RT Book, Section A1 Farcy, David A. A1 Osborn, Tiffany M. A2 Farcy, David A. A2 Chiu, William C. A2 Flaxman, Alex A2 Marshall, John P. SR Print(0) ID 55815608 T1 Chapter 46. Classification of Shock T2 Critical Care Emergency Medicine YR 2012 FD 2012 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-162824-2 LK accessemergencymedicine.mhmedical.com/content.aspx?aid=55815608 RD 2024/03/28 AB Critical illness is defined as “any patient who is physiologically unstable, requiring constant and minute-to-minute titration of therapy according to the evolution of the disease process.”1 It is a continuum often culminating in rapid decline, shock, organ failure, and, frequently, patient demise. Traditionally, shock is defined as a clinical diagnosis identified through physical manifestations observed by medical staff.2 Complementing clinical acumen is the recognition of accumulating oxygen debt due to perturbations of microvascular circulation. Early phases of evolving shock may manifest through biochemical markers with minimal physical alterations.3–5 Although typically considered an intensive care unit (ICU) ailment, shock develops well before ICU admission with patients often initially presenting to the emergency department (ED). Effective, timely shock treatment requires a continuum of care beginning with prehospital providers, continuing within the ED, and concluding within the ICU.6,7 Thus, shock treatments should be defined by level of care rather than location of care.8