final shock

1. SPHMMC Faculty of MedicineDepartment of Anesthesiology Shock By : Hailesllassie B.(MD) Anesthesiology R1

2. Contents • Definition • Classification • Pathophysiology • Management • Summary • References

3. Introduction • Shock is a clinical syndrome characterized by a significant reduction of systemic tissue perfusion • Inadequate oxygen delivery to meet metabolic demands • Results in global tissue hypo perfusion and metabolic acidosis • Shock can occur with a normal blood pressure and hypotension can occur without shock

4. Cont… • Inadequate systemic oxygen delivery activates autonomic responses to maintain systemic oxygen delivery • Sympathetic nervous system • NE, epinephrine, dopamine, and cortisol release • Causes vasoconstriction, increase in HR, and increase of cardiac contractility (cardiac output) • Renin-angiotensin axis • Water and sodium conservation and vasoconstriction • Increase in blood volume and blood pressure

5. Cont… • Cellular responses to decreased systemic oxygen delivery • ATP depletion → ion pump dysfunction • Cellular edema • Hydrolysis of cellular membranes and cellular death • Leads to systemic metabolic lactic acidosis that overcomes the body’s compensatory mechanisms

6. Cont… • Vasoconstriction of splanchnic, musculoskeletal, and renal blood flow • Goal is to maintain cerebral and cardiac perfusion • Severe pain and stress leads to hypothalamic release of ACTH.

7. Classification Of Shock • Hypovolemic • Septic • Cardiogenic • Intrinsic • Compressive • Traumatic • Neurogenic • Hypo adrenal

8. Stages of Shock • Compensated • Maintains end organ perfusion • BP is maintained usually by ↑ HR • Uncompensated • Decreases micro-vascular perfusion • Sign/symptoms of end organ dysfunction • Hypotensive • Irreversible • Progressive end-organ dysfunction • Cellular acidosis results in cell death

9. Hypovolemic shock The most common type of shock that results from reduced circulating blood volume Cause • Hemorrhagic -due to loss of red blood cell mass and plasma. e.g trauma • Non hemorrhagic- due to loss of plasma volume alone e.g -poor fluid intake (dehydration) or -excessive fluid loss -due to vomiting, diarrhea, urinary loss (diabetes)

10. Shock VO2 ≥ MRO2 = Normal Metabolism VO2 < MRO2 = SHOCK

11. Diagnosis • when there are signs of hemodynamic instability and the source of volume loss is obvious. • Rapid assessment of volume, COP, and MA COP –narrow pulse pressure - cold extremities - decreased capillary refill - weak pulse volume status -hx of blood or fluid loss

12. Hypotension + COP - volume status hypovolemic shock - volume status(N) cardiogenic shock (jugular venous distension, rales and S3 gallop) • Hypotension + COP – PVR (septic, neurogenic or anaphylactic shock) NB. • After acute hemorrhage, Hgb and Hct values do not change initially • Plasma vol. loss→heamoconcentration • Free water loss → hypernatremia

13. Management A – Ensure patent airway (intubation) B- adequate oxygenation and ventilation (may need mechanical ventilation) C- cardiovascular resuscitation -correction of intravascular blood volume and interventions to control ongoing loss

14. Cont… • Monitoring -patients in shock require care in the ICU -BP, PR, RR should be monitored continuously -Foley catheter should be inserted to follow urine output. - Mental status should be assessed frequently

15. Cont… • PAC (swan-ganz catheter) used to -measure COP, right atrial and PAP -measure PCWP -provide access for infusions • should be used in patients with significant ongoing blood loss, fluid shifts and underlying cardiac dysfunction

16. Volume resuscitation • Rapid infusion 2-3L isotonic saline/RL over 20-30min Response should be monitored -v/s -mental status if patient is stable continue IV fluid -urine output • If there is hemodynamic instability with significant ongoing blood loss Hgb conc. < 10g/d initiate blood transfusion • Severe and/ or prolonged hypo volemia inotropic and vasopressors like dopamine , noradrenaline and adrenalin

17. Cont… • Goal of resuscitation is to maximize survival and minimize morbidity • Use objective hemodynamic and physiologic values to guide therapy Goal directed approach • Urine output > 0.5 mL/kg/hr • CVP 8-12 mmHg • MAP 65 to 90 mmHg • Central venous oxygen concentration > 70%

18. Persistent Hypotension • Inadequate volume resuscitation • Pneumothorax • Cardiac tamponade • Hidden bleeding • Adrenal insufficiency • Medication allergy

19. Septic shock • Infection- Infection is the invasion of normally sterile tissue by organisms. • Bacteremia- Bacteremia is the presence of viable bacteria in the blood. • Systemic inflammatory response syndrome-SIRS is the clinical syndrome that results from a dysregulated inflammatory response to a noninfectious insult.

20. Septic Shock

21. Septic shock • Septic shock is a combination of the three classic types of shock: • hypovolemic;occurs from intravascular fluid losses through capillary leak • Cardiogenic ; results from • myocardial-depressant effects of inflammatory cytokines • myocarditis • decreased coronary blood flow 3. Distributive ; is the result of decreased systemic vascular resistance.

22. Cont… Sepsis • Is the presence of SIRS in the setting of infection (proven/suspected) Severe sepsis • Sepsis with ≥ 1 signs of organ dysfunction • CVS-SBP≤90 mmHg or MAP ≤70mmHg • RENAL-U/O <0.5mL/Kg/hr for 1 hr • HEMAT-Plt.<80000/Ųl • Unexplained metabolic acid -PH ≤ 7.30… • RESP -Pao2/Fio2 ≤ 250

23. septic shock • Documented infection, organ dysfunction, and hypotension (SBP<90mmHg, 40 mmHg less than patient's normal BP ) for at least 1hr despite adequate resuscitation • Refractory septic shock That lasts for >1 h doesn’t respond to fluid/ pressor administration • MODS Dysfunction of >1 organ requiring intervention to maintain homeostasis MODS

24. Etiology • Any class of microorganisms • Blood culture yield ~20–40% of cases of severe sepsis and 40–70% of cases of septic shock • Respiratory infection was most common (64%).

