March 2014 Diagnosis And Management Volume 16, Number 3 Of Shock In The Emergency Authors Jeremy B. Richards, MD, MA Division of Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Department Deaconess Medical Center, Boston, MA Susan R. Wilcox, MD Department of Anesthesia, Critical Care, and Pain Medicine, Abstract Massachusetts General Hospital, Boston, MA Peer Reviewers Shock is a state of acute circulatory failure leading to decreased organ Rachel Garvin, MD perfusion, with inadequate delivery of oxygenated blood to tissues Assistant Professor, Neurosurgery and Emergency Medicine, University and resultant end-organ dysfunction. The mechanisms that can result of Texas Health Science Center, San Antonio, San Antonio, TX in shock are divided into 4 categories: (1) hypovolemic, (2) distribu- Scott D. Weingart, MD, FCCM Associate Professor of Emergency Medicine, Director, Division of ED tive, (3) cardiogenic, and (4) obstructive. While much is known re- Critical Care, Icahn School of Medicine at Mount Sinai, New York, NY garding treatment of patients in shock, several controversies continue CME Objectives in the literature. Assessment begins with identifying the need for Upon completion of this article, you should be able to: critical interventions such as intubation, mechanical ventilation, or 1. Analyze available clinical data to be able to distinguish between obtaining vascular access. Prompt workup should be initiated with the distinct pathophysiologic mechanisms that cause shock. laboratory testing (especially of serum lactate levels) and imaging, as 2. Describe and apply the initial resuscitative and therapeutic steps in the management of a patient presenting with undifferentiated indicated. Determining the intravascular volume status of patients shock. in shock is critical and aids in categorizing and informing treatment 3. Compare and contrast focused therapeutic interventions for the decisions. This issue reviews the 4 primary categories of shock as well distinct pathophysiologic categories of shock. as special categories, including shock in pregnancy, traumatic shock, 4. Discuss the evidence-based clinical approach to hemorrhagic shock due to trauma. septic shock, and cardiogenic shock in myocardial infarction. Adher- ence to evidence-based care of the specific causes of shock can opti- Prior to beginning this activity, see “Physician CME Information” on the mize a patient’s chances of surviving this life-threatening condition. back page. Editor-In-Chief of Medicine at Mount Sinai, New Pittsburgh Medical Center, Pittsburgh, Icahn School of Medicine at Mount Research Editor Andy Jagoda, MD, FACEP York, NY PA Sinai, New York, NY Michael Guthrie, MD Professor and Chair, Department of Michael A. Gibbs, MD, FACEP Charles V. Pollack, Jr., MA, MD, Scott Silvers, MD, FACEP Emergency Medicine Residency, Emergency Medicine, Icahn School Professor and Chair, Department FACEP Chair, Department of Emergency Icahn School of Medicine at Mount of Medicine at Mount Sinai, Medical of Emergency Medicine, Carolinas Professor and Chair, Department of Medicine, Mayo Clinic, Jacksonville, FL Sinai, New York, NY Director, Mount Sinai Hospital, New Medical Center, University of North Emergency Medicine, Pennsylvania York, NY Carolina School of Medicine, Chapel Hospital, Perelman School of Corey M. Slovis, MD, FACP, FACEP International Editors Professor and Chair, Department Hill, NC Medicine, University of Pennsylvania, Peter Cameron, MD Associate Editor-In-Chief Philadelphia, PA of Emergency Medicine, Vanderbilt Steven A. Godwin, MD, FACEP University Medical Center; Medical Academic Director, The Alfred Kaushal Shah, MD, FACEP Professor and Chair, Department Michael S. Radeos, MD, MPH Emergency and Trauma Centre, Associate Professor, Department of Director, Nashville Fire Department and of Emergency Medicine, Assistant Assistant Professor of Emergency International Airport, Nashville, TN Monash University, Melbourne, Emergency Medicine, Icahn School Dean, Simulation Education, Medicine, Weill Medical College Australia of Medicine at Mount Sinai, New University of Florida COM- of Cornell University, New York; Stephen H. Thomas, MD, MPH York, NY George Kaiser Family Foundation Giorgio Carbone, MD Jacksonville, Jacksonville, FL Research Director, Department of Chief, Department of Emergency Emergency Medicine, New York Professor & Chair, Department of Gregory L. Henry, MD, FACEP Medicine Ospedale Gradenigo, Editorial Board Hospital Queens, Flushing, NY Emergency Medicine, University of William J. Brady, MD Clinical Professor, Department of Oklahoma School of Community Torino, Italy Professor of Emergency Medicine Emergency Medicine, University Ali S. Raja, MD, MBA, MPH Medicine, Tulsa, OK Amin Antoine Kazzi, MD, FAAEM and