Shock More than just low blood pressure

1. ShockMore than just low blood pressure Region VIII Continuing Education February 2010

2. What is Shock? • Inadequate perfusion of body tissue • begins at the cellular level • if left untreated results in death of tissue, organs, organ systems • and ultimately the death of the entire organism • It is not (just) low blood pressure

3. Trauma Fluid loss MI Infection Allergic Reaction Spinal Cord Injury Other reasons Shock is a result of many reasons:

4. What is adequate perfusion? • Constant and necessary passage of blood through the body’s tissue • Delivery of nutrients and oxygen • Removal of CO2 and the waste byproducts of metabolism

5. Perfusion is dependent on a functioning and intact circulatory system

6. Components of circulatory system • The pump (heart) • The fluid (blood) • The container (blood vessels)

8. The Pump • The heart is the pump of the cardiovascular system • Receives blood from the venous system (preload) • Pumps the blood to the lungs for oxygenation • Pressure causes the oxygenated blood to be returned to the heart • Pumped out to the vital organs and peripheral tissues (against afterload)

9. Stroke Volume • The amount of blood ejected by the heart in one contraction • Factors affecting SV • Preload • Force and Rate of Contraction • Afterload

10. Preload • Amount of blood delivered to the heart during ventricular diastole • Includes everything available for next systole • Passive filling • “Atrial kick”

11. Inotropy and Chronotropy • It is affected by circulating hormones called catecholamines • epinepherine • norepinepherine • The strength of contraction of the heart • It is affected by circulating hormones called catecholamines • epinepherine • norepinepherine • The rate per minute of cardiac contractions

12. Frank Starling Mechanism • The greater the stretch of the cardiac muscle, up to a certain point, the greater the force of cardiac contraction (ie: the rubber band effect) Which one of these has optimal athletic stretch? http://www.scienceclarified.com/everyday/images/scet_02_img0144.jpg

13. Afterload • Resistance against which the ventricle must contract • Determined by the degree of peripheral vascular resistance

15. Peripheral Vascular Resistance • Pressure against which the heart must pump • Blood Pressure = CO x PVR

16. Cardiac Output • Amount of blood pumped in one contraction Stroke Volume x Heart Rate = Cardiac Output • Average person - 70 bpm x 70 mL = 4,900 mL/min

17. Fluid • Blood is thicker and more adhesive than water • Consist of plasma and formed elements: Red cells, White cells, Platelets • Transports oxygen, carbon dioxide, nutrients, hormones, and metabolic waste

18. Container • Blood vessels serve as the container • Under control of the autonomic nervous system • They can adjust size and selectively reroute blood through microcirculation • Microcirculation is comprised of the small vessels: • Arterioles, Capillaries, and Venules

19. Rerouting (shunting) blood • Capillaries have a pre-capillary sphincter between the arteriole and capillary that responds to local tissue demands such as acidosis, hypoxia, and opens as more blood is needed • At the end of the capillary between the capillary and venule is a post-capillary sphincter that opens when blood is needed to be emptied into the venous system

20. Fick Principle • The movement and utilization of oxygen in the body is dependent on the following conditions • Adequate concentration of inspired oxygen • Appropriate movement of oxygen across the alveolar/capillary membrane into the arterial bloodstream • Adequate number of red blood cells to carry oxygen • Proper tissue perfusion • Efficient off loading of oxygen at the tissue level Goal of perfusion!

21. Causes of Hypoperfusion Hose Pump Fluid

22. Inadequate Pump • cardiac contractile strength • heart rate (too slow or too fast)

23. Inadequate Fluid • Hypovolemia (abnormally low circulating blood volume) • Not enough preload

24. Container Problems • Dilated container without change in fluid volume • Normal container with low levels of fluid • Leak in container • Afterload too high – causes?