25. Cont… • Grm. postive & Grm. negative account for ~70% of these isolates • Blood culture negative culture or microscopic examination of infected material from a local site • Majority with c/f of severe sepsis or septic shock have negative microbiological data

27. clinical manifestations • Nonspecific symptoms • Systemic symptoms • Localizing symptoms

28. Nonspecific symptoms • Nonspecific symptoms include fever, chills, & constitutional symptoms • Not pathognomonic for infection & ... seen in a wide variety of noninfectious inflammatory conditions • They may be absent in serious infections, especially in elderly individuals,neonates, & in persons with uraemia or alcoholism

29. systemic symptoms • Fever is a common feature of sepsis. • Altered mental status is perhaps the most consistent clinical feature in sepsis. • Mild disorientation or confusion is especially common in elderly individuals. • More severe manifestations include apprehension, anxiety, and agitation

30. Localizing symptoms • head and neck infection • Pulmonary infection • abdominal and GI infection • pelvic and genitourinary infection • Bone and soft tissue infection

31. P/E • Does the patient appear acutely ill? Assess (ABCs) & overall mental status • Attention to skin color and T0 • Pallor, greyish, or mottled skin are signs of poor tissue perfusion • Warm skin initially cold clammy • Petechiae or purpuraDIC

32. Work up

34. Cont… • Sodium and chloride • abnormal in severe dehydration • bicarbonate • can point to acute acidosis • Urea and creatinine • can point to severe dehydration or renal failure. • glucose • hyperglycemia associated with higher mortality

35. Cont… • LFT • levels are important in evaluating for multiorgan failure & potential source of sepsis • Serum lactate • level correlates with mortality, with a level greater than 4 mmol/L associated with a precipitous increase. • PT and PTT • Fibrinogen level

36. Cont… • Urinalysis and urine culture • Gram stain and cultures • Sputum specimen should be obtained if pneumonia is suspected. • Abscesses should be drained promptly, and pus should be sent to the microbiology laboratory for analysis. • CSF specimen should be obtained if meningitis is suspected

37. Imaging studies • Chest X-rays • Plain abdominal film • Abdominal U/S • CT Scan

38. Management • EGDT within the first 6 hrs • 50% Mortality benefit!!! • The goal is to perform all indicated tasks 100% of the time within the first 6 hours of identification of sepsis. • Prehospital CareThe initial treatment of sepsis and septic shock involves the administration of supplemental oxygen and volume infusion with isotonic crystalloids. • Prehospitalpersonnel should initiate these therapies

39. Emergency and hospital care • Address A and B of the ABCs: • Supplemental oxygen • Patients with suspected sepsis should receive an initial crystalloid fluid bolus of 20-30 mL/kg (1-2 L) Treat local site of infection: -remove source of infection -Empirical Antibiotics

40. Cont… • Antibiotics- Survival correlates with how quickly the correct drug was given • Cover gram positive and gram negative bacteria • ceftriaxone 1 gram IV or • Imipenem 1 gram IV • 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

41. Hospital care • persistent hypotension after this initial treatment, 500 mL boluses should be administered every 15 minutes to attain a CVP of 8-12 mm Hg • Patients should be monitored for signs of volume overload and need for intubation • Reassess antimicrobial regimen at 48-72 hrs

42. cont… • Vasopressors should be started once a CVP of 8-12 mm Hg is achieved and the patient remains hypotensive • Norepinephrine is now the first agent recommended in treating septic shock dose ranges from 5 mcg/min up to 20 mcg/min refractory to volume resuscitation

43. Cont… • The overall treatment goal is to achieve a central venous oxygen saturation (SvO2) of greater than 70%. • Transfuse packed RBCs until the hematocrit is greater than 30%. • Administer dobutamine to increase cardiac output in order to optimize red cell delivery to peripheral tissues

44. Ventilator therapy • More than 80% of severe sepsis patients require ventilatory support. • The average duration of mechanical ventilation ranges from 7 to 21 days • 40% of all severe sepsis and 50% of septic shock patients develop ALI • Mortality is greater with ARDS=3x esp when age>75 yrs • Duration of ventilation is longer with ARDS

46. cont… • Adrenal Insufficiency • Common occurrence in sepsis • Use of Etomidate for intubation • Chronic steroid use • Administration of steroids • Hydrocortisone 50mg IV QID or 100mg TID • CORTICUS trial Avoid hydrocortisone if fluids and vasopressors able to restore hemodynamic stability…..no long term survival benefit • HCO3 --> arterial PH<7.2 • FFP + platelets =>DIC, complicated by major bleeding • Nutritional supplementation • prevention of ulcers, DVT, etc…

47. Complications

48. Prognosis • Depends on • severity of illness upon hospital presentation, • patient age • comorbid conditions, • nature of infection, and infecting organism. • Gm–ve associated with high death • Mortality: sever sepsis is 30% septic shock is up to 70%

49. Cardiogenic shock • Systemic hypoperfusion due to • severe depression of the cardiac index [<2.2 (L/min)/m2] • sustained systolic arterial hypotension (<90 mmHg), despite an elevated filling pressure (PCWP) > 18 mmHg].

50. Cont… • It is the leading cause of death of patients hospitalized with MI. • Overall incidence is higher in males. • LV failure accounts for ~80% of the cases of CS complicating acute MI.