Hypotensive Shock

Shock is a condition in which blood flow is not enough to meet the oxygen needs of the body's organs. Low blood pressure, usually an upper (systolic) pressure below 90 mmHg or a mean pressure below 65 mmHg, is one of its main signs. However, early in shock, blood pressure may still be normal because the body tries to compensate by speeding up the heart rate and narrowing the blood vessels in the skin. For this reason, doctors also look for other signs: cold and pale skin, rapid breathing, restlessness or confusion, and passing little urine.

Four Types of Shock

Hypovolemic shock happens when the volume of blood or body fluid drops sharply, for example from bleeding, severe diarrhea and vomiting, extensive burns, or plasma leakage in dengue hemorrhagic fever. Distributive shock happens when blood vessels widen extensively, as in a severe infection that spreads (septic shock), a severe allergic reaction (anaphylaxis), or a spinal cord injury. Cardiogenic shock happens when the heart's pump fails, often due to a heart attack, and is covered on the Cardiogenic Shock page. Obstructive shock happens when blood flow is blocked, for example by a clot in the lungs or fluid pressing on the heart, covered on the Pulmonary Embolism and Cardiac Tamponade pages.

What Happens in the Body

When blood flow is not enough, the body's cells are forced to produce energy without enough oxygen and build up lactic acid. The kidneys reduce urine production, the brain slows down so the person appears restless or confused, and the heart itself also runs short of oxygen. If this continues for a long time, damage can affect several organs at once. That is why time matters so much.

Treatment in the Emergency Room

In the emergency room, the medical team assesses the airway, breathing, and circulation, gives oxygen, places an IV line for fluids, and continuously monitors blood pressure, heart rhythm, and urine output. If blood pressure does not recover with fluids, the doctor gives medicines that raise blood pressure through an IV. At the same time, the cause is treated: stopping the bleeding, antibiotics for infection, medicines for anaphylaxis, or opening a blocked coronary artery in a heart attack. Further care usually takes place in the intensive care unit.

An overview of other types of hypotension, from mild forms to those that need further evaluation, is covered on the Hypotension page.

In shock, testing and treatment happen at the same time. As soon as the patient arrives at the emergency room, the medical team measures blood pressure, pulse, breathing, oxygen level, and consciousness, and then places an IV line. Blood tests check lactate as a marker of oxygen shortage in the tissues, a complete blood count, electrolytes, kidney and liver function, blood clotting, and cultures if an infection is suspected.

An ECG and a troponin test look for a heart attack. Bedside ultrasound and echocardiography assess the heart's pumping, fluid around the heart, and the filling of the large blood vessels. A chest X-ray or CT scan is done depending on the suspected cause. In severe shock, pressures inside the heart and lungs can be measured directly with a catheter to guide fluids and medicines.

Shock cannot be waited out at home. Call emergency services at 119 or get to the nearest emergency room right away if the following signs appear, especially in someone who is ill, recently injured, or recently exposed to an allergy trigger. While waiting for help, lay the person down, keep them warm, and do not give food or drink.

• Pale, cold, and clammy skin with a fast, weak pulse
• Restlessness, confusion, extreme drowsiness, or fainting
• Rapid breathing, shortness of breath, or bluish lips
• No urination for hours along with weakness
• Heavy bleeding, vomiting blood, or black stools
• Swelling of the face, lips, or throat with shortness of breath after eating, taking a medicine, or being stung
• Chest pain with cold sweat and weakness