loss of water, plasma or electrolytes can lead to volume deficiency shock. Possible causes here are losses during severe vomiting, diarrhea, dehydration due to insufficient fluid intake, or hormonal imbalances with increased water losses (for example, adrenocortical insufficiency|Morbus Addison). In severe inflammation of the peritoneum or lung pleura and in extensive burns, the loss of plasma water to the tissues can be so severe that hypovolemic shock develops.
Symptoms, complaints, and signs
If there is a reduction in blood volume due to loss of blood or fluid, the body first attempts to stabilize circulation by increasing cardiac output. In addition, adrenaline and noradrenaline are released to constrict blood vessels. The heart also beats faster due to the adrenaline. These actions result in a redistribution of residual blood. Blood is withdrawn from organs and body structures that are not directly vital, such as the skin, arms and legs, gastrointestinal tract and kidney, to supply organs that are indirectly vital, such as the brain, heart and lungs. This process is called circulatory centralization. Patients who are in shock or about to go into shock are usually very agitated and anxious. The release of adrenaline and noradrenaline causes the pulse rate to increase to more than 100 beats per minute. Patients become cold sweaty. Blood pressure is low due to low blood volume and is systolic below 90mmHg. If circulatory centralization has already occurred, the pulses in the body periphery, for example at the wrist or foot, are no longer palpable. Due to reduced blood flow to the skin, affected individuals are pale gray and feel cold. Skin and mucous membranes are blue in color (cyanotic) due to the lack of oxygen. Urine excretion is limited or completely stopped due to impaired kidney function. Respiratory distress or hyperventilation occurs.Also typical of hypovolemic shock is a strong feeling of thirst.
Diagnosis and course of the disease
Hypovolemic shock is usually diagnosed by the typical clinical picture paired with symptoms of the possible cause. The shock index can be used to assess the dangerousness of the situation. The shock index is the quotient of pulse rate and systolic blood pressure. In a healthy person, this index is about 0.5; in shock, the value increases to more than 1, which means that the pulse is higher than the systolic blood pressure. The recap test is used to diagnose the peripheral circulation situation. In this test, the examiner briefly presses the nail of the affected person into the nail bed. This displaces the blood from the capillaries. If the recapillarization, i.e., the return of blood to the capillaries, lasts longer than one second, it is assumed that there is a reduced blood flow in the periphery.
Complications
If shock is not treated by a physician, the patient usually dies. For this reason, immediate treatment is necessary to keep the patient alive. There is a severe loss of blood and fluid. If these losses continue and are not stopped immediately, the internal organs and the heart can no longer function. Furthermore, the organs are supplied with too little oxygen, so that consequential damage can occur, which is usually irreversible. Due to the low blood pressure, the patient loses consciousness and may suffer various injuries as a result of a fall. Respiratory distress occurs, usually accompanied by hyperventilation. Treatment of shocks is symptomatic and primarily stops bleeding and fluid loss. If done quickly enough, the affected person may survive. However, it cannot be predicted whether irreversible damage to the organs or brain has occurred as a result of the shock. For example, paralysis or other sensory disturbances may occur. Life expectancy may also be limited by the shock.
When should you go to the doctor?
In hypovolemic shock, an emergency physician must be alerted immediately. The patient needs immediate intensive medical care. If there is a sudden drop in blood pressure and shortness of breath, emergency medical services must be called. Also typical of the shock reaction is a strong feeling of thirst that cannot be eliminated by ingesting fluids. If the symptoms are noticed, there may be underlying hypovolemic shock that needs medical evaluation and treatment. People with severe cuts or signs of an aneurysm must see a doctor immediately. People suffering from gastric ulcers or tumors in the intestines are also among the risk groups. Patients suffering from inflammation of the pancreas should talk to the doctor in charge in case of mentioned symptoms. In the event of hypovolemic shock, emergency medical assistance is required in any case. Further contacts are the family doctor or an internist. Individuals who experience shock in conjunction with an existing medical condition should speak with the responsible medical professional.
Treatment and therapy
The most important therapy for volume-deficiency shock is rapid fluid replacement. This is usually done by supplying isotonic infusion solutions. In hypovolemic shock caused by blood loss, stopping the bleeding is, of course, the primary focus of treatment. In addition, any damaged organs must be treated. The occurrence of shock kidney, that is, renal failure in shock, must be prevented at all costs. The same applies to shock lung. As an initial measure in hypovolemic shock, the shock position is recommended. Here, the patient is laid down and the legs are elevated. This causes blood to flow back out of the legs, resulting in a greater volume of blood in the upper body.
Prevention
To prevent hypovolemic shock, always ensure adequate fluid intake during severe infections, diarrhea, or vomiting. Obvious bleeding should be stopped as soon as possible. In any case, even if volume-deficiency shock is merely suspected, the emergency physician should be notified directly.
Follow-up care
After the primary measures for hypovolemic shock, the goal is to return to normal.For this purpose, patients receive red cell concentrates and, depending on the situation, fresh plasma. Volume substitution also supports the recovery of the affected person. For further follow-up treatment, it is important that an intensive discussion takes place between the doctor and the patient. In this way, the persons at risk learn details worth knowing, for example, about the correct behavior in a state of shock. If family members and acquaintances are informed accordingly, worse consequences can be avoided. For good blood circulation to the upper body, the patient’s legs should be slightly higher. Particular precautions should be taken, especially in the case of an infection accompanied by nausea. Here, adequate hydration plays a vital role. Increased attention is also required in the case of open bleeding. A precise line cannot be drawn here between first aid, aftercare and prophylaxis. People with the appropriate indication should learn to be aware of their own bodies so that they can react quickly to any warning signs. In close cooperation with the physician, further complaints such as kidney failure can also be avoided. If trauma occurs in connection with the shock, therapeutic support may also be necessary.
Here’s what you can do yourself
If hypovolemic shock occurs, the emergency physician must be alerted immediately. The cause of the shock must then be determined and, if possible, eliminated, for example, by stopping bleeding or immobilizing a broken bone. The patient must be reassured and, if possible, should be placed in shock positioning – legs about 20 to 30 degrees higher than the rest of the body. The ambulance service will provide oxygen to the injured person and take him to a hospital for further treatment. Further self-help measures are based on the injury. In the case of bone fractures and similar injuries, first and foremost, rest is indicated. The wound should be cared for according to the doctor’s instructions to prevent wound healing disorders and other complications. In parallel, the injury must be regularly examined by the medical professional in charge. Sometimes the patient also needs therapeutic help to deal with trauma. The further steps depend on the physical and mental condition of the affected person and the healing process of the triggering injury.