25. Result of hypoperfusion • Shock at the cellular level • Causes vary, however the ultimate outcome is impairment of cellular metabolism • Can be localized (AMI, CVA, compartment syndrome) or generalized

26. Compensated and Decompensated shock • Usually the body is able to compensate but when these mechanisms fail shock develops and may progress

27. Compensation Mechanisms • Catecholamine Release • Faster • Renin-Angiotensin • Slower • Anti-Diuretic Hormone • Slowest

28. Stages of shock

29. Stages of shock

30. Types of shock commonly seen by EMS • Cardiogenic shock (pump) • Hypovolemic shock (fluid) • Neurogenic shock (container) • Anaphylactic shock (container and fluid) • Septic shock (all three?)

31. Cardiogenic Shock • Pump fails to act as an effective forward pump • Usually the result of left ventricular failure secondary to acute MI or CHF

32. Signs / Symptoms • Pulmonary Edema – wheezes and crackles are heard as fluid levels increase • Difficulty breathing • Rarely - productive cough with white or pink-tinged foamy sputum • Cyanosis • Altered mental status • Oliguria (decreased urination – take a good history)

34. Hypovolemic Shock • Internal or external hemorrhage • Trauma • Long bone or open FX’s • Dehydration • Plasma loss due to burns • Excessive sweating • Diabetic Ketoacidosis with resultant osmotic diuresis

35. Signs / Symptoms • Altered mental status • Pale, cool, clammy skin • Blood pressure may be normal then fall • Pulse may be normal then ↑ (tachy), then ↓ (extreme brady into asystole) • Cardiac dysrhythmias may occur

36. Disclaimer: This slide represents generic treatment for the condition of hypoperfusion from hypovolemia. It does not represent the comprehensive listing of treatments, nor protocols, nor diseases, nor other conditions such as may occur in any and all patients. Void where prohibited by law. Some settling may occur during shipping.

37. Neurogenic Shock • Results from injury to brain or spinal cord causing interruption of nerve impulses to arteries • Arteries lose tone and dilate causing hypovolemia • Sympathetic nerve impulses to the adrenal glands are lost, which prevents the release of catecholamines and their compensatory effects • Neurogenic shock is commonly due to severe injury to spinal cord or total transection of cord (spinal shock)

38. Signs / Symptoms • Warm Skin (no cyanosis or pallor, no diaphoresis) • Low Blood Pressure • Slow Pulse

40. Anaphylatic Shock • Severe immune response to foreign substance • Most signs and symptoms occur within minutes but can take up to hours to occur • The faster the reaction develops the more severe it is likely to be • Death will occur if not treated promptly

41. Signs / Symptoms • Skin • Flushing • Itching • Hives • Swelling • Cyanosis • Respiratory System • Breathing difficulty • Sneezing, Coughing • Wheezing, Stridor • Laryngeal edema • Laryngospasm • Cardiovascular System • Vasodilation • Increased heart rate • Decreased blood pressure • Gastrointestinal System • Nausea, vomiting • Abdominal cramping • Diarrhea

44. Sepsis – what is it? Stages of sepsis based on American College of Chest Physicians/Society of Critical Care Medicine Consensus Panel guidelines Febrile, tachycardic, elevated resps. presume sepsis

46. Sepsis • Symptoms of sepsis usually are nonspecific and include fever, chills, and constitutional symptoms of fatigue, malaise, anxiety, or confusion

47. Septic Shock • An infection enters bloodstream and is carried throughout body • Toxins released overcome compensatory mechanisms • Can cause dysfunction of one organ system or cause multiple organ dysfunction

48. Signs / Symptoms • Signs and symptoms of sepsis with persistent hypotension / hypoperfusion

49. TX of Septic Shock • IMC • Treat per protocol for primary complaint • Syncope (IV fluid challenges) • Dysrhythmia (brady or tachycardia) • Cardiogenic shock (IV fluid challenges – fill the tank)

50. Shock “combo”(you don’t want this “supersized”)