Medicine, Chair, Medical of Michigan Medical School; CEO, Director of Network Operations and Ron M. Walls, MD Associate Professor and Vice Chair, Emergency Response Committee, Medical Practice Risk Assessment, Business Development, Department Professor and Chair, Department of Department of Emergency Medicine, Medical Director, Emergency Inc., Ann Arbor, MI of Emergency Medicine, Brigham University of California, Irvine; and Women’s Hospital; Assistant Emergency Medicine, Brigham and Management, University of Virginia John M. Howell, MD, FACEP American University, Beirut, Lebanon Professor, Harvard Medical School, Women’s Hospital, Harvard Medical Medical Center, Charlottesville, VA Clinical Professor of Emergency Boston, MA School, Boston, MA Hugo Peralta, MD Peter DeBlieux, MD Medicine, George Washington Scott D. Weingart, MD, FCCM Chair of Emergency Services, Professor of Clinical Medicine, University, Washington, DC; Director Robert L. Rogers, MD, FACEP, Associate Professor of Emergency Hospital Italiano, Buenos Aires, Interim Public Hospital Director of Academic Affairs, Best Practices, FAAEM, FACP Medicine, Director, Division of Argentina of Emergency Medicine Services, Inc, Inova Fairfax Hospital, Falls Assistant Professor of Emergency ED Critical Care, Icahn School of Dhanadol Rojanasarntikul, MD Louisiana State University Health Church, VA Medicine, The University of Maryland School of Medicine, Medicine at Mount Sinai, New Attending Physician, Emergency Science Center, New Orleans, LA Shkelzen Hoxhaj, MD, MPH, MBA Baltimore, MD York, NY Medicine, King Chulalongkorn Francis M. Fesmire, MD, FACEP Chief of Emergency Medicine, Baylor Memorial Hospital, Thai Red Cross, Professor and Director of Clinical College of Medicine, Houston, TX Alfred Sacchetti, MD, FACEP Senior Research Editors Thailand; Faculty of Medicine, Assistant Clinical Professor, Research, Department of Emergency Eric Legome, MD Chulalongkorn University, Thailand Medicine, UT College of Medicine, Department of Emergency Medicine, James Damilini, PharmD, BCPS Chief of Emergency Medicine, Clinical Pharmacist, Emergency Suzanne Peeters, MD Chattanooga; Director of Chest Pain Thomas Jefferson University, King’s County Hospital; Professor of Room, St. Joseph’s Hospital and Emergency Medicine Residency Center, Erlanger Medical Center, Philadelphia, PA Clinical Emergency Medicine, SUNY Medical Center, Phoenix, AZ Director, Haga Hospital, The Hague, Chattanooga, TN Downstate College of Medicine, Robert Schiller, MD The Netherlands Brooklyn, NY Chair, Department of Family Joseph D. Toscano, MD Nicholas Genes, MD, PhD Medicine, Beth Israel Medical Chairman, Department of Emergency Assistant Professor, Department of Keith A. Marill, MD Center; Senior Faculty, Family Medicine, San Ramon Regional Research Faculty, Depatment of Emergency Medicine, Icahn School Medicine and Community Health, Medical Center, San Ramon, CA Emergency Medicine, University of Case Presentation Equation 2 MAP = CO x SVR You are working in the ED late one evening when an 82-year- old man is brought in by his son. His son reports that earlier Abbreviations: CO, cardiac output; MAP, mean arte- today, his father had been in his usual state of health, but this rial pressure; SVR, systemic vascular resistance. evening he found his father confused, with labored breath- ing. On arrival, the patient has the following vital signs: As noted in Equation 3, cardiac output is deter- temperature, 38°C; heart rate, 130 beats/min; blood pressure, mined by stroke volume and heart rate, and stroke 110/60 mm Hg; respiratory rate, 34 breaths/min; and oxygen volume is affected by preload, afterload, and con- saturation, 89% on room air. He is delirious and unable to tractility. The concept of preload influencing stroke answer questions. A focused physical examination demon- volume (and thereby affecting cardiac output and strates tachycardia without extra heart sounds or murmurs, DO2) is a core physiologic aspect of the assessment right basilar crackles on lung auscultation, a benign abdomen, and management of patients in shock. and 1+ lower extremity pitting edema. You establish intrave- nous access with a peripheral catheter and send basic labs. A Equation 3 further history obtained from the son reveals that his father has CO = HR x SV congestive heart failure with a low systolic ejection fraction, as well as a history of several prior myocardial infarctions that Abbreviations: CO, cardiac output; HR, heart rate; were treated with stent placement. SV, stroke volume. As you consider this case, you ask yourself whether this patient is in shock, and if he is, what are the specific Changes in preload, stroke volume, system causative pathophysiologic mechanisms? You review vascular resistance, and cardiac