Shock

Shock is characterized by circulatory failure with inadequate end organ perfusion and tissue oxygenation.


Classification Of Shock 

  1. Hypovolemic shock
  2. Cardiogenic shock
  3. Obstructive shock
  4. Distributive shock
  5. Endocrine shock

 

Severity Of Shock

Compensated shock 
  • Autonomic nerve system has the ability to alter the heart rate and peripheral vascular resistance in response to changes on the blood pressure
  • Reduce blood supply to non essential organs to preserve the preload and increase central circulation
  • Decrease of renal blood flow, actives renin-angiotensin-aldosterone system & releases ADH which helps in volume regulation
  • By the above mentioned mechanism our body tries to compensate the loss and preserve the flow to the vital organs Brain, lung, kidney)
Decompensation
  • When the circulatory volume falls becomes 60 – 70% of normal blood pressure starts to decline
Mild shock
  • Tachycardia
  • Tachypnoea
  • Oligouria
  • Mild anxiety
  • Blood pressure is maintained but pulse pressure is decreased
  • Cool and sweaty peripheries
  • Prolong capillary refill time

Moderate shock

  • Tachycardia increases
  • Oligouria becomes more severe
  • Hypotension
  • Confusion

Severe shock 

  • Profound tachycardia & hypotension
  • Anuria
  • Unconsciousness with laboured breathing
 

Difference Between The Severity Of Shock


 

 

Hypovolemic Shock
It occurs due to reduced circulating volume
Most common type of shock found in surgery
Causes
  1. Haemorrhage – Revealed or internal (Ruptured aortic aneurysm, ruptured ectopic pregnancy)
  2. Severe diarrhoea or vomiting
  3. Burns
  4. Urinary loss in diabetes
  5. Third spaces loss – Lost through GIT & interstitial spaces
    • Bowel obstruction
    • Pancreatitis
Clinical features
  1. History of trauma, surgery or illness
  2. Cold, clammy skin
  3. Tachycardia
  4. Initially blood pressure is normal, later become hypotensive
*Symptoms occurs due to increased sympathetic activity
 
Treatment
  1. Positioning the patient in supine position
  2. Elevation of the limbs to autotransfuse prior to IV access
  3. Maintain ABC
    • Ensure the airway is patent
    • High flow oxygenation
    • After ensuring above, address circulation
  4. If operative haemorrhage control is required, it should not be delayed and resuscitation should proceed parallel with surgery
  5. Establish IV access by short wide bore catheter (Capable of rapid infusion)
  6. Dynamic fluid response
    • A bolus of 250 – 500mL of fluid is given over 5 – 10 mins
    • Then the response is observed by measuring the blood pressure
    • By this patients can be categorized as responders, transient responders & non responders
      • Responders has no active bleeding and requires filling till normal volume status
      • Transient responders shows improvement but after sometime revert back to the previous stat due to on going fluid loss
      • Non responders do not show any improvement because of major on going loss
  7. If the patient is responding continue fluid resuscitation
  8. Blood is sent for investigations
    • CBC
    • U&E
    • Clotting time
    • ABO blood grouping, Rh typing and cross matching
    • ABG analysis
  9. Monitoring of the patient
Cardiogenic Shock
It occurs due to primary failure of the heart to pump blood to the tissues
 
Causes
  1. Myocardial infarction
  2. Cardiac dysrrhythmias
  3. Valvular heart diseases (Ruptured mitral or aortic valve)
  4. Cardiomyopathy
Clinical features
  1. History of recent surgery / trauma / illness (MI, CCF)
  2. Chest pain
  3. Palpitations
  4. Dypnoea
  5. Sweating
  6. Tachycardia
  7. Pallor
  8. Cold peripheries

*Symptoms occurs due to increased sympathetic activity

Treatment
  1. Maintain ABC
    • Ensure airway is patent
    • High flow oxygen
  2. Give morphine 2.5mg IV
    • Anxiolytic
    • Venodilator
    • Analgesic
    • Anti-arrhythmic
  3. Send blood for investigations
    • CBC
    • U&E
    • Clotting time
    • Troponin I
    • ABG analysis
  4. Treatment of the cause
    • MI
    • Cardiac arrhythmia
  5. Continuous monitoring of the patient
 
 
Obstructive Shock 
 
It occurs due to mechanical obstruction of cardiac filling resulting in reduced preload
 
Causes
  1. Tension pneumothorax
  2. Pulmonary embolism
  3. Cardiac temponade
 Treatment
  1. Treatment according to the cause 

