Hypovolemic Shock

Hypovolemic shock, the most common type, is caused by insufficient circulating volume, typically from hemorrhage although severe vomiting and diarrhea are also potential causes.

Hypovolemic shock is graded on a four-point scale depending on the severity of symptoms and level of blood loss. Typical symptoms include a rapid, weak pulse due to decreased blood flow combined with tachycardia, cool, clammy skin, and rapid and shallow breathing.

EMS treatment typically includes elevating the feet, preventing heat loss, and administering high flow oxygen. Intravenous fluids may be given to fill the vascular space in an attempt to increase blood pressure. At the hospital, the patient usually receives blood or blood products.

Cardiogenic Shock

Cardiogenic shock is caused by a failure of the heart to pump correctly, either due to damage to the heart muscle through myocardial infarction or through cardiac valve problems, congestive heart failure, or dysrhythmia.

EMS treatment typically includes elevating the feet, preventing heat loss, and administering high flow oxygen. Intravenous fluids may be given to fill the vascular space in an attempt to increase blood pressure. Additional measures include the administration of medications or procedures to increase blood pressure, increase or decrease heart rate.

Obstructive Shock

Obstructive shock is caused by an obstruction of blood flow outside of the heart. This typically occurs due to a reduction in venous return, but may also be caused by blockage of the aorta.

EMS treatment typically includes elevating the feet, preventing heat loss, and administering high flow oxygen. Intravenous fluids may be given to fill the vascular space in an attempt to increase blood pressure. The treatment goal of obstructive shock is to relieve the obstruction. In the case of a tension pneumothorax, the treatment of choice is a needle chest decompression.

Distributive Shock

Distributive shock is caused by an abnormal distribution of blood to tissues and organs and includes septic, anaphylactic, and neurogenic causes.

Septic shock is the most common cause of distributive shock and is caused by an overwhelming systemic infection that cannot be cleared by the immune system, resulting in vasodilation and hypotension.

Anaphylactic shock is caused by a severe reaction to an allergen, leading to the release of histamine that causes widespread vasodilation and hypotension.

Neurogenic shock arises due to damage to the central nervous system, which impairs cardiac function by reducing heart rate and loosening the blood vessel tone, resulting in severe hypotension.

EMS treatment typically includes elevating the feet, preventing heat loss, and administering high flow oxygen. Intravenous fluids may be given to fill the vascular space in an attempt to increase blood pressure. Epinephrine is usually given for anaphylactic shock.