Shock

1. Shock Dr. FaiezAlhmoud Department of Surgery Albashir Hospital

2. Objectives • To develop an understanding of the definition and pathophysiology of shock • To develop an understanding and overview of the different types of shock • To develop a systematic approach to the detection and management of shock • To develop a deeper understanding of sepsis and septic shock • To know how to decrease mortality in shock

3. Definition of Shock What is shock? Inadequate tissue perfusion

4. Why should you care? • High mortality - 20-90% • Early on the effects of O2 deprivation on the cell are REVERSIBLE • Early intervention reduces mortality

5. Understanding Shock Shock results from an inadequate perfusion of the body’s cells with oxygenated blood. Which means : Systemic imbalance between O2 supply & demand Which leads to: • Cellular dysfunction and damage • Organ dysfunction and damage

6. Understanding Shock Tissue perfusion is driven by blood pressure! So……………… • In other words, when the blood flow (pressure) and O2 delivery to the cell are too low, there will be shock!

7. Understanding Shock -BP BP = CO x SVR BP = blood pressure CO = cardiac output SVR = systemic (peripheral) vascular resistance If the blood pressure is low, then either the: CO is low or the SVR is low

8. Understanding Shock -VR • SVR regulated by blood vessel tone. • Dilatation opens blood vessels & increases volume to area but decreases return to heart • Constriction decreases volume to area but increases return to heart

9. Understanding Shock Stroke Volume • Volume of blood pumped by the heart in one cycle • What affect stroke volume ? 1- Blood volume 2- Rhythm problems 3- Heart muscle problem 4- Mechanical obstruction

10. Understanding Shock Blood Volume • What makes up the blood volume? 1- Plasma 2- RBCes 3- Platelets 4- WBCes • What alters blood volume ? 1- Hemorrage 2- Plasma loss 3- Redistribution of extracellular volume

11. Stages of shock • Initial :The cells become leaky and switch to anaerobic metabolism. • Non-progressive:(compensated stage)Attempt to correct the metabolic upset of shock • Progressive: Eventually the compinsation will begin to fail • Refractory : Organs fail and the shock can no longer be reversed.

12. Early Stage of Shock • Compensation (Maintain & Restore) 1- Tissue perfusion 2- Oxygenetion • Symptoms - Almost asymptomatic • Pulse may be slightly elevated • Anxiety /Nervousness • Dizziness • Weakness • Faintness • Nausea & Vomiting • Thirst • Confusion • Decreased UO • Hx of Trauma / other illness • Vomiting & Diarrhoea • Chest Pain • Fevers / Rigors • SOB

13. Non-Progressive shock :(Compensated) • MAP Drops by 10-15mm Hg • Kidneys Release Renin • Hormonal changes:ADH, Aldosterone, epinephrine, norephinephrine • Vasoconstriction:Vessels are clamping down

14. Intermediate or Progressive Shock (Decompensated) The mechanisms compensate for worsening shock will begin to fail. Cellular dysfunction begins to spiral out of control, metabolic acidosis worsens  • MAP drops more than 15mmHg • Hypoxia • Anoxia • Ischemia

15. Refractory; Irreversible Shock • Lack of O2 < 70 • Increase in toxins Difficult to recover from • Enzyme activity increases Disintegrating any remaining organelles • Tissue anoxia Generalized cellular death At this stage organs fail and the shock can no longer be reversed. Death occurs rapidly.

16. Types of Shock • Hypovolemic Blood VOLUME problem • Cardiogenic Blood PUMP problem • Distributive Blood VESSEL problem • Obstructive Extracardiacpump FAILURE problem

17. What Type of Shock is This? • 68 yo M with hx of HTN and DU presents to the ER with epigastric abdominal pain with radiation to his back and diziness. The pt is hypotensive, tachycardic, afebrile, and with cool skin. Hypovolemic Shock

18. Hypo-volemic Shock- causes • Non-hemorrhagic • Vomiting • Diarrhea • Bowel obstruction, pancreatitis • Burns • Neglect, environmental (dehydration) • Hemorrhagic • Trauma • GI bleed • Ectopic pregnancy, post-partum bleeding • Massive hemoptysis • AAA rupture Blood loss - Plasma Loss - ECF Loss

