Resuscitation and Shock

1. Resuscitation and Shock LSU Medical Student Clerkship, New Orleans, LA

2. Goals • Provide an introduction to the ABC’s of resuscitation in the ED • Review available oxygen delivery devices and airway adjuncts • Describe the pathophysiology of shock and its major subtypes • Provide an introduction to the basics of treatment of shock in the ED

3. Emergency Medicine Always Starts with the ABC’s • A – Airway • B - Breathing • C - Circulation

4. Airway • Remove any obstructions • Head tilt, chin lift • Jaw Thrust • Oropharyngeal and nasopharyngeal airways • Orotracheal and nasotracheal intubation • Cricothyroidotomy and Tracheotomy

5. Rapid Sequence Intubation • Assume every ED patient has a full stomach • Combination of sedation and paralysis to facilitate procedure • Evidence based to increase chance of success and decrease incidence of aspiration • Not without its dangers: paralyzing a patient who cannot be ventilated

6. Rapid Sequence Intubation • Assume every ED patient has a full stomach • Combination of sedation and paralysis to facilitate procedure • Evidence based to increase chance of success and decrease incidence of aspiration • Not without its dangers: paralyzing a patient who cannot be ventilated

7. Three Indications for RSI • Airway Protection • Respiratory Failure • Expected Clinical Course

8. Breathing • Hypoxic Respiratory Failure • Hypercapnic Respiratory Failure • Mechanical Respiratory Failure

9. Oxygen Delivery Devices • Nasal Cannula - up to 40% FiO2 • Venturi mask - fixed 25% to 50% FiO2 • Nonrebreather mask - theoretical 100% FiO2 • Bag Valve Mask – 100%FiO2 • Noninvasive Positive Pressure Ventilation (BiPAP or CPAP) FiO2 up to 100% based on setting

10. Circulation • Restoration of a pulse is the first goal • ACLS • However having a pulse is not the end of the story • Adequate circulation requires correction of shock

11. Shock • Shock is defined as circulatory insufficiency that creates an imbalance between tissue oxygen supply and oxygen demand. The result of shock is global tissue hypoperfusion and is associated with a decreased venous oxygen content and metabolic acidosis (lactic acidosis).

12. Pathophysiology of Shock • Imbalance between tissue supply and demand Anaerobic Metabolism Lactic Acid Production

13. Types of Shock • Hypovolemic • Cardiogenic • Distributive • Obstructive

14. Hypovolemic Shock • Caused by inadequate circulating volume (decreased preload) • Hemorrhage (trauma, ruptured AAA, GI bleeding) • Fluid loss (diarrhea, vomiting, poor intake, burns, third spacing)

15. Cardiogenic Shock • Caused by pump failure (decreased cardiac output) • Myopathic – systolic dysfunction, diastolic dysfunction • Arrythmic – disorganized cardiac activity

16. Distributive Shock • Caused by maldistribution of bloodflow from peripheral vasodilatation and decrease in SVR (decreased afterload) • Sepsis • Neurogenic • Anaphylaxis • Toxic shock syndrome

17. Obstructive Shock • Caused by extracardiac obstruction to blood flow • Cardiac tamponade, tension pneumothorax, pulmonary embolus

18. Clinical Presentation of Shock • Clinical presentation varies with type of shock • History and physical are key for determining underlying cause • Hypotension is very common • Lethargy, cool clammy skin, tachypnea, tachycardia, and cyanosis are common as well DIAGNOSE THE UNDERLYING CAUSE!!!!

19. Treating Shock • Early intervention is vital to reducing morbidity and mortality • All efforts are aimed at balancing maximizing tissue oxygen supply decreasing tissue oxygen demand

20. Treating Shock - Breathing • Maximize oxygenation (Keep Sa02 > 93%) • Control the work of breathing. Respiratory muscles are highly metabolic and can greatly increase oxygen demand.

21. Treating Shock – Fluid Resuscitation • Most patients in shock have either an absolute or relative volume deficit, except the patient in cardiogenic shock with pulmonary edema • Central venous catheterization can guide help guide via central venous pressure monitoring and SVCO2 monitoring • A bolus is a bolus!!

22. Treating Shock – Vasopressors • Vasopressor agents are used when there has been an inadequate response to volume resuscitation or when a patient has contraindications to volume infusion • Vasopressors are most effective after fluid resuscitation but may be necessary to avoid prolonged hypotension • Goal is generally a MAP of 65

23. Treating Shock – Vasopressors

24. Treating Shock – Endpoints • No therapeutic end point is universally effective, and only a few have been tested in prospective trials, with mixed results. • Table from Tintinalli

25. Treating Shock – Endpoints

26. Take Home Points • The goal of resuscitation is to maximize survival and minimize morbidity using objective hemodynamic and physiologic values to guide therapy. • The first few hours are vital. • Diagnose and treat the underlying cause!!!