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what is shock?
delivery of oxygenated blood to the body is not adequate to meet the metabolic demand
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what is the pathophysiology of shock? 5 points
- 1) inadequate tissue perfusion
- 2) body switches to anaerobic respiration due to hypoxia
- 3) lactate produced and capillary damage due to hypoxia and tissue waste increasing
- 4) progressive organ failure
- 5) death
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what are the 5 types of shock?
- distributive
- cardiogenic
- dissociative
- hypovolaemic
- obstructive
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what does hypovolaemic mean?
low volume of blood
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when does hypovolaemic shock occur?
blood volume reduces by >15%
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in hypovolaemic shock, what does a reduction in circulation blood volume reduce?
cardiac output
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what can hypovoleamic shock be caused by?
- severe haemorrhage- internal or external
- extensive burns- serum is lost
- severe diarrhoea and/or vomiting- water & electrolytes are lost
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what 5 places do haemorrhages occur?
- blood on the floor (external)
- chest
- abdomen
- pelvis
- long bones
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cause of traumatic internal haemorrhage- chest
haemothorax from blunt or penetrating trauma e.g. stabbing
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cause of traumatic internal haemorrhage- abdomen
bleeding or ruptured organs (e.g. spleen, liver, bowel) from blunt or penetrating trauma e.g. being hit by a car
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cause of traumatic internal haemorrhage- pelvis
vasculature inside pelvis disrupted from fractured pelvis e.g. fall from height
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cause of traumatic internal haemorrhage- long bones
fractured femur or humerus from direct trauma
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what are 6 signs of internal bleeding?
- bruising/ contusions
- haematoma
- abdomen- guarding or rigidity
- open wounds on surface
- swelling/ deformity
- seatbelt injury marks
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what is stage 1 of hypovoleamic shock?
- body is able to cope with losses
- no obvious clinical signs
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what is stage 2 of hypovoleamic shock?
- compensated stage-
- blood loss more significant
- body compensatory mechanisms maintain BP despite reduction in blood volume
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what is stage 3 of hypovoleamic shock?
- decompensated stage-
- despite compensatory mechanisms, blood loss is too severe to maintain BP
- urgent blood transfusion is required
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what is stage 4 of hypovoleamic shock?
- irreversible stage-
- even if circulation is restored patient is still likely to die
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what are the 4 stages of hypovoleamic shock?
- coping
- compensated stage
- decompensated stage
- irreversible stage
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in the compensatory mechanism, how does the body compensate for blood loss in an attempt to maintain perfusion to essential organs?
- 1) increase HR
- 2) increase RR
- 3) blood is diverted away skin causing pale appearance (delays cap refill)
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what happens when venous return continue to fall? compensatory mechanisms for hypovoleamic shock
- right heart filling is impaired
- stroke volume is reduced
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compensatory mechanisms for hypovoleamic shock- what happens when your heart reaches over 150 bpm ?
- heart is unable to refill adequately between its contractions and fails to perfuse the heart muscle itself
- cardiac arrest and death could follow
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what happens when shock becomes more severe?
cardiovascular functions become progressively worse causing hypoxia
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what is hypoxia?
lack of oxygen
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what does hypoxia cause?
- anaerobic respiration
- build up of lactate
- acidosis
- this damages capillaries which further worsens perfusion
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what are the signs and symptoms of shock? 7
- tachycardia
- tachypnoea
- abnormal behaviour (agitation or confusion)
- feeling dizzy/ faint
- pale, cold extremities, delayed cap refill
- sweating, dilated pupils, thirst
- stage 4- near fatal- reduced LOC, bradycardia
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what are the 4 patients that may catch you out when it comes to hypovolaemic shock?
- paediatrics
- young athletic/healthy people
- pregnant patients
- patients on beta blocker medication
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how much more blood to pregnant people have?
50% increase in blood volume at pregnancy term
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how do you manage hypovolaemic shock?
- dress or tourniquet external haemorrhage
- requests para/ hems
- 100% o2 using non re-breather mask
- consider entonox for analgesia
- apply splint for pelvis/ long bones if fracture suspected
- immobilse only if necessary
- minimise unnecessary movement to aid clotting
- prevent hypothermia
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how to transport a patient with hypovolaemic shock?
- time critical, minimal time on scene
- pre- alert to major trauma centre via PD09
- constant reassessment, if possible use and tidal cap to monitor respiration en route
- only do 2nd survey en route if time permits
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