shock - fakultas kedokteran unissula semarang syok... · three major types of shock hypovolemic...
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Shock
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Definition
SHOCK: inadequate organ perfusion to meet the tissue’s
oxygenation demand.
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Three major types of shock Hypovolemic shock
» Decreased intravascular volume resulting form loss of blood, plasma, or fluids and electrolytes
Cardiogenic shock
» Pump failure due to myocardial damage or massive obstruction of outflow tracts
Distributive shock
» Reduction of vascular resistance form
Sepsis
Anaphylaxis
Systemic inflammatory response syndrome (SIRS)
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Cardiogenic Shock
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Cardiogenic Shock
Diminished cardiac output leading to impaired tissue
perfusion
Most extreme form of pump failure
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Cardiogenic Shock
Occurs in about 15% of acute MI patients
Usually occurs when 40% or more of the left ventricular muscle mass infarcts
Mortality is 85% or more with treatment
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Etiologies Acute myocardial
infarction/ischemia
LV failure
Papillary muscle/chordalrupture- severe MR
Ventricular free wall rupture with subacutetamponade
Other conditions complicating large MIs
» Hemorrhage
» Infection
» Excess negative inotropic or vasodilator medications
» Prior valvular heart disease
» Hyperglycemia/ketoacidosis
» Post-cardiac arrest
» Post-cardiotomy
» Refractory sustained tachyarrhythmias
» Acute fulminantmyocarditis
» End-stage cardiomyopathyHypertrophic cardiomyopathy with severe outflow obstruction
» Aortic dissection with aortic insufficiency or tamponade
» Pulmonary embolu
» Severe valvular heart disease -Critical aortic or mitral stenosis, Acute severe aortic or MR
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Pathophysiology
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Characteristics of Cardiogenic Shock
Low cardiac output
Peripheral vasoconstriction
Left sided heart failure leads to pulmonary venous congestion and pulmonary edema
Right sided heart failure leads to systemic venous congestion and peripheral edema
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It is essential to distinguish a cardiogenic from a hypovolemic
shock!Both forms are associated with reduced cardiac out put, and increased peripheral
vascular resistance, however:
Cardiogenic shock:
jugular venous distention (high
CVP)
Hypovolemic shock: collapsed capacitance veins (low CVP)
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Signs/Symptoms
Confusion, restlessness, anxiety, stupor, coma
Cool, clammy skin
Pallor
Weak or absent extremity pulses
Tachycardia
Slow or absent capillary refill
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Signs/Symptoms
BP < 90 systolic or > 30mmHg below normal
»BP is NOT the same as perfusion
» Shock can be present with a “normal” BP
»Evaluate signs of peripheral perfusion in addition to BP
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Cardiogenic Shock
Treatment Priorities:
»Rate
»Rhythm
»BP (Volume, Pump/Vascular tone)
Correct major disorders of rate, rhythm before directly treating BP
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Goals of Management
Improve oxygenation and peripheral perfusion
Avoid increasing cardiac workload
»myocardial oxygen demand
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Management
Primary assessment & Focused Hx
Identify source of problem
»Acute pulmonary edema
»Volume problem
»Pump problem
»Rate problem
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Acute Pulmonary Edema
First line interventions
» IV/O2/ECG Monitor
» If BP > 90-100 mm Hg:
furosemide 0.5 – 1.0 mg/kg slow IV (or twice patient’s single daily dose up to 120 mg)
Morphine 2 – 10 mg slow IV
Nitroglycerin 0.4 mg SL
» If BP < 90 mm Hg:
Vasopressors based on SBP
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Volume Problem
IV/O2/ECG Monitor
Fluid challenge until rales or if evidence of anterior wall AMI
Vasopressors based on SBP
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Pump Problem
IV/O2/ECG Monitor
SBP 100 mm Hg w/o shock
» dobutamine 2 – 20 mcg/kg/min IV inf
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Management
If rate/rhythm adequate, treat BP
»Consider fluid challenge of 250cc LR over 10-15 minutes if relative or absolute hypovolemia possible, including RVF and NO pulmonary edema
»Avoid use of vasopressors until volume deficits corrected or pulmonary edema presents
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BP Treatment Review
If rate, rhythm, volume adequate, treat BP with vasopressors:
»Norepinephrine, or