19. ATLS classification of hemorrhagic shock In a normal adult, a tachycardia after blood loss indicates at least a 15% loss of blood volume (>750 mls)

20. CBC ABG/lactate Electrolytes BUN, Creatinine Coagulation studies Type and cross-match As indicated CXR Pelvic x-ray Abd. US (FAST) Abd/pelvis CT Chest CT GI endoscopy Bronchoscopy Vascular radiology Evaluation of Hypovolemic Shock

21. Hypovolemic Shock- management • ABCs (Control any bleeding) • Establish 2 large bore IVs or a central line • Crystalloids • Normal Saline or Lactate Ringers • Up to 3 liters • PRBCs • O negative or cross matched • Arrange definitive treatment

22. An 81 yo F presents to the ED with chest infection and altered mental status. She is febrile to 39.4, hypotensive with a widened pulse pressure, tachycardic and with warm extremities What Type of Shock is This? Septic

23. Sepsis • Two or more of SIRS criteria • Temp > 38 or < 36 C • HR > 90 • RR > 20 • WBC > 12,000 or < 4,000 • Plus the presumed existence of infection • Blood pressure can be normal!

24. Sepsis,Severe Sepsis and Septic Shock • Sepsis: Systemic host response to infection with SIRS • Severe Sepsis: Sepsis plus end-organ dysfunction or hypo perfusion • Septic Shock: Sepsis with hypotension, despite fluid resuscitation; evidence of inadequate tissue perfusion

25. Septic Shock • Sepsis (remember definition?) • Plus refractory hypotension • After bolus of 20-40 mL/Kg patient still has one of the following: • SBP < 90 mm Hg • MAP < 65 mm Hg • Decrease of 40 mm Hg from baseline

26. Septic Shock • Clinical signs: • Hyperthermia or hypothermia (Hot – early or cold - late phase) • Tachycardia • Wide pulse pressure • Low blood pressure (SBP<90) • Mental status changes • Beware of compensated shock! • Blood pressure may be “normal”

27. Pathogenesis of Sepsis Nguyen H et al. Severe Sepsis and Septic-Shock: Review of the Literature and Emergency Department Management Guidelines. Ann Emerg Med. 2006;42:28-54.

28. Ancillary Studies • Cardiac monitoring • Pulse oximetry • CBC, coags, LFTs, lipase, KFT & UA • ABG with lactate • Blood culture x 2, urine culture • CXR

29. Treatment of Septic Shock • 2 large bore IVs • NS IVF bolus- 1-2 L wide open (if no contraindications) • Supplemental oxygen • Empiric antibiotics, based on suspected source, as soon as possible • Foley catheter (why do you need this?)

30. Treatment of Sepsis • Antibiotics- Survival correlates with how quickly the correct drug was given • Cover gram positive and gram negative bacteria • Add additional coverage as indicated • Pseudomonas- Gentamicin or Cefepime • MRSA- Vancomycin • Intra-abdominal or head/neck anaerobic infections- Clindamycin or Metronidazole • Asplenic- Ceftriaxone for N. meningitidis, H. infuenzae • Neutropenic – Cefepime or Imipenem

31. Persistent Hypotension • If no response after 2-3 L IVF, start a vasopressor (norepinephrine, dopamine, etc) and titrate to effect • Goal: MAP > 60 • Consider adrenal insufficiency: hydrocortisone 100 mg IV

32. A 34 yo F presents to the ER after dining at a restaurant where shortly after eating the first few bites of her meal, became anxious, diaphoretic, began wheezing, noted diffuse pruritic rash, nausea, and a sensation of her “throat closing off”. She is currently hypotensive, tachycardic and ill appearing with dyspnea. What Type of Shock is This?

