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Head trauma - Coggle Diagram

- - - - may result from sympathoadrenal overstimulation, causing marked peripheral vasoconstriction and increased venous return
        
        this results in an increased left ventricular after load, with a rise in pulmonary capillary hypertension, leading to oedema
        
        oedema usually self limiting (hours-days)
        
        dyspnoea, tachypnoea, hypoxaemia
- - - - do until stable
- - - - peptide rich compounds
      - care as sneezing can raise ICP
    - - pharyngostomy tube
      - oesophagostomy tube
      - if brain stem damage a gastrostomy tube should be inserted in case of poor oesophageal function
    - - promotes cerebral acidosis in brain damaged patients
      - associated with increased mortality and morbidity
      - this may be a secondary response to brain injury
  - - - associated with respiratory depression and hypotension
      - safe front line analgesics if titrated to effect
      - Fentanyl as CRI to keep analgesia consistent
      - consider butorphanol as less respiratory and cardiovascular depression, but may need to be repeated every 2 h
- - - - no jugular samples!
  - - - mannitol reverses the blood-brain osmotic gradient, reduces extracellular fluid volume in both normal and damaged brain tissue
      - administer mannitol as a bolus over a 15min period
        
        0.5-1.5g/kg
      - reserve for critical or deteriorating patients
      - repeated administration can cause accompanying diuresis
        
        volume contraction
        
        intracellular dehydration
        
        concomitant risk of hypotension and ischaemia
  - - - Dopamine (2-10microgram/kg/min i.v.)
    - - amlodipine
- - - - contusions, haematomas, lacerations and diffuse axonal injury, leading to vasogenic oedema
  - - - induces nitric oxide production and activates the arachidonic acid cascades
        
        exacerbated by systemic abnormalities in the patient
        
        hypotension
        
        hypoxia
        
        hypoglycaemia
        
        hyperglycaemia
    - - release of excitatory neurotransmitters
      - presence of oxygen free radicals
      - production of nitric oxide
  - - - elevations in ICP lead to decreased perfusion of the brain
      - marked increased in ICP can trigger an ischaemic response or Cushing reflex
        
        decreased cerebral flow leads to elevation in carbon dioxide levels, detected at the vasomotor centre in the brainstem
        
        Elevation in mean arterial pressure, detected by baroreceptors in walls of carotid arteries and aortic arch -> reflex bradycardia
      - drop in heart rate and elevated mean arterial pressure cause further clinical manifestations of increased ICP
        
        anisocoria
        
        miosis
        
        mydriasis
        
        altered mentation
        
        loss of motor function, with development of vertical nystagmus and extensor rigidity toward the end stages
- - - - rapid restoration of blood volume and pressure, whilst limiting fluid administered
      - hypertonic saline administration (4-5ml/kg IV over 2-5min ; 4ml/kg of 7.5% or 5.3ml/kg of 3% solution)
        
        AVOID if...
        
        presence of systemic dehydration
        
        hypernatraemia
        
        may aggravate pulmonary oedema or contusion in patients, with underlying cardiac or respiratory pathology
        
        volume expansion effects of this fluid only lasts between 15-75min, but beneficial effects on ICP maintained for longer
        
        hypertonic solutions dehydrate the tissues, so follow with crystalloid (at rate to account for patient's maintenance demands and insensible losses) to avoid systemic dehydration
        
        COLLOID
        
        can be administered after hypertonic saline to maintain intravascular volume, possibly due to retention of fluids within the intravascular compartments, maintaining an intravascular oncotic gradient.
      - hypertonic saline draws fluid from the interstitial and intracellular spaces into the intravascular space, which improves systemic blood pressure and cerebral blood pressure and flow, with a subsequent decrease in ICP
        
        hypertonic saline also shown to decrease brain excitotoxicity (promotes re-uptake of glutamate into the intracellular space)
    - - this could lead to exacerbation of oedema in head trauma patients
      - isotonic crystalloids appropriate for mild head trauma
        
        90ml/kg dog
        
        60ml/kg cat