As such, shock is a runaway condition of homeostatic failure, where the usual corrective mechanisms relating to oxygenation of the body no longer function in a stable way. When it occurs, immediate treatment is critical in order to return an individuals metabolism into a stable, self-correcting trajectory. Otherwise the condition can become increasingly difficult to correct, surprisingly fast, and then progress to a fatal outcome. In the particular case of anaphylactic shock, progression to death might take just a few minutes. Initial
During the Initial stage (Stage 1), the state of hypoperfusion causes hypoxia. Due to the lack of oxygen, the cells perform lactic acid fermentation. Since oxygen, the terminal electron acceptor in the electron transport chain, is not abundant, this slows down entry of pyruvate into the Krebs cycle, resulting in its accumulation. The accumulating pyruvate is converted to lactate (lactic acid) by lactate dehydrogenase. The accumulating lactate causes lactic acidosis. Compensatory
The Compensatory stage (Stage 2) is characterised by the body employing physiological mechanisms, including neural, hormonal, and bio-chemical mechanisms, in an attempt to reverse the condition. As a result of the acidosis, the person will begin to hyperventilate in order to rid the body of carbon dioxide (CO2). CO2 indirectly acts to acidify the blood, so the body attempts to return to acid–base homeostasis by removing that acidifying agent. The baroreceptors in the arteries detect the hypotension resulting from large amounts of blood being redirected to distant tissues, and cause the release of epinephrine and norepinephrine.
If used at all it should only be considered if the blood pH is less than 7.0.People with anaphylactic shock are commonly treated with epinephrine. Antihistamines, such as Benadryl (diphenhydramine) or ranitidine are also commonly administered. Albuterol, normal saline, and steroids are also commonly given. Mechanical support
Intra-aortic balloon pump (IABP) – a device inserted into the aorta that mechanically raises the blood pressure. Use of Intra-aortic balloon pumps is not recommended in cardiogenic shock. Ventricular assist device (VAD) – A mechanical pump that helps pump blood throughout the body. Commonly used in short term cases of refractory primary cardiogenic shock. Artificial heart (TAH)
Extracorporeal membrane oxygenation (ECMO) – an external device that completely replaces the work of the heart. Treatment goals
The goal of treatment is to achieve a urine output of greater than 0.5 mL/kg/h, a central venous pressure of 8–12 mmHg and a mean arterial pressure of 65–95 mmHg. In trauma the goal is to stop the bleeding which in many cases requires surgical interventions. A good urine output indicates that the kidneys are getting enough blood flow. Epidemiology
Septic shock (a form of distributive shock), is the most common form of shock. Shock from blood loss occurs in about 1–2% of trauma cases. Overall, up to one-third of people admitted to the intensive care unit (ICU) are in circulatory shock. Of these, cardiogenic shock accounts for approximately 20%, hypovolemic about 20%, and septic shock about 60% of cases. Prognosis
The prognosis of shock depends on the underlying cause and the nature and extent of concurrent problems.