33. Anaphylactic Shock

34. Anaphylactic Shock • What are some symptoms of anaphylaxis? • First- Pruritus, flushing, urticaria appear • Next- Throat fullness, anxiety, chest tightness, shortness of breath and lightheadedness • Finally- Altered mental status, respiratory distress and circulatory collapse

35. Anaphylactic Shock - Common Features • Angio-edema • Broncho-constriction • Vasodilatation • Hypotension • Urticareal rash

36. Anaphylactic Shock… Diagnosis • Clinical diagnosis • Defined by airway compromise, hypotension, or involvement of cutaneous, respiratory, or GI systems • Look for exposure to drug, food, or insect bite • Labs have no role

37. Anaphylactic Shock…. Treatment • ABC’s • Angioedema and respiratory compromise require immediate intubation or surgical airway • IV line, cardiac monitor, pulse oximetry • IVFs, oxygen • Epinephrine**** • Second line • Corticosteriods • H1 and H2 blockers

38. Anaphylactic Shock…. Treatment • Epinephrine • 0.3 mg IM of 1:1000 (epi-pen) • Repeat every 5-10 min as needed • Caution with patients taking beta blockers- can cause severe hypertension due to unopposed alpha stimulation • Corticosteroids • Methylprednisolone 125 mg IV • Prednisone 60 mg PO • Antihistamines • H1 blocker- Diphenhydramine 25-50 mg IV • H2 blocker- Ranitidine 50 mg IV • Bronchodilators • Albuterol nebulizer • Atrovent nebulizer • Magnesium sulfate 2 g IV over 20 minutes

39. Anaphylactic Shock…. Management • All patients who receive epinephrine should be observed for 4-6 hours • If symptom free, discharge home • If on beta blockers or h/o severe reaction in past, consider admission

40. A 41 yo M presents to the ER after a car accident complaining of decreased sensation below his waist and is now hypotensive, bradycardic, with warm extremities What Type of Shock is This? Neurogenic

41. Neurogenic Shock • Neurogenic shock is caused by the loss of sympathetic control (tone) of resistance vessels, which leads to decreased tissue perfusion and initiation of the shock response. • Results in hypotension and bradycardia • Neurogenic shock can be caused by spinal cord injury (above T1), CNS injury, general or spinal anesthesia, pain, and anxiety. • Onset is within minutes and may last weeks . • Skin is warm and dry

42. Neurogenic Shock…..Treatment • A,B,Cs • Remember c-spine precautions • Fluid resuscitation • Keep MAP at 85-90 mm Hg for first 7 days • Thought to minimize secondary cord injury • If crystalloid is insufficient use vasopressors • Search for other causes of hypotension • Methylprednisoloneis controversial & given early and in high doses • For bradycardia • Atropine • Pacemaker

43. A 55 yo M with hx of HTN, DM presents with “crushing” substernal pain, diaphoresis, hypotension, tachycardia and cool, clammy extremities What Type of Shock is This?

44. Signs: Cool, mottled skin Tachypnea, tachycardia Hypotension Altered mental status Narrowed pulse pressure (WEAK) Rales, murmur Defined as: shock resulting from inadequate cardiac function Cardiogenic Shock

45. Cardiogenic Shock - Etiology WHAT CAUSES PUMP FAILURE ? • Intrinsic Causes - Myocardial injury - Tachycardia - Valvular defect • Extrinsic (Obstructive Shock) - Pericardial tamponade - Tension pneumothorax - Large pulmonary emblous

46. Pathophysiology of Cardiogenic Shock • Often after ischemia, loss of LV function (Loss of 40% of LV function clinical shock ensues) • CO reduction = lactic acidosis, hypoxia • Stroke volume is reduced • Tachycardia develops as compensation • Ischemia and infarction worsens

47. Ancillary Tests • EKG • CXR • CBC, cardiac enzymes, coagulation studies • Echocardiogram

48. A 24 yo M presents to the ED after an MVC c/o chest pain and difficulty breathing. On PE, you note the pt to be tachycardic, hypotensive, hypoxic, and with decreased breath sounds on left What Type of Shock is This? Obstructive

49. Obstructive Shock

50. Obstructive Shock • Tension pneumothorax • Air trapped in pleural space with 1 way valve, air/pressure builds up • Mediastinum shifted impeding venous return • Chest pain, SOB, decreased breath sounds • No tests needed! • Rx: Needle decompression, chest tube