Shock

Shock is a life-threatening condition in which blood pressure is too low to sustain life. Shock has several causes: a low blood volume, which cause hypovolemic shock; inadequate pumping action of the heart, which cause cardiogenic shock; or excessive widening of blood vessels, which causes distributive shock.

When shock is caused by low blood volume or inadequate pumping of the heart, people may feel lethargic, sleepy, or confused, and their skin becomes cold and sweaty and often bluish and pale. When shock results from excessive dilation of blood vessels, the skin may be warm and flushed, and the pulse may be strong and forceful (bounding) rather than weak. People who are in shock should be kept warm and positioned so their legs are elevated, and then they are given intravenous fluids, oxygen, and sometimes drugs to help restore the blood pressure.

People go into shock when their blood pressure becomes so low that the body’s cells do not receive enough blood and therefore do not receive enough oxygen. As a result, cells in numerous organs, including the brain, kidneys, liver, and heart, stop functioning normally. If blood flow (perfusion) to these cells is not quickly restored, they become irreversibly damage and die. If enough cell is damage or dead, the organ they are in may fail and the person may die. People in shock require immediate emergency treatment. The medical disorder of shock has noting to do with the “shock” that people feel from a sudden emotional stress.

Cause

Shock has several causes: a low blood volume, which causes hypovolemic shock; inadequate pumping action of the heart, which cause cardiogenic shock; or excessive widening of blood vessels, which cause distributive shock.

Symptoms and Diagnosis

Symptoms of shock are similar when the cause is low blood volume or inadequate pumping action of the heart. The condition may begin with lethargy, sleeping, and confusion. The skin becomes cold and sweaty and often bluish and pale. If the skin is pressed, color returns much more slowly than normal. Blood vessels may become more visible as a bluish network of lines under the skin. The pules is weak and rapid, unless a slow heartbeat is causing the shock. Usually, the person cannot sit up without feeling light-headed or passing out. Breathing is rapid but breathing and the pules may both slow down if death is imminent. Blood pressure drops so low that it often cannot be measured with a blood pressured cuff. Eventually, the person may die. When shock results from excessive dilation of blood vessels, the symptoms are somewhat different. The skin may be warm and flushed, and the pulse may be strong and forceful (bounding) rather than weak, particularly at first. However later on, shock due to excessive dilation of blood vessels also produces cold, clammy skin and lethargy.

In the earliest stages of shock, especially septic shock, many symptoms may be absent or may be undetected unless they are specifically looked for. In older people. The only symptom may be confusion. The blood pressure is very low. Urine flow is significantly reduced (because blood supply to the kidneys is reduced), and waste products builds up in the blood.

Prognosis and Treatment

If untreated, shock is usually fatal. If shock is treated, the outlook depends on the cause, the other disorders the person has, the presence and severity of any organ failure, the amount of time that passes before treatment begins, and the type treatment given. Regardless of treatment, the likelihood of death due to shock, especially in older people, is great. The first person to arrive on the scene can take several measures that help, including calling for additional help, A person who is in shock should be laid down and kept warm, with the leg elevated about 12 to 24 inches (about 30 to 60 centimeters) to facilitate the return of blood of the heart. Any bleeding should be stopped, and breathing should be checked. The head should be turned to the side to prevent inhalation of vomit.

Noting should be given by mouth. When emergency medical personnel arrive, they may provide oxygen through a face mask or provide a mechanical device to assist breathing. Fluids are given intravenously at a fast rate and in large volumes to raise pressure. For shock cause by bleeding, a blood transfusion may be given. Usually, blood is cross-matched before transfusion, but in an emergency when there is no time for cross matching, type O negative blood can be given to anyone. Drugs, if needed, are given intravenously. Opioids and sedatives are usually not used because they tend to decrease blood pressure. Shock cause by excessive dilation of the blood vessels also may require drugs that constrict the vessels, such as epinephrine for people with anaphy-laxis or low-dose dopamine for people with other forms of shock.

The cause of the excessive dilation is also treated. For example, a bacterial infection is treated with antibiotics. The intravenous fluid and blood transfusion may not be enough to counteract the shock if bleeding or fluid loss continues or if the shock is cause by a heart attack or another problem unrelated to blood volume. Drugs that constrict the blood vessels may be given to boost blood flow to the brain or heart. However, such drugs should used as briefly as possible because they can reduce blood flow to other tissues in the body. When shock is cause by an inadequate pumping action of the heart, efforts are made to improve the heart’s performance.

The rate and rhythm abnormalities of the heartbeat are corrected, and blood volume is increased if necessary. Atropine may be used to increase a slow heart rate, and other drugs may be given to improve the ability of the heart muscle to contact. If the cause is a heart attack and shock persist after emergency treatment, a balloon pump may be inserted into the aorta to reverse shock temporarily. After this procedure, emergency percutaneous transluminal coronary angioplasty or coronary artery bypass surgery may be needed. By opening a blocked coronary artery (one of the arteries supplying the heart muscle), emergency PTCA can improve the heart’s pumping action and can reverse the shock.

If emergency PTCA or bypass surgency is not performed, a drug that helps breaks up clots (thrombolytic drug) is given as good as possible, unless it could worsen problems in people who have another disorder, such as a bleeding ulcer, or who have had a stroke recently. If the cause is a malfunctioning heart valve or rupture of the septum, surgery may also be needed. If the heart is unable to fill because of blood or fluid in the pericardium (the sac surrounding the heart), the fluid can be removed through a needle inserted into the pericardium.

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