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
•
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
•
Affecting:
- Tissues
- Respiratory function
- Circulatory function
- Mismatch between the circulating blood volume and increased capacity of the blood vessels
•
•Loss of fluid into tissues, causing sudden oedema
•
•Causes difficulties with airway if around the face and neck
•
•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
•
•>50% of fatalities occur within the first hour
•
•75% of fatalities are due to asphyxia from airway obstruction or bronchoconstriction
•
•25% of fatalities occur as a result of circulatory failure and hypotension
things to consider /mangerment
- Consider when compatible history of severe allergic-type reaction with respiratory difficulty and/or hypotension especially if skin changes present – firstly remove from source
- Oxygen - high flow then maintain 94-98%
- Stridor, wheeze, respiratory distress or clinical signs of shock
- Epinephrine (adrenaline) 1:1000 solution i.m. Repeat every 5 minutes as clinically indicated
- Consider Salbutamol for Bronchospasm resistant to IM Adrenaline.
- If clinical manifestations of shock do not respond rapidly to drug treatment:
- Consider paramedic assistance for administration of antihistamine (Chlorpheniramine), fluids and hydrocortisone if the call is more than 30 mins from the hospital
What is Adrenaline 1:1000 (Epinephrine)
what type
what effects
- A sympathomimetic drug
- •Stimulates alpha and beta receptors
- •Alpha effect – reverses vasodilation and reduces oedema
- •Beta effect – causes bronchodilation, increase heart rate and strength of contraction. Suppresses histamine and leukotrine release
Adrenaline 1:1000
side effects:
- Tachycardia
- •Angina
- •Hypertension
- •Ventricular arrhythmias
- Anxiety
- •Headache
- •Cerebral bleeding
- •Nausea & Vomiting
Adrenaline dosage

Salbutamol Dosage

How does the body respond to shock?
Compensatory mechanisms
Abnormal fluid loss:
- Stimulates the Sympathetic Nervous System
- Increased heart rate
- •Selective artery constriction to non vital organs
- •Increased venous tone mobilises reserve blood volume & reduces circulatory capacity
Hormonal Regulation
- RAA= Renin-angiotensin-aldosterone system
- •Activated by baroreptors sensing lowered BP and reduced renal blood flow
- Renin released by kidneys works as an enzyme and converts angiotensinogen (made in the liver) to angiotensin I.
- •Angiotensin I in lungs with ACE (Angiotesin converting enzyme) produces Angiotensin II, a potent vasoconstrictor
- Angiotensin II stimulates release of Aldosterone by adrenal cortex, which increases sodium and water reabsorption
•
•Epinephrine and Noradrenaline
–Increase heart rate
–Increase vascular tone
–•ADH = Antidiuretic Hormone, produced by Hypothalamus and released by pituitary gland in response to blood loss to cause vasoconstriction
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Hypovolaemic shock
how many stages
split in to what
Four Stages
Compensated and Decompensated
