SHOCK

1. SHOCK Prof.M.H.MUMTAZ

2. SHOCK Inadequate perfusion (blood flow) leading to inadequate oxygen delivery to tissues

3. Physiology • Basic unit of life = cell • Cells get energy needed to stay alive by reacting oxygen with fuel (usually glucose) • No oxygen, no energy • No energy, no life

4. 6 O2 GLUCOSE Aerobic Metabolism 6 CO2 6 H2O METABOLISM 36 ATP HEAT (417 kcal)

5. Anaerobic Metabolism 2 LACTIC ACID GLUCOSE METABOLISM 2 ATP HEAT (32 kcal)

6. Inadequate Energy Production Anaerobic Metabolism Lactic Acid Production Metabolic Failure Cell Death! Metabolic Acidosis Anaerobic? So What? Inadequate Cellular Oxygenation

7. Homeostasis is maintenance of balance • Requires proper functioning systems • Cardiovascular • Respiratory • Renal

8. Cardiovascular System • Transports oxygen, fuel to cells • Removes carbon dioxide, waste products for elimination from body Cardiovascular system must be able to maintain sufficient flow through capillary beds to meet cell’s oxygen and fuel needs

9. Flow = Perfusion Adequate Flow = Adequate Perfusion Inadequate Flow = Indequate Perfusion (Hypoperfusion) Hypoperfusion = Shock

10. What is needed to maintain perfusion? • Pump • Pipes • Fluid Heart Blood Vessels Blood

11. How can perfusion fail? • Pump Failure • Pipe Failure • Loss of Volume

12. Factors Affecting The Pump • Preload • Contractile force • Frank-starling mechanism • Afterload

13. Muscle Anatomy

14. Contraction: Sliding Filaments image from: http://www.accessexcellence.com/AB/GG/muscle_Contract.html

15. What Is Blood Pressure? BP = COxSVR CO = Stroke Volume X Heart Rate SVR= B.vessel calibre +viscosity

16. What Affects Blood Pressure? • ANS balance • Contractility • Preload • Starling’s law • Afterload

17. Types of Shock and Their Causes CARDIOGENIC HYPOVOLAEMICSEPTIC NEUROGENIC PSYCHOGENic obstructive ANAPHYLACTIC

18. Cardiogenic Shock • Pump failure • Heart’s output depends on • How often it beats (heart rate) • How hard it beats (contractility) • Rate or contractility problems cause pump failure

19. Cardiogenic Shock • Causes • Acute myocardial infarction • Very low heart rates (bradycardias) • Very high heart rates (tachycardias) Why would a high heart rate caused decreased output? Hint: Think about when the heart fills.

20. Neurogenic Shock • Loss of peripheral resistance • Spinal cord injured • Vessels below injury dilate What happens to the pressure in a closed system if you increase its size?

21. Hypovolemic Shock • Loss of volume • Causes • Blood loss: trauma • Plasma loss: burns • Water loss: Vomiting, diarrhea, sweating, increased urine, increased respiratory loss If a system that is supposed to be closed leaks, what happens to the pressure in it?

22. Psychogenic Shock • Simple fainting (syncope) • Caused by stress, pain, fright • Heart rate slows, vessels dilate • Brain becomes hypoperfused • Loss of consciousness occurs What two problems combine to produce hypoperfusion in psychogenic shock?

23. Septic Shock • Results from body’s response to bacteria in bloodstream • Vessels dilate, become “leaky” What two problems combine to produce hypoperfusion in septic shock?

24. Anaphylactic Shock • Results from severe allergic reaction • Body responds to allergen by releasing histamine • Histamine causes vessels to dilate and become “leaky” What two problems combine to produce hypoperfusion in anaphylaxis?

25. OBSTRUCTIVE SHOCK PUMONARY EMBOLISM ? CRDIAC TEMPONADE ? PNEUMOTHORAX ?

26. Restlessness, anxiety Decreasing level of consciousness Dull eyes Rapid, shallow respirations Nausea, vomiting Thirst Diminished urine output Shock:Signs and Symptoms Why are these signs and symptoms present? Hint: Think hypoperfusion

27. Hypovolemia will cause Weak, rapid pulse Pale, cool, clammy skin Cardiogenic shock may cause: Weak, rapid pulse or weak, slow pulse Pale, cool, clammy skin Neurogenic shock will cause: Weak, slow pulse Dry, flushed skin Sepsis and anaphylaxis will cause: Weak, rapid pulse Dry, flushed skin Shock: Signs and Symptoms Can you explain the differences in the signs and symptoms?

