Impaired tissue perfusion

1. Septic Shock (Endotoxic Shock:: Gram –ve )

2. Cardiogenic Shock:: Myocardial failure, Arrhythmia,

Embolism

3. Hypovoluemic Shock:: Blood loss, Burns

4. Others:: Neurogenic Shock, Anaphylactic Shock

CATEGORIES OF SHOCK

Final event to lethal clinical conditions like::

Severe hemorrhage,

Extensive trauma,

Burns,

Large MI,

Massive Pulmonary Embolism,

Sepsis.

Initially Shock Reversible injury ..Later Irreversible Injury

SHOCK… is syndrome

Cells switch from aerobic to anaerobic metabolism

lactic acid production

Cell function ceases & swells

membrane becomes more permeable

electrolytes & fluids seep in & out of cell

Na+/K+ pump impaired

mitochondria damage

cell death

PATHOPHYSIOLOGY OF SHOCK SYNDROME

70% are due to endotoxin producing Gram –ve bacilli infection

Endotoxins contain Lipopolysacharides

Most common cause of death in ICU

25 to 50% mortality

More technology.. More high risk patients.!!!!

Spread and expansion of initial localized infection

PATHOGENESIS OF SEPTIC SHOCK

LPS contains toxic fatty acid Lipid A and complex

polysaccharide coat

Free LPS binds to LPS binding protein

Binds to receptors on vascular wall, leukocytes and initiate

cytokine cascade

Effects of cytokines is to isolate organisms & trigger innate

immunity

Effect depends on dosage of LPS

PATHOGENESIS OF SEPTIC SHOCK

Same cytokines & mediators at higher levels

Systemic vasodilatation

Diminished Myocardial contraction

Widespread endothelial injury

Alveolar damage .. ARDS

DIC activation

VERY HIGH LPS.. SEPTIC SHOCK

INFECTION

BACTEREAMIA

SIRS

MODS

DEATH

Septic Shock SIRSBacteremia

Infn

Any two or more of the following constitutes SIRS:::

Body temperature > 38° C or < 36° C

Heart rate > 90 / min

Hyperventilation >20 /min

WBC count >12,000/mm³ or < 4000/mm³

SIRS can lead to Septic Shock and MODS

SIRS CRITERIA

1. Non Progressive stage:: Reflex compensatory

mechanisms are activated

2. Progressive stage:: Tissue hypoperfusion, metabolic

imbalance, acidosis

3. Irreversible stage:: Severe Cellular & tissue injury,

Survival is not possible

STAGES OF SHOCK

Changes are those of Hypoxic Injury

Brain:: Ischemic Encephalopathy

Heart:: Coagulative necrosis, Subendocardial hemorrhage.

Kidneys:: Acute Tubular Necrosis

Lungs:: Diffuse alveolar damage Shock Lung

MORPHOLOGY OF SHOCK

Adrenals:: Adrenal cortex lipid depletion:

“Waterhouse Frederickson syndrome”

GIT:: Patchy mucosal hemorrhages “Hemorrhagic

enteropathy”

Liver:: fatty change, Central hemorrhagic necrosis

Tachycardia and tachypnea

Weak pulses

Hypotension

Skin cool & clammy

Mental status changes

Decreased urine output: dark & concentrated

Loss of circulating volume “Empty tank ”

decrease tissue perfusion—Hypovoluemic shock.

ETIOLOGY:

Body Fluid loss-- Nausea & vomiting, diarrhea, massive diuresis, extensive burns.

Most common causes:

Hemorrhage

Dehydration

Clinical Signs of hypovoluemic Shock

% Blood loss Clinical Signs

< 15 Slightly increased heart rate, local

swelling, bleeding

15-30 Increased heart rate, increased

diastolic blood pressure, prolonged

capillary refill

30-50 Above findings plus: hypotension,

confusion, acidosis, decreased urine

output

> 50 Refractory hypotension, refractory

acidosis, death

The impaired ability of the heart to pump blood

Most common cause is LV MI

Occurs when > 40% of ventricular mass damage

Mortality rate of >80 %.

Antigen exposure

Body stimulated to produce IgE antibodies specific to antigen

drugs, bites, contrast, blood, foods, vaccines

Re-exposure to antigen

IgE binds to mast cells and basophils

Anaphylactic response

A type of distributive shock that results from the loss

or suppression of sympathetic tone

Most common etiology: Spinal cord injury above T6

Neurogenic is the rarest form of shock!

COLLABORATIVE MANAGEMENT

Prevention !!!

Find and kill the source of

the infection

Fluid Resuscitation

Vasoconstrictors

Inotropic drugs

Maximize O2 delivery Support

Nutritional Support

Comfort & Emotional support

Hypovoluemia: Blood/ fluid transfusion

Sepsis: Antibiotics, ? steroids

Neurogenic: Steroids

Anaphylactic: Adrenalin

Electrolyte/acid base imbalance

Specific measures