»Dopamine
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Norepinephrine
0.5 - 30 mcg/min
Inotropic and vasoconstrictive properties
Can be used if systolic BP < 70
If systolic BP > 70, use dopamine instead
DO NOT use until hypovolemia corrected
DO NOT allow infiltration
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Dopamine2 - 20 mcg/kg/min
» Place 200 mg/250cc of D5W
» Begin at 5 mcg/kg/min
» In 2 - 10 mcg/kg/min range, effects dominate
» > 20 mcg/kg/min effects dominate
» Use lowest dose that produces good perfusion
Use as initial vasopressor if BP 70-100 systolic
» If dopamine infusion rate is > 20 mcg/kg/min use norepinephrine
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Dopamine
May cause tachycardia, ectopy, nausea
DO NOT use until hypovolemiais corrected
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Distributive Shock
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Distributive Shock
Reduced peripheral vascular tone leads to pooling of blood in extremities poor venous return
Physical exam depends on stage
» Early: Warm extremities, wide pulse pressure, low diastolic pressure
» Late: perfusion pressure falls and acidosis develops
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Distributive Shock
Sepsis
» Due to gram negative or gram positive bacteria
Anaphylaxis
» Due to previous sensitization to an allergen
Neurogenic
» Due to traumatic spinal cord injury
» Effects of epidural or spinal anesthetics
» Reflex parasymapthetic stimulation
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Bacteremia, SIRS, Sepsis
Bacteremia: an identifiable organism cultured from the blood
Systemic Inflammatory Response Syndrome (SIRS): sepsis without organism identified. Meet at least 2 of criteria:
» Hypo or hyperthermia
» Tachycardia or bradycardia
» Tachypnea
» Leukocytosis or leukopenia
Sepsis: SIRS from a systemic illness (bacterial, viral, protozoal)
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Pathogenesis of Septic Shock(vasodilatory shock)
Sepsis is defined as a systemic inflammatory response to a bacterial infection with bacteriemia(though blood cultures can be negative)
Severe sepsis is defined by additional end-organ dysfunction (mortality rate: 25-30%)
Septic shock is defined as sepsis with hypotension despite fluid resuscitation and evidence of inadequate tissue perfusion (40-70%)
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NEJM 2004, Vol. 351;2 pp 159-169
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The syndrome of septic shock is characterized by
Systemic vasodilation (hypotension)
Diminished myocardial contractility
Widespread endothelial injury and activation leading to fluid leakage (capillary leak) resulting in acute respiratory distress syndrome (ARDS)
Activation of the coagulation cascade (DIC)
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Septic Shock Early “Warm Shock”
↑ CO and ↓ SVR and wide pulse pressure
Signs: warm extremities, flushing, bounding pulses, ↑ HR, confusion
Hypocarbia, elevated lactate, hyperglycemia
Late “Cold Shock”
Uncompensated shock with drop in CO
Signs: cyanosis, cold, clammy skin, threadypulse, shallow respiration
Metabolic acidosis, hypoxia, coagulopathy, hypoglycemia
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S/S of Septic Shock
Increased to low blood pressure
High fever, no fever, hypothermic
Skin flushed, Pale, Cyanotic
Difficulty breathing and altered lung sounds
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TX of Septic Shock
Airway control
Administer oxygen
IV of crystalloid solution
Dopamine for blood pressure support
Monitor other vitals
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Anaphylatic Shock
Severe immune response to foreign substance
S/S most often 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
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S/S of Anaphylactic Shock
Skin
- Flushing
- Itching
- Hives
-Swelling
-Cyanosis
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S/S of Anaphylactic Shock
Respiratory System
- Breathing difficulty
- Sneezing, Coughing
- Wheezing, Stridor
- Laryngeal edema
- Laryngospasm
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S/S of Anaphylactic Shock
Cardiovascular System
- Vasodilation
- Increased heart rate
- Decreased blood pressure
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S/S of Anaphylactic Shock
Gastrointestinal System
- Nausea, vomiting
- Abdominal cramping
- Diarrhea
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TX for Anaphylactic Shock
Airway protection which may include Endotracheal Intubation
Establish IV with crystalloid solution
Pharmacological interventions: Epinephrine, Antihistamines(Benadryl), Corticosteroids(dexamethasone), Vasopressors(dopamine, Epinephrine), and inhaled beta agonist(albuterol)