28. Shock: Signs and Symptoms • Patients with anaphylaxis will: • Develop hives (urticaria) • Itch • Develop wheezing and difficulty breathing (bronchospasm) What chemical released from the body during an allergic reaction accounts for these effects?

29. Shock: Signs and Symptoms Shock is NOT the same thing as a low blood pressure! A falling blood pressure is a LATE sign of shock!

30. Treatment • Secure, maintain airway • Apply high concentration oxygen • Assist ventilations as needed • Keep patient supine • Control obvious bleeding • Stabilize fractures • Prevent loss of body heat

31. Treatment • Elevate lower extremities 8 to 12 inches in hypovolemic shock • Do NOT elevate the lower extremities in cardiogenic shock Why the difference in management?

32. Management of Shock • Shock begins when DO2 to the cells is inadequate to meet metabolic demand • The major therapeutic goals in shock therefore are sufficient tissue perfusion and oxygenation • Early diagnosis remains a major problem

33. Treatment • Administer nothing by mouth, even if the patient complains of thirst

34. Hemodynamic Characteristics in Different Types of Shock /

35. Inotropic Agents and Vasodilators • Vasoactive drugs are an important pharmacologic defense in the treatment of shock. • May be required to support BP in the early stages of shock. • These agents may be needed to: • Enhance CO through the use of inotropic agents • Increase SVR through the use of vasopressors

36. Effects of Inotropic Agents and Vasodilators 1 Drug Receptor CO SVR Dose Range 0 - (mg/kg/min)

37. Effects of Inotropic Agents and Vasodilators 2 Drug CO SVR Dose Range (mg/kg/min)

38. Dopamine An endogenous precursor of norepinephrine withmultiple dose-related effects • Low Dose (0.5 - 3 mg/kg/min) • b2 and dopaminergic (DR) effects • Enhanced blood flow to renal and splanchnic beds • Moderate Dose (5 -10 mg/kg/min) • Positive inotropic effects • High Dose (>20 mg/kg/min) • a-actions (vasoconstriction)

39. MANAGEMENT GUIDE • 1,Haemodynamic monitoring Blood pressure/HR SV,HR,CI,CO SVR,SVRI TOOLS ; SWAN GANZ TEMPERATURE LIDCO CENTRAL VENOUS PRESSURE 2, OXYGENATION STATUS FIO2/PAO2/PaO2/DO2/VO2/ Lactate 3, ACID BASE STATUS

40. HAEMODYNAMIC TRUTHS • 1,TACHYCARDIA IS NEVER AGOOD THING. • 2,HYPOTENSION IS ALWAYS PATHOLOGIC • 3,THERE IS NO SUCH THING AS NORMAL CARDIAC OUTPUT. • 4,CENTRAL VENOUS PRESSURE IS ONLY ELEVATED IN DISEASE. • 5,PERIPHERA EDEMA IS OF COSMETIC CONCERN. PINKSY..Chest.2007; 132;2020-2029

41. Bleeding

42. Bleeding Significance • If uncontrolled, can cause shock and death

43. Identification of External Bleeding • Arterial Bleed • Bright red • Spurting • Venous Bleed • Dark red • Steady flow • Capillary Bleed • Dark red • Oozing What is the physiology that explains the differences?

44. Control of External Bleeding • Direct Pressure • gloved hand • dressing/bandage • Elevation • Arterial pressure points

45. Arterial Pressure Points • Upper extremity: Brachial • Lower extramity: Femoral

46. Control of External Bleeding • Splinting • Air splint • Pneumatic antishock garment

47. Control of External Bleeding • Tourniquets • Final resort when all else fails • Used for amputations • 3-4” wide • write “TK” and time of application on forehead of patient • Notify other personnel

48. Control of External Bleeding • Tourniquets • Do not loosen or remove until definitive care is available • Do not cover with sheets, blankets, etc.

49. Epistaxis • Nosebleed • Common problem

50. Epistaxis • Causes • Fractured skull • Facial injuries • Sinusitis, other URIs • High BP • Clotting disorders • Digital insertion (nose picking)