RT Book, Section A1 Walley, Keith R. A2 Hall, Jesse B. A2 Schmidt, Gregory A. A2 Kress, John P. SR Print(0) ID 1107716859 T1 Shock T2 Principles of Critical Care, 4e YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 9780071738811 LK accesssurgery.mhmedical.com/content.aspx?aid=1107716859 RD 2024/10/15 AB Shock is present when there is evidence of multisystem organ hypoperfusion; it often presents as decreased mean blood pressure.Initial resuscitation aims to establish adequate airway, breathing, and circulation. Rapid initial resuscitation (usefully driven by protocol) is fundamental for improved outcome, since “time is tissue.”A working diagnosis or clinical hypothesis of the cause of shock should always be made immediately, while treatment is initiated, based on clinical presentation, physical examination, and by observing the response to therapy.Drug and/or definitive therapy for specific causes of shock must be considered and implemented early (eg, hemostasis for hemorrhage, revascularization for myocardial infarction, appropriate antibiotics, etc).The most common causes of shock are high cardiac output hypotension, or septic shock; reduced venous return despite normal pump function, or hypovolemic shock; reduced pump function of the heart, or cardiogenic shock; and obstruction of the circulation, or obstructive shock. Overlapping etiologies can confuse the diagnosis, as can a short list of other less common etiologies, which are often separated by echocardiography and pulmonary artery catheterization.Shock has a hemodynamic component, which is the focus of the initial resuscitation, but shock has also a systemic inflammatory component (ameliorated by rapid initial resuscitation) that leads to adverse sequelae including subsequent organ system dysfunction.