Mod D Tech 13 Shock and Fainting Flashcards
Definition of shock
Insufficient perfusion of the tissues with blood carrying oxygen and nutrients causing anaerobic metabolism and thus metabolic acidosis
Shock
Name Factors effecting
- Blood volume
- Cardiac output
- Functioning blood vessels
Name Risk factors for shock
- Trauma
- Pregnant patients
- Elderly patients
- Cardiac patients
Name Types of Shock
Cardiogenic shock
Neurogenic shock
Toxic/Septic shock
Anaphylactic shock
Anaphylaxis
Cardiogenic shock
•Impaired cardiac function due to a damaged myocardium from either an infarct, arrhythmia or tamponade.
Describe Hypovolemic shock
- Reduced circulating volume
- Fluid loss
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Major causes
- Haemorrhage
- Burns & scalds
- Diarrhoea & vomiting
Describe Neurogenic shock
- Head injury
- Transection of the spinal cord
Spinal shock
- Loss of nervous control
- Relative Hypovolaemic
Describe Toxic/Septic shock
- Infection such as meningitis causes release of toxins causing arteriolar and capillary dilatation
- Loss of venous tone
- Mismatch between the circulating blood volume and increased capacity of the blood vessels
- Relative hypovolaemia
Describe Anaphylactic shock what does it affect
- Exposure to Antigen
- Previous exposure to Antigen
- Excessive Antigen/ Antibody reaction
- Histamine released with systemic effect
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Affecting:
- Tissues
- Respiratory function
- Circulatory function
- Mismatch between the circulating blood volume and increased capacity of the blood vessels
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•Loss of fluid into tissues, causing sudden oedema
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•Causes difficulties with airway if around the face and neck
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•Histamine may also cause brochospasm preventing adequate pulmonary ventilation
Anaphylaxis
- Anaphylaxis - hypersensitivity reaction
- Anaphylactoid - similar reaction but not dependent on hypersensitivity
- Manifestations and management similar
Causes for Anaphlaxic
- Drugs (e.g. penicillin, aspirin, vaccines)
- Food substances (e.g. peanuts, shellfish, eggs)
- Venom (e.g. wasp stings, bee stings)
- Almost any foreign substance can become an allergen
what is Anaphylaxis
A severe allergic reaction, often affecting the whole body
It often occurs when patients are exposed to an allergen to which they have become over sensitive.
When an allergen is reintroduced into the body, mast cells may vigorously react and release an overdose of histamine
what does Histamine do
- Released by mast cells and basophils
- Causes vasodilation and increased blood vessel permeability
Leukotrines
- Produced by mast cells and basophils
- Cause bronchoconstriction, an increase in blood vessel permeability and coronary vasoconstriction
Physiological effects of anaphalaxiis
- Decreased coronary blood flow
- •Systemic vasodilation
- •Reduced cardiac output
- Increased permeability of the blood vessels
- Spasm and oedema of the bronchi
- •Pulmonary vasoconstriction
- •Laryngeal oedema
Clinical Signs & Symptoms of Anaphlaxis
- Extreme dyspnoea (coughing, wheezing, prolonged sneezing)
- •Tachycardia (often with arrhythmias)
- •Hypotension
- Warm, flushed skin
- •Oedema (particularly facial)
- •Nausea & Vomiting
- •Abdominal cramps
- Urticaria (hives)
- Pruritis (itching)
Anaphylaxis facts and figures
•Hypovolaemia occurs quickly – 50% of blood plasma volume is lost in 10 – 15 minutes
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•>50% of fatalities occur within the first hour
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•75% of fatalities are due to asphyxia from airway obstruction or bronchoconstriction
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•25% of fatalities occur as a result of circulatory failure and hypotension