TY - CHAP M1 - Book, Section TI - Shock A1 - Avila, Jacob A2 - Stone, C. Keith A2 - Humphries, Roger L. PY - 2017 T2 - CURRENT Diagnosis & Treatment: Emergency Medicine, 8e AB - The failure of adequate perfusion and oxygenation to the body, or shock, is a disease entity that is a significant contributor of morbidity and mortality. This sinister illness can be very difficult to diagnose and adequately treat. Transient states of shock, defined as a systolic blood pressure (SBP) less than 100 mm Hg, have been reported to be present in up to 19% of emergency department (ED) patients, however, persistent shock is present in around 1–3% of all ED patients. While it is relatively uncommon, it suffers from an overall mortality rate as high as 20%. Death comes from multiorgan failure (MOF) that is commonly instigated by systemic hypoperfusion. The common denominator of all forms of shock is cellular hypoxia, which can be caused by either decreased oxygen delivery to the organs or from the inability of the tissues to utilize oxygen. The most common forms of shock are caused by decreased oxygen delivery and can be due to decreased oxygen in the blood, decreased quantity of blood in circulation, inability for the cells to adequately utilize oxygen, or an inadequate increase in oxygen content in response to a stress. The two main factors that contribute to tissue perfusion are systemic vascular resistance (SVR) and the cardiac output (CO). CO is determined by both the heart rate (HR) and the stroke volume (SV). An alteration in any of those variables can instigate a state of shock. Early in the disease progression the body is able to compensate if one of those variables is compromised. For example, a healthy patient with low SVR will increase the cardiac output to help maintain systemic perfusion. However, these compensatory mechanisms are finite and the different states of shock often involve more than one system (eg, septic shock can produce relative hypovolemia and myocardial dysfunction). SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1176285309 ER -