Distributive Shock 

 
It is a type of shock which is quite different to other types of shock
In distributive shock, there is reduced vascular resistance, decreasing diastolic filling leading to decrease cardiac output, thus causing hypotension 
 
Causes
  • Septic shock
  • Anaphylaxis
  • Spinal cord injury – Due to sympathetic interruption
Clinical features
  1. Patient is initially warm, in later stage may become cold 
  2. Tachycardia
  3. Hypotension
* In later stages may follow same features as hypovolemic shock
 
Treatment
  1. Treatment according to the cause (Mentioned below)

Endocrine Shock

Causes
  1. Hypothyroidism 
  2. Hyperthyroidism 
  3. Adrenal insufficiency


Difference Between Types Of Shock




Septic Shock 

The cause of septic shock is unclear, but is related to the release of bacterial products like endotoxins that activates cellular and humoral components of the immune system

  • Shock occurs primary due to vasodilation of the peripheral circulation and due to the inflammatory response caused by the release of mediators 
  • DIC can lead to spontaneous haemorrhages

Causes 

  1. Overwhelming sepsis
    • Gram negative organisms (E. coli, Proteus Pseudomonas) are mainly responsible for septic shock
    • But gram positive organisms like (Streptococcus, Pneumococcus) can also cause septic shock

Presentation 

  1. Patient will initially be warm and flushed with tachycardia, bounding pulse and hypotension
  2. In later stages will follow the features of hypovolemic shock

Pathogenesis Of Septic Shock

Endotoxins & exotoxins are produced after infection, by organisms that produce
            ↓
They form a complex with lipopolysaccharide binding protein in the serum
            ↓
The complex binds to CD14 receptors on leukocytes (specially monocytes & macrophages), endothelial cells and other cell types
            ↓
Initiation of synthesis & release or activation of cascade of mediators derived from plasma or cells (monocytes, macrophages, endothelial cells)
            ↓
Endogenous mediators….
Cytokines : TNF, IL-1, 2, 6, 8, NO, PAF, endorphins ;
Arachidonic acid metabolites (prostaglandins & leukotrienes), complement C5a, kinin, coagulation factors, myocardial depressor substance
            ↓
Action of mediators on different organs of the body
Heart: Diminished myocardial contractility
Blood vessels: Systemic vasodilation (hypotension), thrombosis, DIC
Lungs: Acute respiratory distress syndrome (ARDS)
Generalized organ dysfunction

End Results / Fate Of Septic Shock

  1. Recovery
  2. Death due to….. 
    • Refractory hypotension
    • Multiple organ failure (Kidney, brain, heart, adrenal gland)


Treatment
  1. Maintain ABC
    • Ensure airway is patent
    • High flow oxygen 
    • Establish IV accesss
  2. Fluid resuscitation 
  3. Blood is send for investigations
    • CBC
    • Blood culture 
    • CRP 
  4. Broad spectrum antibiotics 
    • Cefuroxime 750mg tds, IV
  5. Corticosteroid injection – Inj. Hydrocortisone 500mg bolus 
  6. Vasopressors & inotropic agents 
    • Noradrenaline – Peripheral vasoconstriction  
    • Dobutamine – Inotropic effect of the heart 
  7. Continuous monitoring of the patient
 
 
Anaphylactic Shock

In surgery, it occurs due to an allergic reaction to a drug or a contrast medium


Presentation

  1. History of sudden onself after administration of a drug 
  2. Hypotension 
  3. Bronchospasm / stridor 
  4. Facial & laryngeal oedema 
  5. Rash & pruritus

Treatment

  1. Prevent further contact with allergen 
  2. Positioning of the patient in upright position 
  3. Maintain ABC
    • Ensure airway is patent
    • High flow oxygen 
    • Establish IV access 
  4. If IV access is established in time
    • 1mL of 1 : 10 000 adrenaline bolus is given IV
    • Flush with 10mL of normal saline 
    • Hydrocortisone 100mg bolus is given IV
    • Flush with 10mL of normal saline 
    • Chlorpheniramine 10mg is given IV 
    • Repeat adrenaline, if no improvement after 5 – 10 mins 
  5. If IV access is not established in time
    • 1mL of 1 : 1000 adrenaline is given IM 
    • Then establish IV access to give the above medication
  6. Wheezing – 5mL nebulized salbutamol 
  7. Continuous monitoring of the patient 
 
Monitoring Of Shock Patient 

  1. Continuous heart rate monitoring – ECG 
  2. Oxygen saturation
  3. Blood pressure 
  4. Urine output – Hourly
  5. Pulse
  6. Temperature
  7. Respiratory rate
  8. Cardiac output 
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